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At least 19 recordsLinked to original sources

PubMed2001

Antimicrobial properties of garlic oil against human enteric bacteria: evaluation of methodologies and comparisons with garlic oil sulfides and garlic powder.

The antimicrobial effects of aqueous garlic extracts are well established but those of garlic oil (GO) are little known. Methodologies for estimating the antimicrobial activity of GO were assessed and GO, GO sulfide constituents, and garlic powder (GP) were compared in tests against human enteric bacteria. Test methodologies were identified as capable of producing underestimates of GO activity. Antimicrobial activity was greater in media lacking tryptone or cysteine, suggesting that, as for allicin, GO effects may involve sulfhydryl reactivity. All bacteria tested, which included both gram-negative and -positive bacteria and pathogenic forms, were susceptible to garlic materials. On a weight-of-product basis, 24 h MICs for GO (0.02 to 5.5 mg/ml, 62 enteric isolates) and dimethyl trisulfide (0.02 to 0.31 mg/ml, 6 enteric isolates) were lower than those for a mixture of diallyl sulfides (0.63 to 25 mg/ml, 6 enteric isolates) and for GP, which also exhibited a smaller MIC range (6.25 to 12.5 mg/ml, 29 enteric isolates). Viability time studies of GO and GP against Enterobacter aerogenes showed time- and dose-dependent effects. Based upon its thiosulfinate content, GP was more active than GO against most bacteria, although some properties of GO are identified as offering greater therapeutic potential. Further exploration of the potential of GP and GO in enteric disease control appears warranted.

Allyl Compounds↗

PubMed1991

[Formation of allicin from dried garlic (Allium sativum): a simple HPTLC method for simultaneous determination of allicin and ajoene in dried garlic and garlic preparations].

In garlic (Allium sativum L.) the enzyme alliin lyase catalyzes the cleavage of alliin into allicin which reacts further to furnish ajoene. A simultaneous determination of allicin and ajoene is introduced which, in contrast to the determination of alliin only, allows for the testing of the activity of alliin lyase. It can be demonstrated that at a pH value of less than 3 the enzyme produces only small amounts of allicin. For this reason preparations from garlic should be administered only as enteric-coated formulations.

Chromatography, Thin Layer↗

PubMed2004

Garlic's ability to prevent in vitro Cu2+-induced lipoprotein oxidation in human serum is preserved in heated garlic: effect unrelated to Cu2+-chelation.

BACKGROUND: It has been shown that several extracts and compounds derived from garlic are able to inhibit Cu2+-induced low density lipoprotein oxidation. In this work we explored if the ability of aqueous garlic extract to prevent in vitro Cu2+-induced lipoprotein oxidation in human serum is affected by heating (a) aqueous garlic extracts or (b) garlic cloves. In the first case, aqueous extract of raw garlic and garlic powder were studied. In the second case, aqueous extract of boiled garlic cloves, microwave-treated garlic cloves, and pickled garlic were studied. It was also studied if the above mentioned preparations were able to chelate Cu2+. METHODS: Cu2+-induced lipoprotein oxidation in human serum was followed by the formation of conjugated dienes at 234 nm and 37 degrees C by 240 min in a phosphate buffer 20 mM, pH 7.4. Blood serum and CuSO4 were added to a final concentration of 0.67% and 0.0125 mM, respectively. The lag time and the area under the curve from the oxidation curves were obtained. The Cu2+-chelating properties of garlic extracts were assessed using an approach based upon restoring the activity of xanthine oxidase inhibited in the presence of 0.050 mM Cu2+. The activity of xanthine oxidase was assessed by monitoring the production of superoxide anion at 560 nm and the formation of uric acid at 295 nm. Data were compared by parametric or non-parametric analysis of variance followed by a post hoc test. RESULTS: Extracts from garlic powder and raw garlic inhibited in a dose-dependent way Cu2+-induced lipoprotein oxidation. The heating of garlic extracts or garlic cloves was unable to alter significantly the increase in lag time and the decrease in the area under the curve observed with the unheated garlic extracts or raw garlic. In addition, it was found that the garlic extracts were unable to chelate Cu2+. CONCLUSIONS: (a) the heating of aqueous extracts of raw garlic or garlic powder or the heating of garlic cloves by boiling, microwave or pickling do not affect garlic's ability to inhibit Cu2+-induced lipoprotein oxidation in human serum, and (b) this ability is not secondary to Cu2+-chelation.

Journal Article↗

PubMed2004

Aversion of European starlings (Sturnus vulgaris) to garlic oil treated granules: garlic oil as an avian repellent. Garlic oil analysis by nuclear magnetic resonance spectroscopy.

European starlings significantly reduced their consumption of a food mixture that was 50% food-grade garlic oil (GO)-impregnated granules, even after overnight food deprivation, as demonstrated by "one-choice" ("no-choice") tests. Food consumption during 3 h following overnight food deprivation was reduced by 61-65% compared to controls. By testing the same subjects with 25, 10, and 1% mixtures of granules in feed, it was shown that commercial GO granules were repellent to birds in lower concentrations, with more than a 50% decrease in feeding for birds presented with a 10% mixture of commercial GO granules in food and a 17% decrease for the 1% treatment. Products containing GO show considerable promise as inexpensive, environmentally benign, nonlethal bird repellents. In comparing various GO preparations used in this work, nuclear magnetic resonance (NMR) spectroscopic methods prove to be particularly useful for rapid quantitation of major and minor components without requiring fractionation or isolation procedures, which could adversely effect the less stable components.

Allyl Compounds↗

PubMedDate not supplied

Garlic hepatotoxicity: safe dose of garlic.

Information on the effect of garlic on the liver and optimal dose of garlic to avoid liver damage is not known. This study was planned to determine the safe dose of garlic. Male wistar rats (110-170g) were fed fresh garlic homogenate (FSH) orally in three different doses (1.0, 2.5 and 5.0 g/kg body weight/day) daily for 28 days. Liver histology, serum transaminases, bilirubin and alkaline phosphatase were estimated at 0, 14, 21 and 28 days in control and experimental animals. 1.0, 2.5 and 5.0 g/kg body weight/day of garlic showed significant (P<0.001) deterioration in liver function tests (LFT's) after 21, 14 and 7 days respectively. A 1.0 g/kg body weight/day dose of garlic was associated with marked histological damage in liver after 21 days. Therefore, three lower doses of garlic (0.1, 0.25 and 0.5 g/kg body weight/day) were given orally to another group of similar rats to determine the safe dose of garlic. LFT's were serially measured and animals were sacrificed on the 29th day of experiment. All three lower doses showed significant deterioration in the LFT's values of animals after 28 days of feeding the freshly prepared garlic homogenate. Both doses of garlic i.e. 0.1 and 0.25 g/kg body weight/day were associated with normal histology of liver, but 0.5 g/kg body weight/day dose of garlic showed morphological changes in the liver of one animal. Therefore, the present study suggests that garlic with high dose has the potential ability to induce liver damage and low doses (0.1 or 0.25 g / kg body weight/day) are safe doses of garlic.

Analysis of Variance↗

PubMed1998

Effects of feeding fresh garlic and garlic oil on detoxifying enzymes and micronuclei formation in rats treated with azoxymethane.

The effect of feeding a fresh garlic or garlic oil-supplemented diet was studied in rats for a period of 23 weeks with or without the treatment of a carcinogen azoxymethane (AOM), on the modulation of detoxification enzymes and micronuclei formation. The results showed that feeding fresh garlic or garlic oil-supplemented diets tended to reduce hepatic lipid peroxidation, though not to significant levels. Glutathione content was also not altered. The catalase activity in liver of rats fed a fresh garlic-supplemented diet was reduced compared to that of the control diet; however, the activity was not affected by AOM treatment. Ingestion of garlic caused a 40 percent increase in the hepatic glutathione peroxidase activity, whereas carcinogen treatment reduced it. The activity of hepatic glutathione-S-transferase was unaffected by the feeding regimen, while it was lowered in the garlic oil diet group treated with AOM. The gamma glutamyl transpeptidase activity was elevated more than sevenfold, in the kidney of rats treated with AOM, while it was reduced almost to half when the AOM-treated rats were fed fresh garlic or garlic oil. Micronuclei formation was increased fourfold, in rats exposed to AOM whereas the increase was reduced to half when AOM-injected groups had either fresh garlic or garlic oil in their diet. From these studies, it is concluded that long-term feeding of garlic, fresh or oil, reduced the toxic effect of AOM in rats.

Allyl Compounds↗

PubMed1990

Inhibition of DMBA-induced mouse skin tumorigenesis by garlic oil and inhibition of two tumor-promotion stages by garlic and onion oils.

A single 2-mg dose of garlic oil applied 30 minutes before a single carcinogenic dose of 7,12-dimethylbenz[a]-anthracene (DMBA) inhibited papilloma production in Sencar mice. The three groups were controls (Group 1), garlic oil applied 30 minutes before DMBA (Group 2), and garlic oil applied 30 minutes after DMBA (Group 3). The percents of mice with papillomas at 20 weeks were 94, 72, and 79, respectively. The decreases in Groups 2 and 3 were significant. The number of papillomas per mouse was 4.2 +/- 0.5 (Group 1), 2.3 +/- 0.8 (Group 2), and 3.4 +/- 0.6 (Group 3). The decrease in Group 2 was significant. A single 5-mg dose of garlic oil maximally inhibited DMBA-induced epidermal DNA synthesis by 86% when applied two hours before the carcinogen. Two-stage promotion in DMBA-initiated Sencar mice was achieved by twice-weekly applications of 8.5 nmol of 12-O-tetradecanoylphorbol-13-acetate (TPA) for 2 weeks followed by twice-weekly applications of 8.5 nmol of mezerein for 18 weeks. The oils were applied 30 minutes after each promotion by TPA or mezerein. Single doses of 1 mg onion or garlic oil inhibited the first and second stages of promotion. The groups used were control (Group 1), garlic oil applied after stage 1 (Group 2), onion oil applied after stage 1 (Group 3), propenyl sulfide applied after stage 1 (Group 4), garlic oil applied after stage 2 (Group 5), onion oil applied after stage 2 (Group 6), and propenyl sulfide applied after stage 2 (Group 7). The percent of mice with papillomas was significantly decreased by all agents in Groups 2-7. The data are 81, 83, 91, 68, 96, and 86, respectively. The number of papillomas per mouse was significantly reduced by onion and garlic oils but not by propenyl sulfide. The data are 9.4 +/- 0.8, 6.3 +/- 0.7, 7.4 +/- 0.5, 9.2 +/- 1.2, 3.7 +/- 0.9, 6.2 +/- 0.6, and 9.1 +/- 1.4 for Groups 1-7, respectively. Onion and garlic oils inhibited the TPA-stimulated DNA synthesis when given as single doses of 5 mg one hour before TPA. The inhibition by garlic oil was most effective when given one hour before TPA but was evident when given from two hours before to two hours after TPA. These results, and those of others (AS Sadhana, Cancer Lett, 40, 193-197, 1988), who obtained inhibition of initiation, indicate that onion and garlic oils inhibit all stages of mouse skin tumorigenesis.(ABSTRACT TRUNCATED AT 400 WORDS)

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1995

Mechanism by which garlic (Allium sativum) inhibits cyclooxygenase activity. Effect of raw versus boiled garlic extract on the synthesis of prostanoids.

We have studied the effect of aqueous extract of raw garlic and boiled garlic on cyclooxygenase activity in rabbit tissues. Raw garlic inhibited cyclooxygenase activity non-competitively and irreversibly. A dose-dependent inhibition of cyclooxygenase activity was observed in tissues treated with raw garlic. The garlic concentrations required for 50% inhibition of platelets, lung and vascular aortic cyclooxygenase activities of rabbits were 0.35, 1.10 and 0.90 mg, respectively. Cyclooxygenase activity of rabbit platelets was more sensitive to inhibition by raw garlic than the enzyme from blood vessels or lungs. Boiled garlic was found to have little effect on cyclooxygenase activity as compared to raw garlic in these tissues. This may be because the active component of raw garlic is destroyed upon heating. These results indicate that garlic may be beneficial in the prevention of thrombosis if ingested raw rather in a cooked form.

Animals↗

PubMed2001

Pharmacologic activities of aged garlic extract in comparison with other garlic preparations.

We investigated the pharmacologic activities of four garlic preparations, raw garlic juice (RGJ), heated garlic juice (HGJ), dehydrated garlic powder (DGP) and aged garlic extract (AGE). The study used three animal models, i.e., testicular hypogonadism (hypospermatogensis and impotence) induced by warm water treatment, intoxication of acetaldehyde and growth of inoculated tumor cells. RGJ was found to be effective only in recovery of testicular function. The efficacy of HGJ was observed in three models; however, it did not improve impotence. DGP was effective in recovery of spermatogenesis and stimulated acetaldehyde detoxification. Significant beneficial effects of AGE were found in all three models. Although all four garlic preparations significantly enhanced natural killer (NK) and killer cell activities of the spleen cells of tumor-bearing mice, only AGE and HGJ inhibited the growth of inoculated tumor cells. These results suggest that different types of garlic preparations have different pharmacologic properties, and among the four garlic preparations studied, AGE could be the most useful garlic preparation.

Acetaldehyde↗

PubMed2001

Garlic and garlic-derived compounds inhibit human squalene monooxygenase.

Although extracts of garlic inhibit cholesterol biosynthesis in cultured hepatocytes, the inhibitory components of garlic and the site or sites of inhibition in the cholesterol biosynthetic pathway have not been established. To elucidate potential mechanisms of inhibition, we examined the effect of fresh garlic extract and 16 water- or lipid-soluble compounds derived from garlic on purified recombinant human squalene monooxygenase. Squalene monooxygenase catalyzes the second and likely rate-limiting step in the downstream pathway for cholesterol biosynthesis. A 50% inhibitory concentration (IC(50)) of squalene epoxidation was achieved with 1 g/L of fresh garlic extract; of the 16 garlic compounds tested, only selenocystine (IC(50) = 65 micromol/L), S-allylcysteine (IC(50) = 110 micromol/L), alliin (IC(50) = 120 micromol/L), diallyl trisulfide (IC(50) = 195 micromol/L), and diallyl disulfide (IC(50) = 400 micromol/L) substantially inhibited the enzyme. Kinetic analysis showed that the inhibition by garlic and by these compounds was slow and irreversible, suggestive of covalent binding to the enzyme; the ability of thiol-containing compounds such as glutathione and 2,3-dimercaptopropanol to prevent and reverse the inhibition indicated that the garlic compounds were reacting with sulfhydryl groups on the protein. Dithiols were better reversal agents than monothiols, further suggesting that these inhibitors bind to the proposed vicinal sulfhydryls present on this enzyme. These results indicate that squalene monooxygenase may be one of the target enzymes through which garlic inhibits cholesterol biosynthesis.

Cysteine↗

PubMed1992

Inhibition of cholesterol synthesis in vitro by extracts and isolated compounds prepared from garlic and wild garlic.

Using a modified liver homogenate model to assay for the inhibition of cholesterol biosynthesis, different garlic and wild garlic extracts as well as pure compounds isolated from them were investigated for their influence on cholesterol synthesis. Chloroform and acetone/chloroform extracts of garlic and wild garlic inhibited cholesterol synthesis 44-52% at a concentration of 166 micrograms/ml, while the 5 individual sulfur-containing compounds ajoene, methylajoene, allicin, 2-vinyl-4H-1,3-dithiin and diallydisulfide inhibited cholesterol synthesis by 37-72% (10(-3) M corresponding to 234, 208, 162, 144, 146 micrograms/ml, respectively). Ajoene, 2-vinyl-4H-1,3-dithiin and allicin show IC50 values of 6.4, 7.2 and 9.4 x 10(-4) M, respectively. The results demonstrate that garlic and wild garlic may reduce serum cholesterol levels primarily by inhibiting cholesterol synthesis if taken in sufficient amount and that this effect arises from a mixture of multiple compounds from the sulfur-containing class of thiosulfinates, ajoenes and dithiines. Wild garlic extracts showed nearly identical efficiency to garlic extracts.

Animals↗

PubMed1983

Allergic contact dermatitis to garlic (Allium sativum L.). Identification of the allergens: the role of mono-, di-, and trisulfides present in garlic. A comparative study in man and animal (guinea-pig).

Garlic (Allium sativum L.) water- and ethanol-soluble extracts were prepared and purified by column chromatography. They were tested on garlic-sensitive patients and showed that the allergenic fraction was well located in a few column chromatography fractions. Guinea-pigs were sensitized with garlic water-soluble extracts and tested (open epicutaneous tests) with several fractions. The presence of diallyldisulfide was detected in the sensitizing chromatographic fractions. Guinea-pigs were successfully sensitized to this product and cross-reacted to garlic; animals sensitized to garlic extracts cross-reacted to diallyldisulfide. Both groups reacted to allicin, an oxidized derivative of diallyldisulfide present in garlic. Garlic-sensitive patients showed positive tests to diallyldisulfide, allylpropyldisulfide, allylmercaptan and allicin.

Allergens↗

PubMed2005

Complete nucleotide sequences of attenuated and severe isolates of Leek yellow stripe virus from garlic in northern Japan: identification of three distinct virus types in garlic and leek world-wide.

We have determined the complete nucleotide sequence of three isolates (two severe and one attenuated) of the potyvirus Leek yellow stripe virus (LYSV), the main causal agent of the garlic mosaic disease that is prevalent in Aomori prefecture, northern Japan. They contained 10,296-10,297 nucleotides and encoded a deduced polyprotein of 3,215 amino acids. Sequence variation among the three isolates was 1.5% at both the nucleotide and amino acid levels. Surprisingly, the sequences of all three isolates were quite different from that of recently described garlic isolate of LYSV from China. Sequence similarities among the 5'-UTR and P1 regions were only 56-57% and 52-53%, respectively, raising the possibility that these isolates may actually be distinct virus species. Phylogenetic analyses using 5'-UTR, P1 protein and coat protein revealed that all LYSV isolates described to date can be divided into three groups; i.e., those from leek, those from garlic in northern Japan, and those from garlic in southern Japan, China, and other parts of the world. The garlic isolates from northern Japan were more closely related to LYSV isolates from leek than to garlic isolates from southern Japan and China, suggesting a different origin for the garlic cultivars now cultivated in northern Japan.

5' Untranslated Regions↗

PubMed1992

Inhibition of whole blood platelet-aggregation by compounds in garlic clove extracts and commercial garlic products.

The inhibitory effects of adenosine and 16 quantitatively determined organosulfur compounds derived from garlic cloves or commercial garlic preparations on collagen stimulated in vitro platelet aggregation in whole blood were determined. An estimation of the anti-aggregatory activity of several brands of the major types of commercial garlic preparations was determined from the activities of the individual compounds present in each sample. In platelet rich plasma (PRP) most of the anti-aggregatory activity of garlic clove homogenates was due to adenosine; however, in whole blood neither adenosine nor the polar fraction had any effect and all of the anti-aggregatory activity was due to allicin and other thiosulfinates. Allicin was equally active in whole blood and PRP. Among brands there was a several-fold variation in content of the organosulfur compounds and activity for all types of garlic products tested. The best garlic powder tablets were equally as active as clove homogenates whereas steam-distilled oils were 35% as active and oil-macerates (due to low content) only 12% as active. A garlic product aged many months in aqueous alcohol had no activity. For steam-distilled oils, most of the activity was due to diallyl trisulfide. For the oil-macerates, most of the activity was due largely to the vinyl dithiins. Ajoene, an exclusive component of the oil-macerates, had highest specific activity of all the compounds tested but, because of its low concentration, had only 13% of the activity of diallyl trisulfide and 3% of the activity of allicin. Compounds which may be active in vivo are discussed.

Adenosine↗

PubMed1992

Mammary cancer prevention by regular garlic and selenium-enriched garlic.

The anticarcinogenic activities of regular (soil-grown) garlic and selenium-enriched garlic (cultivated in the greenhouse) were evaluated using the 7,12-dimethylbenz[a]anthracene-(DMBA) induced mammary tumor model in rats. In Experiment 1, milled regular garlic powder was added to the basal AIN-76A diet at 20 g/kg. The results from different schedules of supplementation suggested that a continuous treatment, which started before DMBA and persisted for the entire duration of the study, was most effective in tumor suppression. In Experiment 2, selected allyl group-containing sulfides that are normal constituents of garlic extract were given by gavage in three single doses immediately before DMBA. Several structurally related compounds were found to be protective during the initiation phase in the mammary cancer model. Although the present study was not designed specifically to elucidate the structure-activity relationship with respect to sulfur chain length or alkyl versus alkenyl substitution, our data showed that diallyl disulfide was more active than diallyl sulfide or allyl methyl sulfide. In Experiment 3, the anticarcinogenic activity of selenium-enriched garlic (containing 150 ppm Se dry weight from growth in a selenium-fertilized medium) was compared with that of regular garlic as well as selenite. Animals given the selenium-enriched garlic (final concentration 3 ppm Se in the diet) developed the fewest mammary tumors. Tissue selenium levels, however, were lower in these animals than in those fed the same amount of selenium from selenite. Our study demonstrated the feasibility of achieving cancer prevention with the use of a selenium-rich food system.(ABSTRACT TRUNCATED AT 250 WORDS)

9,10-Dimethyl-1,2-benzanthracene↗

PubMedDate not supplied

Ultraviolet derivatization of steroidal saponin in garlic and commercial garlic products as p-nitrobenzoate for liquid chromatographic determination.

A method is described for determination of the steroidal saponin, eruboside B, originating in garlic and garlic products as the p-nitrobenzoyl chloride (PNBC) derivative by reversed-phase liquid chromatography (with ultraviolet detection at 260 nm. Proto-eruboside B was extracted from garlic (Allium sativum L.); subjected to solid-phase extraction (SPE) with a C18 cartridge, Florisil column chromatography, and silica gel column chromatography; and then enzymatically converted to eruboside B, which was applied as an external standard. Steroidal saponins in garlic and commercial garlic products were extracted with methanol and purified by SPE cartridges, followed by enzymatic treatment. A frostanol saponin such as proto-eruboside B is enzymatically transformed to a spirostanol saponin, eruboside B. After the derivatization with PNBC, the saponin derivative was chromatographed on a C8 column with a gradient elution of (A) 80% aqueous acetonitrile and (B) 100% acetonitrile. The detection limit of the developed method was 1 microg/g for the samples. The method was applied to the analysis of garlic and garlic health food products available in Japan.

Chromatography, Liquid↗

PubMedDate not supplied

Electrophoretic identification of garlic and garlic products.

We developed a rapid and simple method for identifying garlic and garlic products using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with silver staining. Samples were homogenized with 1% SDS or 6M urea and centrifuged. Supernatant containing garlic proteins was mixed with the same volume of loading buffer containing SDS and mercaptoethanol, heated in boiling water for 2 min, and applied to the wells of a ready-to-use polyacrylamide gradient gel (4-20%). Electrophoresis was performed 20 mA constant current for 2 h. The gel was stained with a silver staining kit and dried. Protein patterns of garlic and garlic products are different from those of other Allium plants such as onion, rakkyo, and caucas. The method was used to analyze samples of spice and garlic clove products. Absence of protein bands in garlic extract products suggests the products may contain less proteins and/or denatured proteins.

Electrophoresis, Polyacrylamide Gel↗

PubMed2005

Aged garlic extract, garlic powder extract, S-allylcysteine, diallyl sulfide and diallyl disulfide do not interfere with the antibiotic activity of gentamicin.

It was shown that aged garlic extract (AGE), garlic powder and the following garlic-derived compounds: S-allylcysteine (SAC), diallyl sulfide (DAS) and diallyl disulfide (DADS), ameliorate gentamicin (GM)-induced nephrotoxicity in rats. However, it was not established if the above mentioned extracts and compounds of garlic could interfere with the antibiotic action of GM. To address this point, AGE, garlic powder extract (GPE), SAC, DAS and DADS were assessed for their ability to interfere with the in vitro antibiotic activity of GM in Escherichia coli cultures. It was found that the above mentioned extracts and compounds of garlic were unable to decrease the antibiotic capacity of GM and even SAC, DAS and DADS alone inhibited the growth of Escherichia coli and enhanced the antibiotic effect of GM. Our data show that SAC, DAS and DADS are antibacterial compounds against E. coli and suggest that AGE, GPE, SAC, DAS and[sol ]or DADS may be administered along with GM-treatment to ameliorate GM-induced nephrotoxicity without interfering with its antibiotic activity.

Allyl Compounds↗