ABSTRACT

Hypericum perforatum L. (St. John’s Wort) is a reputed plant with a long service to humankind. In the current study, antioxidant activity of the methanol extract of the aerial parts of H. perforatum growing in Turkey along with hyperoside and hyperforin was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, metal-chelation, and ferric-reducing antioxidant power (FRAP) assays. The major components including chlorogenic acid, the flavonoid derivatives; rutin, hyperoside, quercitrin, quercetin, and biapigenin, the naphthodianthrons; pseudohypericin and hypericin, and the phloroglucinol derivatives; hyperforin and adhyperforin were quantified in the extract by LC-DAD-MS. Hypericin (16 ± 0.08 μg/g) and hiperforin (1164 ± 0.02 μg/g) contents in H. perforatum were found to be in accordance with the amounts required by the European Pharmacopeia. The extract and hyperoside exerted a remarkable antioxidant activity in DPPH radical scavenging and FRAP assays, whereas they did not have metal-chelation capacity.