Evaluation of the Modulatory Effect of Annona muricata Extracts on the Activity of Some Selected Antibiotics against Biofilm-Forming MRSA

The study investigated the influence of Annona muricata extracts on the action of selected antibiotics against biofilm-forming MRSA. The various parts of the plant were processed into powder and extracted with ethanol or hot water and then screened for the presence of phytochemicals. The modulatory effect of the Annona muricata extract was also tested on some antibiotics against Methicillin-resistant Staphylococcus aureus (MRSA). The findings from this study revealed that the various parts of the Annona muricata extract (ethanolic and aqueous) contained different proportions of secondary metabolites. Varied antimicrobial activities were observed when the extract of the A. muricata was exposed to MRSA strain at a concentration of 100 mg/mL. The stem recorded the highest (17.00 and 18.00 mm) inhibitory activity against MRSA for both the aqueous and the ethanolic extract, respectively, and this was not different from the control, tetracycline. Again, the results on the modulatory action indicated that out of the 10 extracts of A. muricata, 4 of them antagonized the activity of ampicillin against the tested MRSA by a factor of 0.5 folds and the rest potentiated the drug within 1–4 folds, respectively. On the other hand, the various test extracts significantly potentiated the efficacy of streptomycin and tetracycline against the MRSA by a range of 1–32 folds with the aqueous root extract recording the highest synergistic effect and ethanol seed extract with the least effect. The findings of this study support the antibacterial activities of the A. muricata plant parts.