Abstract
A liquid chromatography-diode array detection-electrospray ionization mass spectrometric (HPLC–PDA-ESI/MS/MS) method was used for the analysis of the phenolic composition of the ethanolic extract obtained from the leaves of Pleiogynium timorense (DC.) Leenh. Twenty compounds were detected and tentatively characterized. In addition, further phytochemical investigations of the extract resulted in the isolation of twelve major phenolic compounds. Evidence of the structures of these compounds was obtained based on the interpretation of the UV, 1H NMR, 13C NMR and DQF-COSY spectral data. The antioxidant effect of the ethanolic extract was examined in vitro using 1,1-diphenyl-2-picrylhydrazyl (DPPH.) and super oxide anion radical scavenging assays. DPPH. radical scavenging activity was observed for the extract, with an IC50 of 21.9 μg/mL, while its super oxide anion scavenging activity was less pronounced, with an IC50 of 123.5 μg/mL The ethanolic extract showed significant hypoglycemic, antioxidant and anti-inflammatory properties. This study suggests that the ethanolic extract of Pleiogynium timorense is a potential source of antioxidant compounds, relatively non-toxic, and have possible beneficial health effects.