Antibacterial Activity, Phytochemical and Molecular Docking Analysis of Croton macrostachyus Root Extracts Growing in Wolaita, Ethiopia

Background and objectives: Croton macrostachyus Hochst ex. Delile (Euphorbiaceae) is a medicinal plant used as a traditional medicine for treating infectious diseases in Ethiopia. This study was aimed for investigating the phytochemicals, in vitro antibacterial and molecular docking of the Croton macrostachyus roots extract. Methods: Silica gel column chromatographic separations afforded four known compounds. In vitro antibacterial activity of the isolated compounds, (1-4), and extracts of C. macrostachyus were evaluated against four human reference pathogens. Insilco molecular docking was performed for isolated compounds against two target proteins of Escherichia coli DNA gyrase B (PDB: 6F86) and Staphylococcus aureus Sortase A (PDB: 1T2P). Results: From the root extract of C. macrostachyus, four known compounds of lupeol (1), β-sitosterol (2), stigmasterol (3), and linoleic acid (4) were isolated and characterized. The extracts and isolated compounds exhibited in vitro antibacterial activity. Molecular docking results revealed that the isolated compounds interacted with the target proteins with the minimum binding energy ranging from -7.38 kCal/mol to -5.57 kCal/mol against DNA gyrase B and -7.40 kCal/mol to -5.54 kCal/mol against Sortase A. Conclusion: Our study proved that extracts and isolated compounds possess potential antibacterial activity, and the findings support the use of C. macrostachyus as a traditional medicine for treating skin infections, cough, respiratory tract problems, stomachache, and influenza virus by local people in Ethiopia.