Botanical survey, phytochemical investigation, and antibacterial activity of aqueous extract of Enantia polycarpa (DC) Engl. and Diels stem bark against methicillin resistant Staphylococcus aureus (MRSA)

Abstract

The present study was carried out to make botanical description, chemical analysis, and to evaluate the antibacterial activity of the aqueous extract from Enantia polycarpa (DC) Engl. and Diels stem bark against methicillin resistant Staphylococcus aureus (MRSA) strains isolated from clinical specimen. The methods of agar well diffusion and microbroth dilution in liquid media were used for susceptibility testing and minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) determination. The tests were performed on eleven MRSA strains isolated from patients and one reference (ATCC 25923) strain. Enantia polycarpa (Annonaceae) is used in Africa to treat many diseases. The aqueous extract of this plant showed inhibitory activity against all tested bacteria and described zones of inhibition between 8.33 ± 0.58 mm and 16.33 ± 0.58 mm at 25 mg/ml. The lowest MIC and MBC values were observed with MRSA 564 UB/15(3.125 mg/ml and 12.5 mg/ml, respectively). The aqueous stem bark extract of Enantia polycarpa had a bactericidal activity on 75% of MRSA strains tested. The phytochemical analysis showed the presence of saponins, alkaloids, and tannins in aqueous extract. This could justify the antibacterial activity and the use of Enantia polycarpa stem bark in the treatment of various diseases in traditional society.