摘要: AIM:To investigate the in vitro antioxidant activity and total phenolic content of the methanolic leaf extract of Nyctanthes arbor-tristis L.(NA).METHODS:The sample was tested using five in vitro antioxidant methods(1,1-diphenyl-2-picryl hydrazine radical scavenging activity(DPPH),hydroxyl radical-scavenging activity(-OH),nitric oxide scavenging activity(NO),superoxide radical-scavenging activity,and total antioxidant activity) to evaluate the in vitro antioxidant potential of NA and the total phenolic content(Folin-Ciocalteu method).The extract showed good free radical scavenging property which was calculated as an IC50 value.RESULTS:IC50(Half maximal inhibitory concentration) of the methanolic extract was found to be 57.93 μg·mL-1 for DPPH,98.61 μg·mL-1 for-OH,91.74 μg·mL-1 for NO,and 196.07 μg·mL-1 for superoxide radical scavenging activity.Total antioxidant capacity of the extract was found to be(1198±24.05) mg ascorbic acid for the methanolic extract.Free radical scavenging activity observed in the extracts of NA showed a concentration-dependent reaction.The in vitro scavenging tested for free radicals was reported to be due to high phenolic content in the leaf extract.The leaf extract of NA showed the highest total phenolic content with a value of 78.48±4.2 equivalent mg TAE/g(tannic acid equivalent).CONCLUSIONS:N.arbor-tristis leaf extract exhibited potent free radical scavenging activity.The finding suggests that N.arbor-tristis leaves could be a potential source of natural antioxidant.