Background Staphylococcus aureus has prevailed against the majority of antibiotics currently in clinical use, making it a significant global public health problem. As a safer alternative, bioactive compounds have been explored. Annona muricata has been shown to possess antimicrobial activity. However, there are few reports on the molecular activity of A. muricata bioactive compounds against S. aureus. Thus, this study was aimed at evaluating the antimicrobial activity of its crude extract as well as investigating the potential of its bioactive compounds against the Cap5O capsular polysaccharides (CPS) of S. aureus via molecular docking. Methods Collection of plant leaves, preparation of extracts, anti-nutrient analysis, phytochemical screening via crude method and gas chromatography-mass spectrophotometer (GC-MS), isolation and characterization of S. aureus and the antimicrobial activity test were all done using standard protocols. Molecular docking was done using the MCULE online tool with emphasis on docking scores, toxicity, and other properties. Results Crude screening of the extracts showed the presence of polyphenols, hydroxyanthraquinones, reducing compounds, flavonoids, saponins, glycosides, alkaloids, anthraquinones, phlobatannins and tannins in different concentrations. Anti-nutrient analysis showed the presence of allowable levels of evaluated anti-nutrients. GC-MS revealed a total of twenty-nine (29) bioactive compounds, out of which only 4 (13.80%) docked without toxicity and these were bicyclo[4.1.0]heptan-2-one 6-methyl, trichloromethane, carbonic acid 2-dimethylaminoethyl propyl ester, and 1-methyl-4-phenyl-5-thioxo-1,2,4-triazolidin-3-one on either the NAD-binding or C-terminal substrate binding domain of Cap5O. Conclusion Results obtained show that Cap5O could be a potential drug target for multi-drug resistant S. aureus, however, further studies aimed at evaluating these bioactive compounds individually and in combination are highly needed.

Background Potable water have been shown to be a source of contamination due to poor handling during its supply chain process. It is common practice for sachet water, a widely consumed potable water across Nigerian and West African cities to be exposed to sunlight for hours daily before they are sold to consumers. This practice coupled with the polyethene plastic packaging could cause leaching of heavy metals and other chemical components of the plastic package into the sachet water, and also cause its biological quality to deteriorate posing great public health concerns which prompted this study. Methods Three (3) sachet water brands (n = 4 per brand) were collected and exposed to sunlight daily for 14, 28, and 48 days were analyzed for heavy metals, total hardness, and other physico-chemical parameters using standard protocols. In addition, we also evaluated total heterotrophic bacteria and coliform counts, and antibiotic susceptibility of resulting isolates. Results All brands of the exposed sachet water recorded increased levels of physico-chemical parameters (except pH) and heavy metals compared to the control group in a linear fashion to exposure time. Zn was the most ingested from sachet water brands. The ADD, HQ, and HI evaluations revealed that consuming these brands of sachet water exposed to different durations of sunlight could be expose consumers to Cr, Cd, Pb, As, and Ni toxicities. The CR of Cr, As, and Ni in all brands of the sachet water exposed to sunlight were above the safe value of 10− 4, indicating a likelihood of the population having cancer after over 60 years of exposure. Ni posed the highest carcinogenic risk in all sachet water brands exposed to sunlight for 42 days. All the brands evaluated failed to meet the World Health Organization and national safety limits for total heterotrophic bacteria and total coliform counts. Six out nine isolates elaborated extracellular amylase while all produced protease, enzymes linked with biofilm formation and pathogenicity, respectively. Furthermore, the isolates showed multi-drug resistance. Conclusion The potential health risk inherent in this practice has significant public health implications for the consumers across Nigeria and the West African region.

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