In vitro antimicrobial activity and the major polyphenol in leaf extract of Mangifera indic L
Malaysian Journal of Microbiology
Use of plant extracts as antimicrobials has recently gained wide attention over the continued use of synthetic antibiotics. In this work, Chinese mango leaves were subjected to different extraction regimes namely decoction (50 °C for 48 h and boiling for 3 h) and solvent extraction (50% ethanolic solution at 62 °C for 1 h). The extract solutions were lyophilized yielding 24-26% powdered extracts that were used for the antimicrobial tests against four pathogenic (Salmonella typhi, Escherichia
... phi, Escherichia coli, Staphylococcus aureus, Bacillus cereus) and two generally regarded as safe (Streptococcus thermophilus, and Lactobacillus acidophilus) microbial strains. Antimicrobial activity was assessed by inhibition diameters which were found to range from 9-15.5 mm for the three extracts against all the bacterial strains tested and inhibition growth curves which showed the extracts as first acting within the first 20 min after which a steady state (bacteriostatic) was attained and maintained throughout the testing time (360 min) with a significant difference (p<0.05) from the negative control. The minimum inhibitory concentrations for the extracts were later determined by two fold serial dilutions method and they ranged from 36.2-18.2 mg/mL against all the strains. The extracts were then subjected to reversed-phase HPLC to identify and quantify the polyphenol mangiferin which was found to be the abundant compound in the extracts at 100 μg/mL with no significant difference (p<0.05) in quantity among the three extracts.