Antioxidant potential in non-extractable fractions of dried persimmon (Diospyros kaki Thunb.)

Dried fruits of persimmon (Diospyros kaki Thunb.) are a traditional food in Japan and contain large quantities of tannins. In this study, we investigated the in vitro and in vivo antioxidant potentials of non-extractable fractions from dried persimmons. Hydrolysed non-extractable fractions showed the highest antioxidant activities in vitro. In subsequent experiments, the plasma oxygen radical absorbance capacity (ORAC) values in rats supplemented with a 5% non-extractable fraction were approximately 1.5 times higher than those in control rats after 1 week in vivo. Furthermore, using an in vitro model of the gastrointestinal tract, the ORAC values of the non-extractable fraction were significantly increased with colonic fermentation in the large bowel stage. These data indicate that non-extractable fractions may possess significant antioxidant potential in vitro and in vivo.