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

Abstract

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 μg ml^{− 1}. The extracts of G. verna were also found to be more active in the antioxidant tests.

Keywords::

• antioxidant activity
• cholinesterase inhibition
• Gentiana
• gentian
• Gentianella

Declaration of interest. F. S. Senol expresses her genuine gratitude to the Scientific and Technological Research Council of Turkey (TÜBİTAK) for the scholarship provided for her Ph.D. programme. The authors are thankful to Dr Ufuk Koca from Department of Pharmacognosy, Faculty of Pharmacy, Gazi University, Ankara (Turkey) for providing the standards of pure compounds used in this study. The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper.