Identification on antibacterial activity and antioxidant activity of nine Apocynaceae and Euphorbiaceae plants

ObjectivePlants secondary metabolites with antibacterial and antioxidant activities were screened to pro-vide theoretical basis for the development and utilization of Apocynaceae and Euphorbiaceae plants.MethodThis study focused on five common Apocynaceae plants and four common Euphorbiaceae plants in southern China.The plant extracts were prepared by methanol soaking extraction at room temperature and ethyl acetate extraction.The antibacterial and anti-oxidant activities of the extracts from nine plants were determined by thin layer chromatography(TLC)autobiography method.Polarity and activity of the compound in samples were preliminarily evaluated by spots and mobility of the spots (Rf),and the activity of the compounds were determined by spot diameter.ResultEight plant extracts except for Aporu-sa dioica extract showed inhibitory activities against the tested bacteria.Excoecaria cochinchinensis,Alchornea trewioi-des and Cleidiocarpon cavaleriei performed strong antibacterial activities against seven test bacteria,and the diameters of the inhibition spot of both E.cochinchinensis and C.cavaleriei were more than 10 mm.Rfvalues fell into the range be-tween 0 and 0.13,which indicated that the polarity of active compounds were large.In addition,apart from Strophanthus divaricatus in Apocynaceae,the remaining eight plant extracts performed certain antioxidant activities.Among them,A.trewioides showed the strongest antioxidant activity,whose Rfvalue was 0-0.52 and antioxidant spot diameter was 5-10 mm.ConclusionTLC-autobiography method can determinate and screen plant extracts with antibacterial and antioxidant activities rapidly.A.trewioides,E.cochinchinensis and C.cavaleriei can be candidate plant resources with antibacterial ac-tivities and Alchornea trewioides is candidate plant resource with antioxidant activity.