Abstract: The in vivo antioxidant capacity of total flavonoids from the seeds of Passiflora edulis Sims were studied by measuring total superoxide dismutase (T-SOD) activity, catalase (CAT) activity, glutathione peroxidase (GSH-Px) activity, malondialdehyde (MDA) content and the content of protein carbonyl in liver and kidney tissues of a mouse model of D-galactose-induced oxidative damage after oral administration with the total flavonoids. Results showed that the total flavonoids could significantly increase T-SOD, CAT and GSH-Px activities (P < 0.05), and reduce the contents of MDA and protein carbonyl in mouse liver and kidney tissues (P < 0.05), indicating good antioxidant capacity in vivo. Based on gradient elution using methanol (A) and 0.25% formic acid (B) as mobile phase, the flavonoids were analyzed by liquid chromatography coupled with electrospray ionization-quadrupole-time of flight mass spectrometry (LC-ESI-Q-TOF-MS). According to the accurate mass spectral information obtained from excimer and fragment ions as well as literature data, 4 constituents were tentatively presumed, including 2-(3,4-dihydroxyphenyl)-5,7-dihydroxy-6-isopentyl-4H-chromen-4-one, 2-(4-hydroxyphenyl)-3,6-dimethoxy-8,8-dimethyl-4H,8H-pyrano[2,3-f]chromen-4-one, 5-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-3-methoxy-7-((3-methylbut-2-en-1-yl)oxy)-4H-chromen-4-one, and 7-((4-methoxybenzyl)oxy)-3-(2-methoxyphenyl)-4-oxo-4H-chromene-2-carboxylate.

Key words: seeds of Passiflora edulis Sims, flavonoids, in vivo antioxidant activity, liquid chromatography coupled with electrospray ionization-quadrupole-time of flight mass spectrometry