Phenolic content and antioxidant activity of Phymatopteris hastata

Various solvent extracts of Phymatopteris hastata, a traditional Chinese medicinal material, were screened for their antioxidant activities. Four systems of in vitro testing were employed to investigate the antiradical and antioxidant effect, i.e., the 2,2-diphenyl-1-picryhydrazyl (DPPH) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) systems, the hydroxyl radical scavenging assay and the reducing power. In addition, butylated hydroxytoluene (BHT), a widely used synthetic antioxidant, was also studied for comparison. The results revealed that the ethyl acetate extract exhibited outstanding antioxidant activities, which was close or even superior to BHT. Furthermore, the total phenolic (TP) and total flavonoid (TF) contents of different extracts were measured, expressed as gallic acid and rutin equivalent, respectively. The antioxidant activities and the TP/TF content of different extracts followed the same order: ethyl acetate extract > butyl alcohol extract > >petroleum ether extract, showing a good correlation between the antioxidant activities and the TP/TF content. The results showed that these extracts, especially the ethyl acetate extract, were rich in phenolics and flavonoids and could be considered as natural antioxidants.