Research Perspective on Biological Science Vol. 11

Staphylococcus aureus is a prominent causative agent across a spectrum of conditions, from superficial skin lesions to invasive diseases and remains difficult to manage because of antimicrobial resistance and biofilm-associated tolerance.  This study evaluated aqueous and ethanolic leaf extracts of Neem (Azadirachta indica) and Papaya (Carica papaya) for anti-virulence activity against S. aureus ATCC 25923. Bacteria were exposed to extracts (125 μg/mL) in tryptic soy broth; growth (metabolic activity) was quantified spectrophotometrically. Biofilm formation on glass plates (60 mm) was assessed by a crystal violet–acetic acid assay, and haemolysis was evaluated on blood agar containing 7% sheep blood. Antibacterial activity of aqueous and ethanolic extracts (125–250 μg/mL) was examined by disc diffusion on Mueller–Hinton agar. Data were analysed by one-way ANOVA with Dunnett’s multiple comparisons test (p < 0.05). Neem reduced growth relative to the untreated control, whereas Papaya alone did not reduce growth at the tested concentration. Both extracts reduced biofilm formation, with ethanolic extracts showing stronger inhibitory effects in disc diffusion (15.6 mm for Neem and 14.0 mm for Papaya at 250 μg/mL; antibiotic control ~17–18 mm). None of the extracts altered haemolytic activity under the conditions tested. These findings suggest Neem and Papaya leaf extracts can attenuate S. aureus biofilm formation and exhibit modest antibacterial activity, supporting further fractionation and mechanistic studies.