Qualitative phytochemical screening and anti-bacterial activities of ethanolic mulberry leaf extract (MORUS SPP) against isolated gram-positive bacteria

Mulberry (Morus spp.) leaves have long been recognized in traditional medicine and are now studied extensively for their antibacterial, antioxidant, anti-inflammatory, and antidiabetic properties. Their abundance in tropical and subtropical regions, including Malaysia, makes them an accessible and sustainable resource for health applications. The accelerating threat of antimicrobial resistance has highlighted the importance of plant-derived compounds as potential alternatives or complements to conventional antibiotics. However, systematic evaluation of mulberry leaf extracts against environmental bacterial isolates remains limited. This study aimed to identify the phytochemical constituents of ethanolic mulberry leaf extract and evaluate its antibacterial activity against Grampositive bacteria isolated from different sources. Dried mulberry leaves were extracted in 70% ethanol, and the resulting crude extract was subjected to Fourier Transform Infrared (FTIR) spectroscopy and qualitative phytochemical assays. The antibacterial potential was assessed using the disc diffusion method against Grampositive isolates collected from the toilet and laboratory door handles. Extract concentrations of 20, 15, and 10 mg/mL were tested alongside penicillin (positive control), ethanol (solvent control), and distilled water (negative control). FTIR and phytochemical tests confirmed the presence of bioactive compounds, including tannins, flavonoids, alkaloids, and terpenoids, which are known contributors to antimicrobial activity. Gram staining of isolates revealed purple cocci in clusters, consistent with Gram-positive Staphylococcus spp. Antibacterial assays demonstrated measurable inhibition zones across all extract concentrations, with the highest inhibition observed at 20 mg/mL (up to 5.49 mm). While inhibition zones were smaller than those of penicillin (14.30–23.95 mm), they exceeded those of solvent and negative controls, confirming bioactivity attributable to phytochemicals. In conclusion, ethanolic mulberry leaf extract exhibited modest but consistent antibacterial activity against Grampositive environmental isolates, reinforcing its potential as a cost-effective, plant-based antibacterial source.