Antioxidant Activity of Moutan Cortex Extracts by Multiple-Stage Extraction

Moutan cortex, a widely used traditional Chinese medicine for the treatment of various diseases, is the root bark of Peaonia suffruticosa Andrews (Paeoniaceae). In this study, the crude polysaccharides (CPS), paeonol and the crude total glycosides (CTG) of moutan cortex were extracted by the multiple-stage extraction. CPS was extracted by water, paeonol was distilled by steam distillation method, and CTG was extracted with ethanol after above two stages. The antioxidant activity of the extracts was evaluated with superoxide dismutase (SOD) and DPPH (1, 1-diphenyl-2-picryhydrazyl) radical scavenging activity assays. Among the three extracts, CTG exhibited the strongest SOD-like activity (510 U/mg) and DPPH radical-scavenging activity (EC50, 14.4 μg/ml), CPS had a weak SOD-like activity and DPPH radical-scavenging activity. Paeonol, however, was inactive. The different biological activities among the three extracts may be attributed to differences in their chemical composition, partially supported by polysaccharides, and polyphenolic contents.