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[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

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

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

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

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

Toxic effects of garlic extract and garlic oil in rats.

Significant rise in urea and D-aspartate aminotransferase and inhibition of alkaline phosphatase in serum were observed in rats fed garlic extract (2 ml/100 g body wt, intragastrically) for 10 days. The liver showed histological changes. Garlic oil feeding (10 mg/100 g body wt, intragastrically) after 24 hr fasting was found lethal. The cause of death appears to be acute pulmonary oedema. On histological examination, all the organs of the dead rats revealed severe congestion. However, similar feeding of garlic oil was well tolerated by rats in the fed state. Also, 24 hr fasted rats could tolerate this dose of garlic oil, provided they were previously adapted to garlic oil feeding.

Alkaline Phosphatase

[Garlic as phytogenic antilipemic agent. Recent studies with a standardized dry garlic powder substance].

Garlic (Allium sativum L.) is a commonplace drug. It is now available in the form of dragees made of garlic powder, standardized to 1.3% alliin. The lipid-lowering potential of such preparations has not been reviewed yet. In 7 out of 8 studies, including over 500 patients, a daily dose of 0.6 g to 0.9 g garlic powder reduced plasma cholesterol and triglyceride levels by 5 to 20 percent. The metabolic mechanisms of these reductions are not known.

Garlic

Identification and HPLC quantitation of the sulfides and dialk(en)yl thiosulfinates in commercial garlic products.

The content of dialk(en)yl thiosulfinates, including allicin, and their degradation products has been determined by high performance liquid chromatography (HPLC), using the respective determined extinction coefficients, for a number of commercially available garlic products. Quantitation has been achieved for the thiosulfinates; diallyl, methyl allyl, and diethyl mono-, di-, tri-, tetra-, penta-, and hexasulfides; the vinyldithiins; and (E)- and (Z)-ajoene. The thiosulfinates were found to be released only from garlic cloves and garlic powder products. The vinyldithiins and ajoenes were found only in products containing garlic macerated in vegetable oil. The diallyl, methyl allyl, and dimethyl sulfide series were the exclusive constituents found in products containing the oil of steam-distilled garlic. Typical steam-distilled garlic oil products contained about the same amount of total sulfur compounds as total thiosulfinates released from freshly homogenized garlic cloves; however, oil-macerated products contained only 20% of that amount, while garlic powder products varied from 0 to 100%. Products containing garlic powder suspended in a a gel or garlic aged in aqueous alcohol did not contain detectable amounts of these non-ionic sulfur compounds. A comparison of several brands of each type of garlic product revealed a large range in content (4-fold for oil-macerates and 33-fold for steam-distilled garlic oils), indicating the importance of analysis before garlic products are used for clinical investigations or commercial distribution.

Alkenes

Evidence for the mechanism by which garlic inhibits platelet aggregation.

Aqueous extract of garlic inhibited aggregation induced by ADP, collagen, arachidonate (AA), epinephrine and calcium ionophore A23187 in a dose-dependent manner. In an attempt to clarify the mechanism of inhibition of aggregation, metabolism of arachidonic acid in platelets was examined in the presence of garlic extract. It was found that: garlic reduced the formation of thromboxane from exogenous AA; garlic inhibited the phospholipase activity; garlic inhibited the formation of thromboxane and lipoxygenase products formed in platelets prelabelled with AA; and garlic inhibited the incorporation of arachidonate into platelet phospholipids. These effects may explain, in part, inhibition of platelet aggregation. Further, since garlic was also effective in inhibiting aggregation induced by calcium ionophore A23187 it may be suggested that the antiaggregation effect may be related to intraplatelet mobilization of calcium. Inhibition of epinephrine-induced aggregation by garlic extract may suggest that it may be inhibiting uptake of calcium into platelets thereby lowering cytosolic calcium concentrations. Thus garlic appears to be in possession of components which might exert their effects at various stages involved in the process of platelet aggregation.

Arachidonic Acid

In vitro virucidal effects of Allium sativum (garlic) extract and compounds.

Garlic (Allium sativum) has been shown to have antiviral activity, but the compounds responsible have not been identified. Using direct pre-infection incubation assays, we determined the in vitro virucidal effects of fresh garlic extract, its polar fraction, and the following garlic associated compounds: diallyl thiosulfinate (allicin), allyl methyl thiosulfinate, methyl allyl thiosulfinate, ajoene, alliin, deoxyalliin, diallyl disulfide, and diallyl trisulfide. Activity was determined against selected viruses including, herpes simplex virus type 1, herpes simplex virus type 2, parainfluenza virus type 3, vaccinia virus, vesicular stomatitis virus, and human rhinovirus type 2. The order for virucidal activity generally was: ajoene > allicin > allyl methyl thiosulfinate > methyl allyl thiosulfinate. Ajoene was found in oil-macerates of garlic but not in fresh garlic extracts. No activity was found for the garlic polar fraction, alliin, deoxyalliin, diallyl disulfide, or diallyl trisulfide. Fresh garlic extract, in which thiosulfinates appeared to be the active components, was virucidal to each virus tested. The predominant thiosulfinate in fresh garlic extract was allicin. Lack of reduction in yields of infectious virus indicated undetectable levels of intracellular antiviral activity for either allicin or fresh garlic extract. Furthermore, concentrations that were virucidal were also toxic to HeLa and Vero cells. Virucidal assay results were not influenced by cytotoxicity since the compounds were diluted below toxic levels prior to assaying for infectious virus. These results indicate that virucidal activity and cytotoxicity may have depended upon the viral envelope and cell membrane, respectively. However, activity against non-enveloped virus may have been due to inhibition of viral adsorption or penetration.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals

Contact dermatitis due to topical treatment with garlic in Hong Kong.

Contact dermatitis due to garlic is usually due to handling of garlic for cooking. Among the Chinese, garlic is also used as a form of topical medicament. 8 patients developed contact dermatitis after rubbing the cut end of a fresh garlic bulb onto the skin to treat fungal and other infections at the groin, neck, lower limb, hand or face. The distribution and morphology of the lesions were different from the classical form as described in the literature. Repeated open application tests with fresh garlic were all positive and patch tests with garlic extract were all negative. 5 controls tested by repeated open application with fresh garlic juice were also positive and patch tests in 10 controls with garlic extract were also negative. The results confirmed that the contact dermatitis was due to irritation. The patients were treated successfully with topical fluorinated steroid. For prevention, the practice of direct application of fresh garlic onto the skin for treating infections should be discouraged.

Administration, Cutaneous

Inhibition of 7,12-dimethylbenz[a]anthracene-induced mammary tumors and DNA adducts by garlic powder.

The present studies determined the influence of dietary supplements of garlic powder (0, 1, 2 or 4%) on 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary tumors and on the in vivo occurrence of mammary DMBA-DNA adducts in rats. Diets were offered 2 weeks before and 2 weeks following DMBA treatment (25 mg/kg body wt). An additional group was fed the 2% garlic powder diet throughout the 20 week study. Although food intake and weight gain were not influenced, dietary garlic powder supplementation did significantly delay the onset of first tumors (P < 0.01) and did reduce the final mammary tumor incidence (P < 0.01). Consumption of garlic powder also significantly depressed the in vivo binding of DMBA to mammary cell DNA. Binding of both anti- and syn-dihydrodiol epoxides to DNA was depressed in rats fed supplemental garlic powder. The activity of glutathione S-transferase (GST) in mammary and liver tissue from rats fed 2% dietary garlic powder was higher than observed in tissues from rats fed the basal diet. No further increase in GST activity occurred when the dietary garlic content was increased from 2 to 4%. Final mammary tumor incidence was found to correlate positively with total DMBA-DNA binding and the quantities of individual DMBA-DNA adducts. The present studies demonstrate that garlic powder is effective in inhibiting DMBA-induced mammary tumors, possibly by reducing DMBA-DNA binding.

9,10-Dimethyl-1,2-benzanthracene

[The characteristics of the antibacterial activity of garlic (author's transl)].

It has been found by Cavallito (1944) that garlic (Allium sativum L.) has a strong antibacterial activity and the active principle of garlic is named "Allicin" and it has been confirmed by Stoll et al. (1948) that the allicin is derived from the alliin-alliinase system. Nevertheless, one worker in Japan (1951) stands on another view point which the effective component of garlic is some sugar-proteim because he could not find alliin in the native garlic. We intend to make sure that the alliin is contained in the native garlic, by using Hitachi Amino acid Analyser with Fraction Collecter and compared with garlic of other countrys' production. As the result of examinations, we found that the good amounts of alliin is contained in the native garlic also. The contents of alliin in garlic is varied by the species, the cultivation mode, and the district of production. The form of alliin in the tissue is a free style, and thereupon it is easy to change its chemical conformation by the method of extraction. We compared the relative capacity between 1 allicin unit by Klein (1954) and 1 cup unit by Schmidt et al. (1947). Furthermore we tested the antibiotic spectrum, using the pure crystallized alliin with the sufficient amount of raw alliinase gained by the isoelectric point precipitation and checked upon wide spectrum for Mycobacterium tuberculosis, Gram-positive and negative bacteria, and some fungi.

Allyl Compounds

Effect of essential oil of onion and garlic on experimental atherosclerosis in rabbits.

The effects of the essential oils of onion (extracted from 2 g of raw onion per kg body weight) and garlic (extracted from 1 g of raw garlic per kg body weight) have been observed on experimental atherosclerosis produced by cholesterol feeding (0.5 g/kg) in rabbits. The rise in serum cholesterol and serum triglycerides was significantly reduced by both onion and garlic during the 4-month period of study. Cholesterol feeding significantly increased beta-(P less than 0.01) and pre-beta (P less than 0.001) lipoproteins while decreasing the alpha-fraction (P less than 0.001). Onion and garlic both prevented these changes. The beta/alpha ratio, which was initially 1.6 : 1, rose to 4.5 : 1 and 5.7 : 1 at the end of 2 months and 4 months of cholesterol feeding. However, this ratio did not increase significantly, both at the 2-month and 4-month period, when onion and garlic were added. Fibrinolytic activity significantly increased with onion (P less than 0.001) and garlic (P less than 0.001) while feeding only cholesterol actually decreased it (P less than 0.001). Onion and garlic reducec aortic atheroma by about half. It is suggested that the essential oils of onion and garlic protect against experimental atherosclerosis by preventing the fall in the alpha lipoprotein fraction and by enhancing fibrinolytic activity, as well as by lowering the serum cholesterol and triglyceride levels.

Animals

The inhibitory effect of oral administration of garlic on experimental carcinogenesis in hamster buccal pouches by DMBA painting.

The inhibitory effect of oral administration of garlic on experimental carcinogenesis in buccal pouches induced by painting 9,10-dimethyl-1,2-benz(a)anthracene (DMBA) was studied on 40 golden Syrian hamsters. The animals were grouped at random into four experimental groups (oral administration of garlic, NTP, BP or mineral oil followed by DMBA painting on buccal pouches), three chemical control groups (oral administration of garlic, NTP or BP without DMBA painting) and a DMBA control group (only painted DMBA on buccal pouches). Starting from the fourth week after DMBA painting, the pouch mucosae were examined biweekly for its tumor formation and blood vessel architecture. Animals were sacrificed 25 weeks after DMBA application. Tumors and pouch mucosae were dissected to examine tumor nature and biochemical reactions of DNA synthesis and GGTase activity. The inhibitory efficacy of garlic, BP and NTP were evaluated according to the results of these examinations. Garlic was found to have a higher inhibitory efficacy than BP and NTP through the probable mechanism of competitive binding with nuclear DNA and diminishing the opportunity of DMBA to initiate carcinogenesis. Other factors related to cancer inhibition included insufficient local blood flow, low GGTase activity and lesser DNA synthesis. The inhibitory effect of fractions of garlic on experimental carcinogenesis should be a reasonable and necessary continuation in future studies of the series of cancer prevention by garlic.

9,10-Dimethyl-1,2-benzanthracene

Studies on the antimutagenic activities of garlic extract.

Experiments with Salmonella tester strains indicated that aqueous garlic extract possesses antimutagenic properties toward ionizing radiation, peroxides, adriamycin, and N-methyl-N'-nitro-nitrosoguanidine. The assumption that radical scavenging garlic constituents, i.e., molecules with sulfur moieties, might be responsible for the inhibitory effect of aqueous extract toward mutagenesis induced by radiation and radiomimetic compounds was confirmed by the results of subsequent experiments; 1) garlic extract attenuated the lethal effects of gamma-rays on repair-deficient E. coli strains; 2) the garlic constituent allicin (thio-2-propene-1-sulfinic acid S-allyl ester) is partly responsible for the reduced radiation-induced mutagenesis in Salmonella typhimurium TA 102. No such inhibitory effects were detected with alliin (S-allyl-L-cysteine sulfoxide) or cysteine; 3) aqueous garlic extract inhibited hydrogen-peroxide-induced lipid peroxidation. Results obtained in preliminary experiments with Chinese hamster ovary cells suggest that the antimutagenic properties of garlic extract are not restricted to procaryotic cells.

Animals

Effect of garlic on human platelet aggregation in vitro.

In 6 healthy adults the effect of essential oil of garlic on platelet aggregation was studied in vitro with an aggreganometer. The blood was collected in a siliconized centrifuge tube containing sodium citrate. The aggregating agents used were ADP, epinephrine and collagen. In each subject aggregation was studied 3 times: (i) initial fasting control; (ii) immediately after (i) but with essential oil of garlic drawn into the syringe together with the sodium citrate; (iii) 5 days after feeding 0.5 mg of essential oil of garlic daily. Addition of essential oil of garlic inhibited in-vitro platelet aggregation induced by ADP, epinephrine or collagen; the effect was dose-related. Oral administration of garlic also decreased platelet aggregation. Thus, garlic seems to inhibit some aspects of thrombus formation.

Adenosine Diphosphate