Antioxidant properties of the methanol extracts from the leaves of Paullinia pinnata.

Paullinia pinnata is an African woody vine widely used in traditional medicine for the treatment of malaria. In order to throw more light into its mechanisms of pharmacological actions, the in vitro antioxidant activities of the methanol extract of its leaves were evaluated using different testing systems. Its scavenging activities on 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid radicals as well as its ferric ion reducing power were assessed. The results showed that P. pinnata possessed strong scavenging activity and moderate reducing power. The total phenol, flavonoid, and proanthocyanidin contents of the extracts were very close to those reported for most medicinal plants and showed good correlation with its antioxidant activities. These properties are probably part of the reasons why P. pinnata is effective in folk medicine.