Abstract

• Developing countries, where dysentery and diarrhea are endemic, depend strongly on traditional medicine as a source for inexpensive treatments because it is based on plants which are abundantly available in these countries. Consequently, Myanmar indigenous medicinal plants (Curcuma longa L., Nigella satia L. and Piper betel L.) which are used for the treatment of dysentery and diarrhea in Myanmar were selected to study in order to find the scientific basis for such use. The selected plants were screened for antibacterial activity by using agar disc diffusion technique. Polar and non-polar extracts of the selected plants were tested on 33 species of standard and hospital bacterial strains. The Minimum Inhibitory Concentration (MIC) of the active extracts was also determined by agar plate dilution method. Three curcuminoids, namely curcumin (5.9 %), desmethoxy curcumin (0.018 %) and bisdesmethoxy curcumin (0.0136 %) were isolated from C. longa rhizomes. N. satia seeds were fractionated by column chromatography to give thymoquinone (0.01 %), kaempferol (0.12 %) and quercetin (0.001 %). Eugenol (0.1 %) was isolated from essential oil of P. betel. The isolated compounds were identified by UV, FT IR, 1H NMR, 13C NMR and mass spectroscopic methods. The isolated compounds were also found to show bactericidal activity. Thus the extracts of the three plants have high potential for the production of combined formulation to treat infections caused by bacteria