Showing papers on "Allicin published in 1999"

Antibacterial effect of garlic and omeprazole on Helicobacter pylori

Abstract: The antibacterial effect of a home-made raw garlic extract and commercial garlic tablets alone and in combination with antibiotics or omeprazole was determined against clinical isolates of Helicobacter pylori. MIC values of raw garlic extract and three types of commercial garlic tablets ranged from 10,000 to 17,500 mg/L. When MIC values of the commercial tablets were based on the allicin content, no differences between the three types were observed. The combination of garlic and omeprazole, studied with killing curves, showed a synergic effect which was concentration dependent. Further clinical evaluation of garlic in combination with the conventional agents for H. pylori treatment seems warranted.

Allicin-induced decrease in formation of fatty streaks (atherosclerosis) in mice fed a cholesterol-rich diet.

Abstract: BACKGROUND Garlic (Allium sativum) has been considered to exhibit therapeutic features for many years. The effects of garlic on levels of serum lipids and on atherosclerosis have been investigated extensively. We have previously demonstrated that allicin, an active component of garlic, exerts a beneficial effect on lipid profile in hyperlipidemic rabbits. OBJECTIVE To investigate the effects of allicin on formation of fatty streaks (atherosclerosis) and lipid profile in mice. METHODS Allicin was extracted from garlic and kept in a buffer citrate solution at 4 degrees C. Sixty C57BL/6 mice were fed Paigen diet (17% fat, 1.25% cholesterol) for 15 weeks. Thirty randomly selected animals were administered allicin solution (9 mg/kg) and 30 were administered placebo. Blood lipid profile was evaluated five times during the study. At the end of the 15-week period, the animals were killed and the aortic sinus was evaluated for formation of fatty streaks (atherosclerosis). RESULTS We observed no statistically significant differences between blood lipid profiles of groups. Microscopic evaluation of aortic sinus formation of fatty streaks (atherosclerosis), however, showed that values for mice in the allicin-treated group were significantly lower: areas of formation of fatty streaks (atherosclerosis) were 13,440 +/- 3310 and 23,410 +/- 3723 micron 2, respectively, for allicin-treated and control mice (means +/- SEM; P = 0.023). CONCLUSIONS These results indicate that allicin reduces formation of fatty streaks (atherosclerosis) in hyperlipidemic mice. These changes do not seem to occur through an alteration in blood lipid profile.

Metabolism of Diallyl Disulfide by Human Liver Microsomal Cytochromes P-450 and Flavin-Containing Monooxygenases

Abstract: The metabolism of diallyl disulfide (DADS), a garlic sulfur compound, was investigated in human liver microsomes. Diallyl thiosulfinate (allicin) was the only metabolite observed and its formation followed Michaelis-Menten kinetics with a Km = 0.61 +/- 0.2 mM and a Vmax = 18.5 +/- 4.2 nmol/min/mg protein, respectively (mean +/- S.E. M., n = 4). Both flavin-containing monooxygenase and the cytochrome P-450 monooxygenases (CYP) were involved in DADS oxidation, but the contribution of CYP was predominant. The cytochrome P-450 isoforms involved in this metabolism were investigated using selective chemical inhibitors, microsomes from cells expressing recombinant CYP isoenzymes, and studying the correlation of the rate of DADS oxidation with specific monooxygenase activities of human liver microsomes. Diethyldithiocarbamate and tranylcypromine inhibited allicin formation, whereas other specific inhibitors had low or no effect. Most of the different human microsomes from cells expressing CYP were able to catalyze this reaction, but CYP2E1 showed the highest affinity with a substantial activity. Furthermore, allicin formation by human liver microsomes was correlated with p-nitrophenol hydroxylase activity, a marker of CYP2E1, and tolbutamide hydroxylase activity, a marker of CYP2C9. Among these approaches only CYP2E1 was identified in each case, which suggested that DADS is preferentially metabolized to allicin by CYP2E1 in human liver. However the minor participation of other CYP forms and flavin-containing monooxygenases is likely.

Quality of herbal remedies from Allium sativum: differences between alliinase from garlic powder and fresh garlic.

Abstract: Alliinase (EC 4.4.1.4) has been isolated from commercially available garlic (Allium sativum L., Alliaceae) powder and was investigated with respect to its use as ingredient of herbal remedies. The enzyme was purified to apparent homogeneity and results were compared with those obtained from a sample of fresh A. sativum var. pekinense. The purification of the enzyme involved a gel filtration step as well as affinity chromatography on concanavalin-A agarose. Vmax using L-(+)-alliin as substrate (252 mumol min-1 mg-1) was at the lower range of data given in the literature (214-390 mumol min-1 mg-1). L-(-)-Alliin was also accepted as substrate (54 mumol min-1 mg-1). Vmax for alliinase from A. sativum var. pekinense was at 332 mumol min-1 mg-1 and 90 mumol min-1 mg-1 for L-(+)- and L-(-)-alliin, respectively. The Km values for alliinase from garlic powder were estimated to be 1.6 mM for L-(+)-alliin and 2.8 mM for L-(-)-alliin. In contrast to literature values, both temperature and pH optima were somewhat higher (36 degrees C and pH 7.0 versus 33 degrees C and pH 6.5, respectively). The enzyme was found to be active in a range from pH 5 to pH 10. Gel electrophoresis gave evidence that the alliinase obtained from garlic powder consisted of two slightly different subunits with molecular weights of 53 and 54 kDa whereas alliinase obtained from fresh garlic consists of two identical subunits. It is assumed that the alliinase gets significantly altered during the drying process of garlic powder but is still capable to convert alliin to allicin.

Antimicrobial Activity of the Thiosulfinates Isolated from Oil-Macerated Garlic Extract

Abstract: Three thiosulfinates were isolated from oil-macerated garlic extract, and their structures were identified as 2-propene-1-sulfinothioic acid S-(Z,E)-1-propenyl ester [AllS(O)SPn-(Z,E)], 2-propenesulfinothioic acid S-methyl ester [AllS(O)SMe], and methanesulfinothioic acid S-(Z,E)-1-propenyl ester [MeS(O)SPn-(Z,E)]. This is the first report of isolating these thiosulfinates from oil-macerated garlic extract. Antimicrobial activities of AllS(O)SPn-(Z,E) and AllS(O)SMe against Gram-positive and negative bacteria and yeasts were compared with 2-propene-1-sulfinothioic acid S-2-propenyl ester [AllS(O)SAll, allicin] which is well-known as the major thiosulfinate in garlic. Antimicrobial activity of AllS(O)SMe and AllS(O)SPn-(Z,E) were comparable and inferior to that of allicin, respectively. This result suggested that the antimicrobial activity of 2-propene sulfinothioic acid S-alk(en)yl esters were affected by alk(en)yl groups. The order for antimicrobial activity was: allyl≥methyl>propenyl.

In vitro inhibition of the growth of Helicobacter pylori by oil-macerated garlic constituents.

Abstract: Helicobacter pylori, a gram-negative curved rod bacterium, is relevant to the disease of gastric and duodenal mucosae, and the H. pylori-infected populations have a high risk of gastric cancer (3). Some epidemiological reports showed that high intake of Allium vegetables including garlic (Allium sativum L.) reduces the risk of gastric cancer (4). Oil maceration is one method for processing garlic, and this type of garlic product is common as health food in Europe. In a previous study, we isolated some antimicrobial compounds from oil-macerated garlic extract (OMGE), and they inhibited gram-positive and -negative bacteria and yeast (6, 8–10). Sivam et al. (7) have demonstrated the antibacterial effect of crude garlic extracts against H. pylori; however, the antibacterial activity of each garlic constituent against H. pylori has not been reported. Therefore, we attempted to examine the antibacterial effect of OMGE constituents against H. pylori. An OMGE was prepared according to the method of Yoshida et al. (8, 9). H. pylori strains used are indicated in Table ​Table1.1. To analyze the anti-H. pylori activity of OMGE, each OMGE constituent was purified. E- and Z-ajoenes (E- and Z-4,5,9-trithiadodeca-1,6,11-triene-9-oxide) (2) and two vinyldithiins (2-vinyl-4H-1,3-dithiin and 3-vinyl-4H-1,2-dithiin) (1) were purified according to the methods described by Block et al. (1, 2), and Z-10-devinylajoene (Z-10-DA; Z-4,5,9-trithiadeca-1,6-diene-9-oxide) (8), iso-E-10-devinylajoene (iso-E-10-DA; E-4,5,9-trithiadeca-1,7-diene-9-oxide) (9), and thiosulfinates (10) were purified according to the methods described by Yoshida et al. (8–10). Allicin was prepared by the method of Mayeux et al. (5). The MICs of all constituents and several antibiotics were determined as described elsewhere (6, 8), i.e., each preculture containing 103 cells was plated onto solid medium consisting of brain heart infusion agar containing 0.25% yeast extract and 10% fetal bovine serum (Biowhittaker, Wakersville, Md.) with or without various concentrations of the constituents or antibiotics and cultivated under microaerophilic conditions for 5 days. The surviving cells were detected on the plate as colonies, and the MIC was defined as the concentration leaving no survivors. Results are shown in Table ​Table1.1. The differences in MICs between the three H. pylori strains were not significant. Ajoenes (Z- and E-ajoene, Z-10-DA, and iso-E-10-DA), which are the main constituents of OMGE, showed inhibition of the H. pylori growth at 10 to 25 μg/ml. Two different vinyldithiins did not inhibit H. pylori growth at concentrations of <100 μg/ml. Among the thiosulfinates, 2-propene-1-sulfinothioic acid S-methyl ester [AllS(O)SMe] inhibited H. pylori growth at 20 to 25 μg/ml. However, 2-propene-1-sulfinothioic acid S-(E,Z)-1-propenyl ester [AllS(O)SPn-(E,Z)] did not inhibit H. pylori growth at concentrations of <100 μg/ml. Allicin, which is not an OMGE constituent, inhibited H. pylori growth at 20 to 30 μg/ml. AllS(O)SPn-(E,Z), allicin, and AllS(O)SMe differ with respect to the S-1-alk(en)yl group. In this part of the structure, methyl and allyl groups were effective but the propenyl group was ineffective for H. pylori inhibition. TABLE 1 MICs of OMGE constituents and antibiotics for H. pylori From these results, it is obvious that the OMGE contained many anti-H. pylori compounds, and their MICs were 10 to 25 μg/ml. These results suggest that OMGE should be tested for efficacy against H. pylori in vivo.

Effect of garlic on vancomycin-resistant enterococci.

Abstract: There is great concern about the worldwide increase in antibiotic resistance, especially of gram-positive bacteria such as vancomycin-resistant enterococci (VRE). As garlic, especially the thiosulfinate allicin, has been known for its antibacterial activity against facultative aerobic bacteria (2), the antibacterial effect of garlic alone and in combination with vancomycin on VRE was studied. Fourteen clinical isolates of VRE (MIC > 8 μg/ml), one vancomycin-sensitive isolate, and three reference strains (BM4147, V583, and ATCC 29212) were studied. Fresh Spanish garlic was peeled, mashed, filtered, and freeze-dried. Allicin was kindly supplied by L. D. Lawson. The interaction between garlic, allicin, and vancomycin, measured as fractional inhibitory concentration (FIC), was determined by the checkerboard titration method (3). Dilutions of garlic ranged from 63 to 8,000 μg/ml, dilutions of allicin ranged from 1 to 64 μg/ml, and dilutions of vancomycin ranged from 0.06 to 128 μg/ml. The bactericidal effects of the combination of garlic and vancomycin with the lowest FICs on VRE strains BM4147 and V583 were determined with killing curves (3). One hundred thousand CFU of each microorganism per ml was inoculated in separate tubes with garlic (1,000 to 2,000 μg/ml), vancomycin (8 μg/ml), and the combination and incubated at 37°C. Samples were taken for a bacterial count at 0, 2, 4, 8, and 24 h. In addition, the influence of cysteine and β-mercaptoethanol on the combination of vancomycin and garlic was studied. A growth control was always included. All experiments were performed twice. The MIC of vancomycin for VRE decreased from 32 to 256 μg/ml without garlic to 0.5 to 16 μg/ml in the presence of garlic (1,000 to 2,000 μg/ml) or allicin (8 to 16 μg/ml). The FICs (<0.5) indicated a synergistic effect between the compounds tested on all VRE except KH32V and the vancomycin-sensitive ATCC 29212 and F346 (Table ​(Table1).1). Killing curves showed a bacteriostatic effect of the combination of garlic and vancomycin: bacterial counts remained 105 CFU/ml for 24 h. TABLE 1 Effects of garlic, allicin, and vancomycin on VRE In the presence of garlic, vancomycin, and cysteine (0.1 or 0.01%) or β-mercaptoethanol (0.01 or 0.001%), bacterial growth increased from 105 CFU/ml at 0 h to 108 CFU/ml at 24 h. The data show an antibacterial bacteriostatic effect of garlic and allicin on VRE. In addition, inhibitory synergism between these compounds was observed. The MICs of garlic corresponded to only one clove of garlic in an empty stomach. Findings with allicin (MIC and FIC) confirmed a major contribution of this thiosulfinate to the antibacterial effect of garlic. SH groups in allicin can theoretically form disulfide bonds with SH groups in bacterial enzymes or nutrients (4, 5). By binding to enzymes located on transposon Tn1546 encoding vancomycin resistance (1), garlic (i.e., allicin) may inhibit their activity and thereby enhance the susceptibility of VRE to vancomycin. The inhibition of the synergistic effect by cysteine (which interacts with allicin via the sulfhydryl group) and β-mercaptoethanol (which breaks disulfide bonds) suggests a role of the formation of disulfide bonds. Further research regarding the application and mechanisms of the synergistic effects may be warranted.

Stabilization and pharmaceutical use of alliinase.

Abstract: In recent years, numerous clinical trials were undertaken in order to elucidate the active principle of garlic (Allium sativum L., Alliaceae). The most prominent effect of garlic preparations is a contribution to the prevention of stroke and arteriosclerosis. Allicin[(2-propenyl)-2-propenethiosulfinate] and other sulfur containing compounds were suggested as active compounds. The extremely unstable allicin itself is liberated from the more stable alliin [S-(+)-2-propenyl-L-cysteine sulfoxide] by the enzyme alliinase (EC 4.4.1.4) if fresh garlic is crunched or garlic powder is moistened. Therefore, an active enzyme is required in alliin containing remedies like those prepared from garlic powder. In order to investigate enzyme stability, alliinase was isolated from garlic powder. The partially purified enzyme could be stabilized over several months by addition of sodium chloride, sucrose, and pyridoxal-5'-phosphate. Alliinase may also be freeze-dried. This allows combinations of synthetic alliin and purified alliinase as components of an acid resistant tablet or capsule. In the intestine, the pro-drug alliin would be enzymatically converted to allicin. In clinical trials, highly dosed preparations of this kind should yield a precise information about the physiological effects of allicin. In addition, alliin-homologues substances which bear a modified alkyl side chain and do not occur in nature may be tested.

Garlic supplementation and lipid oxidation in chicken breast and thigh meat after cooking and storage

Abstract: The effects of garlic supplementation on lipid oxidation of chicken muscles after cooking and after refrigerated storage were studied. Breast and thigh meat from 8 weeks broiler chicken fed diets supplemented with 10, 25 and 50 g garlic kg -1 feed compared with 200 mg α-tocopherol acetate were cooked and stored at 4 °C for 5 days. Sulfur compounds were analyzed by High Performance Liquid Chromatography in garlic homogenate and allicin was determined. Lipid oxidation was followed after cooking and after storage of breast and thigh meat by determination of the fatty acid composition of triacylglycerol and phospholipid fractions and by measuring peroxide values, thiobarbituric acid reactive substances, cholesterol oxidation products and sensory evaluation. Thigh meat contained two times the total lipids and more unsaturated fatty acids than breast meat and showed higher levels of lipid oxidation products than breast meat. Lipid oxidation products increased in both control breast and thigh meat after storage at 4 °C for 5 days. Allicin content was 0.48 % in fresh garlic homogenate with 50 % sunflower oil supplemented to the chicken feed. The formation and generation of primary and secondary oxidation products were reduced by increasing levels of garlic supplementation. Supplementation with 50 g garlic kg -1 feed was adequate to inhibit lipid oxidation in both cooked and stored breast and thigh meat similar as or even better than 200 mg α-tocopherol acetate. This amount of garlic supplementation was able to protect unsaturated fatty acids of both breast and thigh meat from oxidation and decreased peroxide value and thiobirbaturic acid reactive substances to a low level as well as prevented formation of cholesterol oxidation products in cooked meat. In general, garlic supplementation improved the oxidative stability of lipids extracted from cooked and stored chicken breast and thigh meat.

Sperm enhancing food and its production

Abstract: PROBLEM TO BE SOLVED: To obtain a sperm enhancing food having effects on extreme increase in the number of spermatozoa, activity of sperm movement and reduction in the number of abnormal spermatozoa by using natural Allium sativum L. (subspecies) not containing a volatile sulfur-containing compound such as alliin allicin, etc., among garlic. SOLUTION: This sperm enhancing food is obtained by extracting natural Allium sativum L. (subspecies) not containing or containing a small amount of a volatile sulfur-containing compound such as alliin, allicin, etc., among garlic with a water-soluble organic solvent such as methanol, ethanol, etc., freeze-drying the edible part of garlic as it is. Preferably the sperm enhancing food is formulated with an excipient such as a vitamin agent, a mineral, etc.

Study on apoptosis of human acute T-lymphocyte leukemia cell line induced by allicin

Abstract: Objective: To explore the law and role of apoptosis inducing effect of allicin on human acute T-lymphocyte leukemia cell line (6T-CEM).Methods: Terminal deoxylnucleotide transferase directed X-UTP nick and end labeling (TUNEL) assay, DNA gel electrophoresis, light microscopy and revers transcription-polymerase chair reaction (RT-PCR) were used to observe apoptosis of cells.Results: Allicin showed significant inducing effect on apoptosis of 6T-CEM cell when the concentration was 0.1 μg/ml, reaching its peak effect when the concentration was 50 μg/ml, with the apoptosis rate as 36.4%. Allicin (15 μg/ml) acted on 6T-CEM for 2 h and induced obvious cell apoptosis, the highest effect reached after 24 h of action, with the apoptosis rate as 56.9%. Actidione or actinomycin D could induce apoptosis of 6T-CEM, the allicin could not enhance their apoptosis inducing effect. Allicin could cause significant reduction of bcl-2 and bax gene expression of 6T-CEM, especially the bcl-2.Conclusion: Allicin could induce cell apoptosis of 6T-CEM with significant time and dose effect. Mechanism of the effect is through inhibiting the bcl-2 gene expression to reduce bcl-2/bax ratio.