In-vitro antibacterial activity and cytotoxicity of selected medicinal plant extracts from Penang Island Malaysia on metronidazole-resistant-Helicobacter pylori and some pathogenic bacteria.

Abstract

researchHelicobacter pylori is the major agent in the etiology of chronic active gastritis, duodenal and gastric ulcers and has been linked to gastric carcinoma. The increasing antibiotic resistance of this organism and other bacteria has led to increased treatment failures, especially in therapies involving commonly used antibiotics. Malaysia has an unexplored potential of medicinal plants. This study evaluates the in-vitro antimicrobial activity of 32 selected medicinal plants used in Malaysian traditional medicine for gastrointestinal disorders and wounds. Extracts were tested against H. pylori by disc diffusion and agar dilution methods. Toxicity of the most potent extracts was also investigated. Organic solvent extracts of Derris trifoliata Lour. selectively inhibited H. pylori, and thus was further studied. Petroleum ether (PE), chloroform (CHL) and methanol (MET) extracts were tested against 13 other bacterial isolates representing eight genera. Petroleum ether and chloroform extracts showed strong activity against metronidazole-resistant clinical isolates of H. pylori with MIC90 and MIC50 ranging from 1- 4mg/l. All extracts of D. trifoliata produced higher inhibition zone diameters against H. pylori than for other bacteria. Toxicity tests showed Lc50 of PE, CHL and MET extracts on Artemia salina Leach as 1.14, 1.1, and 54.9mg/l respectively. Chemical analysis revealed the presence of fatty acids, steroids, triterpenoids, alkaloids, phenols, and phenyl propanoids, tannin, and mucilage in the extracts. Derris trifoliata shows potential as a source of selective anti-H. pylori agent