Ethnomedicinal Knowledge Verification for the Antidiarrheal and Antioxidant Effects of Rhus chinensis Mill. Fruits with Identification of Thirty Constituents

Abstract

Background: Ethnobotanical survey in the rural villages in Nepal revealed that the fruits of Rhus chinensis Mill. have been using for the treatment of diarrhea and dysentery. Objective: To evaluate antimicrobial and antioxidant effects, and identification of chemical constituents in the fruits of R. chinensis. Materials and Methods: Phytochemical screening was performed on the hexane and 70% methanolic extracts of the sample followed by gas chromatographymass spectrometry (GC-MS). Total phenolic content (TPC) was estimated using Folin-Ciocalteu method. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) free radical and hydrogen peroxide scavenging assays were used to evaluate the antioxidant capacity. Antibacterial effect was estabilished by the Agar well diffusion assay. Results: A total of 30 compounds belonging to phenolics, anhydrides, aldehydes, fatty acids and hydrocarbons were identified in the extracts. The TPC value of 123.52±1.29 mg GAE/g dry extract was estimated. IC50 value of 135.54±0.82 μg/mL was calculated in DPPH free radical scavenging assay. Scavenging of 42.69±0.1% DPPH free radical and 63.20±1.48% hydrogen peroxide at 100 μg/mL concentration of 70% methanolic extract were estimated. The maximum zone of inhibition (ZOI) observed was 23.00±0.57 mm against Escherichia coli at loading dose of 5 mg of the extract. Conclusion: All together 30 compounds were identified in the fruits. The extracts efficiently inhibited the growth of E. coli and Shigella dysenteriae verifying the rural knowledge. At the same time, the extracts displayed efficient antioxidant activity. The phytochemicals identified were responsible for these activities. Key Words: Antibacterial susceptibility assay, DPPH radical scavenging assay, GC-MS, Hydrogen peroxide scavenging activity, Total phenolic content.