Antioxidative activity of water extracts of herbs

Antioxidative activity of water extract of herbs was investigated. The fresh leaves of herbs were cutted to small pieces and were allowed to stand for 10-15 minutes in hot buffer, then they were filtered off. The antioxidative activity of the water extracts was determined by ferric thiocyanate method and 1, 1-diphenyl-2-picrylhydrazyl (DPPH) method. As the result, the high antioxidative activity of curry plant and sweet lavender against linoleic acid was newly revealed by the ferric thiocyanate method, and nutmeg, sweet lavender, and super aloe showed a quite high radicalscavenging activity by the DPPH method. The antioxidative activity of polyphenols in curry plant, which was extracted with ethyl acetate from water extract of curry plant, was measured by the DPPH method. Resultingly, 25% of the total radical-scavenging activity of curry plant seemed to depend on the polyphenols. The polyphenols in curry plant were identified as gallic acid, pyrocatechol, catechin, dihydroxybenzoic acid, and epigallocatechin gallate (EGCg), and so on by using high performance liquid chromatography using ODS column. The main components of polyphenols were dihydroxybenzoic acid, EGCg, and catechin. EGCg had the greatest DPPH radical-scavenging activity.