Isolation of bioactive compounds from Bergenia ciliata (haw.) Sternb rhizome and their antioxidant and anticholinesterase activities

Abstract

Background: Bergenia ciliata is a medicinal plant used for the treatment of diarrhea, vomiting, fever, cough, diabetes, cancer, pulmonary disorders and wound healing. Methods: In this study, Bergenia ciliata crude extract, subfractions, and isolated compounds were evaluated for their antioxidant and anticholinesterase potential. The free radical scavenging capacities of the extracts determined using DPPH and ABTS assays. The anticholinesterase potentials were determined using acetylcholine esterase and butyryl choline esterase enzymes. To determine the phytochemical composition, the extracts were subjected to HPLC analysis and silica gel column isolation. Based on HPLC fingerprinting results, the ethyl acetate fraction was found to have more bioactive compounds and was therefore subjected to silica gel column isolation. As a result, three compounds; pyrogallol, rutin, and morin were isolated in the pure state. The structures of the isolated compounds were elucidated using spectroscopic techniques like 1H-NMR, IR and UV-Visible. Results: The crude extract showed maximum anticholinesterase (acetylcholinesterase = 90.22 ± 1.15% and butyrylcholinesterase = 88.22 ± 0.71%) and free radical scavenging (87.37 ± 2.45 and 83.50 ± 0.70% respectively against DPPH and ABTS radicals) potentials. The total phenolic contents (expressed as equivalent of gallic acid; mgGAE/g) were higher in ethyl acetate fraction (80.96 ± 1.74) followed by crude extract (70.65 ± 0.86) while the flavonoid contents (expressed as quercetin equivalent; mgQE/g) and were higher in crude extract (88.40 ± 1.12) followed by n-butanol fraction (60.10 ± 1.86). The isolated bioactive compounds pyrogallol, rutin, and morin were found active against ABTS and DPPH free radicals. Amongst them, pyrogallol was more active against both free radicals. Reasonable anticholinesterase activities were recorded for pyrogallol against selected enzymes. Conclusion: The extracts and isolated compounds showed antioxidant and acetylcholinesterase inhibitory potentials. It was concluded that this plant could be helpful in the treatment of oxidative stress and neurological disorders if used in the form of extracts.