Objective:To evaluate in vitro antioxidant and apoptotic activities ofCyperus rotundus(C. rotundus).Methods:The phytochemical study and the antioxidant activities of both methanol and aqueous extracts fromC. rotundus aerial part were determined.In addition, these extracts were also investigated for their cytotoxic and apoptotic activities.The major compound of the methanol extract was isolated.Both methanol and aqueous extracts(300,150, and50 μg/mL) were evaluated for their antioxidant activity by the xanthine/xanthine oxidase assay system.However, 16,8, and4 mg/mL of each extract were tested to investigate theirOH. formation scavenging potential.Aqueous extract(800,400, and200 μg/mL) and methanol extract(350,175, and88 μg/mL) were tested against lipid peroxidation, induced by75 μMH2O2.The cytotoxicity(byMTT assay) andcellDNA fragmentation of both extracts were evaluated towardsK562 andL1210 cell lines. The major compound was obtained from the butanol fraction of methanol extract and its structure was determined byRMN spectroscopic analysis.Results:The methanol and aqueous extracts showed respectively,88% and19% inhibition of xanthine oxidase activity.Yet, the same extracts inhibited lipid peroxidation by61.5% and42.0%, respectively.Both extracts inhibitedOH. formation by27.1% and25.3%, respectively.Only methanol extract inducedDNA degradation. Orientin was determined as the major compound isolated from the butanol fraction of methanol extract.Conclusions:It appears thatC. rotundus extracts exhibit a potential use as a natural antioxidant and an apoptosis inducer.