In vitro pharmacological investigations of Oxystelma esculentum R.Br. and in silico molecular docking analysis of its leaf constituents on diabetic related target

Abstract

The current investigation is to determine the preliminary chemical compounds present in Oxystelma esculentum R. Br. (Apocynaceae) leaf extracts and their pharmacological activities such as antioxidant and antibacterial anti-diabetic, assays. Total antioxidant capacity was evaluated by DPPH, SO, FRAP, MC, and PHM assays, and antibacterial activity was determined by the minimal inhibitory concentration method against 10 pathogenic bacteria. The α-amylase and α-glucosidase inhibitory assays were used for the enzymatic properties and its molecular docking approaches were examined through the screening of chemical characterization of the phytocompounds. The highest amount of total TPC and TFC obtained in ethyl acetate extract was 77.65 ± 0.65 mg/g GAE and 130.75 ± 0.01 mg/g QE, respectively. All the three extracts used in this study exhibited significant antioxidant activity at various concentrations and the results mentioned in the 50% inhibition and gram equivalents were respected with the assays. Ethyl acetate, ethanol, and acetone extracts exhibited significant results at the concentration of 118.75 µg/mL against S. flexneri. The highest inhibition was achieved by both enzyme activities, α-amylase and α-glucosidase activity on ethanol (IC50 17.96 ± 2.6 µg/ml) and acetone (25.35 ± 1.43 µg/ml) extract respectively. GC-MS screening of ethanol leaf extract revealed the presence of 13 phytocompounds. Among these, 6 compounds possess anti-diabetic properties namely p-Chloroamphetamine, 1-Heptadecanol, Pentadecane, Hexadecanoic acid-2-hydroxy-1-(hydroxymethyl) ethyl ester, Octadecanoic acid-2,3-dihydroxy propyl ester, and Solanesol were chosen for in silico modeling against human diabetic receptor (1B2Y). From these compounds, solanosol shows less binding affinity with the highest docking score of −7.3 than standard and other compounds. In conclusion, Oxystelma esculentum leaf extracts have significant pharmacological properties due to the presence of various phytocompounds.