Evaluation of The Antimicrobial Activity of Saponins-Rich Fraction of Zanthoxylum zanthoxyloides Leaf

Abstract

Zanthoxylum zanthoxyloides has been reported to have several medicinal uses and has also been documented to be rich in saponins. Thus, this study aimed to evaluate the in vitro antimicrobial properties of saponins-rich extract of Z. zanthoxyloides leaf. The extraction of saponins from the methanolic extract of Z. zanthoxyloides leaf was done using standard procedure. The antimicrobial property of the extract was also tested by agar well diffusion method for activity against Staphylococcus aureus, Klebsiella pneumonia and Moraxella catarrhalis isolated from clinical samples. The susceptibility patterns of test isolates against the saponins-rich fraction were determined at extract concentrations of 100, 125 and 250 mg/ml, respectively. Ciprofloxacin was used as positive control while methanol was used as the negative control. Phytochemical screening of the crude methanol extract of the leaf of Z . zanthoxyloides showed the presence of saponins, alkaloids, flavonoids and tannins. The antimicrobial results revealed that the extract had no inhibitory effect on S. aureus at all the concentrations but the largest zone of inhibition for the extract was recorded with K. pneumoniae and M catarrhalis with mean diameter zone of inhibition of 15.04±0.167 mm at 250 mg/ml. The minimum inhibitory concentration of the extract on M. catarrhalis, S. aureus and K. pneumonia were at 50, 125 and 500 mg/ml, respectively. The apparent antimicrobial activity of the saponins-rich fraction of Z. zanthoxyloides , as shown by the results of this research, suggests its potential usefulness in the prevention and treatment of infectious diseases.