Phenolic contents, antioxidant and anticholinesterase potentials of crude extract, subsequent fractions and crude saponins from Polygonum hydropiper L

摘要

Background We investigated Polygonum hydropiper L. (P. hydropiper) for phenolic contents, antioxidant, anticholinesterase activities, in an attempt to rationalize its use in neurological disorders. Methods Plant crude extract (Ph.Cr), its subsequent fractions: n-hexane (Ph.Hex), chloroform (Ph.Chf), ethyl acetate (Ph.EtAc), n-Butanol (Ph.Bt), aqueous (Ph.Aq) and saponins (Ph.Sp) were evaluated for 1,1-diphenyl,2-picrylhydrazyl (DPPH), 2,2-azinobis[3-ethylbenzthiazoline]-6-sulfonic acid (ABTS) free radical scavenging potential. Further, acetylcholinesterase (AChE) & butyrylcholinesterase (BChE) inhibitory activities were performed using Ellman's assay. Moreover, total phenolic contents of plant extracts were determined and expressed in mg of gallic acid equivalent per gram of dry sample (mg GAE/g dry weight). Results Among different fractions, Ph.Cr (90.82), Ph.Chf (178.16), Ph.EtAc (203.44) and Ph.Bt (153.61) exhibited high phenolic contents. All fractions showed concentration dependent DPPH scavenging activity, with Ph.EtAc 71.33% (IC₅₀ 15?μg/ml), Ph.Bt 71.40% (IC₅₀ 3?μg/ml) and Ph.Sp 71.40% (IC₅₀ 35?μg/ml) were most potent. The plant extracts exhibited high ABTS scavenging ability i.e. Ph.Bt (91.03%), Ph.EtAc (90.56%), Ph.Sp (90.84%), Ph.Aq (90.56%) with IC₅₀?50 330?μg/ml), Ph.Hex, 87.49% (IC₅₀ 35?μg/ml), Ph.Chf, 84.76% (IC₅₀ 55?μg/ml), Ph.Sp, 87.58% (IC₅₀ 108?μg/ml) and Ph.EtAc 79.95% (IC₅₀ 310?μg/ml) at 1?mg/ml). Furthermore the BChE inhibitory activity was most prominent in Ph.Hex 90.30% (IC₅₀ 40?μg/ml), Ph.Chf 85.94% (IC₅₀ 215?μg/ml), Ph.Aq 87.62% (IC₅₀ 3?μg/ml) and Ph.EtAc 81.01% (IC₅₀ 395?μg/ml) fractions. Conclusions In this study, for the first time, we determined phenolic contents, isolated crude saponins, investigated antioxidant and anticholinestrase potential of P. hydropiper extracts. The results indicate that P. hydropiper is enriched with potent bioactive compounds and warrant further investigation by isolation and structural elucidation to find novel and affordable compounds for the treatment of various neurological disorders.