Full Length Research Paper

 Abstract

Helicobacter pylori is the most important risk factor in gastritis, peptic ulcer and gastric cancer. This study explored the antimicrobial activity of the stem bark of Peltophorum africanum on H. pylori isolated in South Africa. Strains were isolated from patients presenting with gastric related morbidities at the Livingston Hospital, Port Elizabeth for endoscopy. Five extracts of P. africanum and clarithromycin were tested for the zone diameters of inhibition against 31 clinical strains of H. pylori, followed by the Minimum Inhibitory Concentration (MIC) using metronidazole and amoxicillin as control antibiotics; and thereafter the rate of kill. Zone diameters of inhibition which ranged from 0 - 23 mm were observed for all the five extracts and 0 - 35 mm for clarithromycin. Marked susceptibility of strains (100%) was recorded for the ethyl acetate extract (P < 0.05). The MIC₅₀ ranged from 0.0048 - 0.313 mg/mL and MIC₉₀ from 0.156 - 0.625 mg/mL for the ethyl acetate extract (P. africanum EA). There was a significant statistical difference observed in potency with P. africanum EA compared to metronidazole and amoxicillin (P < 0.05) at MIC₉₀. Complete killing of strain PE466C by P. africanum EA was observed at 0.05 mg/mL (½ x MIC) in 66 and 72 h and 0.2 mg/mL (2 x MIC) in 72 h. For strain PE252C, total killing was observed at 0.2 mg/mL (2 x MIC) in 66 h and at 0.05 mg/mL (½ x MIC), 0.1 mg/mL (MIC), 0.2 mg/mL (2 x MIC) and 0.4 mg/mL (4 x MIC) in 72 h, respectively. Our findings demonstrate the in vitro activity of the crude extracts of P. africanum and therefore provide evidence to justify the use of this plant in traditional medicine.

Key words: Helicobacter pylori, Peltophorum africanum, medicinal plant, antibacterial activity, MIC, rate of kill, South Africa.