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PubMed1991

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↗
PubMed2004

Prevention of garlic-induced hemolytic anemia using some tropical green leafy vegetables.

Garlic (Allium sativum) is popularly consumed in Nigeria because of its health benefit in treatment and management of several disease conditions. However, excessive intake of garlic may cause hemolytic anemia. This project sought to investigate the ability of some commonly consumed tropical green leafy vegetables-namely, Amaranthus cruentus, Baselia alba, Solanum macrocarpon, Ocimum gratissimum, and Corchorus olitorius-to prevent garlic-induced hemolytic anemia. Wister strain albino rats were fed diet containing 4% garlic with or without 40% vegetable supplement. The study showed that there was a decrease in daily feed intake (6.7-7.2 g/rat/day), daily weight gain (0.7-1.5 g/rat/day), and digestibility (70.4-91.5%) of rats fed diet with garlic (4%), with or without vegetable (40%) supplement, compared with those rats fed the basal diet without garlic (4%) and vegetable (40%) supplement (digestibility, 95.5%; daily feed intake, 7.5 g/rat/day; and daily weight gain, 2.0 g/rat/day). However, there was a significant decrease (P < .05) in the packed cell volume (PCV) (31.0%), hemoglobin (Hb) (10.2 g/dL), red blood cells (RBCs) (4.3 x 10(6)/microL), and white blood cells (WBCs) (3.5 x 10(6)/microL) of rats fed diet with garlic (4%) but without vegetable compared with those rats fed diet without garlic (4%) and vegetable (40%) supplements (PCV, 38.2%; Hb, 13.0 g/dL; RBCs, 5.5 x 10(6)/microL; and WBCs, 4.0 x 10(6)/microL). Conversely, there was a significant increase in the PCV (33.5-35.6%), Hb (12.0-12.5 g/dL), and RBCs (4.9-5.3 x 10(6)/microL) of rats fed diet with garlic (4%) and vegetable (40%) supplement compared with rats fed diet with 4% garlic supplement (except S. macrocarpon and C. olitorius). Furthermore, there was a significant decrease (P < .05) in mean corpuscular volume (69.2-72.0 fL) of rats fed the basal and those fed diet with garlic and vegetable (except C. olitorus and S. macrocarpon) supplement compared with the rats fed diet with garlic but without vegetable supplement (74.5 fL). This therefore implies that garlic could induce hemolytic anemia in rats. However, such anemia could be prevented by some tropical green leafy vegetables such as A. cruentus, B. alba, and O. gratissimum.

Anemia, Hemolytic↗
PubMed1995

Efficacy of cancer prevention by high-selenium garlic is primarily dependent on the action of selenium.

We reported previously that garlic cultivated with selenite fertilization showed powerful chemopreventive activity in the rat dimethylbenz[a]anthracene (DMBA)-induced mammary tumor model (Carcinogenesis 15, 573-576, 1994). In order to ascertain that the efficacy of the high-selenium garlic in cancer protection is primarily dependent on the action of selenium we compared the effects of two batches of garlic powder with marked differences in their level of selenium enrichment, 112 or 1355 p.p.m. Se dry weight. Both products were added to the diet to achieve the same final concentration of 2 p.p.m. Se. The supplementation protocol was designed to evaluate the efficacy during either the initiation phase or post-initiation phase of DMBA mammary carcinogenesis. Significant tumor reduction was observed with either treatment protocol. Furthermore, the magnitude tumor suppression, as well as the extent of DMBA-DNA adduct inhibition, were very similar with the two batches of garlic, even though the amounts of garlic in the diet varied considerably between them (1.8% for the 112 p.p.m. Se garlic versus 0.15% for the 1355 p.p.m. Se garlic). This suggests that the anti-cancer activity of the high-selenium garlic was likely to be accounted for by the effect of selenium, rather than the effect of garlic per se. A continuous feeding of the high-selenium garlic produced a modest increase in total selenium in various tissues. In general the profile of selenium accumulation was comparable in rats ingesting either the 112 or the 1355 p.p.m. Se garlic. Thus, based on the results of several biological responses, it appears that the ability of the high-selenium garlic to protect against tumorigenesis is primarily dependent on increased intake of selenium provided by the vegetable. Future research will be focused on the chemical form of selenium in the garlic.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1996

Effect on an aqueous extract of selenium-enriched garlic on in vitro markers and in vivo efficacy in cancer prevention.

Previous work has shown that the efficacy of cancer prevention by selenium-enriched garlic (Se-garlic) is primarily dependent on the action of selenium. An aqueous extract containing 43 micro Se/ml was prepared from lyophilized Se-garlic powder by the Soxhlet method. The activity of this Se-garlic extract was evaluated in a transformed mammary epithelial cell culture model for its effect on cell morphology, cell growth, cell cycle progression and the induction of single and double stranded breaks in DNA. Comparisons were also made with a similarly prepared extract from regular garlic, Se-methylselenocysteine (a major water-soluble seleno-amino acid identified in Se-garlic) and selenite (used for fertilizing Se-garlic). In contrast to the regular garlic extract which produced little or no modulation of the above parameters, treatment with the Se-garlic extract resulted in growth inhibition, GI phase cell cycle arrest and apoptotic DNA double strand breaks in the absence of DNA single strand breaks. This pattern of cellular responses was duplicated with exposure to Se-methylselenocysteine. Selenite, on the other hand, induced cell cycle blockage in the S/G2-M phase, and a marked increase in DNA single strand breaks (a measure of genotoxicity) in addition to growth suppression. The chemopreventive efficacy of the two garlic extracts was also investigated in the rat methylnitrosourea mammary tumor model. Both extracts were supplemented in the diet for 1 month immediately following carcinogen administration. Significant cancer protection was observed with treatment by the Se-garlic extract (at 3 p.p.m. Se in the diet), while little benefit was noted with treatment by the regular garlic extract. Based on the above in vitro and in vivo findings, it is hypothesized that the Se-garlic extract, in part via the action of Se-methylselenocysteine, is able to inhibit tumorigenesis by suppressing the proliferation and reducing the survival of the early transformed cells. Furthermore, the data also support the concept that the modulation of certain in vitro markers may be of value in predicting the effectiveness of novel forms of selenium for cancer prevention.

Animals↗
PubMed1999

Combined effects of ethanol and garlic on hepatic ethanol metabolism in mice.

The combined effects of ethanol and components in fresh garlic on ethanol metabolism were investigated in the livers of mice. Male, 11-wk-old C3H/HeNCrj mice were intragastrically administered 2 g ethanol/kg body weight after being administered fresh garlic juice for 8 d (garlic group), and changes in the concentrations of ethanol, acetaldehyde and acetate in the serum, and changes in the activity of hepatic enzymes related to ethanol metabolism in mice were examined. The increases in the concentrations of acetaldehyde and acetate in the serum after ethanol administration tended to be diminished following garlic administration. The microsomal ethanol-oxidizing system (MEOS) in the livers of the garlic groups was significantly lower than that of the control microsomes at 2 h after ethanol administration. It therefore seems that the decrease of MEOS in hepatic microsomes caused a smaller increase in the acetaldehyde concentration in the serum of the garlic groups because cytosolic alcohol dehydrogenase showed no significant difference between the control and garlic groups. After ethanol administration, the content of cytochrome P-450 in the hepatic microsomes of the control groups increased, while that of the garlic groups did not change although cytochrome P-450 (CYP) 2E1 and 1A2 in the hepatic microsomes of the garlic groups increased. These results indicate that the induction of isozymes of cytochrome P-450 other than CYP 2E1 and 1A2 was inhibited following garlic administration. Cytosolic high Km and total aldehyde dehydrogenase (AIDH) in the liver of the garlic groups tended to be lower than those activities of the control groups at 1 and 2 h after ethanol administration. It therefore seems that the decreases of AIDH in the hepatic cytosols diminished the increase of acetate in the serum of the garlic groups after ethanol administration. These results suggest that the ethanol metabolism in the mouse liver is controlled by components in fresh garlic juice.

Acetaldehyde↗
PubMed2002

[Studies on the stabilities of bioactive selenocompounds in selenium-enriched garlic and onion].

It is reported that selenium (Se) incorporation into garlic increases the bioactivities of garlic. Hence, the chemical changes of selenocompounds during processing and storage will influence the bioactive effectiveness of Se-enriched garlic. The principal selenocompounds in Se-enriched garlic are water-soluble, and several comparative experiments are thus conducted to examine the stabilities of the selenocompounds in water extracts of Se-enriched garlic and Se-enriched onion. The results show that preparing the garlic powder by freeze-drying technique can maintain the chemical properties of the selenium compounds in Se-enriched garlic. Se-methyl-selenocysteine is unstable in water extract of Se-enriched garlic when the extract is prepared and stored at room temperature. Specific alliinase inhibitor hydroxylamine (NHOH.HCl) effectively prevents the loss of Se-methyl-selenocysteine, which suggests that the decomposition of Se-methyl-selenocysteine may be catalyzed by alliinase. Se-methyl-selenocysteine is one of the main bioactive selenocompounds in Se-enriched garlic. The procedures of processing and storage should be carefully chosen to prevent the loss of selenocompounds and the decrease of the bioactivity of Se-enriched garlic. Se-enriched onion also contains alliinase and Se-methyl-selenocysteine, but its Se-methyl-selenocysteine is proved to be stable in the same water extract as that of Se-enriched garlic. The stability differences of Se-methyl-selenocysteine in Se-enriched garlic and onion, the mechanism of selenocompound decomposition and the bio-activities of decomposed compounds in Se-enriched garlic need to be further studied.

Carbon-Sulfur Lyases↗
PubMed2006

Nitric oxide mediates the blood-pressure lowering effect of garlic in the rat two-kidney, one-clip model of hypertension.

Garlic reduces blood pressure (BP) in two-kidney, one-clip (2K-1C) rats, and enhances nitric oxide (NO) synthesis in in vivo and in vitro experiments. NO is an important modulator of BP in the 2K-1C model. This study investigated the role of NO in the BP-lowering effect of garlic in the 2K-1C model. BP readings (mm Hg) were obtained from 2K-1C rats in 4 groups treated intraperitoneally for 2 wk with either normal saline (NS), garlic, L-nitroarginine-methylester (L-NAME), or L-NAME+garlic (n=4x5). BP was determined using the tail-cuff method and compared with data of 4 similarly treated groups of normal (unclipped) rats (NRs). The BP readings of NR groups were 120+/-3 mm Hg for the NS-treated group, 120+/-2 mm Hg for the garlic-treated group, 167+/-3 mm Hg for the L-NAME treated group (higher than NS or garlic, P<0.001) and 128+/-5 mm Hg for the garlic+L-NAME-treated group (lower than L-NAME, P<0.001). The BP readings of 2K-1C rat groups were: for the NS group, 169+/-6 mm Hg (higher than NRs, P<0.001); for the garlic group, 116+/-7 mm Hg (lower than NS, P<0.001); for the L-NAME group: 184+/-8 mm Hg (higher than garlic, P<0.001), and for the L-NAME+garlic group: 130+/-6 mm Hg (lower than garlic or NS, P<0.001). The data show that L-NAME increases the BP of both NRs and 2K-1C rats, with the rise more evident in the NRs (39 vs. 9%, respectively). Garlic counteracts the hypertensive effect of L-NAME in NRs as well as 2K-1C rats. We conclude that the BP-lowering effect of garlic in the rat 2K-1C model may be partly mediated through the NO pathway.

Analysis of Variance↗
PubMed1999

The effects of garlic preparations against human tumor cell proliferation.

Epidemiological studies in China provide reason to suspect that a rich garlic content in the diet might reduce the proliferation of tumors in humans. We conducted experiments on human tumor cell lines and determined the influence of a garlic powder preparation, a garlic extract (reported as 8-10% L(+)-alliin enriched), and a combination thereof, on cellular proliferation in cell cultures, employing the widely used indirect neutral red procedure. Garlic powder failed to inhibit the growth of human hepatoma HepG2 or human colorectal carcinoma Caco2 cells at concentrations of up to 1000 micrograms/ml. Garlic extract, in which the alliin content was highly enriched was also unable to inhibit the growth of these cells. However, when the garlic extract was supplemented with garlic powder (to 10% final concentration) there was a concentration-dependent clear inhibition of tumor cell growth (IC50 values of 330 micrograms/ml for HepG2 and 480 micrograms/ml for Caco-2 cells). The growth of the human lymphatic leukemia cell line CCRF CEM was significantly inhibited in a dose-dependent manner by both garlic powder and garlic extract at concentrations as low as 30 micrograms/ml. However, no potentiation of this effect occurred upon mixing of the two preparations. Our results suggest that the antiproliferative effects of garlic may be due to breakdown products of alliin, such as allicin or polysulfides, rather than alliin itself, since the addition of an alliinase system (garlic powder) to an alliin enriched preparation without alliinase (garlic extract) potentiated the effects observed with the two preparations alone.

Animals↗
PubMed1999

Effects of garlic preparations on superoxide production by phorbol ester activated granulocytes.

Sulfur containing constituents of garlic are considered responsible for conveying the antioxidative properties of garlic preparations. The radical scavenging properties of garlic preparations against oxygen radicals, specifically their ability to inhibit the formation of superoxide anions, were investigated using human granulocytes activated with 10 nM phorbol myristyl acetate (PMA). A garlic powder preparation inhibited the production of superoxide with a calculated IC50 of 390 micrograms/ml. An 8-10% alliin enriched garlic extract (alliinase inactivated) did not inhibit superoxide production even at concentrations as high as 1000 micrograms/ml. When the extract was mixed with garlic powder (90% garlic powder, 10% garlic extract), there was a clear inhibition of superoxide production with an IC50 value of 295 micrograms/ml. An even stronger inhibitory effect could be achieved when garlic powder was added to garlic extract (10% garlic powder, 90% extract, IC50 = 160 micrograms/ml). These experimental results suggest that the alliin metabolite allicin may be responsible for the oxygen radical scavenging properties of garlic.

Carcinogens↗
PubMed1997

Effect of garlic and fish-oil supplementation on serum lipid and lipoprotein concentrations in hypercholesterolemic men.

This study examined the effects of garlic and fish-oil supplementation (alone and in combination) on fasting serum lipids and lipoproteins in hypercholesterolemic subjects. After an initial run-in phase, 50 male subjects with moderate hypercholesterolemia were randomly assigned for 12 wk to one of four groups: 1) 900 mg garlic placebo/d + 12 g oil placebo/d; 2) 900 mg garlic/d + 12 g oil placebo/d; 3) 900 mg garlic placebo/d + 12 g fish oil/d, providing 3.6 g n-3 fatty acids/d; and 4) 900 mg garlic/d + 12 g fish oil/d. In the placebo group, mean serum total cholesterol, low-density-lipoprotein cholesterol (LDL-C), and triacylglycerols were not significantly changed in relation to baseline. Mean group total cholesterol concentrations were significantly lower with garlic+fish oil (-12.2%) and with garlic (-11.5%) after 12 wk but not with fish oil alone. Mean LDL-C concentrations were reduced with garlic+fish oil (-9.5%) and with garlic (-14.2%) but were raised with fish oil (+8.5%). Mean triacylglycerol concentrations were reduced with garlic+fish oil (-34.3%) and fish oil alone (-37.3%). The garlic groups (with and without fish oil) had significantly lower ratios of total cholesterol to high-density-lipoprotein cholesterol (HDL-C) and LDL-C to HDL-C. In summary, garlic supplementation significantly decreased both total cholesterol and LDL-C whereas fish-oil supplementation significantly decreased triacylglycerol concentrations and increased LDL-C concentrations in hypercholesterolemic men. The combination of garlic and fish oil reversed the moderate fish-oil-induced rise in LDL-C. Coadministration of garlic with fish oil was well-tolerated and had a beneficial effect on serum lipid and lipoprotein concentrations by providing a combined lowering of total cholesterol, LDL-C, and triacylglycerol concentrations as well as the ratios of total cholesterol to HDL-C and LDL-C to HDL-C.

Adult↗
PubMed2001

Intake of garlic and its bioactive components.

The health benefits of garlic likely arise from a wide variety of components, possibly working synergistically. The complex chemistry of garlic makes it plausible that variations in processing can yield quite different preparations. Highly unstable thiosulfinates, such as allicin, disappear during processing and are quickly transformed into a variety of organosulfur components. The efficacy and safety of these preparations in preparing dietary supplements based on garlic are also contingent on the processing methods employed. Although there are many garlic supplements commercially available, they fall into one of four categories, i.e., dehydrated garlic powder, garlic oil, garlic oil macerate and aged garlic extract (AGE). Garlic and garlic supplements are consumed in many cultures for their hypolipidemic, antiplatelet and procirculatory effects. In addition to these proclaimed beneficial effects, some garlic preparations also appear to possess hepatoprotective, immune-enhancing, anticancer and chemopreventive activities. Some preparations appear to be antioxidative, whereas others may stimulate oxidation. These additional biological effects attributed to AGE may be due to compounds, such as S-allylcysteine, S-allylmercaptocysteine, N(alpha)-fructosyl arginine and others, formed during the extraction process. Although not all of the active ingredients are known, ample research suggests that several bioavailable components likely contribute to the observed beneficial effects of garlic.

Allyl Compounds↗
PubMed2006

Inhibition of sterol 4alpha-methyl oxidase is the principal mechanism by which garlic decreases cholesterol synthesis.

Clinical and experimental evidence indicates that garlic ingestion lowers blood cholesterol levels, and treatment of cells in culture with garlic and garlic-derived compounds inhibits cholesterol synthesis. To identify the principal site of inhibition in the cholesterolgenic pathway and the active components of garlic, cultured hepatoma cells were treated with aqueous garlic extract or its chemical derivatives, and radiolabeled cholesterol and intermediates were identified and quantified. Garlic extract reduced cholesterol synthesis by up to 75% without evidence of cellular toxicity. Levels of squalene and 2,3-oxidosqualene were not altered by garlic, indicating that the site of inhibition was downstream of lanosterol synthesis, and identical results were obtained with 14C-acetate and 14C-mevalonate, confirming that 3-hydroxy-3-methylglutaryl-CoA reductase activity was not affected in these short-term studies. Several methylsterols that accumulated in the presence of garlic were identified by coupled gas chromatography-mass spectrometry as 4,4'-dimethylzymosterol and a possible metabolite of 4-methylzymosterol; both are substrates for sterol 4alpha-methyl oxidase, pointing to this enzyme as the principal site of inhibition in the cholesterolgenic pathway by garlic. Of 9 garlic-derived compounds tested for their ability to inhibit cholesterol synthesis, only diallyl disulfide, diallyl trisulfide, and allyl mercaptan proved inhibitory, each yielding a pattern of sterol accumulation identical with that obtained with garlic extract. These results indicate that compounds containing an allyl-disulfide or allyl-sulfhydryl group are most likely responsible for the inhibition of cholesterol synthesis by garlic and that this inhibition is likely mediated at sterol 4alpha-methyl oxidase.

Animals↗
PubMed2001

Prophylactic action of garlic on the histological and histochemical patterns of hepatic and gastric tissues in rats injected with a snake venom.

The present study aimed to examine the prophylactic action of oral administration of two doses of garlic on the histological and histochemical patterns of the gastric and hepatic tissues in rats envenomed with cobra snake. The study included the following groups: Group I contained control rats orally administered distilled water for ten days. Group II included rats orally administered daily for ten days with the equivalent therapeutic dose of garlic to rat (18 mg/kg body weight). Group III included rats orally administered daily for ten days with double the equivalent therapeutic dose of garlic to rat (36 mg/kg body weight). Group IV contained rats intramuscularly (i.m.) injected with 1/2 LD50 of cobra venom (0.0125 microg venom/gm body weight) and dissected after 6 hr from injection. Groups V and VI contained rats daily administered with the previous two doses of garlic for ten days, respectively, followed by a single i.m. injection of the above dose of cobra venom after 24 hr from the last garlic application. Rats of these two groups were dissected after 6 hr from venom injection. Administration of the therapeutic dose of garlic induced slight cytoplasmic granulation in some hepatic cells. However, administration of double the therapeutic dose caused swelling, necrosis, and damage of the gastric glandular epithelia together with signs of erosion, exfoliation, and necrosis of the surface mucosal cells. It also induced swelling and coalescence of the hepatic cells, loss of the normal arrangement of the hepatic cords, and hypertrophy of Kupffer cells. Injection with cobra venom caused loss of the normal characteristic appearance of the gastric glands and the epithelial lining cells of the gastric folds and the appearance of numerous inflammatory cells in the lamina properia. It also induced the occurrence of highly swollen hepatic cells, hepatic cellular necrosis and damage, as well as activated Kupffer cells. Nevertheless, pretreatment with the therapeutic dose of garlic for ten days induced a prophylactic activity against the pathogenic effects of the venom in both tissues, which appeared more or less normal except for very minor abnormalities. However, application of double the therapeutic dose of garlic for the same duration did not induce any prophylactic activity. Histochemically, slight alterations were noticed in the polysaccharide, protein, and nucleic acid contents of the gastric mucosa and the hepatic tissues due to administration of the therapeutic doses of garlic. However, severe depletions of these components were recorded in both tissues due to administration of double the therapeutic doses of garlic or injection of cobravenom or the application of both of them together. On the contrary, minor changes were noticed in the histochemical patterns of both tissues in rats pretreated with the therapeutic doses of garlic prior to venom application. It could be concluded that oral administration of the therapeutic dose of garlic for ten days has no serious side effects on gastric and hepatic tissues and could be used as a prophylactic tool against cobra snake envenomation.

Administration, Oral↗
PubMed2003

Garlic as an antioxidant: the good, the bad and the ugly.

Garlic has played an important dietary and medicinal role throughout the history of mankind. In some Western countries, the sale of garlic preparations ranks with those of leading prescription drugs. The therapeutic efficacy of garlic encompasses a wide variety of ailments, including cardiovascular, cancer, hepatic and microbial infections to name but a few. However, the elucidation of its mechanism for therapeutic action has proved to be more elusive and a unifying theory, which could account for its reported multifarious activities, is yet to emerge. Reactive oxygen species (ROS) seem to be at the core of many disease processes and it is an attractive and convenient hypothesis that garlic might exert its activities through modulatory effects on ROS. A literature search on garlic and its antioxidant potential churned up a surprisingly large amount of data, some of it good, some bad and some of its definitely ugly. Various preparations of garlic, mainly aged garlic extract (AGE), have been shown to have promising antioxidant potential. However, the presence of more than one compounds in garlic, with apparently opposite biological effects, has added to the complexity of the subject. Raw garlic homogenate has been reported to exert antioxidant potential but higher doses have been shown to be toxic to the heart, liver and kidney. So where do we stand today on this issue of garlic? Is garlic always good for health? How safe is it? Is it necessary to isolate the antioxidant compounds for its medicinal use in a more effective way? These issues are addressed in this review.

Antioxidants↗
PubMed2004

High-performance liquid chromatographic-inductively coupled plasma mass spectrometric evidence for Se-"alliins" in garlic and onion grown in Se-rich soil.

Garlic and onion, are well known for their medical value, especially in against cancer and anticardiovacular diseases. "Alliins" (S-alk(en)yl-L-cysteine sulphoxides) are sources of major active compounds in Allium plants. Se incorporation into garlic significantly increases activities of garlic in cancer prevention and inhibition. Selenomethionine, selenocysteine and Se-methylselenocysteine have been identified in garlic and onion. Previously we identified gamma-glutamyl-Se-methyl-L-selenocysteine, in extracts of garlic cultivated in Se-rich soil [Med. Res. Rev. 16 (1) (1996) 111], suggesting the possible existence of Se-alk(en)yl-L-cysteine selenoxides (Se-"alliins") in garlic. Several comparative experiments were carried out to demonstrate the existence of Se-"alliins" in Se-enriched garlic and onion. We found that there was one similar time-dependent Se signal in HPLC-inductively coupled plasma MS chromatograms of cold-water extracts of freeze-dried garlic powder and fresh garlic. This signal was lost when the extracts of garlic powder and fresh garlic were stored for 1 day at >4 degrees C, but remained in fresh onion extract at the same storage conditions. These phenomena and possible mechanisms are discussed. An additional experiment showed that Allium species cultivated in Se-rich soil might contain two different Se-"alliins".

Chromatography, High Pressure Liquid↗
PubMed1999

Characterization of lactic acid bacteria isolated from a Thai low-salt fermented fish product and the role of garlic as substrate for fermentation.

Lactic acid bacteria (LAB) isolated from raw materials (fish, rice, garlic and banana leaves) and processed som-fak (a Thai low-salt fermented fish product) were characterized by API 50-CH and other phenotypic criteria. Lactococcus lactis subsp. lactis and Leuconostoc citreum were specifically associated with fish fillet and minced fish, Lactobacillus paracasei subsp. paracasei with boiled rice and Weisella confusa with garlic mix and banana leaves. In addition, Lactobacillus plantarum, Lactobacillus pentosus and Pediococcus pentosaceus were isolated from raw materials. A succession of aciduric, homofermentative lactobacillus species, dominated by Lb. plantarum/pentosus, was found during fermentation. In total, 9% of the strains fermented starch and 19% fermented garlic, the two main carbohydrate components in som-fak. The ability to ferment garlic was paralleled by a capacity to ferment inulin. An increased percentage of garlic fermenting strains was found during fermentation of som-fak, from 8% at day 1 to 40% at day 5. No starch fermenting strains were isolated during fermentation. Three mixed LAB cultures, composed of either starch fermenting Lc. lactis subsp. lactis and Lb. paracasei subsp. paracasei, or garlic fermenting Lb. plantarum and Pd. pentosaceus, or a combination of these strains were inoculated into laboratory prepared som-fak with or without garlic. In som-fak without garlic, pH was above 4.8 after three days, irrespective of addition of mixed LAB cultures. The starch fermenting LAB were unable to ferment som-fak and sensory spoilage occurred after three days. Fermentation with the combined mix of starch and garlic fermenting strains led to production of 2.5% acid and a decrease in pH to 4.5 in two days. The fermentation was slightly slower with the garlic fermenting strains alone. This is the first report describing the role of garlic as carbohydrate source for LAB in fermented fish products.

Animals↗
PubMed2004

Comparison of the chemopreventive efficacies of garlic powders with different alliin contents against aflatoxin B1 carcinogenicity in rats.

Garlic (Allium sativum) is well known for its beneficial effects on health and particularly for its chemopreventive potential against cancer. The present study was designed to compare the chemopreventive efficacies of several garlic powders with various levels of alliin, a precursor of active sulfur compounds. For this purpose we used the medium-term hepatocarcinogenesis protocol (resistant hepatocyte model), which allows the detection of preneoplasic foci expressing the placental form of glutathione S-transferase (GST-P) as an end-point. Rats were fed diets containing three garlic powders (5% of the diet) with various alliin contents for 3 weeks. Garlic powders were obtained from bulbs grown on soils with different levels of sulfur fertilization. During the period of garlic feeding hepatocarcinogenesis was initiated by administration of 10 i.p. injections of 0.025 mg/kg body weight aflatoxin B1 (AFB1). The rats were later submitted to 2-acetylaminofluorene treatment and partial hepatectomy, and GST-P foci were detected and quantified. Consumption of diets containing garlic powders decreased the appearance and size of hepatic GST-P foci. A strong reduction was observed in rats fed garlic containing the highest level of alliin. In addition, increased alliin content of the garlic powder was associated with a proportional decrease in the number and area of preneoplastic foci. Elsewhere, garlic powder ingestion increased hepatic ethoxyresorufin deethylase, glutathione S-transferase and UDP glucuronosyl transferase activities while no modification of nifedipine oxidase activity was found. We also observed an increase in the levels of GST A5 and AFB1 aldehyde reductase. It is suggested that garlic partly exerts its anticarcinogenic effects through increasing enzymes involved in AFB1 detoxification. This study highlights the possibility of controlling the cultivation conditions to improve the chemopreventive efficacy of garlic.

Aflatoxin B1↗
PubMed1983

Suppression of avian hepatic lipid metabolism by solvent extracts of garlic: impact on serum lipids.

The effects of garlic on lipid metabolism were examined in White Leghorn pullets that had been fed for 4 weeks either a control diet based on corn and soybean meal or an experimental diet containing either 3.8% garlic paste, a solvent extract (petroleum ether, methanol and water in sequence) of garlic paste, the residue or commercial garlic oil. Significant decreases in hepatic 3-hydroxy-3-methylglutaryl-CoA reductase (79-83%), cholesterol 7 alpha-hydroxylase (43-51%), fatty acid synthetase (17-29%) and in representative pentose-phosphate pathway (23-39%) activities accompanied the feeding of the petroleum ether-, methanol- and water-soluble fractions of garlic. Garlic paste and oil also suppressed these activities. Significant decreases in serum lipids occurred in response to the feeding of these garlic fractions: serum total cholesterol by 20-25%, low density lipoprotein cholesterol by 28-41% and triglycerides by 10-26%; but high density lipoprotein cholesterol failed to respond to these treatments. The residue remaining after solvent fractionation had little influence on these parameters. These findings were substantiated by a second study in which pullets of a commercial broiler line were fed the garlic fractions. The results confirm that garlic oil and odorous components of garlic lower cholesterol levels. An odorless water-soluble component of garlic also has this effect. The mechanism of the hypocholesterolemic action is at the level of the suppression of cholesterol biosynthesis.

Animals↗