Assessment of phenolics contents and antioxidant properties in Cimicifuga dahurica (Turcz.) Maxim during drying process

Cimicifuga dahurica (Turcz.) Maxim is usually used as traditional Chinese medicine and functional tea. In present work, the change of its phenolics profiles and antioxidant activities during drying processes were investigated. Nineteen main bioactive analytes of C. dahurica were simultaneously quantified by HPLC-DAD to assess the effect of drying method. Meanwhile, the influence of different drying processes on antioxidant activities were evaluated by DPPH (1,1-diphenyl-2-picrylhydrazyl), ABTS [2,2′-Azino-bis-(3-ethylbenzthiazoline-6-sulphonate)], FRAP (ferric reducing antioxidant power) and hydroxyl radical scavenging method. Results showed that drying method had significant effects on the contents of phenolics and antioxidant properties. The appropriate drying method was oven-dried at 110 °C. Moreover, the content of phenolic acids and antioxidant activity showed significant correlation coefficient. And the most effective constituents contributing to antioxidant activity were isoferulic acid (8), cimicifugic acid B (14) and 2-isoferuloyl piscidic acid (16).