Characterisation of water-soluble proanthocyanidins of Pyracantha fortuneana fruit and their improvement in cell bioavailable antioxidant activity of quercetin

Proanthocyanidins (PCs) with poor bioavailability were argued for their health benefits. In this study, water-soluble polymeric polyphenolic PCs fractions from Pyracantha fortuneana fruit were used to investigate whether the presence of PCs is correlated with the increased cell antioxidant activities (CAA) of quercetin (Q). The results indicated that the most decrement in the values of EC50, which Q inhibited peroxyl radical-induced DCFH oxidation effective in the HepG2 cells, was observed to be 2.91 (vs. control 5.97) in the present of the fraction with 15.8 of the average degree of polymerisation of PCs (ADP). Also, the order of efficacy was the same with the ADP of PCs. Further, this effect is associated with the improvement of the solubility and stability of Q after the addition of the PCs. Our current study suggests that the additive effects of PCs on small molecular polyphenols may be responsible for their antioxidant benefits in vivo.