Phenolic profile, antioxidant and enzyme inhibitory potential of Onosma tauricum var. tauricum

Abstract

This study focused on phytochemical characterization and biological evaluation, both antioxidant and enzymatic inhibition, of ethyl acetate (OTT-EtOAc), methanol (OTT-MeOH), and water (OTT-W) extracts from Onosma tauricum var. tauricum aerial parts. The OTT-W extract was found to be the richest one in terms of its phenolic and flavonoid contents. Amounts of the phenolic and flavonoid compounds were determined as 40.88 mu mol GAEs/g and 7.40 mu mol REs/g dry plant (dp), respectively. The OTT-MeOH and OTT-W extracts were also found to contain significant amounts of chlorogenic acid, rosmarinic acid, p-hydroxybenzoic acid, caffeic acid, rutin, p-coumaric acid, trans-cinnamic acid, luteolin, and apigenin. The OTT-W extract showed remarkable antioxidant activity in phosphomolybdenum, ferrous ion chelating, reducing power, and radical scavenging assays. The OTT-MeOH extract exhibited inhibitory activity on acetylcholinesterase (AChE) (54.62 mu mol GALAEs/g dp), while the extracts remained almost inactive on butyrylcholinesterase (BChE). The OTT-W extract also exhibited inhibitory activity on tyrosinase (90.66 mu mol KAEs/g dp) and alpha-glucosidase (2258.87 mu mol ACEs/g dp). The results suggest that especially the OTT-MeOH and OTT-W extracts can be used as a source of alternative natural products in the treatment of diseases caused by the enzymes evaluated here.