Hydroxyl Radical-scavenging Effects of Spices and Scavengers from Brown Mustard (Brassica nigra)

The effects of methanol extracts of 51 spices on ·OH scavenging were studied in detail. 2-Deoxyribose oxidation and sodium benzoic acid hydroxylation methods were used for detecting the scavenging activity of ·OH. Mustard varieties, thyme, oregano, clove, and allspice all exhibited strong ·OH-scavenging activity. In particular, 3 varieties of mustard had above 90% ·OH-scavenging activity with a 1 μg/ml concentration of their extracts. The ·OH scavenger of Brassica nigra (brown mustard) was isolated and purified by XAD-2 column chromatography and preparative HPLC, and was identified as a 3,5-dimethoxy-4-hydroxycinnamic acid methyl ester by MS, 'H-NMR, and 13C-NMR. The 3,5-dimethoxy-4-hydroxycinnamic acid methyl ester was prepared by methylating of sinapic acid with diazomethane.