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

Ip C, Lisk DJ.

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

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.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7586181&dopt=Abstract garlic



garlic
Light and electron microscopic immunocytochemical localization of two major proteins in garlic bulb.

Wen GY, Mato A, Wisniewski HM, Malik MN, Jenkins EC, Sheikh AM, Kim KS.

New York State Institute for Basic Research in Developmental Disabilities, Staten Island 10314, USA.

Garlic is known as a potent spice and a medicine with broad therapeutic properties ranging from antibacterial to anticancer, antidiabetic, and anticoagulant. Two major proteins of 40 KD and 14 KD constituting approximately 96% of total garlic proteins have been recently purified at our Institute. This immunocytochemical and ultrastructural study revealed that the 40 KD protein was localized in the parenchyma sheath cells (PSC) of garlic bulbs, whereas the 14 KD protein was present in the cortical cells (CC). Immunogold electron microscopy study indicated that the 40 KD protein was specifically localized in the globular granules of the cytoplasmic area of PSC. Each globular granule was amorphous and homogenous with membrane limiting its outermost layer. The yellowish color of PSC in freshly cut slices of garlic bulb suggested that PSC may have sulfur-containing compounds such as allicin, the primary contributor of the pungency and medicinal properties of garlic. Ellman's reagent test quantitatively revealed that there were 17.8 n moles sulfhydryl (SH)/ml of 40 KD garlic protein. Microtubule tubulin in mitotic figures from PHA-stimulated human short-term whole blood cultures reacted strongly with antitubulin antibody but reacted negatively with anti-40 KD garlic protein antibodies and therefore was not related to the 40 KD garlic protein immunocytochemically.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7593270&dopt=Abstract garlic



garlic
The radical scavenging ability of garlic examined in various models.

Rietz B, Belagyi J, Torok B, Jacob R.

Institute of Physiology II, University of Tubingen, Germany.

The influence of an intake of garlic powder (1% added to a standard chow for an 8 week period) on the susceptibility to ventricular arrhythmias under radical reperfusion was investigated in the isolated rat heart perfused with a modified Krebs-Henseleit solution and the generating system hypoxanthine/xanthine oxidase. The incidence of ventricular fibrillation (VF) after the reopening of the LAD was significantly reduced in the garlic group as compared to the untreated controls (VF: 50% vs 89%). As this protective effect might relate to radical scavenging capacities, two in vitro radical generating test systems were chosen where the garlic activity could be determined. Dose-dependently, garlic was able to capture the radicals. Interestingly, only the garlic extract, was active. The ethanol extract hardly showed any radical scavenging ability. According to this result, we concluded that an intact alliin-alliinase system is important for the activity of garlic. Further investigations were done with different tissues under oxidative stress conditions. The kinetics of each organ, were measured chemiluminometrically. Especially liver and kidney of garlic fed rats showed inhibiting effects. Finally, an attempt was made to relate these radical scavenging and lipidperoxidation inhibiting effects to respective garlic compounds. Two substances, allylmercaptane and diallyldisulfide, were proposed.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7598835&dopt=Abstract garlic



garlic
Inhibition of adenosine deaminase activity of aortic endothelial cells by extracts of garlic (Allium sativum L.).

Melzig MF, Krause E, Franke S.

Research Institute for Molecular Pharmacology, Berlin.

Aqueous extracts of fresh garlic (Allium sativum L.) inhibited efficiently the activity of adenosine deaminase (ADA) of cultivated endothelial cells. The IC50 value (range between 6 and 120 micrograms per ml) depended on the origin and storage time of the fresh garlic. The aqueous extraction of dried garlic powder showed also an inhibition if ADA activity, but the IC50 value was in the range of 2.5 mg per ml indicating that parts of the active principle were lost during the preparation of the garlic powder. The inhibition of endothelial ADA by garlic extracts seems to contribute to the hypotensive activity and vessel protective effects of A. sativum L.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7604070&dopt=Abstract garlic



garlic
How does garlic exert its hypocholesterolaemic action? The tellurium hypothesis.

Larner AJ.

University of Cambridge Department of Anatomy, UK.

The efficacy of garlic as a lipid-lowering agent is being increasingly recognized, but the biochemical mechanisms underlying this action are currently unknown. It is proposed that organic tellurium compounds, which are found in high concentration in fresh garlic buds, may contribute to this action by inhibiting squalene epoxidase, the penultimate enzyme in the synthetic pathway of cholesterol. Weanling rats fed a diet rich in tellurium develop a demyelinating polyneuropathy due to inhibition of this enzyme in peripheral nerves. Chronic exposure to small amounts of tellurium found in garlic might reduce endogenous cholesterol production through inhibition of hepatic squalene epoxidase and so reduce cholesterol levels. Tellurium may also contribute to the characteristic odour of garlic since the most obvious clinical sign of tellurium poisoning is a garlic-like odour.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7666832&dopt=Abstract garlic