Helicobacter pylori, a gram negative microaerophilic bacterium is a major etiological agent in duodenal, peptic and gastric ulcers. In this study, gastric biopsy samples were obtained from patients presentingwith gastroduodenal complications. H. pylori was isolated from the specimens following standard microbiology procedures, and isolates subjected to pure fractions of Lycopodium cernuum extracts forantimicrobial assays. Extracts were fractionated by partition chromatography with solvents of increasing polarity to obtain pure fractions. The disk diffusion method was used to determine thesusceptibility of 15 strains of H. pylori to the fractions. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for the most active fraction was also determined by thebroth dilution method. Results were analyzed by the Fisher’s exact test. All the fractions tested demonstrated antimicrobial activity with zone diameters of inhibition between 0 - 30 mm. Of the 5 fractions obtained, the hexane (Hex) fraction was the most active. The lowest MIC and MBC recorded for the hexane (Hex) fraction were 0.016 and 0.125 mg/mL, respectively. There was no statistically significant difference (P>0.05) in the potency of the fraction on the different bacterial strains tested, both for the MIC and MBC. It is concluded that this plant may contain compounds with therapeutic activity, which may be found in the Hex fraction (100%).
