Antibacterial activity of Mitragyna speciosa Korth. leaves

The crude extracts of red vein kratom leaves (hexane, dichloromethane, ethyl acetate, ethanol, and 50% acetic acid) and mitragynine were tested for antibacterial activity against gram-positive Staphylococcus aureus and gram-negative Escherichia coli using the disk diffusion method. The minimum inhibitory concentration (MIC) values against S. aureus and E. coli were determined. The acetic acid crude extract was effective against both S. aureus and E. coli with an inhibition zone of 5.52±0.44 and 4.65±1.02 mm, at a minimum concentration of 6 and 9 mg/mL, respectively. Mitragynine was active against S. aureus with an inhibition zone of 4.35±0.68 mm and a MIC of 6 mg/mL.