DPPH RADICAL SCAVENGING ACTIVITY OF SOME MEDICINAL PLANT EXTRACTS AND COMPOUNDS

Tóm tắt

The DPPH^• radical scavenging activity assay was used to screen and evaluate the antioxidant activities of eight methanol extracts and 22 pure compounds. The results revealed the high antioxidant potential of four extracts from Decaspermum gracilentum, Uvaria simaensis, Syzygium attopeuense, and Cratoxylum cochinchinensis with the greatest ascorbic acid equivalent and gallic acid equivalent of 0.25 mg ascorbic acid (AA) equivalents/mg sample, and 0.05 mg gallic acid (GA) equivalents/mg sample, respectively. Two pure compounds quercetin 3-O-(6-O-α-L-rhamnopyranosyl)-β-D-glucopyranoside isolated from Anodendron paniculatum and epi-catechin isolated from Uvaria fauveliana had ascorbic acid equivalent greater than 0.30 mg AA equivalents/mg sample. Epi-catechin expressed higher antioxidant activity than ascorbic acid. This is the first time the antioxidant activity of these extracts and compounds has been reported. Furthermore, our adapted DPPH assay employing a microplate reader offers a convenient and relatively high-throughput approach for antioxidant screening.