garlic
Endothelium-dependent and independent effects of garlic on rat aorta.

Ozturk Y, Aydin S, Kosar M, Baser KH.

Anadolu University, Medicinal Plants Research Centre, Eskisehir, Turkey.

Effects of garlic on isolated rat aorta were investigated by comparing with those of acetylcholine and L-arginine in the presence and absence of endothelium. For this purpose, certain linear and non-linear regression models were applied for concentration-response curves obtained by acetylcholine, L-arginine and garlic in the rat aorta. Garlic caused dose-dependent relaxations in isolated rat aorta which were attenuated by the removal of endothelium as in the case of acetylcholine. However, the relaxant responses to acetylcholine, L-arginine and garlic were not completely abolished by the endothelial denudation. Application of a number of regression models for the vasorelaxant effects of acetylcholine and garlic revealed that mechanism(s) of the effect of garlic may be different from that of acetylcholine. Furthermore, it was noted that L-arginine-induced relaxations, but not those induced by acetylcholine and garlic, are enhanced by a 2 or 4 h incubation period in the bathing medium. The findings obtained strongly suggested that the vasorelaxant effect of garlic is important in its hypotensive activity and mediated by the production of endothelium-and/or muscle-derived relaxing factors.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7853861&dopt=Abstract garlic



garlic
Comparative study of the post-translational processing of the mannose-binding lectins in the bulbs of garlic (Allium sativum L.) and ramsons (Allium ursinum L.).

Smeets K, Van Damme EJ, Peumans WJ.

Laboratory for Phytopathology and Plant Protection, Katholieke Universiteit Leuven, Belgium.

The biosynthesis and processing of the homodimeric and heterodimeric lectins from the bulbs of garlic (Allium sativum) and ramsons (wild garlic; Allium ursinum) were studied using pulse and pulse-chase labelling experiments on developing bulbs. By combining the results of the in vivo biosynthesis studies and the cDNA cloning of the respective lectins, the sequence of events leading from the primary translation products into the mature lectin polypeptides could be reconstructed. From this it is demonstrated that garlic and ramsons use different schemes of post-translational modifications in order to synthesize apparently similar lectins from totally different precursors. Both the homomeric garlic lectin (ASAII) and its homologue in ramsons (AUAII) are synthesized on the endoplasmic reticulum (ER) as nonglycosylated 13.5 kDa precursors, which, after their transport out of the ER are converted into the mature 12.0 kDa lectin polypeptides by the cleavage of a C-terminal peptide. The heterodimeric garlic lectin ASAI is synthesized on the ER as a single glycosylated precursor of 38 kDa, which after its transport out of the ER undergoes a complex processing which gives rise to two mature lectin subunits of 11.5 and 12.5 kDa. In contrast, both subunits of the heterodimeric ramsons lectin AUAI are synthesized separately on the ER as glycosylated precursors, which after their transport out of the ER are deglycosylated and further processed into the mature lectin polypeptides by the cleavage of a C-terminal peptide.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7873927&dopt=Abstract garlic



garlic
Enrichment of selenium in allium vegetables for cancer prevention.

Ip C, Lisk DJ.

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

We previously reported that garlic cultivated with selenium fertilization is superior to regular garlic in mammary cancer prevention in the rat 7,12-dimethylbenz[a]anthracene (DMBA) model (Nutr. Cancer, 17, 279-286, 1992). A new crop of high-selenium garlic was harvested in 1992 and was used in a dose-response study to confirm the reproducibility of the product and the bioassay. Supplementation of 1 or 2 p.p.m. Se in the diet from the high-selenium garlic produced a 56% or 75% reduction respectively in the total tumor yield. Since both garlic and onion belong to the same allium family of vegetables, we were also interested in finding out whether our experience with garlic could be similarly applied to onion. A high-selenium onion crop was grown in the same season and location and with the same schedule of selenium fertilization. Two distinct differences were noted with the high-selenium onion regarding its capacity to accumulate selenium and its efficacy in cancer prevention. First, the selenium concentration in onion was considerably lower (28 p.p.m. Se dry wt) as compared to that found in garlic (110-150 p.p.m. Se). Second, given the same levels of selenium supplementation, the high-selenium onion was apparently not as powerful as the high-selenium garlic in mammary cancer inhibition. Thus different plants, even those of the same genus, may respond in their unique way to selenium fertilization and the biological benefits of selenium enrichment may vary depending on the species. Additional information from our study indicated that the high-selenium garlic/onion might provide an ideal system for delivering selenium-substituted analogs in a food form for cancer prevention: (i) they expressed a good range of anticancer activity and could be easily adapted for human consumption on a regular basis; (ii) their ingestion did not result in an excessive accumulation of tissue selenium, a concern that is associated with the standard selenium compounds such as selenite and selenomethionine; (iii) no perturbation in the maintenance of functional selenoenzymes were observed even at high levels of supplementation.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7923581&dopt=Abstract garlic



garlic
A prospective cohort study on Allium vegetable consumption, garlic supplement use, and the risk of lung carcinoma in The Netherlands.

Dorant E, van den Brandt PA, Goldbohm RA.

Department of Epidemiology, University of Limburg, Maastricht, The Netherlands.

The association between the consumption of onions and leeks (vegetables belonging to the Allium genus), garlic supplements, and the risk of lung carcinoma was investigated in a large-scale prospective cohort study on diet and cancer in the Netherlands. The Netherlands Cohort Study was started in 1986 among 120,852 men and women, ages 55-69 years, by collecting information on usual diet and important life-style characteristics. After 3.3 years of follow-up, 550 incident lung carcinoma cases were observed. Information on Allium vegetable consumption was available for 484 lung carcinoma cases and 3123 members of a randomly sampled subcohort. In stratified analysis, a lower lung carcinoma risk was observed in the highest onion intake category [rate ratio (RR) = 0.65; 95% confidence interval, 0.45-0.95] compared to the lowest consumption category. After including other, dietary and nondietary, determinants of lung carcinoma in the multivariable models and using pack years for past and current smoking, instead of using smoking status categorized as never, ex-, and current smoking, the rate ratio in the highest intake category increased to 0.80 and was no longer significantly different from unity (95% confidence interval, 0.52-1.24). Leek consumption was not associated with risk for lung carcinoma (RR = 1.08; 95% confidence interval 0.80-1.45 in the highest intake category, compared to the lowest). No statistically significant trends in the rate ratios associated with increasing consumption of these vegetables were detected for lung carcinoma or the four histological subtypes. A higher lung carcinoma risk was observed for those subjects who used exclusively garlic supplements (RR = 1.78; 95% confidence interval, 1.08-2.92), compared to those not taking dietary supplements. A lower lung carcinoma risk was seen for those using garlic supplements together with any other supplement (RR = 0.93; 95% confidence interval 0.46-1.86) compared to those using any other supplement. In conclusion, we found no evidence of a relation between the consumption of onions or leeks and the risk of lung carcinoma or any of the histological subtypes. Garlic supplement use seems not associated with a lower risk of lung carcinoma.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7954460&dopt=Abstract garlic



garlic
Anti-arrhythmic profile of a garlic dialysate assayed in dogs and isolated atrial preparations.

Martin N, Bardisa L, Pantoja C, Vargas M, Quezada P, Valenzuela J.

Departamento de Farmacologia, Facultad de Ciencias Biologicas, Universidad de Concepcion, Chile.

The effects of garlic (Allium sativum L., Liliaceae) dialysate were studied on arrhythmias induced in anaesthetized dogs and on isolated left rat atria. Garlic dialysate suppressed premature ventricular contractions (PVC) and ventricular tachycardia (VT) in ouabain-intoxicated dogs as well as the ectopic rhythms induced by isoprenaline (10(-6) M) and aconitine (10(-8) M) on electrically driven left rat atria. The effective refractory period (ERP) and the sinus node recovery time (SNRT) of isolated rat atria were prolonged in a dose-dependent manner by the administration of this extract. Garlic dialysate decreased the positive inotropic and chronotropic effects of isoprenaline in a concentration-dependent manner. These last effects were increased by propranolol. The results suggest that garlic dialysate has a significant antiarrhythmic effect in both ventricular and supraventricular arrhythmias.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7967644&dopt=Abstract garlic