Antioxidant Activity of Fruits of Ligustrum japonicum

Abstract

The objective of this study is to evaluate the antioxidant activity of the fruits of Ligustrum japonicum. The crude extract was successively fractionated into n-hexane, 85% aqueous methanol (85% aq.MeOH), n-butanol (n-BuOH), and water fractions by means of solvent polarity. The crude extract and its solvent fractions were evaluated for their antioxidant effect by four different assay systems: scavenging power on peroxynitrite and intralcellular ROS produced in HT-1080 cells; DNA oxidation inhibition; ferric reducing antioxidant power (FRAP). The n-BuOH fraction exhibiting potent antioxidant activity was further purified by C18 silica gel column chromatography and RP-HPLC to give tyrosol (1) and salidroside (2). The structure of isolated compounds was determined by extensive 2 D NMR experiments such as H COSY, NOESY, HSQC and HMBC as well as by comparison with the published spectral data.