Abstract

In an attempt to identify novel sources of cheap starting material for the synthesis of new anti-infective agents, the antimicrobial activity of crude acetone, ethanol and methanol extracts of the stem bark of Combretum molle were investigated against 32 clinical strains of Helicobacter pylori and a standard control strain NCTC 11638 by agar well diffusion and micro-broth dilution. Metronidazole, clarithromycin and amoxicillin were included in these experiments as positive control antibiotics. All the extracts tested exhibited anti-H. pyloriactivity with zone diameters of inhibition between 0 to 38 mm. The acetone extract showed potent anti-H. pylori activity, giving a percentage susceptibility of 87.5%. Minimum inhibitory concentration (MIC) values for this extract ranged from 0.078 to 2.50 mg/ml while those for amoxicillin and metronidazole ranged from 0.001 to 1.25 mg/ml and 0.004 to 5.0 mg/ml respectively. The inhibitory activity of the acetone extract was similar to amoxicillin (P>0.05) as opposed to metronidazole (P<0.05). These results demonstrate that the acetone extract may contain compounds with therapeutic activity and therefore a potential source of new anti-H. pylori regimen.

Key words: Antimicrobial activity, crude extracts, drug discovery, Helicobacter pylori, Minimum inhibitory concentration (MIC).