Beneficial effects of garlic (Allium sativum Linn) on rats fed with diets containing cholesterol and either of the oil seeds,coconuts or groundnuts

Feeding of 2% cholesterol diet increased lipid parameters in serum and tissues of rats during a period of one month. In addition to the above, lipid peroxidation also increased and activities of certain enzymes were significantly altered in the tissues. Similar changes were also observed to a greater extent with diets containing 40% by weight of coconut kernel or groundnut with and without 2% cholesterol. The enzymes studied were HMGCoA reductase, AST, ALT and ALP in tissues and serum as the case may be. In general the atherogenic effects were observed more with groundnut containing diets than those with coconut. Even though the oil from the former is mostly unsaturated and that from the latter is mostly saturated, these analytical criteria do not relate to their atherogenic effects. When 5% garlic was incorporated with any of the high fat diets, the lipid parameters, their peroxidation and alterations in enzyme activities were significantly decreased. These results show that garlic contains some principles that counteract the atherogenicity of the above oil seeds.     

Effect of onion (Allium cepa Linn.) and garlic (Allium sativum Linn.) on plasma triglyceride content in Japanese quail (Coturnix coturnix japonicum)

Dietary onion and garlic caused an increase in the level of plasma triglyceride which could be due to insulin like activity of dietary alliums and other factors that promote lipogenesisi in growing stages. Changes in the plasma triglyceride level in the control group due to change in age and sex were also noted. The triglyceride level was more in female birds when compared to males of similar age group. The plasma trigelyceride level increased with age in both sex except for the level being similar in the 6 and 9-week old females and 3 and 6-week old male birds. The results suggest that the effects of alliums in growing and adult stages may be different which needs further study.     

The C-S Lyases of Higher Plants : Direct Comparison of the Physical Properties of Homogeneous Alliin Lyase of Garlic (Allium sativum) and Onion (Allium cepa)

Garlic and onion alliin lyases, although from closely related species, have many differences. The two enzymes differ in their K_m values, pH optima, and isoelectric points. There is a major difference in their molecular weight and subunit structure. The garlic holoenzyme has a molecular weight of 85,000 and consists of two subunits of molecular weight 42,000. The onion enzyme has a holoenzyme molecular weight of 200,000 composed of four subunits of molecular weight 50,000. The onion enzyme is much more difficult to dissociate into its subunits which suggests differences in subunit interaction between the two enzymes. The dimeric stucture of the garlic and the tetrameric structure of the onion enzyme is consistent with a coenzyme content (pyridoxal-5′-phosphate) equivalent to one mole per subunit. The two enzymes vary vastly in their spectra, the onion enzyme having a lower pyridoxal-5′-phosphate absorbance at 430 nanomoles and an inability to react with l-cysteine. Both enzymes are glycoproteins and bind to concanavalin A-Sepharose columns. The onion alliin lyase binds more tightly than the garlic enzyme. The amino acid content of both enzymes is similar as is the carbohydrate content. However, upon hydrolysis the onion lyase does yield more mannose units than the garlic enzyme which is consistent with the former's stronger affinity for concanavalin A.     

Origins of Allium ampeloprasum horticultural groups and a molecular phylogeny of the section Allium (Allium: Alliaceae)

The subgenus Allium section Allium includes economically important species, such as garlic and leek, as well as other polyploid minor crops. Phylogenetic studies within this section, with a focus on horticultural groups within A. ampeloprasum, were performed on 31 accessions of 17 species using the nuclear ribosomal DNA internal transcribed spacer (ITS) region and the chloroplast trnL-F and trnD-T regions. The results confirmed the monophyly of section Allium. Four main clades were identified on all ITS analyses but the relationships among those and the remaining species studied within section Allium remained unresolved. Trees based on cpDNA recovered two major clades and a topology only partly congruent with that of the ITS tree. Intra-individual polymorphism of the ITS region proved useful in tracking putative parent species of polyploid taxa. The allopolyploid origin of great headed garlic (GHG), A. iranicum and A. polyanthum was confirmed. No signs of hybridization in leek or kurrat were detected but possible introgression events were identified in pearl onion and bulbous leek. Although GHG is often used as a garlic substitute, molecular analysis revealed only a distant relationship with garlic. We also clarified the previous incorrect classification of cultivated forms within A. ampeloprasum, by showing that leek, kurrat, pearl onion, and bulbous leek should be considered separately from GHG.     

Beneficial effects of a polar fraction of garlic (Allium sativum Linn) oil in rats fed with two different high fat diets

Feeding a diet containing 20% of sesame oil (SO) or coconut oil (CNO) along with 2% cholesterol to rats for two months showed differences in their serum and tissue lipid profile and certain enzyme activities. Hyperlipidemia and related oxidative effects were more pronounced in coconut oil fed rats than those fed sesame oil. Feeding a combination of the oils (10% CNO +10% SO) lowered significantly the hyperlipidemia and certain other deleterious effects of CNO. Feeding a polar fraction of garlic oil (PFGO) prepared in the same way as for ajoene and administered at a dosage of 100 mg/kg along with each of the above oil containing diets counteracted significantly the hyperlipidemic, oxidant and also most of the other deleterious effects of the oils like raised lipid levels in serum and tissues, raised serum levels of AST and tissue levels of HMGCoA reductase and the lowered serum and tissue levels of glutathione reductase. The results support the claims that ajoene, the major polar compound of garlic oil, has very good biological action, which warrants further study.     

The C-S lyases of higher plants. Purification and characterization of homogeneous alliin lyase of leek (Allium porrum)

The characteristic odors of freshly macerated tissue of Allium species such as garlic and onion are due to the action of the enzyme alliin lyase (EC 4.4.1.4) on endogenous S-alkyl-I-cysteine sulfoxides which are present as secondary amino acids yielding volatile sulfur-containing products. Purification and characterization of the alliin lyase of leek ( Allium porrum L.) has been carried out for comparison with the analogous enzymes previously characterized from garlic and onion. The purification involved homogenization, followed by ammonium sulfate fractionation, elution from an hydroxylapatite column, concentration of the active fractions and passage through a concanavalin A-Sepharose 4B affinity column. The purified enzyme was found to be a glycoprotein with a pH optimum for activity of 8.0. Sodium dodecylsulfate-urea polyacrylamide gel electrophoresis gels of the homogeneous leek enzyme showed it consisted of 1 subunit with a molecular weight of 48000. By gel filtration, 2 stable forms of the native enzyme with molecular weights of 386000 and 580000 were found.     

Production of inulinase by Xanthomonas campestris pv phaseoli using onion (Allium cepa) and garlic (Allium sativum) peels in solid state cultivation

AIMS: To access inulinase production by Xanthomonas campestris pv phaseoli using the submerged and solid state cultivation (SSC) methods. METHODS AND RESULTS: Various carbon sources, inulin-rich solid substrates and pure synthetic inulin were tested for their efficiency in inulinase induction. The highest inulinase production (17.42 IU ml(-1)) in submerged cultures of X. campestris was observed with inulin as a carbon source with an initial pH, temperature and agitation of 7.0, 37 degrees C and 150 rev min(-1) respectively. Among the various substrates, garlic peels (117 IU gds(-1)) and onion peels (101 IU gds(-1)) were found to be the best for inulinase production. CONCLUSION: The inulinase production level of X. campestris was 6.7-fold higher in garlic and 5.8-fold in onion, under optimized SSC conditions compared with the submerged culture. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report on inulinase production from garlic and onion peels by X. campestris using SSC. SSC is an efficient method for inulinase production by X. campestris for commercial applications.     

Isolation and Characterization of Viruses Present in Four Clones of Garlic (Allium sativum) in Venezuela

Isolation and characterization of viruses infecting garlic in Venezuela indicate the presence of onion yellow dwarf virus [OYDV] in most field-grown plants of the clones Criollo venezolano, Morado peruano and Blanco, while 14% of the Criollo venezolano plants showed co-infection of leek yellow stripe virus [LYSV] and OYDV. In leaf tissues OYDV showed an average concentration of 165 μg/g fresh wt., the value being similar among clones. In Criollo venezolano plants co-infected by LYSV and OYDV the concentration of the former was three fold lower than that of OYDV. Serological tests on leaf extracts of garlic plants indicated the absence of the garlic yellow streak virus [GYSV], shallot latent virus [SLV] and garlic latent virus [GLV] in the clones Criollo venezolano, Morado peruano and Blanco. GLV was found to infect plants of the clone Gigante. Physicochemical analysis of purified GLV strongly supports the inclusion of this virus as a definitive member of the carlavirus group.     

Isolation and Characterization of Viruses Present in Four Clones of Garlic (Allium sativum) in Venezuela

Isolation and characterization of viruses infecting garlic in Venezuela indicate the presence of onion yellow dwarf virus [OYDV] in most field-grown plants of the clones Criollo venezolano, Morado peruano and Blanco, while 14% of the Criollo venezolano plants showed co-infection of leek yellow stripe virus [LYSV] and OYDV. In leaf tissues OYDV showed an average concentration of 165 μg/g fresh wt., the value being similar among clones. In Criollo venezolano plants co-infected by LYSV and OYDV the concentration of the former was three fold lower than that of OYDV. Serological tests on leaf extracts of garlic plants indicated the absence of the garlic yellow streak virus [GYSV], shallot latent virus [SLV] and garlic latent virus [GLV] in the clones Criollo venezolano, Morado peruano and Blanco. GLV was found to infect plants of the clone Gigante. Physicochemical analysis of purified GLV strongly supports the inclusion of this virus as a definitive member of the carlavirus group.     

Antidiabetic effects of S-allyl cysteine sulphoxide isolated from garlic Allium sativum Linn.

S-allyl cysteine sulphoxide (SACS), a sulphur containing amino acid of garlic which is the precursor of allicin and garlic oil, has been found to show significant antidiabetic effects in alloxan diabetic rats. Administration of it at a dose of 200 mg/kg body weight decreased significantly the concentration of serum lipids, blood glucose and activities of serum enzymes like alkaline phosphatase, acid phosphatase and lactate dehydrogenase and liver glucose-6-phosphatase. It increased significantly liver and intestinal HMG CoA reductase activity and liver hexokinase activity.     

The C-S lyases of higher plants: preparation and properties of homogeneous alliin lyase from garlic (Allium sativum)

Alliin lyase from garlic (Allium sativum) has been purified to homogeneity. The purification procedure involves the use of affinity chromatography on concanavalin A-Sepharose 4B. Addition of polyvinylpolypyrrolidone to the homogenizing medium greatly improves the specific activity of the extract. The enzyme is a glycoprotein as seen by its ability to bind to concanavalin A-Sepharose 4B and by its positive periodic acid-Schiff base stain. It has a carbohydrate content of 5.5%. Km values for this enzyme were estimated to be 5.7 mM for S-ethyl-L-cysteine sulfoxide and 3.3 mM for S-allyl-L-cysteine sulfoxide. The molecular weight of this garlic enzyme, as determined by gel filtration, was found to be 85,000; the molecule consists of two equal subunits of Mr 42,000. The amino acid content was found to be similar to that reported previously for onion alliin lyase, although there is twice as much tryptophan in the garlic alliin lyase as in the onion enzyme. By both chemical and spectral methods the enzyme was found to have two molecules of pyridoxal 5-phosphate per enzyme molecule, suggesting one per subunit. There are significant differences in the nature of these findings from those previously reported from this laboratory for the onion enzyme. Studies are in progress to compare further the alliin lyases from garlic and onion.     

Heat stable antimicrobial activity of Allium ascalonicum against bacteria and fungi

To study antimicrobial activity of shallot in comparison with that of garlic and onion against 23 strains of fungi and bacteria, water extracts of garlic, shallot and onion bulbs were prepared. Each extract was studied in different forms for their antimicrobial activity viz., fresh extract, dry extract and autoclaved extract. Minimal inhibitory concentration and minimal lethal concentrations of these extracts were determined against all organisms by broth dilution susceptibility test. Fresh extract of garlic showed greater antimicrobial activity as compared to similar extracts of onion and shallot. However, dried and autoclaved extracts of shallot showed more activity than similar extracts of onion and garlic. Fungi were more sensitive to shallot extract than bacteria. Amongst bacteria, B. cereus was most sensitive (MIC=5 mg ml(-1)). The lowest minimum bactericidal concentration of shallot extract amongst bacteria tested was 5 mg ml(-1) for B. cereus. Amongst fungi, Aureobasidium pullulans and Microsporum gypseum were most sensitive (MIC= 0.15 mg ml(-1)). The lowest minimum lethal concentration was 2.5 mg ml(-1) for Microsporum gypseum and Trichophyton mentagrophytes. It was therefore, expected that the antimicrobial principle of shallot was different than the antimicrobial compounds of onion and garlic. In addition, the antimicrobial component of the shallot extract was stable at 121 degrees C.     

Effect of raw versus boiled aqueous extract of garlic and onion on platelet aggregation.

The effects of aqueous extracts of raw and boiled garlic and onions were studied in vitro on the collagen-induced platelet aggregation using rabbit and human platelet-rich plasma. A dose dependant inhibition of rabbit platelet aggregation was observed with garlic. Onion also showed dose-dependent inhibitory effects on the collagen-induced platelet aggregation but this inhibition was of a lesser magnitude compared to garlic when related to dose. The concentration required for 50% inhibition of the platelet aggregation for garlic was calculated to be approximately 6.6 mg ml(-1) plasma, whereas the concentration for onion was 90 mg ml(-1) plasma. Boiled garlic and onion extracts showed a reduced inhibitory effect on platelet aggregation. Garlic but not onion significantly inhibits human platelet aggregation in a dose-dependent fashion. The potency of garlic in inhibiting the collagen-induced platelet aggregation is approximately similar to that of rabbit platelets (8.8 mg ml(-1) produced 50% inhibition of platelet aggregation). The results of this study show that garlic is about 13 times more potent than onion in inhibiting platelet aggregation and suggest that garlic and onion could be more potent inhibitors of blood platelet aggregation if consumed in raw than in cooked or boiled form.     

Cadmium accumulation and oxidative burst in garlic (Allium sativum)

To investigate the temporal sequence of physiological reactions of garlic (Allium sativum) to cadmium (Cd) treatment, seedlings developed from cloves were grown in increasing concentrations of CdCl2, ranging from 1-10 mM, for up to 8 days in sand. Analysis of Cd uptake indicated that most Cd accumulated in roots, but some was also translocated and accumulated in leaves at longer exposure time (after 12h) and higher concentrations (5 and 10mM) of CdCl2. Changes in activities of antioxidative enzymes, including superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), were characterized in leaves of garlic seedlings. Cd (5 and 10 mM) initially inhibited the activities of SOD and CAT but thereafter recovered or even increased compared with control plants. POD activities at 5 and 10 mM of Cd increased more than 3-4 times over control plants within 12 h and then dropped, but were still higher than controls at the end of the experiment. Otherwise lipid peroxidation enhanced with the increasing of incubation time and concentrations of external Cd. Leaves exposed to 1 mM CdCl2 showed a less pronounced response and only a small reduction in shoot growth. These results suggested that in leaves of garlic seedlings challenged by CdCl2 at higher concentrations, induction of these various enzymes is part of a general defense strategy to cope with overproduction of reactive oxygen. The possible mechanism of antioxidative enzymes changing before Cd accumulation in leaves of garlic seedlings is discussed.     

Agrobacterium tumefaciens-mediated transformation of leek (Allium porrum) and garlic (Allium sativum)

Transgenic leek (Allium porrum) and garlic (Allium sativum) plants have been recovered by the selective culturing of immature leek and garlic embryos via Agrobacterium-mediated transformation using a method similar to that described by Eady et al. (Plant Cell Rep 19:376–381, 2000) for onion transformation. This method involved the use of a binary vector containing the m-gfp-ER reporter gene and nptII selectable marker, and followed the protocol developed previously for the transformation of onions with only minor modifications pertaining to the post-transformation selection procedure which was simplified to have just a single selection regime. Transgenic cultures were selected for their ability to express the m-gfp-ER reporter gene and grown in the presence of geneticin (20 mg/l). The presence of transgenes in the genome of the plants was confirmed using TAIL-PCR and Southern analysis. This is the first report of leek and true seed garlic transformation. It now makes possible the integration of useful agronomic and quality traits into these crops.     

The production by species of Allium of alkyl sulphides and their effect on germination of sclerotia of Sclerotium cepivorum Berk

A number of n -propyl and allyl sulphides were shown to stimulate germination of sclerotia of Sclerotium cepivorum in soil. Several of these sulphides were evolved by chopped garlic cloves and onion bulbs, and by their extracts, as well as by distillates and condensates prepared from extracts. Sulphides produced by garlic were methyl and allyl compounds, whereas those of onion were methyl and n -propyl derivatives. Few or no volatile sulphides were detected by gas chromatography of head spaces of intact Allium plants although it is considered that small quantities of sulphides may be produced from these plants in soil. The stimulatory activity of distillates and condensates appears to be entirely due to their alkyl sulphide content and that of extracts at least partially so.     

Thromboxane-B(2) levels in serum of rabbits receiving a single intravenous dose of aqueous extract of garlic and onion

We have shown previously that fresh garlic extract is effective in reducing thromboxane formation by platelets both in vivo and in vitro animal models of thrombosis. In the present study, the effect of different concentrations of a single dose of aqueous extracts of garlic and onion were evaluated on serum thromboxane-B(2)synthesis in rabbits. Different concentrations of garlic and onion were administered as single doses in the ear vein of rabbits. Rabbits were bled before and at different intervals after the infusion of garlic or onion extracts. Venous blood was collected and allowed to clot at 37 degrees C for 1 h. Thromboxane-B(2)level was measured in the serum by radioimmunoassay. It was observed that garlic inhibits the thrombin-induced platelet synthesis of TXB(2)in a dose-and time-dependent manner. Maximum inhibition of TXB(2)occurred between 0.5 h and 6 h at 25 and 100 mg kg(-1)garlic. At 24 h post-garlic infusion TXB(2)inhibition was reduced to 15% of the control and TXB(2)levels were comparable to that of the control values at 72 h pots-garlic infusion. Infusion of 100 mg kg(-1)onion extract did not elicit any inhibitory effect on TXB(2)synthesis in the serum of rabbit during the treatment period. The rapid recovery of platelet cyclooxygenase activity after infusion of a single dose of garlic suggests that garlic should be taken more frequently in order to achieve beneficial effects in the prevention of thrombosis.     

Effect of alliums on total lipid in plasma and tissues of Japanese quails (Coturnix coturnix japonica) with respect to age and sex

Dietary onion and garlic caused an increase in the level of liver and plasma total lipids in Coturnix coturnix japonica. This increase could be due to the effect of an increased feed intake, bile production, digestion and absorption that in turn caused an increased utilisation of dietary fat, increased transfer of dietary lipids to the liver and/or due to increased lipogenesis as such. However, there was no increase in the muscle lipid content. This effect in the muscle could be due to inhibitory effect of onion or garlic on lipoprotein lipase activity. Further, the changes in the tissue total lipid level in the control group due to change in age and sex were also observed.