[en] The cyanidin-3-O-xylosylrutinoside (cya-3-O-xylrut) is one of the most abundant anthocyanin, which is responsible for the red, purple, and blue colors of most fruits and vegetable, in the fruit of Schisandra chinensis Baillon and raspberries. Especially the cya-3- O-xylrut is a major anthocyanin accounting for about 94% in the fruits of S. chinensis, which is a unique source of highly pure cya-3-O-xylrut, and exhibits high antioxidant activity. Previously, we reported that the red color of the S. chinensis fruit extract dramatically disappeared in a dose-dependent manner of gamma irradiation. The color of S. chinensis was effectively removed at 2 kGy of gamma irradiation, even at 1 kGy resulted in a 50% reduction. Interestingly, the destruction of cya-3-O-xylrut by gamma irradiation led to generate flavonoids such as quercetin and unknown compounds. Quercetin, a typical flavonoltype flavonoid, is one of the most prominent dietary antioxidants. It is ubiquitously present in fruits and vegetables. Quercetin exhibits various biological activities such as anti-oxidative, anti-inflammatory, anti-allergic, vasodilating, and anti-cancer effects. In the present study our purpose is to develop a promising tool for bio-conversion of organic compounds by combination treatment of H₂O₂ and gamma ray