Asian Journal
Of Traditional Medicines

Abstract: The medicinal uses of the leaves of four Combretum (Combretaceae) species which grow in northern Thailand, viz. Combretum
deciduum Coll. & Hemsl., Combretum griffithii Heur. & M. A., Combretum latifolium Bl. and Combretum quadrangulare Kurz,
were studied. The antibacterial activities of the crude extracts (obtained using n-hexane, dichloromethane, methanol and hot
water) from the leaves of these four species were evaluated by the agar dilution method. All methanolic extracts showed potent
antibacterial activity and unique antibacterial spectra. These were active against the Gram-positive bacterium, Staphylococcus
aureus, and the Gram-negative bacterium, Pseudomonas aeruginosa but they were inactive against other Gram-negative bacteria,
viz. Esherichia coli, Klebsiella pneumoniae, Enterobacter cloacae and Serratia marcescens. The degree of antibacterial activity
of the methanolic extracts of the leaves of these four species was very similar, although the antibacterial activity of C. deciduum
against S. aureus was slightly lower. These results support the ethnomedical use of these plants. The antibacterial activities of
C. deciduum and C. latifolium are reported here for the first time. This is also the first report of the antibacterial activity of C.
griffithii against a number of pathogenic bacteria.

Key words: Combretum, antibacterial activity, agar dilution method, methanolic extracts