The main objective of the current study was intended for isolation of bioactive compounds from the leaves of Ageratina adenophora (Sprengel) and their characterization. Crude extracts of A.adenophora were prepared using various solvents such as petroleum ether, chloroform, ethyl acetate, and methanol. The chloroform extract showed the presence of higher flavonoid content when compared with other solvent extracts. The chloroform extract was subjected to column chromatography and the eluted fractions were checked by thin layer chromatographywith different solvent ratio. Single compound was isolated which was subjected to spectral characterization. The characterization techniques confirmed that the isolated compound wasQuercetin. Petroleum ether and methanol extracts were subjected tofree radical scavenging activitieswhich suggests that petroleum ether and methanol extracts exhibited better activity and actsaneffective source of antioxidants and anti-cancer agents.