Alnus sibirica (AS) is geographically distributed in Korea, Japan, Northeast China, and Russia. Various anti-oxidant, anti-inflammation, anti-atopic dermatitis and anti-cancer biological effects of AS have been reported. Enzymatic hydrolysis decomposes the sugar bond attached to glycoside into aglycone which, generally, has a superior biological activity, compared to glycoside. Enzymatic hydrolysis of the extract (EAS) from AS was processed and the isolated compounds were investigated-hirsutanonol (1), hirsutenone (2), rubranol (3), and muricarpon B (4). The structures of these compounds were elucidated, and the biological activities were assessed. The ability of EAS and the compounds (1-4) to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and Nitroblue tetrazolium (NBT) superoxide, and to inhibit NO production was evaluated in vitro. EAS showed more potent antioxidant and anti-inflammatory activity than AS. All investigated compounds showed excellent antioxidant and anti-inflammatory activities.
Keywords: Alnus sibirica; anti-inflammatory; antioxidant; enzymatic hydrolysis; hirsutanonol; oregonin.