Inhibitory and bactericidal potential of crude acetone extracts of combretum molle (Combretaceae) on drug-resistant strains of Helicobacter pylori

Infection with helicobacter pylori is strongly associated with a number of gastroduodenal pathologies. antimicrobial resistance to commonly-used drugs has generated a considerable interest in the search for novel therapeutic compounds from medicinal plants. as an ongoing effort of this search,the susceptibility of 32 clinical strains of h. pylori and a reference strain-nctc 11638-was evaluated against five solvent extracts of combretum molle,a plant widely used for the treatment of gastric ulcers and other stomach-related morbidities in south africa. the extracts were screened for activity by the agar-well diffusion method,and the most active one of them was tested against the same strains by micro-broth dilution and time kill assays. metronidazole and amoxicillin were included in these experiments as positive control antibiotics. the solvent extracts all demonstrated anti-h. pylori activity with zone diameters of inhibition between 0 and 38 mm. the most potent anti-h. pylori activity was demonstrated by the acetone extract,to which 87.5% of the clinical strains were susceptible. the minimum inhibitory concentration (mic90) values for this extract ranged from 1.25 to 5.0 mg/ml while those for amoxicillin and metronidazole ranged from 0.001 to 0.94 mg/ml and from 0.004 to 5.0 mg/ml respectively. the acetone extract was highly bactericidal at a concentration of 2.5 and 5.0 mg/ml,with complete elimination of the test organisms in 24 hours. its inhibitory activity was better than that of metronidazole (p<0.05) as opposed to amoxicillin (p<0.05). the results demonstrate that c. molle may contain therapeutically-useful compounds against h. pylori,which are mostly concentrated in the acetone extract. © international centre for diarrhoeal disease research,bangladesh.