An in vitro perspective to cholinesterase inhibitory and antioxidant activity of five Gentiana species and Gentianella caucasea

The dichloromethane (DCM), ethyl acetate (EtOAc), and methanol extracts from the leaves, roots, and flowers of the five species of Gentiana (Gentiana asclepiadea, Gentiana cruciata, Gentiana olivieri, Gentiana septemfida, and Gentiana verna) and Gentianella caucasea were investigated for their inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) and antioxidant effect using 2,2-diphenyl-1-picrylhydrazyl radical scavenging, metal-chelation capacity, and ferric-reducing antioxidant power assays. Total phenol and flavonoid contents of the extracts were determined spectrophotometrically. The presence of some characteristic compounds found in Gentiana species (gentiopicroside, swertiamarin, isoorientin, isovitexin and vitexin) was analyzed in the extracts by thin layer chromatography. The flower DCM extract of G. verna exerted the highest inhibition against AChE (53.65 +/- 1.03%), whereas the root EtOAc extract of G. cruciata was the most effective in BChE inhibition assay (50.72 +/- 0.75%) at 100 mu g ml(-1). The extracts of G. verna were also found to be more active in the antioxidant tests.