Phytochemical Composition and In vivo Antibacterial Activity of the Aqueous Leaf Extract of Polygonum limbatum on Escherichia coli-infected Guinea Pigs

Background: Polygonum limbatum Meisn (Polygonaceae) extracts have been used in West region of Cameroon for the treatment of urogenital infections. The therapeutic efficacy of the aqueous leaf extract of Polygonum limbatum against urogenital infections was investigated on Escherichia coli-infected guinea pigs.

Methods: The infected animals received the extract orally at 200, 500 and 700 mg/kg body weight for 15 days during which the vaginal bacterial load was measured every 72 h. The side effects of the extract were also evaluated through hematological and biochemical analyses. Phytochemical screening was done using standard methods.

Results: In general, a considerable decrease in the bacterial load was observed in the treated groups with time. On the 13th day of treatment, the doses of 700, 500 and 200 mg/kg induced 98.45%, 93.02% and 67.05% decrease in the bacterial load, respectively. After 15 days of treatment, WBC counts significantly increased in infected animals. Significant decreases were observed in the protein titers of the heart, lungs and kidneys. Serum total proteins and transaminases were significantly decreased. Urinary protein concentration significantly decreased at the dose 200 mg/kg and increased at 700 mg/kg of extract. Serum and urinary creatinine significantly decreased. Flavonoids, alkaloids, triterpenes, polyphenols, tannins and saponins were found in the extract.

Conclusion: This study demonstrated marked therapeutic effects of P. limbatum aqueous leaf extract against urogenital infection caused by Escherichia coli. Also, no critical sign of toxicity was observed in treated animals.