Effects of different pretreatments on flavonoids and antioxidant activity of <i>Dryopteris erythrosora</i> leave

Abstract Flavonoids with wide bioactivity for medcine are vital secondary metabolite of plant. The factors influenced on flavonoids had been reported. However, as the key processes lead to metabolite alterations, the influences of the different pretreatments of samples on flavonoids and antioxidant activity of ferns were with little information. Therefore, Dryopteris erythrosora leaves were chosen as the materials for analyzing flavonoids alterations, which would not only provide the significant basic data for flavonoid metabolism of fern, but also for further developing fern resources. The results showed that a) The total flavonoids contents of D. erythrosora leaves with different pretreatments were obviously different. The total flavonoid contents of samples, which was dried in shade firstly and then dried at 75 °C in oven, finally smashed, was the highest (7.6%), but that of samples, which was quickly dried at 75 °C in oven directly after cleaning and then smashed, was the lowest (2.17%); b) Antioxidant activities of D. erythrosora leaves with different pretreatments were variant. Samples, which were dried in shade firstly and then dried at 75 °C in oven, finally smashed and samples which were firstly dried in the sun and then dried at 75 °C in oven, ultimately smashed, both showed stronger antioxidant activity; c) Total twenty-three flavonoids with four different pretreatments were tentatively identified by HPLC-ESI-TOF-MS. In conlusion, a) The influences of different pretreatments on flavonoids and antioxidant activity of D. erythrosora Leaves were obvious. b) The best pretreatment in respect to conserving fern medical application was drying in shade firstly and then drying at 75 °C in oven, finally smashed.