Phytochemical Screening, Antiproliferative and Antioxidant Properties of Various Extracts from Endemic Origanum acutidens

Aim and Objective: Origanum acutidens (Hand.–Mazz.) Ietsw. is an endemic and perennial plant grown mainly in East Anatolia. Recently, natural plant products have attracted interest due to their safety and therapeutic effects. Therefore, the aim of this study was to investigate phytochemical contents and biological effects of Origanum acutidens. Materials and Methods: The aerial parts of O. acutidens were extracted with water, ethyl acetate, nbutanol, and methanol/chloroform solvents. Phenolic compounds and other constituents of the extracts were analyzed by HPLC/TOF-MS. The Ethyl Acetate extract (EA) was fractionated by flash chromatography. The extracts and fractions were investigated for their antiproliferative activities on human cervical adenocarcinoma (HeLa) cell line by using BrdU ELISA assay. Antioxidant activities of the extracts and fractions were evaluated by complementary test systems, namely determination of total phenolic contents, metal chelating ability and DPPH radical scavenging assay. Results: Among the extracts, Ethyl Acetate extract (EA) exhibited the highest antiproliferative activity (IC50 = 15.71 ± 0.04 μg/mL) on HeLa cells. It was therefore fractionated by flash chromatography to obtain 10 fractions which were investigated for their phenolic compounds and bioactivities. Rosmarinic acid was determined as the major component of EA and its fractions. EA exhibited higher antiproliferative activity against HeLa cell line than its fractions and 5-fluorouracil (5-FU) at the concentration of 100 μg/mL. EA and its fractions (F10, F6, F4, F7, F3, and F2) displayed higher radical scavenging activity compared to Butylated Hydroxytoluene (BHT). These effects may be attributed to the presence of rosmarinic acid in EA and its active fractions. Conclusion: This study demonstrated that O. acutidens is an essential natural source of polyphenols and a potent natural antioxidant and antiproliferative agent for food and pharmaceutical industries.