Antimicrobial activities and the Bactericidal Kinetics of Allium ascalonicum Linn. (Whole plant) against standard and clinical strains of Helicobacter pylori: Support for Ethnomedical Use

Abstract

Helicobacter pylori are the causative agents of gastroduodenal disorders, such as peptic ulcer, acute gastritis and even stomach cancer. It is believed to infect over half the world’s population. Recently, there have been cases of chemotherapy – failures and emergence of resistant strains. This necessitated the search for more active drugs. Crude n-hexane and methanol extracts were used to screen Helicobacter pylori ATCC 43504 and forty-two other clinical isolates of Helicobacter pylori, using the agar diffusion method in Mueller-Hinton agar supplemented with 5% defibrinated horse blood. The strains were incubated in a microaerophilic incubator, and it was observed that the standard strain and twenty-eight out of the forty-two clinical strains were susceptible to the methanol extract with the diameter of zone of inhibition ranging from 10 + 0.00 to 20 + 0.00 mm at test concentrations of 100 mg/mL to 200 mg/mL. The minimum inhibitory concentrations of susceptible strains ranged between 100 mg/mL to 200 mg/mL. The kill kinetics showed that at 4×MIC, equivalent to the minimum bactericidal concentration (MBC), the methanol extract of Allium ascalonicum gave 96-98% and 100% kill of the organisms within the contact time of 6 and 24 hours respectively. The n-hexane fraction did not show any inhibitory potential against any of the strains. Phytochemical screening of the extract showed the presence of alkaloids, saponins, flavonoids, essential oil and cardiac glycosides. Anthraquinones, tannins and terpenoids were not detected. The presence of these secondary metabolites and the observed activity of Allium ascalonicum provide a scientific rationale for the use of this plant in folk medicine in Nigeria and other parts of the world.

Keywords: Allium ascalonicum, Helicobacter pylori, antimicrobial activities, bactericidal kinetics