Context: Centaurea L. (Asteraceae) species used as herbal remedies in Turkish traditional medicine have shown several biological properties. Objective: Extracts obtained from the aerial parts of Centaurea aphrodisea Boiss., Centaurea athoa DC. , Centaurea hyalolepis Boiss ., Centaurea iberica Trev . and Centaurea polyclada DC. were evaluated for their antioxidant, cytotoxic and anti-inflammatory activities. Materials and methods: Extracts of Centaurea species were tested for their antioxidant activity in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) screening assays and for i n vitro anti-inflammatory activity by Nf-κB and iNOS inhibition assays. The extracts were tested for their in vitro cytotoxicities against a panel of human solid tumor cell lines (SK-MEL: malignant melanoma, KB: oral epidermal carcinoma, BT-549: breast ductal carcinoma and SK-OV-3: ovary carcinoma) as well as non-cancerous kidney fibroblast (Vero) and kidney epithelial cells (LLC-PK1) by Neutral Red assay. In vivo anti-inflammatory activity of C. athoa was evaluated by the carrageenan-induced paw edema test in rats. Results: Antioxidant activities were observed for methanol extracts of plants. C. polyclada had the strongest effect on BT-549, KB and SK-OV-3 cell lines (30, 33 and 47 µg/ml, respectively). Nf-κB inhibition of chloroform extract of C. athoa was determined equivalent to positive control parthenolide (IC50: 6 µg/ml). This extract also showed anti-inflammatory activity by the carrageenan-induced paw edema test in rats, in all hours at a dose of 50 mg/kg compared to the control group. Discussion and conclusion: C. athoa is suggested to be a potential source of lead compounds for inflammatory diseases due to the significant in vitro and in vivo anti-inflammatory results. [ABSTRACT FROM AUTHOR]