Enzyme and biological activities of the water extracts from the plants Aesculus hippocastanum, Olea europaea and Hypericum perforatum that are used as folk remedies in Turkey

Phenolic compounds are secondary metabolites that are found ubiquitously in plants, fruits, and vegetables. Many studies have shown that regular consumption of these compounds could have a positive effect on our healthiness. The aim of this study was to compare the phytochemical contents of the water extracts from three different plants used as folk remedies in Turkey: Aesculus hippocastanum, Olea europaea, and Hypericum perforatum. A liquid chromatography–electrospray tandem mass spectrometry (LC–ESI–MS/MS) analysis was performed to explore the phenolic profiles. The biological activities of these extracts were also evaluated in terms of their antioxidant activities (DPPH, ABTS, FRAP, CUPRAC, β-carotene, phosphomolybdenum and metal chelating) and enzyme inhibitory properties (against acetylcholinesterase, butyrylcholinesterase, and tyrosinase). The aqueous extract of H. perforatum showed the highest levels of total phenolic, flavonoid and saponin contents. Protocatechuic acid, vanillic acid, verbascoside, hesperidin, hyperoside, apigenin-7- hexosides and quercetin were the most common compounds found in this species. The results confirm that A. hippocastanum, O. europaea and H. perforatum represent a potential source of natural-derived molecules with positive properties that could be used as valid starting point for new food supplements, and drugs in the pharmaceutical, cosmetic and food industries.