Antioxidant activities and chemical constituents of roots of Mondia whiteii (Hook. f.) Skeels

The antioxidant activities of different fractions of Mondia whiteii (Hook. f.) Skeels were measured by using three different assays (DPPH (1,1-diphenyl-2-picrylhydrazyl), ABTS(2,2'-azinobis-3-ethylbenzthiazoline-6-sulfonic acid) and FRAP (Ferric-Reducing Antioxidant Power), respectively). Total flavonoid and total phenol contents were also tested, and the chemical constituents of the dichloromethane fraction were further isolated and purified by AB-8 macroporous resin column chromatography (CC), Octadecylsilyl(ODSCC), Sephadex LH-20CC, and preparative-HPLC(High Performance Liquid Chromatography). Results showed that the dichloromethane fraction had the highest antioxidant activities and total phenol content. Furthermore, 10 compounds were obtained and identified, including 2-hydroxy-4-methoxybenzaldehyde(1), fraxetin(2), 7-metho-xycoumarin (3), α-hydroxypropiosyringone (4), ω-hydroxypropioguaiacone (5), cinnamic acid (6), salicylic acid (7), 4-methoxysalicylic acid (8), syringic acid (9), and azelaic acid (10). To the best of our knowledge, this study is the first to isolate compounds 3-10 from Mondia whiteii.