[Study on antioxidant activity of constituents from mulberry leaf].

Objective: To study the chemical constituents with antioxidant activity from mulberry leaf.

Methods: Siliga gel column chromatography was used to isolate, and their structures were identified by spectras.

Methods: Isolated constituents were tested in vitro for antioxidant activity against 1, 1-diphenyl -2-picrylhydrazyl (DPPH) and 2, 2' -azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS+) radicals.

Results: Four known flavonoids were isolated from mulberry leaf and their structures were identified as kaempferol-3-O-beta-D-glucopyranoside (I), quercetin-3-O-beta-D-glucopyranoside (II), quercitrin (III), morin-3-O-beta-D-glucopyranoside (IV). All these compounds showed DPPH and ABTS+ radicals scavenging activity.

Conclusion: Compound IV has the strongest ABTS+ radicals scavenging effects.