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Garlic in health and disease

Published online by Cambridge University Press:  13 May 2011

S. V. Rana*
Affiliation:
Department of Gastroenterology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
R. Pal
Affiliation:
Department of Gastroenterology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
K. Vaiphei
Affiliation:
Department of Histopathology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
Sanjeev K. Sharma
Affiliation:
Department of Gastroenterology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
R. P. Ola
Affiliation:
Department of Gastroenterology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
*
*Corresponding author: Dr S. V. Rana, fax +91 172 2744401, email svrana25@hotmail.com
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Abstract

The present article reviews the historical and popular uses of garlic, its antioxidant, haematological, antimicrobial, hepatoprotective and antineoplastic properties and its potential toxicity (from sulfoxide). Garlic has been suggested to affect several cardiovascular risk factors. It has also been shown that garlic and its organic allyl sulfur components are effective inhibitors of the cancer process. Since garlic and its constituents can suppress carcinogen formation, bioactivation and tumour proliferation, it is imperative that biomarkers be established to identify which individuals might benefit most. Garlic powder, aged garlic and garlic oil have demonstrated antiplatelet and anticoagulant effects by interfering with cyclo-oxygenase-mediated thromboxane synthesis. Garlic has also been found to have synergistic effects against Helicobacter pylori with a proton pump inhibitor. The active compound allicin may affect atherosclerosis not only by acting as an antioxidant, but also by other mechanisms, such as lipoprotein modification and inhibition of LDL uptake and degradation by macrophages. Freshly prepared garlic homogenate protects against isoniazid+rifampicin-induced liver injury in experimental animal models. Several mechanisms are likely to account for this protection.

Type
Review Article
Copyright
Copyright © The Authors 2011

Introduction

Garlic (Allium sativum) is a popular spice, a remedy for a variety of ailments and is also known for its medicinal uses as an antibiotic, anti-thrombotic and antineoplastic agent. It has been used for thousands of years for culinary, medicinal and spiritual purposes.

Biochemistry

Potentially active chemical constituents of garlic are:

  1. (a) Sulfur compounds: alliin, allicin, ajoene, allylpropyl disulfide, diallyl trisulfide (DATS), S-allylcysteine (SAC), vinyldithiins, S-allylmercaptocysteine and others.

  2. (b) Enzymes: alliinase, peroxidases, myrosinase and others.

  3. (c) Amino acids and their glycosides: arginine and others.

  4. (d) Se, Ge, Te and other trace minerals.

Garlic contains at least thirty-three sulfur compounds, several enzymes and seventeen amino acids(Reference Fenwick and Hanley1). Additional constituents of intact garlic include steroidal glycosides and lectins(Reference Matsuura, Ushiroguchi and Itakura2, Reference Kaku, Goldstein and Van Damme3). It contains higher concentrations of sulfur compounds than any other Allium species. The sulfur compounds are responsible both for garlic's pungent odour and many of its medicinal effects.

Chemical changes in garlic

When garlic is ‘damaged’, i.e. attacked by microbes, crushed, cut, chewed, dehydrated, pulverised or exposed to water, the vacuolar enzyme alliinase rapidly lyses the cytosolic cysteine sulfoxides (alliin). The transiently formed compound, allicin, comprises 70–80 % of the thiosulfinates. Typically, alliin is converted to allicin by alliinase (Fig. 1). Allicin instantly decomposes to other compounds, such as diallyl sulfide (DAS), diallyl disulfide (DADS), dithiins and ajoene. At the same time, γ-glutamyl cysteine is converted to SAC, via a pathway other than the alliin–allicin pathway.

Fig. 1 Chemical changes in garlic. DAS, diallyl sulfide; DADS, diallyl disulfide; DATS, diallyl trisulfide.

The dozens of brands of garlic on store shelves can be classified into four groups, i.e. garlic essential oil, garlic oil macerate, garlic powder and aged garlic extract (Table 1)(Reference Amagase, Petesch and Matsuura4).

Table 1 Main brands of garlic on the market

DAS, diallyl sulfide; DADS, diallyl disulfide; SAC, S-allylcysteine.

Garlic oil, aged garlic and steam-distilled garlic do not contain significant amounts of alliin or allicin, but contain various products of allicin transformation, among which none appears to have as much physiological activity as fresh garlic or garlic powder(Reference Lawson and Gardner5). In rats, alliin is well absorbed orally, reaching maximum serum concentrations within 10 min, and is excreted within about 6 h. Allicin and vinyldithiins are absorbed more slowly, reaching peak levels between 30 and 120 min and persisting in the body for up to 4 d(Reference Egen-Schwind, Eckard and Kemper6). In rats, mice and dogs, SAC is well absorbed (98–100 %) orally(Reference Lachmann, Horenz and Radeck7). Excretion occurs through the renal system and through hepatic breakdown, faecal excretion and exhalation.

Anti-carcinogenic actions of garlic

Epidemiological and animal studies have shown that consumption of garlic and its allyl sulfur compounds reduces the incidence of cancer, for example, stomach, oesophagus, colon, breast, cervix, skin, uterine and lung cancers(Reference Su, Chen and Tan8).

The diverse array of compounds and target tissues involved suggests either that garlic or its associated constituents have multiple mechanisms of action or, more logically, influence a fundamental step in the overall cancer process. Metabolic activation is a necessary event for many of these carcinogens used in animal studies, and possibly for environmental exposures faced by humans. Thus, phase I and II enzymes involved in carcinogen bioactivation and removal may be key in explaining the response to garlic and allyl sulfur compounds. However, few studies have noted significant changes in cytochrome P450 1A1, 1A2, 2B1 or 3A4 activities after supplementation with garlic or related sulfur compounds(Reference Manson, Ball and Barrett9, Reference Wang, Zuzel and Rahman10). Therefore, other enzymes involved in the bioactivation or removal of carcinogenic metabolites may play a role.

Singh et al. provided evidence that the efficacy of various organosulfides to suppress benzo(a)pyrene tumorigenesis correlated with their ability to suppress NAD(P)H:quinone oxidoreductase, an enzyme involved with the removal of quinones associated with this carcinogen(Reference Singh and Shukla11). Depressed carcinogen bioactivation because of reduction in cyclo-oxygenase and lipoxygenase activity may also account for some of the lower incidence of tumours after treatment with some carcinogens(Reference Hughes, Chamulitrat and Mason12, Reference Roy and Kulkarni13). Enhanced glutathione availability and an elevation in the activity of specific glutathione S-transferase (GST), both factors involved in phase II detoxification, may also be significant in the protection provided by garlic and associated allyl sulfur components. Ingestion of garlic by rats increases the activity of GST in both liver and mammary tissue(Reference Manson, Ball and Barrett9, Reference Singh and Singh14). It should be noted that not all GST isozymes are influenced equally. Hu et al. provided evidence that the induction of GST π may be particularly important in the anticarcinogenic properties associated with garlic and allyl sulfur components(Reference Hu, Benson and Srivastava15).

Medical uses of garlic

More than 3000 publications in the past have confirmed the efficacy of garlic for the prevention and treatment of a variety of diseases, acknowledging and validating its traditional uses. It may influence the risk of heart disease and is also used for the treatment of fatigue, although the mechanism involved remains unclear. The anti-fatigue function of garlic may be closely related to its many favourable biological and pharmacological effects(Reference Morihara, Nishihama and Ushijima16). Garlic has historically been used to treat aches and pains, leprosy, deafness, diarrhoea, constipation, parasitic infection and fever and to relieve stomachache(Reference Tattelman17). It has also been used to lower blood pressure, food poisoning, tumours and as a mild anticoagulant(Reference Ryzhenkov and Makarov18). Arabian herbalists use garlic to treat abdominal pain, infantile colic, diarrhoea, diabetes, eye infections, snake bites, dandruff and tuberculosis(Reference Ghazanfar19). In Ayurvedic medicine, garlic is used to treat respiratory problems, colic and flatulence. Garlic oil drops are used to treat earache(Reference Kapoor20). Louis Pasteur demonstrated garlic's antiseptic activity in 1858. In African countries, it is also used to treat dysentery(Reference Peirce21). Garlic is commonly used to treat chronic bronchitis, recurrent upper respiratory tract infections and influenza(Reference Barnes, Anderson and Phillipson22). In India and Europe, garlic remedies are used to treat coughs, colds, hay fever and asthma(Reference Woodward23).

Antioxidant actions of garlic

Protection with aged garlic extract and Nigella sativa oil has been shown to prevent most of the haematological and biochemical changes and to markedly improve the antioxidant capacity of schistosomiasis-infected mice compared with infected-untreated ones. The antioxidant and antischistosomal action of aged garlic extract and N. sativa oil was greatly diverse according to treatment regimen(Reference El Shenawy, Soliman and Reyad24).

Garlic oil could be an effective agent or food supplement in reducing the toxicity of tributyltin(Reference Liu and Xu25). Allicin-mediated lipoperoxide production in fungal plasma membranes is the cause of the enhancement in the cellular uptake of polymyxin B as well as its action against the vacuole(Reference Ogita, Nagao and Fujita26). Supplementation of garlic oil at 5 mg/kg body weight has been shown to have an anticoagulation effect in an animal study(Reference Chan, Yin and Chao27).

Whole garlic and aqueous garlic extract exhibit direct antioxidant effects and enhance the serum levels of two antioxidant enzymes: catalase and glutathione peroxidase(Reference Kumaraguruparan, Chandra Mohan and Abraham28). Garlic extract and allicin efficiently scavenged exogenously generated hydroxyl radicals in a dose-dependent fashion(Reference Prasad, Haxdal and Yu29). Other garlic constituents, such as SAC, also demonstrated significant antioxidant effects in vitro (Reference Imai, Ide and Nagae30). The sulfur compounds found in fresh garlic appear to be nearly 1000 times more potent as antioxidants than those found in aged garlic extract(Reference Melaleb31).

Garlic (both the 10 % homogenate in physiological saline solution and its supernatant fraction) was able to reduce the radicals that were generated by the Fenton reaction and trapped by phenyl-butyl-nitron; radicals present in cigarette smoke were also reduced by garlic(Reference Torok, Belaggi and Reitz32). In rat liver microsomes, garlic extract prevented the formation of thiobarbituric acid-reactive substances in cell membranes during lipid peroxidation in a dose dependent fashion(Reference Chang, Yamato and Yamasaki33). An aqueous extract obtained from 1 mg of a garlic preparation was as effective as an antioxidant as 30 nmol ascorbic acid and/or 3·6 nmol α-tocopherol(Reference Lewin and Popev34). Glycation endproduct formation is increased under conditions of oxidative stress, such as glutathione depletion, and glycated proteins produce 50-fold more toxic free radicals than non-glycated proteins. A recent study suggested that aged garlic extract inhibits the formation of glycation endproducts in vitro and the formation of glycation-derived free radicals(Reference Ahmad and Ahmed35).

Garlic and its constituents protect tissue against oxidative damage and improve organ functions in various animal models(Reference Park, Ki and Ko36). In male Wistar rats, administration of garlic extract against nicotine hydrogen bitartrate for 21 d increased glutathione levels and decreased malondialdehyde levels in aorta, heart, kidney and urinary bladder tissues(Reference Sener, Sehirli and Ipçi37). Aqueous garlic administration protects the tissues against nicotine-induced oxidative damage and improves renal function and histological damage. Similarly, oral administration of garlic oil in carbon tetrachloride-intoxicated rats significantly decreases the tissue lipid profile, lipid peroxidation levels, alkaline phosphatase, serum transaminases and protects the liver from damage by carbon tetrachloride as effectively as vitamin E. These changes induced by garlic oil in these rats are comparable with that of vitamin E(Reference Augusti38). DAS, DADS and DATS are principal constituents of garlic. The effect of these sulfides on phase II drug-metabolising enzymes and on the rat model of acute liver injury induced by carbon tetrachloride has been studied. A highly purified form of each sulfide was administered to rats at a concentration of 10 or 100 μmol/kg body weight for 14 consecutive days. DATS (10 μmol/kg) and DADS (100 μmol/kg) significantly increased the activities of GST and quinone reductase, whereas DAS did not. In the rat model of carbon tetrachloride-induced acute liver injury, DATS (10 μmol/kg) significantly suppressed the increase in plasma lactate dehydrogenase and serum glutamate oxaloacetate transaminase activities. Therefore, hepatic phase II enzymes were induced strongly by the trisulfide and weakly by the disulfide, but not by DAS. DATS significantly reduced the liver injury caused by carbon tetrachloride. DATS may be one of the important factors in garlic oil that protects our body against the injury caused by radical molecules(Reference Fukao, Hosono and Misawa39).

Another study showed the modifying effects of aqueous extracts of garlic and neem leaf during the pre-initiation and post-initiation phases of gastric carcinogenesis induced by N-methyl-N′-nitro-N-nitrosoguanidine in rats. Enhanced lipid peroxidation in the liver and blood of tumour-bearing animals was accompanied by significant decreases in the activities of glutathione-dependent antioxidants in the pre-initiation as well as in the post-initiation phases, but these alterations were reduced by combined supplementation of garlic and neem. It was suggested that the modulatory effects of garlic and neem leaf on hepatic and blood oxidant–antioxidant status may play a key role in preventing cancer development at extra-hepatic sites(Reference Arivazhagan, Velmurugan and Bhuvaneswari40). SAC, a water-soluble compound of garlic, also has been shown to have antioxidant activity in experimental animals. Much experimental evidence suggests that the actions of quinolinic acid also involve reactive oxygen species (ROS) formation and oxidative stress as major features of its pattern of toxicity. The effect of a garlic-derived compound and well-characterised free radical scavenger, SAC, on quinolinic acid-induced striatal neurotoxicity and oxidative damage has been studied in rats. SAC at a dose of 150 mg/kg resulted effective to prevent quinolinate-induced lipid peroxidation, whereas the systemic administration of 300 mg/kg of this compound to rats decreased effectively the quinolinic acid-induced oxidative injury measured as striatal ROS formation and lipid peroxidation. SAC (300 mg/kg) also prevented the striatal decrease of Cu/Zn-superoxide dismutase (SOD) activity produced by quinolinate. In addition, SAC, at the same dose tested, was able to reduce the quinolinic acid-induced neurotoxicity evaluated as circling behaviour and striatal morphological alterations. SAC ameliorates the in vivo quinolinate striatal toxicity by a mechanism related to its ability to: (a) scavenge free radicals, (b) decrease oxidative stress and (c) preserve the striatal activity of Cu/Zn-SOD. This antioxidant effect seems to be responsible for the preservation of the morphological and functional integrity of the striatum(Reference Pérez-Severiano, Rodríguez-Pérez and Pedraza-Chaverrí41). Aged garlic extract, through its scavengenig property on oxidants, increases SOD, catalase, glutathione peroxidase and glutathione levels, and inhibits lipid peroxidation and inflammatory prostaglandins in CVD and dementia(Reference Borek42).

Garlic increases cellular glutathione in a variety of cells including those in normal liver and mammary tissues(Reference Liu, Lin and Milner43). The ability of garlic to increase glutathione peroxidase and other ROS-scavenging enzymes is important in radioprotection and UV suppression of certain forms of immunity(Reference Wang, Peng and Keng44).

Oxidative stress and increased systemic inflammation may contribute to endothelial dysfunction. Aged garlic extract containing antioxidant compounds increases NO production and decreases the output of inflammatory cytokines from cultured cells. A recent study showed the effect of treatment with aged garlic extract on brachial artery flow-mediated endothelium-dependent dilation and circulating markers of oxidative stress and systemic inflammation in fifteen men with 2 weeks of treatment. During aged garlic extract supplementation, endothelium-dependent dilation increased (44 %) significantly from baseline and mainly in men with lower baseline endothelium-dependent dilation. Levels of endothelium-dependent dilation at the end of aged garlic extract treatment were significantly higher compared with the corresponding levels at the end of placebo treatment. Although markers of oxidative stress (plasma oxidised LDL and peroxides), systemic inflammation (plasma C-reactive protein and IL-6) did not change significantly during the study, short-term treatment with aged garlic extract may improve impaired endothelial function in men with coronary artery disease treated with aspirin and statin(Reference Williams, Sutherland and McCormick45).

Short-term garlic supplementation may have a protective role in hypertensive patients and on indices of oxidative stress. Garlic pearls at a dose of 250 mg/d for 2 months in hypertensive patients were found to decrease lipids and lipoprotein subfractions, plasma-oxidised LDL, plasma and urinary concentrations of 8-iso-PG F2α as a biomarker of oxidative stress and increase total antioxidant status. With 2 months of garlic pearl supplementation, there was also a significant decline in both systolic and diastolic blood pressures. It could be suggested that dietary supplementation of garlic may be beneficial in reducing blood pressure and oxidative stress in hypertensive individuals(Reference Dhawan and Jain46).

Epidemiological as well as laboratory studies have shown that garlic consumption reduces the incidence of cancer in the stomach, colon, mammary glands, cervix, etc. Some of the hypothesised mechanisms of the anticarcinogenic effects of garlic are: (i) scavenging of free radicals, (ii) increasing glutathione levels, (iii) increasing the activities of GST and catalase, (iv) inhibition of cytochrome p450 2E1, (v) DNA repair and prevention of chromosomal damage(Reference Khanum, Anilakumar and Viswanatham47). Durak et al. (Reference Durak, Aytac and Atmaca48) showed that the ingestion of garlic extract (1 ml garlic extract/kg body weight daily for 6 months) leads to significantly lowered plasma and erythrocyte malondialdehyde levels in atherosclerotic patients, even in the absence of changes in antioxidant enzyme activities. They also demonstrated the presence of oxidant stress in blood samples from patients with atherosclerosis which was eliminated by ingesting garlic extract. Thus, it is possible that reduced peroxidation processes may play a part in some of the beneficial effects of garlic in atherosclerotic diseases. In addition, the relationship between the effects of garlic extract supplementation on the blood lipid profile and oxidant–antioxidant status in hypertensive patients suggests a protective effect.

Antilipaemic actions of garlic

Garlic has demonstrated effects on several risk factors for CVD–hyperlipidaemia, hypertension and platelet aggregation(Reference Zahid, Hussain and Fahim49). Its anti-atherosclerotic properties are mainly attributed to allicin, which is produced upon crushing of the garlic clove. By using a pure allicin preparation, Gonen et al. were able to show that allicin may affect atherosclerosis not only by acting as an antioxidant, but also by other mechanisms, such as lipoprotein modification and inhibition of LDL uptake and degradation by macrophages(Reference Gonen, Harats and Rabinkov50).

In rat hepatocytes, garlic paste, garlic oil, allicin and ajoene were found to significantly reduce cholesterol biosynthesis by inhibiting 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase and 14-α-demethylase(Reference Gebhardt and Beck51). Some authors postulate that garlic's trace minerals, such as Te, also inhibit hepatic cholesterol synthesis(Reference Larner52). But most attribute garlic's antilipaemic effects to DADS, a decomposition product of allicin(Reference Yeh and Liu53).

Garlic lowers hyperlipidaemia in animal studies(Reference Augusti38). In rats, both garlic and garlic oil have been shown to exhibit significant lipid-lowering effects, primarily through a decrease in hepatic cholesterogenesis(Reference Mathew, Daniel and Augusti54). Rats that were on an atherogenic diet were supplemented with freeze-dried garlic powder; garlic exerted a dose–effect response, with the highest doses lowering serum cholesterol significantly, enhancing the ratio of HDL-cholesterol:LDL-cholesterol(Reference Chetty, Calaham and Harris55). Chickens whose diets were supplemented with garlic powder had significant reductions of plasma and tissue cholesterol and plasma TAG(Reference Chowdhury, Chowdhury and Smith56). Garlic supplementation also significantly decreased HMG-CoA reductase activity and cholesterol 7α-hydroxylase activity(Reference Liu and Yeh57). In an experimental model, where rabbits were fed with a high-cholesterol diet supplemented with garlic or allicin, hypercholesterolaemia was significantly inhibited by 50 %, indicated by decreased tissue cholesterol, LDL concentrations, raised HDL concentrations, and reduced atheromatous changes(Reference Kweon, Song and Choi58). Garlic also provided significant protection for the enzymes of the glutathione-dependent peroxide detoxification system, which is strongly impaired under hypercholesterolaemia(Reference Hsu, Huang and Hung59). In another study, rats were given garlic, ginger or garlic and ginger supplements for 4 weeks. All groups exhibited significant decreases in blood glucose, serum total cholesterol and serum alkaline phosphatase. Cholesterol was significantly decreased in animals fed with a combination of the two, compared with either alone, indicating that a combination of garlic and ginger is much more effective in reducing blood glucose and serum lipids(Reference Ahmed and Sharma60). Since 1975, many human studies have evaluated garlic's lipid-lowering effects. Controlled trials in healthy adults given garlic supplementation along with cholesterol-rich diets suggest that garlic can reduce mean serum cholesterol levels and increase fibrinolytic activity(Reference Durak, Aytac and Atmaca48). Although the quality of randomised trials has been only modest, recent meta-analyses have concluded that in over a dozen trials published between 1979 and 1993, there was an average improvement in serum cholesterol concentrations of 9–12 % and a significant reduction in serum TAG in hyperlipidaemic patients taking standardised garlic powder supplements of 600–900 mg daily, with improvement evident within 1 month(Reference Silagy and Neil61). In a single-blind, placebo-controlled cross-over study, forty hypercholesterolaemic adults were assigned to either placebo for 1 month or fish oil with garlic powder (1200 mg) capsules daily for 1 month. Supplementation with garlic resulted in an 11 % decrease in cholesterol, a 34 % decrease in TAG, and a 10 % decrease in LDL levels, as well as a 19 % decrease in cholesterol/HDL risk(Reference Jain, Varges and Gotzkowsky62).

In cell cultures, aqueous solutions of dried garlic powder containing allicin and ajoene have been found to significantly inhibit the proliferative activity of smooth muscle cells from atherosclerotic aortic plaques(Reference Campbell, Efendy and Smith63). In hypercholesterolaemic rabbits, garlic supplements significantly reduced the aortic lesions and lipid content of existing fatty plaques(Reference Ismail, Gad and Handy64). In a randomised placebo-controlled trial in ten healthy adults, there was a significant improvement in plasma viscosity and capillary blood flow within 5 h of taking 900 mg of standardised garlic powder(Reference Jung, Jung and Mrowietz65). In a prospective 4-year clinical trial of patients treated with 900 mg daily of standardised garlic powder, there was a 9–18 % reduction in plaque volume, a 4 % decrease in LDL levels, an 8 % increase in HDL concentrations and a 7 % decrease in blood pressure(Reference Siegel, Walter and Engel66).

Hepatoprotective actions of garlic

Garlic oil constituents, particularly DAS, activate constitutive androstane receptor (CAR) and nuclear factor E2-related factor 2 (Nrf2) to induce drug-metabolising enzymes(Reference Fisher, Augustine and Maher67).

SAC decreases CCl4-induced liver injury by attenuation of oxidative stress, and can be a useful regimen for chronic liver disease(Reference Kodai, Takemura and Minamiyama68). Freshly prepared garlic homogenate has been shown to protect against isoniazid+rifampicin-induced liver injury in an experimental animal model(Reference Pal, Vaiphei and Sikander69). In rat liver cultures, garlic administration before exposure to hepatotoxins (such as carbon tetrachloride, galactosamine and doxorubicin) provided protection against histological and biochemical evidence of damage(Reference Fancelli, Castro and de Toranzo70).

In mice, rats and chickens, pretreatment with oral garlic supplements provided significant protection against the toxicity of known hepatotoxins, including heavy metals(Reference Senapati, Dey and Dwivedi71, Reference Arora, Seth and Shukla72). In toads and rats, pretreatment with garlic protected against aflatoxin- and chemically induced liver tumours(Reference Bergès, Siess and Arnault73). Aged garlic and garlic's diallyl sulfur compounds protected against acute chemically induced hepatotoxicity in rats(Reference Kalantari and Salehi74).

In rats, daily pretreatment with garlic oil against buthionine sulfoximine and carbon tetrachloride effectively prevented increases in plasma aminotransferases and lactate dehydrogenase activities, liver injuries as evidenced by elevations in central necrosis, hepatocyte degeneration and inflammation and increases in plasma TAG contents(Reference Park, Ki and Ko36). In the carbon tetrachloride-induced acute liver injury model of rats, DADS and DATS given at a higher dose (100 μmol/kg), by increasing the activities of GST, quinone reductase, and the antioxidative enzyme glutathione peroxidase, reduced the injury caused by the induction of phase II enzymes with carbon tetrachloride(Reference Fukao, Hosono and Misawa39). Garlic reduced the toxic effects exerted by carbon tetrachloride in other organs in rats, through inhibition of the cytochrome P450 system that activates carbon tetrachloride into its active metabolite, the trichloromethyl radical(Reference Sheweita, Abd El-Gabar and Bastawy75). In ischaemia and reperfusion injury, garlic has been shown to have a protective effect. Aqueous garlic extract (1 ml/kg) was given to Wistar albino rats during an ischaemia and reperfusion period. Liver transaminases, malondialdehyde levels, glutathione levels, myeloperoxidase activity and hepatic collagen content, as a fibrosis marker, were increased in the ischaemia and reperfusion group. But these changes were reduced back to control levels by the aqueous garlic extract treatment. Therefore, aqueous garlic extract administration alleviated the ischaemia–reperfusion-induced injury of the liver and improved hepatic structure and function. It seems likely that garlic extract, with its antioxidant and oxidant-scavenging properties, may be of potential therapeutic value in protecting the liver against oxidative injury due to ischaemia–reperfusion(Reference Sener, Sehirli and Ipçi37).

In another study, induced liver fibrosis in male Wistar albino rats by bile duct ligation was reduced by aqueous garlic extract. It seems that aqueous garlic extract with its antioxidant and antifibrotic properties protects the liver from oxidative injury resulting in fibrosis(Reference Gedik, Kabasakal and Sehirli76). In one case report, a patient with severe hepatopulmonary syndrome, who failed somatostatin therapy and declined liver transplantation, began taking large daily doses of powdered garlic. She experienced partial palliation of her symptoms and some objective signs of improvement over 18 months of continuous self-medication(Reference Caldwell, Jeffers and Narula77).

Other potential effects of garlic

Haematological effects

In a study on horses, the ability of a herbal composite containing garlic, white horehound, boneset, aniseed, fennel, licorice, thyme and hyssop to reduce the clinical signs of recurrent airway obstruction was investigated; it was hypothesised that the product would safely reduce signs and would improve the inflammatory cell profile within the lungs(Reference Pearson, Charch and Brewer78). It has been reported by Wojcikowski et al. (Reference Wojcikowski, Myers and Brooks79) that garlic oil should not be relied on in individuals in which reduction in platelet aggregation is desired.

Fresh garlic, garlic powder, aged garlic and garlic oil have demonstrated antiplatelet and anticoagulant effects by interfering with cyclo-oxygenase-mediated thromboxane synthesis(Reference Chang, Yamato and Yamasaki33). Garlic compounds contributing to the anti-thrombotic effect were: alliin, ajoene, allicin, vinyldithiins and DADS(Reference MacDonald, Marchand and Langler80). These effects appear to be important contributors to garlic's beneficial role in atherosclerotic conditions(Reference Ide, Keller and Weiss81).

Antimicrobial effects

Garlic oil and allyl alcohol, both derived from alliin in garlic using different preparation methods, cause potent growth inhibition in yeasts(Reference Chung, Kwon and Shim82). The Gram-negative diarrhoeagenic pathogens from stool samples were highly sensitive to garlic, while ciprofloxacin was most effective against Escherichia coli (Reference Eja, Asikong and Abriba83). The antimicrobial activity was compromised by storage and heating; therefore it is advisable to use fresh garlic and avoid boiling it for more than 5 min during cooking(Reference Al-Waili, Saloom and Akmal84). Chopped garlic has a slowing-down effect on microbiological growth in ground meat depending on the garlic concentration, but this effect was not at an expected level even at the highest concentration, because potential antimicrobial agents in chopped garlic were probably insufficiently extracted(Reference Aydin, Bostan and Erkan85). Garlic cloves have antimicrobial properties in vitro against streptococci and anticariogenic properties against oral micro-organisms in spite of their adverse effects(Reference Groppo, Ramacciato and Motta86). Fresh garlic and garlic powder, through their combined antioxidant and antimicrobial effects, are potentially useful in preserving meat products(Reference Sallam, Ishioroshi and Samejima87). A wide variety of these organosulfur compounds, whether naturally occurring or synthetic, exhibit antibacterial properties. Mechanistically, organosulfur groups in garlic compounds can act as metal chelators, powerful nucleophiles or electrophiles depending on the local environment in which a given reaction occurs(Reference Konaklieva and Plotkin88).

Garlic is nicknamed ‘Russian penicillin’ for its widespread use as a topical and systemic antimicrobial agent(Reference Amin and Kapadnis89). Crude garlic extracts exhibited activity against both Gram-negative and Gram-positive bacteria at room temperature, but there were no significant effects if the garlic had been boiled for 5 min before testing(Reference Maldonado, Chanez and Pedraza90). Aged garlic extract demonstrated dose-dependent antimicrobial activity against three different reference strains of Helicobacter pylori at concentrations of 2–5 mg/ml; however, heat treatment of the extracts reduced the anti-bacterial effects(Reference Cañizares, Gracia and Gómez91). Garlic was also found to have synergistic effect against H. pylori with a proton pump inhibitor(Reference Sivam, Lampe and Ulness92). Garlic inhibited the growth of twenty different strains of intracellular Mycobacterium avium isolated from AIDS patients and non-AIDS patients(Reference Cellini, Di Campli and Masulli93). In rabbits, aqueous garlic extract and allicin had significant antibacterial activity against Shigella flexneri, fully curing the infected rabbits within 3 d compared with a mortality rate of 80 % within 48 h in the untreated rabbits; antibacterial activity against the challenge strain was observed in the sera of the treated rabbits within 30–60 min of administration of the agent(Reference Chowdhury, Ahsam and Islam94).

Antineoplastic effects

S-allylmercaptocysteine (SAMC) may promote docetaxel-induced cell death through promoting G2/M cell cycle arrest and apoptosis. The study by Howard et al. implies a potential role for SAMC in improving docetaxel-based chemotherapy for the treatment of hormone-refractory prostate cancer(Reference Howard, Lee and Chiu95). With the dynamic expression of cyclin B1, DADS induces reversible cell cycle arrest in the G2/M phase of HCT-116 cells through a p53-independent mechanism(Reference Jo, Song and Kim96).

Garlic has been known to have anti-inflammatory, anti-cancer and antioxidant effects. Owing to these effects, garlic and its preparations have been used for the treatment of prostate cancer and relief of benign prostatic hyperplasia symptoms for decades(Reference Devrim and Durak97). DAS can effectively check the mutations induced by environmental toxicants, as reported by Nigam & Shukla(Reference Nigam and Shukla98). The protective effects of high doses of garlic oil were more pronounced as compared with those in a vitamin E-administered group(Reference Kaur and Singh99).

The results demonstrated that DADS induced the expression of signal transducer and activator of transcription 1 (STAT1), which was also confirmed using Western blotting. STAT1 decoy oligonucleotides were also used to block STAT1 mRNA and led to a decrease in the levels of STAT1 and to a subsequent decrease in the percentage of apoptosis induced by DADS in examined colo 205 cells(Reference Lu, Yang and Lin100). Polybutylcyanoacrylate nanoparticles of DATS (DATS-PBCA-NP) were found to have a good prolonged release effect in vivo and hepatic-targeted activity, and a significant anti-tumour effect on the orthotopic transplantation hepatocellular carcinoma model in mice in association with the suppression of proliferation and the induction of apoptosis of tumour cells. These advantages are probably due to their liver-targeting characteristics and consequently bring a higher anti-tumour activity(Reference Zhang, Yang and Deng101). Garlic compounds induced apoptosis in glioblastoma cells due to the production of ROS, increase in endoplasmic reticulum stress, decrease in Δψm, and activation of stress kinases and cysteine proteases(Reference Das, Banik and Ray102).

The promising chemopreventive nature of liposomal DAS may form the basis for establishing effective means of controlling various forms of cancer, including skin papilloma(Reference Khan, Shukla and Kalra103). DAS is capable of acting efficiently and selectively only in the liver and can be used for hepatoprotection during chemotherapy(Reference Iciek, Marcinek and Mleczko104). DADS is an effective antifungal agent able to trigger cell death in Candida, most probably by eliciting oxidative stress as a consequence of thiol depletion and impaired mitochondrial function(Reference Lemar, Aon and Cortassa105). The ubiquitous efficiency of Z-ajoene, a new compound, has been demonstrated to fight against cancers of various origins including those that harbour viruses(Reference Terrasson, Xu and Li106). The role of oxidative stress and its relation to tumour promotion suggest protective effects of garlic oil against ferric nitrilotriacetate-induced hepatic toxicity and that it can serve as a potent chemopreventive agent to suppress oxidant-induced tissue injury and carcinogenesis(Reference Agarwal, Iqbal and Athar107).

Garlic and its extracts appear to protect against DNA damage in vitro. In animal and epidemiological studies, garlic is associated with a reduced risk of cancer(Reference Schulz, Lahmann and Boeing108). At least two anti-carcinogenic agents have been identified in garlic: DAS and GST(Reference Bose, Guo and Zimniak109). In the glandular stomach mucosa of rats, pretreatment with DAS significantly and dose dependently inhibited chemically induced nuclear aberrations and ornithine decarboxylase activity(Reference Hu110). Similarly, oral administration of a garlic supplement inhibited the development of benzopyrene-induced neoplasia and induced increased GST activity in the forestomach(Reference Srivastava, Hu and Xia111). In a study, supplementation with high-Se garlic before exposure to a known carcinogen significantly reduced DNA damage, normalised hepatic enzymes, and increased the concentrations of GST and uridine 5′-diphosphate-glucuronyltransferase in the liver and kidney, thus suggesting that garlic may suppress tumour development by enhancing detoxification(Reference Ip and Disk112).

Effects of garlic have been summarised in Fig. 2.

Fig. 2 Summary of the effects of garlic. GPX, glutathione peroxidase; HMG, 3-hydroxy-3-methylglutaryl; Nrf2, nuclear factor E2-related factor 2.

Potential toxicity of garlic

At present, there are no known toxic compounds in garlic and its extracts. Chronic administration of garlic powder (50 mg/d) resulted in inhibition of spermatogenesis in rats. Reduced concentration of sialic acid in the testes, epididymis and seminal vesicles together with decreased leydig cell function reflect anti-androgenic effects of garlic(Reference Augusti and Mathew113). A higher concentration of garlic powder (200 mg/ml) or allicin isolated from garlic caused considerable cell injuries in the portal hepatic zone in isolated perfused rat liver(Reference Dixit and Joshi114), which was not observed at a lower concentration.

Another in vitro study showed that DAS at 5 mm significantly decreased cell viability in the liver(Reference Egen-Schwind, Eckard and Jekat115). This evidence suggests the cautious use of garlic in animals to monitor blood levels simultaneously. In another study in dogs and rats, raw garlic caused severe mucosal damage(Reference Egen-Schwind, Eckard and Kemper6). In another study, toxic effects of oral and intraperitoneal administration of garlic extracts on lung and liver tissue of rats were studied. Administration of low doses of garlic (50 mg/kg) to rats either orally or intraperitoneally had no effect on lung and liver tissue as compared with control animals. Administration of higher dose of garlic (500 mg/kg) resulted in profound changes in lung and liver tissue of rats, indicating dose-related toxicity(Reference Alnaqeeb, Thomson and Bordia116). The toxic effect of a high dose of garlic was further confirmed in another experimental model where 300 and 600 mg of garlic bulb extract was administered to both male and female rats for 21 d, which resulted in growth retardation and effects on biological parameters and histological structures(Reference Fehri, Aiache and Korbi117).

Banerjee et al. (Reference Banerjee, Maulik and Manchanda118) investigated long-term effects of a low-dose garlic extract in an animal model using endogenous antioxidant enzymes and lipid peroxidation in the liver and kidney. Rats were fed with fresh garlic homogenate daily in three different doses (250, 500 and 1000 mg/kg per d) for 30 d. In comparison with saline-treated rats, the 250 mg/kg per d dose resulted in significantly reduced lipid peroxidation and glutathione peroxidase, no change in catalase and reduced glutathione; SOD was increased significantly. Both the 500 and 1000 mg/kg per d doses significantly reduced endogenous antioxidants (catalase and SOD) without altering lipid peroxidation level. Animals treated with 1000 mg/kg per d showed morphological changes in the liver both at light microscopy and ultrastructural levels. Histologically, liver showed focal non-specific injury to the hepatocytes. The reason for such type of injuries could be the sulfoxides present in the garlic extract that can undergo exchange reactions with –SH groups of enzymes and proteins in the body, spontaneously at physiological pH and temperature, inhibiting their activity(Reference Jocelyn119). Therefore, it seems that garlic in low doses has the potential to enhance the endogenous antioxidant status, although at higher doses a reversal of these effects is observed.

Intraperitoneal and oral administration of high doses (5 ml garlic juice/kg) led to weight loss, and hepatic and pulmonary toxicity in rats(Reference Shashikanth, Basappa and Sreenivasa Murthy120). However, in one study, hypertensive rats given garlic supplements four times daily developed erratic pulses, dehydration, weight loss and lethargy(Reference Ruffin and Hunter121).

In humans garlic is considered as safe by the US Food and Drug Administration but is also known to cause gastric irritation if taken in high doses by sensitive individuals. In randomised controlled trials, side effects included heartburn, nausea, vomiting, diarrhoea, flatulence, bloating, mild orthostatic hypotension, flushing, tachycardia, headache, insomnia, sweating and dizziness as well as offensive body odour(Reference Desai, Kalro and Choksi122).

Doses of garlic and its compounds

Yadav et al. (Reference Yadav and Verma123) have shown that garlic in low doses is safe in frogs. They suggested that garlic extract has some beneficial effects on heart rate, rhythm and force of contraction, but very high doses may exert non-desirable effects as well. The comparative toxic effects of oral and intraperitoneal administration of garlic extracts on lung and liver tissue of rats have also been studied. Administration of a low dose of garlic (50 mg/kg per d) to rats either orally or intraperitoneally had little effect on lung and liver tissues as compared with control animals(Reference Alnaqeeb, Thomson and Bordia116). In contrast, administration of a high dose of garlic (500 mg/kg per d) resulted in profound changes in lung and liver tissues of rats. Moreover, intraperitoneal administration of a high dose of garlic was more damaging to lung and liver tissues of rats than oral administration. Therefore, these reports highlight some of the adverse and toxic effects of high doses of garlic in animals. In support to this, it has been shown that higher concentrations of garlic extract are clastogenic in mice(Reference Das, Roychoudhury and Sharma124), which was appreciably reduced at lower concentrations. Female and male rats were given 300 and 600 mg/kg per d of a garlic aqueous extract for 21 d and the results showed that garlic extract causes toxic effects affecting weight growth, biological parameters and histological structures in rats(Reference Fehri, Aiache and Korbi117). Banerjee et al. (Reference Banerjee, Maulik and Manchanda118) also studied the effects of chronic fresh garlic homogenate in three different doses (250, 500 and 1000 mg/kg per d) for 30 d on various endogenous antioxidant enzymes and lipid peroxidation in two major organs, the liver and kidney. It was observed that in comparison with saline-treated rats, the 250mg/kg per d dose significantly reduced the lipid peroxidation levels and increased SOD activity significantly. But higher doses of garlic (500 and 1000 mg/kg per d) significantly reduced endogenous antioxidants (catalase and SOD) without altering lipid peroxidation levels. A 1000 mg/kg per d dose of garlic caused marked histopathological and ultrastructural changes in both liver and kidneys. Thus, garlic in low doses has the potential to enhance antioxidant status, although at higher doses a reversal of these effects is observed. Garlic has the potential ability with a high dose to induce morphological changes in the liver and kidneys, indicating the need to identify a safe dose range for garlic. Prolonged feeding of high levels of raw garlic in rats has resulted in anaemia, weight loss and failure to grow due to the lysis of erythrocytes(Reference Augusti38). Raw garlic juice at a dose of 5 ml/kg has resulted in the death of rats due to stomach injury(Reference Nakagawa, Masamoto and Sumiyoshi125). Surviving rats exhibited swelling of the liver, hypertrophy of the spleen and adrenal glands and the decrease of erythrocyte count with various morphological changes after 3 and 8 d. Chen et al. (Reference Chen, Hong and So126) have also reported that treatment of rats with fresh garlic homogenate for 7 d caused a significant decrease in liver catalase activity in doses of 2 and 4 g/kg per d. Garlic oil fed to rats at a dose of 100 mg/kg per d in fasting conditions has also been found to be lethal. The cause of death appears to be acute pulmonary oedema with severe congestion(Reference Joseph, Rao and Sundaresh127). Garlic oil and DADS (200 mg/kg) significantly reduced the body-weight gain of rats(Reference Sheen, Chen and Kung128). One possible explanation for all the above-mentioned toxicity reports is that the sulfoxides present in garlic extract undergo exchange reactions with –SH groups of enzymes and other proteins in the body at physiological pH and temperature, so inhibiting their activity(Reference Banerjee and Maulik129).

The effect of raw garlic at a dietary dose on platelet function has been studied by Scharbert et al. who reported that single consumption of fresh garlic up to 4·2 g/d has no inhibitory effect on platelet function in healthy volunteers(Reference Scharbert, Kalb and Duris130). Gadkari et al. (Reference Gadkari and Joshi131) showed increased clotting times from 4·15 to 5·02 min by investigating the in vivo effect of raw garlic intake of 10 g for 2 months. Asdaq & Inamdar have concluded that garlic in a moderate dose (250 mg/kg) with added hydrochlorothiazide possesses synergistic cardioprotective and antihypertensive properties against fructose- and isoproterenol-induced toxicities(Reference Asdaq and Inamdar132). A dose of garlic homogenate (250 mg/kg per d) either alone or with propranolol showed significant increase in activities of antioxidant enzymes such as SOD and catalase during ischaemia–reperfusion injury(Reference Asdaq, Inamdar and Asad133). Satitvipawee et al. (Reference Satitvipawee, Rawdaree and Indrabhakti134) showed no statistically significant changes in serum total cholesterol, TAG, LDL-cholesterol and HDL-cholesterol after 12 weeks of treatment with enteric-coated Thai garlic extract tablet once daily (standardised to 1·12 % allicin or 5·6 mg/tablet). In addition, no changes in plasma glucose, liver and renal functions were found(Reference Satitvipawee, Rawdaree and Indrabhakti134).

Summary

In the present review, antioxidant, antilipaemic, hepatoprotective, haematological, antimicrobial and antineoplastic actions of garlic have been shown. The studies reviewed reveal that the benefits of garlic are not limited to a specific species, a particular tissue, or a specific carcinogen. Oil-soluble compounds such as DADS have been observed to be effective in reducing the proliferation of neoplasms. However, it has also been reported that higher concentrations of garlic powder cause considerable cell injury in the liver of rats, which is not observed at lower concentrations.

Thus, although the evidence supports the benefits of garlic, additional evidence is needed to determine the quantity required by humans to minimise cancer, cardiovascular risks and haematological diseases, and to provide hepatoprotection and antilipaemic and antimicrobial effects.

Acknowledgements

The help of Mr Manu Rana for typing and of Miss Jaspreet Kaur for correcting the manuscript is acknowledged. The typing of this article has been funded by the Department of Gastroenterology, PGIMER, Chandigarh.

All authors have contributed in searching the literature, writing, typing and correcting this article.

There are no conflicts of interests to declare.

References

1Fenwick, GR & Hanley, AB (1985) The genus Allium. Part 2. Crit Rev Food Sci Nutr 22, 273277.CrossRefGoogle ScholarPubMed
2Matsuura, H, Ushiroguchi, T, Itakura, T, et al. . (1988) A furostanol glycoside from garlic bulbs of Allium sativum L. Chem Pharm Bull 36, 36593663.CrossRefGoogle Scholar
3Kaku, H, Goldstein, IJ, Van Damme, EJM, et al. . (1992) New mannose-specific lectins from garlic (Allium sativum) and ramsons (Allium ursinum) bulbs. Carbohydr Res 229, 347353.CrossRefGoogle ScholarPubMed
4Amagase, H, Petesch, LB, Matsuura, H, et al. . (2001) Intake of garlic and its bioactive compounds. J Nutr 31, 955S962S.CrossRefGoogle Scholar
5Lawson, LD & Gardner, CD (2005) Composition, stability, and bioavailability of garlic products used in a clinical trial. J Agric Food Chem 53, 62546261.CrossRefGoogle Scholar
6Egen-Schwind, C, Eckard, R & Kemper, FH (1992) Metabolism of garlic constituents in the isolated perfused rat liver. Planta Medica 58, 301305.CrossRefGoogle ScholarPubMed
7Lachmann, G, Horenz, D, Radeck, W, et al. . (1994) The pharmacokinetics of the S-35 labeled garlic constituents alliin, allicin and vinyldithiine (article in German). Arzeimitteforschung 44, 734743.Google Scholar
8Su, CC, Chen, GW, Tan, TW, et al. . (2006) Crude extract of garlic induced caspase-3 gene expression leading to apoptosis in human colon cancer cells. In Vivo 20, 8590.Google ScholarPubMed
9Manson, MM, Ball, HW, Barrett, MC, et al. . (1997) Mechanism of action of dietary chemoprotective agents in rat liver: induction of phase I and II drug metabolizing enzymes and aflatoxin B1 metabolism. Carcinogenesis 18, 17291738.CrossRefGoogle ScholarPubMed
10Wang, BH, Zuzel, KA, Rahman, K, et al. . (1999) Treatment with aged garlic extract protects against bromobenzene toxicity to precision cut rat liver slices. Toxicology 132, 215225.CrossRefGoogle ScholarPubMed
11Singh, A & Shukla, Y (1998) Antitumor activity of diallyl sulfide in two-stage mouse skin model of carcinogenesis. Biomed Environ Sci 11, 258263.Google ScholarPubMed
12Hughes, MF, Chamulitrat, W, Mason, RP, et al. . (1989) Epoxidation of 7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene via a hydroperoxide-dependent mechanism catalyzed by lipoxygenases. Carcinogenesis 10, 20752080.CrossRefGoogle Scholar
13Roy, P & Kulkarni, AP (1999) Co-oxidation of acrylonitrile by soybean lipoxygenase and partially purified human lung lipoxygenase. Xenobiotica 29, 511531.CrossRefGoogle ScholarPubMed
14Singh, A & Singh, SP (1997) Modulatory potential of smokeless tobacco on the garlic, mace or black mustard-altered hepatic detoxication system enzymes, sulfhydryl content and lipid peroxidation in murine system. Cancer Lett 118, 109114.CrossRefGoogle ScholarPubMed
15Hu, X, Benson, PJ, Srivastava, SK, et al. . (1997) Induction of glutathione S-transferase π as a bioassay for the evaluation of potency of inhibitors of benzo(a)pyrene-induced cancer in a murine model. Int J Cancer 73, 897902.3.0.CO;2-0>CrossRefGoogle Scholar
16Morihara, N, Nishihama, T, Ushijima, M, et al. . (2007) Garlic as an anti-fatigue agent. Mol Nutr Food Res 51, 13291334.CrossRefGoogle ScholarPubMed
17Tattelman, E (2005) Health effects of garlic. Am Fam Physician 72, 103106.Google ScholarPubMed
18Ryzhenkov, VE & Makarov, VG (2003) Biologically active substances in garlic (Allium sativum L.) and their application in nutrition for humans (article in Russian). Vopr Pitam 72, 4246.Google Scholar
19Ghazanfar, SA (1994) Handbook of Arabian Medicinal Plants. Boca Raton, FL: CRC Press.Google Scholar
20Kapoor, LD (1990) CRC Handbook of Ayurvedic Medicinal Plants. Boca Raton, FL: CRC Press.Google Scholar
21Peirce, A (1999) The ABC Clinical Guide to Herbs: The American Pharmaceutical Association Practical Guide to Natural Medicines. New York: William Morrow and Company, Inc.Google Scholar
22Barnes, J, Anderson, LA & Phillipson, ID (1996) Herbal Medicines: A Guide for Health-Care Professionals. London: Pharmaceutical Press.Google Scholar
23Woodward, PW (1996) Garlic and Friends: The History, Growth and Use of Edible Alliums. Melbourne: Hyland House Publishing.Google Scholar
24El Shenawy, NS, Soliman, MF & Reyad, SI (2008) The effect of antioxidant properties of aqueous garlic extract and Nigella sativa as anti-schistosomiasis agents in mice. Rev Inst Med Trop Sao Paulo 50, 2936.CrossRefGoogle ScholarPubMed
25Liu, HG & Xu, LH (2007) Garlic oil prevents tributyltin-induced oxidative damage in vivo and in vitro. J Food Prot 70, 716721.CrossRefGoogle ScholarPubMed
26Ogita, A, Nagao, Y, Fujita, K, et al. . (2007) Amplification of vacuole-targeting fungicidal activity of antibacterial antibiotic polymyxin B by allicin, an allylsulfur compound from garlic. J Antibiot (Tokyo) 60, 511518.CrossRefGoogle Scholar
27Chan, KC, Yin, MC & Chao, WJ (2007) Effect of diallyl trisulfide-rich garlic oil on blood coagulation and plasma activity of anticoagulation factors in rats. Food Chem Toxicol 45, 502507.CrossRefGoogle ScholarPubMed
28Kumaraguruparan, R, Chandra Mohan, KV & Abraham, SK (2005) Attenuation of N-methyl-N′-nitro-N-nitrosoguanidine induced genotoxicity and oxidative stress by tomato and garlic combination. Life Sci 76, 22472255.CrossRefGoogle ScholarPubMed
29Prasad, K, Haxdal, A, Yu, M, et al. . (1995) Antioxidant activity of allicin, an active principle in garlic. Mol Cell Biochem 148, 183189.CrossRefGoogle ScholarPubMed
30Imai, J, Ide, N, Nagae, S, et al. . (1994) Antioxidant and radical scavenging effects of aged garlic extract and its constituents. Planta Medica 60, 417420.CrossRefGoogle ScholarPubMed
31Melaleb, R (1993) Antioxidant, antitumor and cardiovascular actions of garlic. Herbal Gram 29, 1872.Google Scholar
32Torok, B, Belaggi, J & Reitz, B (1994) Effectiveness of garlic on the radical activity in radical generating system. Arzeimittelfrschung 44, 608611.Google Scholar
33Chang, HS, Yamato, O, Yamasaki, M, et al. . (2005) Modulatory influence of sodium 2-propenyl thiosulfate from garlic on cyclooxygenase activity in canine platelets: possible mechanism for the anti-aggregatory effect. Prostaglandins Leukot Essent Fatty Acids 72, 351355.CrossRefGoogle ScholarPubMed
34Lewin, G & Popev, I (1994) Antioxidant effect of aqueous garlic extract. 2nd communication: inhibition of the Cu(2+)-initiated oxidation of low density lipoproteins. Arzneimettelforchung 44, 604607.Google ScholarPubMed
35Ahmad, MS & Ahmed, N (2006) Antiglycation properties of aged garlic extract: possible role in prevention of diabetic complications. J Nutr 136, 796S799S.CrossRefGoogle ScholarPubMed
36Park, EY, Ki, SH, Ko, MS, et al. . (2005) Garlic oil and DDB, comprised in a pharmaceutical composition for the treatment of patients with viral hepatitis, prevents acute liver injuries potentiated by glutathione deficiency in rats. Chem Biol Interact 155, 8296.CrossRefGoogle Scholar
37Sener, G, Sehirli, O, Ipçi, Y, et al. . (2005) Aqueous garlic extract alleviates ischaemia–reperfusion-induced oxidative hepatic injury in rats. J Pharm Pharmacol 57, 145150.CrossRefGoogle ScholarPubMed
38Augusti, KT (1996) Therapeutic values of onion (Allium cepa L.) and garlic (Allium sativum L.). Indian J Exp Biol 34, 634640.Google Scholar
39Fukao, T, Hosono, T, Misawa, S, et al. . (2004) The effects of allyl sulfides on the induction of phase II detoxification enzymes and liver injury by carbon tetrachloride. Food Chem Toxicol 42, 743749.CrossRefGoogle ScholarPubMed
40Arivazhagan, S, Velmurugan, B, Bhuvaneswari, V, et al. . (2004) Effects of aqueous extracts of garlic (Allium sativum) and neem (Azadirachta indica) leaf on hepatic and blood oxidant–antioxidant status during experimental gastric carcinogenesis. J Med Food 7, 334339.CrossRefGoogle ScholarPubMed
41Pérez-Severiano, S, Rodríguez-Pérez, M, Pedraza-Chaverrí, J, et al. . (2004) S-Allylcysteine, a garlic-derived antioxidant, ameliorates quinolinic acid-induced neurotoxicity and oxidative damage in rats. Neurochem Int 45, 11751183.CrossRefGoogle ScholarPubMed
42Borek, C (2006) Garlic reduces dementia and heart-disease risk. J Nutr 136, 810S812S.CrossRefGoogle ScholarPubMed
43Liu, Jz, Lin, XY & Milner, JZ (1992) Dietary garlic powder increase glutathione content and glutathione S-transferase activity in rat liver and mammary tissues. FASEB J 6, A3230A3231.Google Scholar
44Wang, Z, Peng, Z, Keng, R, et al. . (1998) Effect of allicin in ethanol-induced hepatotoxicity in mice. Wei Sheng Yan Jiu 27, 415457.Google ScholarPubMed
45Williams, MJ, Sutherland, WH, McCormick, MP, et al. . (2005) Aged garlic extract improves endothelial function in men with coronary artery disease. Phytother Res 19, 314319.CrossRefGoogle ScholarPubMed
46Dhawan, V & Jain, S (2004) Effect of garlic supplementation on oxidized low density lipoproteins and lipid peroxidation in patients of essential hypertension. Mol Cell Biochem 266, 109115.CrossRefGoogle ScholarPubMed
47Khanum, F, Anilakumar, KR & Viswanatham, KR (2004) Anticarcinogenic properties of garlic: a review. Crit Rev Food Sci Nutr 44, 479488.CrossRefGoogle ScholarPubMed
48Durak, I, Aytac, B, Atmaca, Y, et al. . (2004) Effects of garlic extract consumption in plasma and erythrocyte antioxidant parameters in atherosclerotic patients. Life Sci 75, 19571966.CrossRefGoogle ScholarPubMed
49Zahid, AM, Hussain, ME & Fahim, M (2005) Antiatherosclerotic effects of dietary supplementations of garlic and turmeric: restoration of endothelial function in rats. Life Sci 77, 837857.CrossRefGoogle Scholar
50Gonen, A, Harats, D, Rabinkov, A, et al. . (2005) The antiatherogenic effect of allicin: possible mode of action. Pathobiology 72, 325334.CrossRefGoogle ScholarPubMed
51Gebhardt, R & Beck, H (1996) Differential inhibitory effects of garlic-derived organosulfur compounds on cholesterol biosynthesis in primary rat hepatocyte cultures. Lipids 31, 12691276.CrossRefGoogle ScholarPubMed
52Larner, AJ (1995) How does garlic exert its hypocholesterolaemic action? The tellurium hypothesis. Med Hypotheses 44, 295307.CrossRefGoogle ScholarPubMed
53Yeh, YY & Liu, L (2001) Cholesterol lowering effect of garlic extracts and organosulfur compounds: human and animal studies. J Nutr 131, 989S993S.CrossRefGoogle ScholarPubMed
54Mathew, BC, Daniel, RS & Augusti, KT (1996) Hypolipidemic effect of garlic protein substituted for casein in diet of rats compared to those of garlic oil. Indian J Exp Biol 34, 337340.Google ScholarPubMed
55Chetty, KN, Calaham, L, Harris, KC, et al. . (2003) Garlic attenuates hypercholesterolemic risk factors in olive oil fed rats and high cholesterol fed rats. Pathophysiology 9, 127132.CrossRefGoogle ScholarPubMed
56Chowdhury, SR, Chowdhury, SD & Smith, TK (2002) Effects of dietary garlic on cholesterol metabolism in laying hens. Poult Sci 81, 18561862.CrossRefGoogle ScholarPubMed
57Liu, L & Yeh, YY (2002) S-alk(en)ylcysteines of garlic inhibit cholesterol synthesis by deactivating HMG-CoA reductase in cultured rat hepatocytes. J Nutr 132, 11291144.CrossRefGoogle Scholar
58Kweon, MJ, Song, YS, Choi, MS, et al. . (2003) Cholesteryl ester transfer protein activity and atherogenic parameters in rabbits supplemented with cholesterol and garlic powder. Life Sci 72, 29532964.CrossRefGoogle Scholar
59Hsu, CC, Huang, CN, Hung, YC, et al. . (2004) Five cysteine-containing compounds have antioxidative activity in Balb/cA mice. J Nutr 134, 149152.CrossRefGoogle ScholarPubMed
60Ahmed, RS & Sharma, SB (1997) Biochemical studies on combined effects of garlic (Allium sativum Linn) and ginger (Zingiber officinale Rosc) in albino rats. Indian J Exp Biol 35, 841843.Google Scholar
61Silagy, C & Neil, A (1994) Garlic as a lipid lowering agent – a meta-analysis. J R Coll Physicians Lond 28, 3945.Google ScholarPubMed
62Jain, AK, Varges, R, Gotzkowsky, S, et al. . (1993) Can garlic reduce levels of serum lipids? A controlled clinical study. Am J Med 94, 632635.CrossRefGoogle ScholarPubMed
63Campbell, JH, Efendy, JL, Smith, NJ, et al. . (2001) Molecular basis by which garlic suppresses atherosclerosis. J Nutr 131, 1006S1009S.CrossRefGoogle ScholarPubMed
64Ismail, MF, Gad, MZ & Handy, MA (1999) Study of the hypolipidemic properties of pectin, garlic and ginseng in hypercholesterolemic rabbits. Pharmacol Res 39, 157166.CrossRefGoogle ScholarPubMed
65Jung, F, Jung, EM, Mrowietz, C, et al. . (1990) Influence of garlic powder on cutaneous microcirculation: a randomized, placebo-controlled, double-blind, crossover study in apparently healthy subjects. Br J Clin Pract 69, 3035.Google ScholarPubMed
66Siegel, G, Walter, A, Engel, S, et al. . (1999) Pleiotropic effects of garlic. Wien Med Wochenschr 149, 217224.Google ScholarPubMed
67Fisher, CD, Augustine, LM, Maher, JM, et al. . (2007) Induction of drug-metabolizing enzymes by garlic and allyl sulfide compounds via activation of constitutive androstane receptor and nuclear factor E2-related factor 2. Drug Metab Dispos 35, 9951000.CrossRefGoogle ScholarPubMed
68Kodai, S, Takemura, S, Minamiyama, Y, et al. . (2007) S-allyl cysteine prevents CCl4-induced acute liver injury in rats. Free Radic Res 41, 489497.CrossRefGoogle Scholar
69Pal, R, Vaiphei, K, Sikander, A, et al. . (2006) Effect of garlic on isoniazid and rifampicin-induced hepatic injury in rats. World J Gastroenterol 12, 636639.CrossRefGoogle ScholarPubMed
70Fancelli, SL, Castro, GD, de Toranzo, FG, et al. . (1998) Mechanisms of the preventive properties of some garlic components in the carbon tetrachloride-promoted oxidative stress. Diallyl sulfide; diallyl disulfide; allyl mercaptan and allyl methyl sulfide. Res Commun Mol Pathol Pharmacol 102, 163174.Google Scholar
71Senapati, SK, Dey, S, Dwivedi, SK, et al. . (2001) Effect of garlic (Allium sativum L.) extract on tissue lead level in rats. J Ethnopharmacol 76, 229232.CrossRefGoogle ScholarPubMed
72Arora, A, Seth, K & Shukla, Y (2004) Reversal of P-glycoprotein-mediated multidrug resistance by diallyl sulfide in K562 leukemic cells and in mouse liver. Carcinogenesis 25, 941949.CrossRefGoogle ScholarPubMed
73Bergès, R, Siess, MH, Arnault, J, et al. . (2004) Comparison of the chemopreventive efficacies of garlic powders with different alliin contents against aflatoxin B1 carcinogenicity in rats. Carcinogenesis 25, 19531959.CrossRefGoogle ScholarPubMed
74Kalantari, H & Salehi, M (2001) The protective effect of garlic oil on hepatotoxicity induced by acetaminophen in mice and comparison with N-acetylcysteine. Saudi Med J 22, 10801084.Google ScholarPubMed
75Sheweita, SA, Abd El-Gabar, M & Bastawy, M (2001) Carbon tetrachloride induced changes in the activity of phase II drug metabolizing enzymes in the liver of male rats: role of antioxidants. Toxicology 165, 217224.CrossRefGoogle ScholarPubMed
76Gedik, N, Kabasakal, L, Sehirli, O, et al. . (2005) Long-term administration of aqueous garlic extract (AGE) alleviates liver fibrosis and oxidative damage induced by biliary obstruction in rats. Life Sci 76, 25932606.CrossRefGoogle ScholarPubMed
77Caldwell, SH, Jeffers, LI, Narula, OS, et al. . (1992) Ancient remedies revisited: does Allium sativum (garlic) palliate the hepatopulmonary syndrome? J Clin Gastroenterol 15, 248250.CrossRefGoogle ScholarPubMed
78Pearson, W, Charch, A, Brewer, D, et al. . (2007) Pilot study investigating the ability of an herbal composite to alleviate clinical signs of respiratory dysfunction in horses with recurrent airway obstruction. Can J Vet Res 71, 145151.Google ScholarPubMed
79Wojcikowski, K, Myers, S & Brooks, L (2007) Effects of garlic oil on platelet aggregation: a double-blind placebo-controlled crossover study. Platelets 18, 2934.CrossRefGoogle ScholarPubMed
80MacDonald, JA, Marchand, ME & Langler, RF (2004) Improving upon the in vitro biological activity of antithrombotic disulfides. Blood Coagul Fibrinolysis 15, 447450.CrossRefGoogle ScholarPubMed
81Ide, N, Keller, C & Weiss, N (2006) Aged garlic extract inhibits homocysteine-induced CD36 expression and foam cell formation in human macrophages. J Nutr 136, 755S757S.CrossRefGoogle ScholarPubMed
82Chung, I, Kwon, SH, Shim, ST, et al. . (2007) Synergistic antiyeast activity of garlic oil and allyl alcohol derived from alliin in garlic. J Food Sci 72, M437M440.CrossRefGoogle ScholarPubMed
83Eja, ME, Asikong, BE, Abriba, C, et al. . (2007) A comparative assessment of the antimicrobial effects of garlic (Allium sativum) and antibiotics on diarrheagenic organisms. Southeast Asian J Trop Med Public Health 38, 343348.Google ScholarPubMed
84Al-Waili, NS, Saloom, KY, Akmal, M, et al. . (2007) Effects of heating, storage, and ultraviolet exposure on antimicrobial activity of garlic juice. J Med Food 10, 208212.CrossRefGoogle ScholarPubMed
85Aydin, A, Bostan, K, Erkan, ME, et al. . (2007) The antimicrobial effects of chopped garlic in ground beef and raw meatball (ciğ köfte). J Med Food 10, 203207.CrossRefGoogle Scholar
86Groppo, FC, Ramacciato, JC, Motta, RH, et al. . (2007) Antimicrobial activity of garlic against oral streptococci. Int J Dent Hyg 5, 109115.CrossRefGoogle ScholarPubMed
87Sallam, KI, Ishioroshi, M & Samejima, K (2007) Antioxidant and antimicrobial effects of garlic in chicken sausage. Lebenson Wiss Technol 37, 849855.CrossRefGoogle Scholar
88Konaklieva, MI & Plotkin, BJ (2006) Antimicrobial properties of organosulfur anti-infectives: a review of patent literature 1999–2005. Recent Patents Anti-Infect Drug Disc 1, 177180.CrossRefGoogle ScholarPubMed
89Amin, M & Kapadnis, BP (2005) Heat stable antimicrobial activity of Allium ascalonicum against bacteria and fungi. Indian J Exp Biol 43, 751754.Google ScholarPubMed
90Maldonado, PD, Chanez, CME & Pedraza, CJ (2005) Aged garlic extract, garlic-powder extract, S-allylcysteine, diallyl sulfide and diallyl disulfide do not interfere with the antibiotic activity of gentamicin. Phytother Res 19, 252254.CrossRefGoogle Scholar
91Cañizares, P, Gracia, I, Gómez, LA, et al. . (2004) Allyl-thiosulfinates, the bacteriostatic compounds of garlic against Helicobacter pylori. Biotechnol Prog 20, 397401.CrossRefGoogle ScholarPubMed
92Sivam, GP, Lampe, JW, Ulness, B, et al. . (1997) Helicobacter pyloriin vitro susceptibility to garlic (Allium sativum) extract. Nutr Cancer 27, 118121.CrossRefGoogle ScholarPubMed
93Cellini, L, Di Campli, E, Masulli, M, et al. . (1996) Inhibition of Helicobacter pylori by garlic extract (Allium sativum). FEMS Immunol Med Microbial 13, 273277.CrossRefGoogle Scholar
94Chowdhury, AK, Ahsam, M, Islam, SN, et al. . (1991) Efficacy of aqueous extract of garlic and allicin in experimental shigellosis in rabbits. Indian J Med Res 93, 3336.Google ScholarPubMed
95Howard, EW, Lee, DT, Chiu, YT, et al. . (2008) Evidence of a novel docetaxel sensitizer, garlic-derived S-allylmercaptocysteine, as a treatment option for hormone refractory prostate cancer. Int J Cancer 122, 19411948.CrossRefGoogle ScholarPubMed
96Jo, HJ, Song, JD, Kim, KM, et al. . (2008) Diallyl disulfide induces reversible G2/M phase arrest on a p53-independent mechanism in human colon cancer HCT-116 cells. Oncol Rep 19, 275280.Google ScholarPubMed
97Devrim, E & Durak, I (2007) Is garlic a promising food for benign prostatic hyperplasia and prostate cancer? Mol Nutr Food Res 51, 13191323.CrossRefGoogle ScholarPubMed
98Nigam, N & Shukla, Y (2007) Preventive effects of diallyl sulfide on 7,12-dimethylbenz[a]anthracene induced DNA alkylation damage in mouse skin. Mol Nutr Food Res 51, 13241328.CrossRefGoogle ScholarPubMed
99Kaur, P & Singh, R (2007) In vivo interactive effect of garlic oil and vitamin E against stavudine induced genotoxicity in Mus musculus. Indian J Exp Biol 45, 807811.Google ScholarPubMed
100Lu, HF, Yang, JS, Lin, YT, et al. . (2007) Diallyl disulfide induced signal transducer and activator of transcription 1 expression in human colon cancer colo 205 cells using differential display RT-PCR. Cancer Genomics Proteomics 4, 9397.Google ScholarPubMed
101Zhang, ZM, Yang, XY, Deng, SH, et al. . (2007) Anti-tumor effects of polybutylcyanoacrylate nanoparticles of diallyl trisulfide on orthotopic transplantation tumor model of hepatocellular carcinoma in BALB/c nude mice. Chin Med J (Engl) 120, 13361342.Google ScholarPubMed
102Das, A, Banik, NL & Ray, SK (2007) Garlic compounds generate reactive oxygen species leading to activation of stress kinases and cysteine proteases for apoptosis in human glioblastoma T98G and U87MG cells. Cancer 110, 10831095.CrossRefGoogle ScholarPubMed
103Khan, A, Shukla, Y, Kalra, N, et al. . (2007) Potential of diallyl sulfide bearing pH-sensitive liposomes in chemoprevention against DMBA-induced skin papilloma. Mol Med 13, 443451.Google ScholarPubMed
104Iciek, M, Marcinek, J, Mleczko, U, et al. . (2007) Selective effects of diallyl disulfide, a sulfane sulfur precursor, in the liver and Ehrlich ascites tumor cells. Eur J Pharmacol 569, 17.CrossRefGoogle ScholarPubMed
105Lemar, KM, Aon, MA, Cortassa, S, et al. . (2007) Diallyl disulphide depletes glutathione in Candida albicans: oxidative stress-mediated cell death studied by two-photon microscopy. Yeast 24, 695706.CrossRefGoogle ScholarPubMed
106Terrasson, J, Xu, B, Li, M, et al. . (2007) Activities of Z-ajoene against tumour and viral spreading in vitro. Fundam Clin Pharmacol 21, 281289.CrossRefGoogle ScholarPubMed
107Agarwal, MK, Iqbal, M & Athar, M (2007) Garlic oil ameliorates ferric nitrilotriacetate (Fe-NTA)-induced damage and tumor promotion: implications for cancer prevention. Food Chem Toxicol 45, 16341640.CrossRefGoogle ScholarPubMed
108Schulz, M, Lahmann, PH, Boeing, H, et al. . (2005) Fruit and vegetable consumption and risk of epithelial ovarian cancer. The European Prospective Investigation into Cancer and Nutrition. Cancer Epidemol Biomarkers Prev 14, 25312535.CrossRefGoogle ScholarPubMed
109Bose, C, Guo, J, Zimniak, L, et al. . (2002) Critical role of allyl groups and disulfide chain in induction of Pi class glutathione transferase in mouse tissues in vivo by diallyl disulfide, a naturally occurring chemopreventive agent in garlic. Carcinogenesis 23, 16611665.CrossRefGoogle ScholarPubMed
110Hu, DJ (1990) Protective effect of diallyl sulfide, a natural extract of garlic, on MNNG-induced damage of rat glandular stomach mucosa. Zhonghua Zhonghua Zhong Liu Za Zhi 12, 429431.Google ScholarPubMed
111Srivastava, SK, Hu, X, Xia, H, et al. . (1997) Mechanism of differential efficacy of garlic organosulfides in preventing benzo(a)pyrene-induced cancer in mice. Cancer Lett 118, 6167.CrossRefGoogle ScholarPubMed
112Ip, C & Disk, DJ (1997) Modulation of phase I and phase II xenobiotic-metabolizing enzymes by selenium-enriched garlic in rats. Nutr Cancer 28, 184188.CrossRefGoogle ScholarPubMed
113Augusti, KT & Mathew, PT (1975) Effect of allicin on certain enzymes of liver after a short term feeding to normal rats. Experientia 31, 148149.CrossRefGoogle Scholar
114Dixit, VP & Joshi, S (1982) Effects of chronic administration of garlic (Allium sativum Linn) on testicular function. Indian J Exp Biol 20, 534566.Google ScholarPubMed
115Egen-Schwind, C, Eckard, R, Jekat, FW, et al. . (1992) Pharmacokinetics of vinyldithiins, transformation products of allicin. Planta Med 58, 813.CrossRefGoogle ScholarPubMed
116Alnaqeeb, MA, Thomson, M, Bordia, T, et al. . (1996) Histopathological effects of garlic on liver and lung of rats. Toxicol Lett 85, 157164.CrossRefGoogle ScholarPubMed
117Fehri, M, Aiache, JM, Korbi, S, et al. . (1991) Toxic effects induced by the repeat administration of Allium sativum L. J Pharm Belg 46, 363374.Google ScholarPubMed
118Banerjee, SK, Maulik, M, Manchanda, SC, et al. . (2001) Garlic-induced alteration in rat liver and kidney morphology and associated changes in endogenous antioxidant status. Food Chem Toxicol 39, 793797.CrossRefGoogle ScholarPubMed
119Jocelyn, PC (1972) Biochemistry of the SH Group: The Occurrence, Chemical Properties, Metabolism and Biological Functions of Thiols and Disulphides, p. 107. New York: Academic Press.Google Scholar
120Shashikanth, KN, Basappa, SC & Sreenivasa Murthy, VA (1984) A comparative study of raw garlic extract and tetracycline on caecal microflora and serum proteins of albino rats. Folia Microbial 29, 348352.CrossRefGoogle ScholarPubMed
121Ruffin, J & Hunter, SA (1983) An evaluation of the side effects of garlic as an antihypertensive agent. Cytobios 37, 8589.Google ScholarPubMed
122Desai, HG, Kalro, RH & Choksi, AP (1990) Effect of ginger and garlic on DNA content of gastric aspirate. Indian J Med Res 92, 139141.Google ScholarPubMed
123Yadav, RK & Verma, NS (2004) Effects of garlic (Allium sativum) extract on the heart rate, rhythm and force of contraction in frog: a dose dependent study. Indian J Exp Biol 42, 628631.Google ScholarPubMed
124Das, T, Roychoudhury, A, Sharma, A, et al. . (1996) Effects of crude garlic extract on mouse chromosomes in vivo. Food Chem Toxicol 34, 4347.CrossRefGoogle ScholarPubMed
125Nakagawa, S, Masamoto, K, Sumiyoshi, H, et al. . (1980) Effect of raw and extracted-aged garlic juice on growth of young rats and their organs after peroral administration (article in Japanese). J Toxicol Sci 5, 91112.CrossRefGoogle Scholar
126Chen, L, Hong, JY, So, E, et al. . (1999) Decrease of hepatic catalase level by treatment with diallyl sulfide and garlic homogenates in rats and mice. J Biochem Mol Toxicol 13, 127133.3.0.CO;2-X>CrossRefGoogle ScholarPubMed
127Joseph, PK, Rao, KR & Sundaresh, CS (1989) Toxic effects of garlic extract and garlic oil in rats. Indian J Exp Biol 27, 977979.Google ScholarPubMed
128Sheen, LY, Chen, HW, Kung, YL, et al. . (1999) Effects of garlic oil and its organosulfur compounds on the activities of hepatic drug-metabolizing and antioxidant enzymes in rats fed high- and low-fat diets. Nutr Cancer 35, 160166.CrossRefGoogle ScholarPubMed
129Banerjee, SK & Maulik, SK (2002) Effect of garlic on cardiovascular disorders: a review. Nutr J 1, 4.CrossRefGoogle ScholarPubMed
130Scharbert, G, Kalb, ML, Duris, M, et al. . (2007) Garlic at dietary doses does not impair platelet function. Anesth Analg 105, 12141218.CrossRefGoogle Scholar
131Gadkari, JV & Joshi, VD (1991) Effect of ingestion of raw garlic on serum cholesterol level, clotting time and fibrinolytic activity in normal subjects. J Postgrad Med 37, 128131.Google ScholarPubMed
132Asdaq, SM & Inamdar, MN (2011) The potential benefits of a garlic and hydrochlorothiazide combination as antihypertensive and cardioprotective in rats. J Nat Med 65, 8188.CrossRefGoogle ScholarPubMed
133Asdaq, SM, Inamdar, MN & Asad, M (2010) Pharmacodynamic interaction of garlic with propranolol in ischemia–reperfusion induced myocardial damage. Pak J Pharm Sci 23, 4247.Google ScholarPubMed
134Satitvipawee, P, Rawdaree, P, Indrabhakti, S, et al. . (2003) No effect of garlic extract supplement on serum lipid levels in hypercholesterolemic subjects. J Med Assoc Thai 86, 750757.Google ScholarPubMed
Figure 0

Fig. 1 Chemical changes in garlic. DAS, diallyl sulfide; DADS, diallyl disulfide; DATS, diallyl trisulfide.

Figure 1

Table 1 Main brands of garlic on the market

Figure 2

Fig. 2 Summary of the effects of garlic. GPX, glutathione peroxidase; HMG, 3-hydroxy-3-methylglutaryl; Nrf2, nuclear factor E2-related factor 2.

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