garlic
The in vitro susceptibility of Scedosporium prolificans to ajoene, allitridium and a raw extract of garlic (Allium sativum).

Davis SR, Perrie R, Apitz-Castro R.

Mycology Unit, Women's and Children's Hospital, 72 King William Road, North Adelaide, South Australia 5006, Australia. sdavis esc.net.au

The in vitro susceptibility of 20 medical isolates of Scedosporium prolificans to ajoene, allitridium and raw garlic extract derived from cloves of garlic (Allium sativum) was tested using the NCCLS reference method (with minor modifications) for broth microdilution. The results demonstrate that both garlic derivatives and raw garlic extract appear to have in vitro activity against S. prolificans.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12615859&dopt=Abstract garlic



garlic
Arginine is not responsible for the activation of nitric oxide synthase by garlic.

Das I, Hirani J, Sooranna S.

Academic Department of Psychiatry, Charing Cross and Westminster Medical School, London, UK.

Garlic (Allium sativum L., Liliaceae) has had an important dietary and medicinal role for centuries. Its chemical constituents have beneficial effects on cardiovascular risk factors and other medicinal effects in the body. Several components of garlic are known but the individual compounds responsible for its divergent properties have yet to be established. There is a link between garlic and the L-arginine-nitric oxide pathway. Amino acid analysis of garlic powder demonstrates that it is a rich source of arginine, the precursor for nitric oxide. However, neither arginine nor alliin-derived products were found to be responsible for the activation of nitric oxide synthase by garlic in cell-free homogenates. Heat treatment of garlic preserved its capacity for enzyme activation.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8807470&dopt=Abstract garlic



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

Ali M.

Department of Biochemistry, Kuwait University, Safat.

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

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8821119&dopt=Abstract garlic



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

Lu J, Pei H, Ip C, Lisk DJ, Ganther H, Thompson HJ.

Division of Laboratory Research, AMC Cancer Research Center, Denver, CO 80214, USA.

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.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8824512&dopt=Abstract garlic



garlic
Selenium-enriched garlic inhibits the early stage but not the late stage of mammary carcinogenesis.

Ip C, Lisk DJ, Thompson HJ.

Department of Surgical Oncology, Roswell Park Cancer Institute, Buffalo, NY 14263, USA.

Previous work has shown that the efficacy of cancer prevention by selenium-enriched garlic (Se-garlic) is primarily dependent on the action of selenium. Additionally, supplementation of Se-garlic inhibited the post-initiation phase of mammary carcinogenesis when it was given continuously to the animals. In this report, experiments were carried out in which treatment with the Se-garlic was started after carcinogen dosing (DMBA or MNU) but was restricted to either the early or late stage of neoplastic progression. The results from these two models showed that a short-term exposure to the Se-garlic for 1 month immediately following carcinogen administration was just as effective in cancer prevention as the continuous exposure regimen (5 months), suggesting that the Se-garlic may irreversibly alter the process of clonal expansion and/or selection of transformed cells during their early stage of development. Plasma and mammary tissue selenium levels essentially returned to basal levels at 1 month after withdrawal of supplementation. These observations imply that the outcome of cancer protection by short-term Se-garlic intervention was not due to a slow turnover, and therefore a lingering presence, of selenium in the target organ or in the circulation. The above finding was in contrast to that of a second study in which Se-garlic was supplemented starting at 13 weeks after carcinogen treatment. With this protocol, the number of new tumors and the number of new tumor-bearing rats found during the intervention period (weeks 13 to 22) were not statistically different between the control and supplemented groups, suggesting that Se-garlic had a minimal effect on the later stages of mammary carcinogenesis.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8824523&dopt=Abstract garlic