Bioactive constituents from the methanolic extract (ME) and ethylacetate extract (EA) of Plumbago zeylanica were characterized by gas chromatography-mass spectrometry. The free radical scavenging activities of ME and EA was determined using 1,1-diphenyl-2-picryl-hydrazyl (DPPH). Major bioactive compounds found in the ME includes oxalic acid allyltridecyl ester, decane, 2-piperidinone-N-[4-bromo-n-butyl] and tetradecane, compounds obtained from EA were 1-(ethenyloxyl) octadecane and cis-13-octadecenoic acid. Cis-13-octadecenoic acid, though known, was isolated for the first time from the root of P. zeylanica. The highest percentage antioxidant activities of ME and EA were 98.5% and 45.5% respectively at 350 µg/ml concentration of extracts. Results obtained from this study justify the use of P. zeylanica in traditional medicine for treatment of different ailments and it could be a potential source for novel drug compounds.
Keywords: DPPH, Plumbago zeylanica, bioactive compounds, gas chromatography-mass spectrometry