This is the first study on phytochemical analysis and biological evaluation of Hypericum capitatum Choisy var. capitatum (HCC) endemic to Turkey with exception of essential oil analysis. Hyperoside and isoquercetin (25.7 +/- 0.02 and 17.8 +/- 0.02 mu g/mg extract, respectively) were determined as the main compounds of the methanol extract. The major compounds of essential oil of HCC were found to be spathulenol and iso-longifolene (12.9% and 11.2%, respectively), and linoleic and palmitic acids (26.8% and 18.3%, respectively) were the main fatty acids. The methanol extract whose antioxidant activities studied for the first time was found to have moderate activity in beta-carotene bleaching method (IC50: 41.69 +/- 1.29 mu g/mL) and was found to be the most active extract in scavenging of DPPH free radical (IC50: 16.82 +/- 0.58 mu g/mL) and ABTS cation radical (IC50: 9.24 +/- 0.28 mu g/mL) and CUPRAC assays. Among the prepared four extracts of HCC, the methanol extract showed highest activity against Escherichia coli with an MIC value of 10 mu g/mL, and the methanol extract was also found to have high DNA damage protective activity. The methanol extract exhibited high butyrylcholinesterase inhibitory activity (70.74%). Thus, H. capitatum var. capitatum can be regarded as a potential natural antioxidant, antimicrobial, anticholinesterase source and DNA damage inhibitor. (C) 2016 SAAB. Published by Elsevier B.V. All rights reserved.