Antibacterial potential of Malaysian ethnomedicinal plants against methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA)

This study aimed to evaluate the antibacterial activities of 61 plant extracts from 49 Malaysian ethnomedicinal plants and to investigate the interaction of the active plant extracts in combination with synthetic antibiotics against the MSSA and MRSA strains. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the plant extracts were determined using a microdilution method against MSSA and MRSA strains. The interaction between active plant extracts and the antibiotics was assessed using the checkerboard method. The total fractional inhibitory concentration (Sigma FIC) indices from the combination were calculated to determine the nature of the interaction. Out of the 61 plant extracts tested against the MSSA strain, 7 plant extracts (similar to 11%) showed MIC values of less than 200 mu g/mL, 17 extracts (similar to 28%) showed MIC between 200 and 800 mu g/mL and seed extracts of Areca catechu showed MBC values of 400 mu g/mL. The seed extract of A. catechu showed MIC and MBC of 400 mu g/ mL against the MRSA strains while leaf extract of Cocos nucifera showed MIC of 400 mu g/mL against MRSA NCTC 12493. When the active plant extracts (MIC <= 200 mu g/mL for MSSA, and <= 400 mu g/mL for MRSA) were tested in combination with vancomycin and ciprofloxacin, they showed no interaction against both MSSA and MRSA with Sigma FIC between 1.06 and 2.03. These findings provide a preliminary overview of the anti-MSSA and anti-MRSA properties of Malaysian ethnobotanical plants to combat Staphylococcal infections. Further research is needed to establish an antibacterial profile of the tested plant extracts. (C) 2021 The Authors. Published by Elsevier B.V. on behalf of King Saud University.