Enhanced formation of quercetin by combined use of gamma ray and H ₂O ₂ from cyanidin-3-O-xylosylrutinoside

Cyanidin-3-O-xylosylrutinoside (cya-3-O-xylrut), a major pigment in Schizandra chinensis Baillon, was effectively removed by gamma irradiation of greater than 2kGy, whereas quercetin, the most abundant of the flavonoids and has anti-inflammatory and anti-allergic effects, could be generated by degradation of cya-3-O-xylrut. In the present study, we investigated the effect of combination treatment of gamma irradiation and hydrogen peroxide (H ₂O ₂) on the formation of quercetin through the degradation of cya-3-O-xylrut. Cya-3-O-xylrut was significantly degraded (~93%) by gamma irradiation at 2kGy and it was completely removed by a combination treatment (0.2% H ₂O ₂ and 2kGy gamma ray). The formation of quercetin was significantly appeared at 2kGy of gamma ray, together with disappearance of cya-3-O-xylrut. The quercetin formation by gamma ray is 3.2μg/ml and combination treatment is 7.7μg/ml. Therefore, the combination treatment of H ₂O ₂ and gamma ray is more effective to convert cya-3-O-xylrut into quercetin than gamma irradiation only. In conclusion, gamma ray combined with H ₂O ₂ would be a promising tool for bio-conversion of organic compounds.