Lipid peroxidation and cyclooxygenase enzyme inhibitory activities of acidic aqueous extracts of some dietary supplements.

The botanical supplement market is growing at a fast pace with more and more people resorting to them for maintaining good health. Echinacea, garlic, ginkgo, ginseng, Siberian ginseng, grape seed extract, kava kava, saw palmetto and St John's wort are some of the popular supplements used for a variety of health benefits. These supplements are associated with various product claims, which suggest that they possess cyclooxygenase (COX) enzyme and lipid s inhibitory activities. COX enzymes are found to be at elevated levels in inflamed and cancerous cells. To test some of the product claims, selected supplements were analysed for their ability to inhibit COX-1 and -2 enzymes and lipid peroxidation in vitro. The supplements were extracted with acidified water (pH 2) at 37 degrees C to simulate the gastric environment. The supplements tested demonstrated varying degrees of COX enzyme inhibition (5-85% for COX-1 and 13-28% for COX-2). Interestingly, extracts of garlic (Meijer), ginkgo (Solaray), ginseng (Nature's Way), Siberian ginseng (GNC, Nutrilite, Solaray, Natrol), kava kava (GNC, Sundown, Solaray) and St John's wort (Nutrilite) selectively inhibited COX-2 enzyme. These supplements also inhibited lipid peroxidation in vitro (5-99%). The results indicated that the consumption of these botanical supplements studied possess health benefits.