Phytochemical screening and study of comparative antibacterial activity of aqueous and alcoholic extracts of the leaves and barks of Terminalia catappa on multiresistant strains.

Abstract

Objectives: In this study, methanol, ethanol and aqueous extracts of Terminalia catappa L. leaves and barks were compared for antibacterial activity against clinical (sensitive and multidrug-resistant) and ATCC strains of Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus (MRSA). Methodology and Results: The confirmation of the Enterobacteriaceae Extended-Spectrum-β-Lactamases (ESBL) producing strains was done by the double-disc synergy tests, the MRSA by disk diffusion method (cefoxitin 30 µg) according to the methods of CA-SFM, 2009. The agar dilution and broth dilution method was used for the determination of the antimicrobial parameters (MIC and MBC) on these sensitive, ESBL producing and MRSA strains. The bark extracts generally showed better activity compared to leaves extracts; but methanolic extracts of barks were the most active of all the extracts, exhibiting a broad-spectrum activity. However, Staphylococcus aureus were sensitive compared to Escherichia coli and Klebsiella pneumoniae. Antibacterial activity showed value ranged from 0.52 ± 0.13 to 4.16 ± 1.04 mg/ml (MIC) and 1.56 to 10.42 ± 2.08 mg/ml (MBC). Phytochemical screening showed the presence of Flavonoids, Alkaloid, Steroid, Terpenoids, Gallic Tannins, Saponins and with the exception of the aqueous extract for Coumarins. Conclusions: The results obtained suggest that methanolic extracts of T. catappa barks can be used in treating bacterial diseases.