Abstract

• The leaves of Acacia concinna DC. (Kin-mun-gyin) are used as folk medicine for the treatment of jaundice, malarial fever, laxative, diarrhoea and boils. The Kin-mun-gyin leaves were chosen for determination of antibacterial activity and organic constituents. The plant sample was collected from Mingalardon Township, Yangon Region. The meso-tartaric acid and myristic acid were isolated from aqueous and ethyl acetate extracts of Kin-mungyin leaves by column and preparative thin layer chromatographic methods. It was identified by UV, FT IR, 1H NMR, 1 3C NMR and ESI MS spectroscopic methods. Then, in vitro screening of antibacterial activity was done on four crude extracts (PE, EtOAc, EtOH and H2O) of Kin-mun-gyin leaves against 3 species of Staphylococcus aureus and 2 species of Escherichia coli, one species of Bacillus subtilis, one species of Proteus morganii and one species of Vibrio cholerae by employing agar disc diffusion method. Except PE extract, all of the crude extracts were found to exhibit the inhibition zones against all of the organisms tested. Minimum inhibitory concentration (MIC) values of two isolated compounds were also determined by microplate dilution method on above 8 species of bacteria. The lowest MIC values of meso-tartaric acid and myristic acid from A. concinna leaves were respectively found to be 0.0058 mg mL-1 , 0.0937 mg mL-1 against S. aureus ws. From this study, it may be concluded that meso-tartaric acid and myristic acid possess antibacterial activities useful for the medicinal purposes for the curing of diseases caused by the microorganisms tested.