Antioxidant activity and phytochemical composition of Osmanthus fragrans' pulps

•Eight compounds were isolated from O. fragrans' pulps for the first time.•DPPH, ABTS, and FRAP assays are used for evaluating the antioxidant capacity.•n-Butanol fraction (NBF) shows the best antioxidant activity.•Salidroside and phillyrin may be for the antioxidant activity in NBF.

Purification of the ethanol extract of Osmanthus fragrans' pulps led to the isolation of eleven compounds, namely 5-hydroxymethylfurfural (1), hydroxytyrosol (2), pinoresinol (3), oleoside-7,11-dimethyl ester (4), oleoside-11-methyl ester (5), verbenalin (6), phillyrin (7), salidroside (8), β-sitosterol (9), octadecanoic acid (10), and octane (11). Their structures were identified by mass and various nuclear magnetic resonance spectroscopic techniques. All compounds except for 5, 7, and 9 were isolated from O. fragrans for the first time. Ethanol extract and its fractions of O. fragrans' pulps were investigated for their antioxidant properties using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2′,2′-azinobis (3-ethylbenzothiazline-6-sulfonic acid) (ABTS) radical scavenging capacity assay, and ferric reducing antioxidant potential (FRAP) assay. Based on the antioxidant experiments of crude ethanol extract and its fractions, n-butanol fraction shows the best antioxidant activity, salidroside and phillyrin may be the highest contributors and responsible for the antioxidant activity in the n-butanol fraction.