Abstract: The metabolites of procyanidin A2 (PCA2) were analyzed using ultra performance liquid chromatographyquadrupole- time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS) after incubation with the rat intestinal microbiota in vitro. The total antioxidant capacity (T-AOC) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azino-bis-(3- ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging ability of PCA2 and its metabolites at different incubation times were measured and compared. PCA2 was degraded by 77.28% at 6 h and by 90.07% at 24 h of incubation. Eight metabolites were identified namely: 4-hydroxyphenylacetic acid, epicatechin, 3-(4-hydroxyphenyl) propionic acid, B type proanthocyanidins, 5,7,2’-trihydroxyflavanone, and three unknown compounds. The antioxidant capacity of PCA2 was enhanced significantly after incubation. T-AOC, DPPH, ABTS radical scavenging ability after incubation for 6 h were significantly increased by 2.01, 2.16 and 1.34 times, respectively compared with that before incubation. The results suggested that the activity of PCA2 might be partially attributed to its intestinal microbial metabolites.

Key words: procyanidins A2, intestinal microbiota, metabolites, antioxidant activity