Phytochemical profile, antioxidant capacity, and carbonic anhydrase inhibition of Olea europaea L. (cv. Gemlik and Ayvalik) leaves: a green extraction approach

Abstract

The extraction of medicinal plants has received attention due to their antioxidant and enzymatic properties and their potential in herbal remedies. In this study, the antioxidant activity, inhibitor effect of the carbonic anhydrase enzyme, and phytochemical content of two different varieties of Olea europaea L. extracts ( Olea europaea L. Ayvalik, Olea europaea L. Gemlik), which were obtained using ultrasound-assisted extraction (UE) that has two different solvents and two different extraction times, were evaluated using Spectrophotometric assays and Ultra Performance Liquid Chromatography-UV (UPLC-UV) analysis. The hydroalcoholic extracts from Olea europaea L. Ayvalik specie obtained by a 30-min UE procedure exhibit the highest rosmarinic acid content (8.42 ± 0.02 µg/mL extract), as well as a significant inhibitor effect of the carbonic anhydrase enzyme (IC 50 334.64 ± 1.16 µg/mL), and Olea europaea L. Gemlik specie obtained by a 15-min UE has the the highest antioxidant capacity with EC 50 211.75 µg/mL. In addition, the contribution of rosmarinic acid content to the diuretic activity of Olea europaea L. extracts was revealed for the first time using a new proposed UPLC-UV method. The hydroalcoholic extracts from the leaves of Olea europaea L. represent a potential source of rosmarinic acid and exhibit beneficial antioxidant and diuretic properties in pharmaceuticals, food supplements, nutraceuticals, and as a herbal remedy.