Isolation and Purification of Bioactive Compounds from the Stem Bark of Jatropha podagrica

This paper reports the successive isolation and purification of bioactive compounds from the stem bark of , a widely known medicinal plant. The ethyl acetate extract of the stem bark exhibited the strongest antioxidant activity assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging, and ferric reducing antioxidant power (FRAP) assays (IC = 46.7, 66.0, and 492.6, respectively). By column chromatography (CC) with elution of hexane and ethyl acetate at 8:2, 7:3, and 6:4 ratios, the isolation of this active extract yielded five fractions ( ⁻ ). Chemical structures of the constituents included in ⁻ were elucidated by gas chromatography-mass spectrometry (GC-MS), electrospray ionization-mass spectrometry (ESI-MS), and nuclear magnetic resonance (NMR) and resolved as methyl gallate ( , , , ), gallic acid ( , ), fraxetin ( , , , ), and tomentin ( ). Mixture (IC DPPH and ABTS = 2.5 µg/mL) and (IC FRAP = 381 µg/mL) showed the highest antioxidant properties. Among the isolated fractions, was the most potential agent in growth inhibition of six bacterial strains including , , , and (MIC = 5, 20, 30, 20, 25, and 20 mg/mL, respectively). All identified constituents exerted an inhibitory activity on the growth of , of which the mixture performed the maximal inhibition on shoot (IC = 49.4 µg/mL) and root (IC = 47.1 µg/mL) growth. Findings of this study suggest that gallic acid, methyl gallate, fraxetin, and tomentin isolated from possessed antioxidant, antibacterial, and growth inhibitory potentials.