Antioxidant activities of extracts from five anti-viral medicinal plants.

The antioxidant activities of five medicinal plants (Ampelopsis sinica, Ampelopsis humiliforlia var. heterophylla, Potentilla freyniana, Selaginella labordei and Chrysanthemum multiflorum), used in the Hubei province of China, have been investigated using both enzymatic and non-enzymatic in vitro antioxidant assays. Extracts from all five of the plants inhibited xanthine oxidase and lipoxygenase activities, and were scavengers of the ABTS*+ radical cation using the Trolox equivalent antioxidant capacity assay (TEAC). Extracts from Potentilla freyniana and Selaginella labordei down-regulated cyclooxygenase-2 gene expression, measured by real-time RT-PCR, in human colon adenocarcinoma CaCo-2 cells.