Abstract

The aim of this study was to examine the antioxidant activities and phenolic components of the crude extracts of 10 Desmodium species from Taiwan. In this study, DPPH free radical scavenging activity, ABTS radical monocation scavenging activity, ferric-reducing antioxidant power (FRAP) and reducing power of the 10 Desmodiumspecies were evaluated for their antioxidant activities. The results showed that, of all the samples, Desmodium sequax was the most active in ABTS, DPPH, FRAP and reducing power assays. The total polyphenol, total flavonoid and total flavonol contents of the crude extract were calculated. The correlation coefficient (R²) values of TEAC with phenolic compounds indicated strong positive correlations, except for total flavonoid content. Furthermore, HPLC chromatographic fingerprints were established, and chlorogenic acid and vitexin in D. sequax were quantified. Chlorogenic acid was confirmed to express strong antioxidant activities in ABTS, DPPH, FRAP and reducing power assays. The present study indicated the antioxidant activities of the 10Desmodium species were related to their phenolic components. D. sequax is a potent antioxidant medicinal plant, and chlorogenic acid may be an important factor in the antioxidant activity of this plant.

Key words: Desmodium, antioxidant activity, chlorogenic acid, vitexin