Abstract

ANTIBACTERIAL ACTIVITY OF EXTRACTS FROM THE STEM BARK OF Alafia multiflora (Stapf) ON EXTENDED BETA-LACTAMASE-POSITIVE MULTI-DRUG RESISTANT HOSPITAL BACTERIA

Armanda Laetitia Kengne Toam, Pierre René Fotsing Kwetche*, Sandrine Gamwo Dongmo, Josué Simo Louokdom, Joëlle Diane Mbieleu, Théophile Dimo

ABSTRACT

The present study focused on the semi-quantitative chemical screening and antibacterial potential of extracts from the stem bark of Alafia multiflora (A. multiflora) grown in Cameroon. A total of six metabolite categories were targeted namely polyphenols, flavonoids, tannins, saponosides, triterpens and glycosides in the crude hydro-methanolic extract and its fractions obtained with water, hexane, chloroform, and ethyl-acetate according to previous works protocols. The antimicrobial potential was tested on five Gram-negative and three Gram-positive multidrug-resistant hospital strains expressing extended beta-lactamases. The parameters investigated included the minimal inhibitory and bactericidal concentrations (MIC and MBC, respectively), the diameter of the inhibition zone and the MBC/MIC ratios, with Gentamicin as reference for extract activity. All chemicals targeted were present in the crude product but not in all fractions. The highest metabolite diversity was observed with water, water-methanol mixture and ethyl-acetate; and the highest activity with the ethyl-acetate fraction (MIC: 2.5 mg/mL - 5 mg/mL and MBC: 2.5 - 10 mg/mL). Though at varying degree, extract bactericidal potential was recorded for all strains, substantiating the broad spectrum activity that eluded various resistance mechanisms including ESBL expression; clue that this plant could be a reliable source of candidates for new antimicrobial drugs. Effectiveness with water as solvent could justify the cost-effective use of A. multiflora stem bark extract in traditional medicine despite such constrains as dosage, standards and references in addition to the large quantities of raw plant material required with regards to the low output.

Keywords: A. multiflora, stem bark, chemical screening, antibacterial.