Phenolic content, enzyme inhibitory and antioxidative activity potentials of Phlomis nissolii and P. pungens var. pungens

Due to the excellent ethnopharmacological uses or scientifically proved biological properties, members of the genus Phlomis is worth investigating. In this study, we reported antioxidant and enzyme inhibitory activities of the ethyl acetate, methanol and water extracts of Phlomis nissolii L. and P. pungens WILLD. var. pungens as well as their phenolic contents. Antioxidant activities were screened by β-carotene bleaching and phosphomolybdenum assays. Scavenging activities of the species were determined against 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2-Azino-bis (3-ethylbenzothiazloine-6-sulfonic acid) (ABTS), superoxide anion, and nitric oxide radicals. Additionally, reducing power (by cupric ion reducing activity - CUPRAC and ferric reducing antioxidant power - FRAP assays) and metal chelating effects of the samples were tested in vitro. The samples were also evaluated for their inhibitory activities against acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), tyrosinase, α-amylase, and α-glycosidase. Antioxidant activity of P. nissolii was found slightly higher than P. pungens var. pungens. In general, the best antioxidant activity was exhibited by the polar fractions (water extracts). In enzyme inhibition assays, both plants showed remarkable inhibition potential. Ethyl acetate extracts, especially, showed better inhibition capacity. Data presented for the antioxidant activities of the samples were found consistent with their phytochemical contents. According to HPLC analysis, (+)-catechin, chlorogenic acid, benzoic acid, and rosmarinic acid found as the major compounds for P. nissolii, while chlorogenic acid was the major phytochemical for the all fractions of P. pungens var. pungens.