Antibacterial and Antioxidant Superoxide Anion Radical Inhibitors from Myrmecodia pendans: An In silico Study

Abstract

Background: Background: Ant-nest (Myrmecodia pendans) is an epiphytic plant that can prevent several diseases, including bacterial infections. Diarrhea is caused by Escherichia coli bacteria, while infections in the oral cavity can be caused by Enterococcus faecalis bacteria. Antibacterial activity is also influenced by conditions of Reactive Oxygen Species (ROS). Antioxidants are needed to inhibit the formation of excess ROS in the body. Superoxide anion radicals are included in the generation of ROS, which is produced by several enzymes, such as nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase or commonly known as Nox and xanthine oxidase (XO). Objective: This study aimed to determine the potential of M. pendans as an antibacterial in vitro and in silico correlation in the formation of superoxide anion radicals. Methods: The compounds were obtained by column chromatography method, followed by a spectroscopic examination. In vitro test using the disc diffusion method and in silico test using AutoDock 4.2 program were conducted with positive control fosfomycin and allopurinol, tethered to MurA, Nox, and XO enzymes, and visualized using the Discovery Studio 2020. Results: Compound 1 (oleanolic acid) and compound 2 (pomolic acid) demonstrated antibacterial activity against E. coli but no activity against E. faecalis. Compound 3 (3-hydroxy-eupan-20,24-dien-26-oic acid) demonstrated no activity against these two bacteria. Based on the in silico results, compound 3 had the best binding energy affinity for all MurA, Nox, and XO enzymes of -6.89, -9.35, and -9.75 Kcal/mol, respectively. Similarly, compounds 1 and 2 had good binding energies for Nox protein of -9.29 Kcal/mol and -6.54 Kcal/mol and XO of -7.66 and -4.7 Kcal/mol, respectively. Conclusion: In vitro results against E. coli and E. faecalis bacteria showed inhibition by compounds 1 and 2 but not by compound 3. Meanwhile, in in silico analysis, all the compounds showed potential as an inhibitor of superoxide anion radicals generated by enzymes Nox and XO.