Determination of Photosensitizing Potential of Lapachol for Photodynamic Inactivation of Bacteria

Antimicrobial photodynamic inactivation (aPDI) offers a promising alternative to combat drug-resistant bacteria. This study explores the potential of lapachol, a natural naphthoquinone derived from , as a photosensitizer (PS) for aPDI. Lapachol's photosensitizing properties were evaluated using and strains under blue LED light (450 nm). UV-vis spectroscopy confirmed lapachol's absorption peak at 482 nm, aligning with effective excitation wavelengths for phototherapy. Photoinactivation assays demonstrated significant bacterial growth inhibition, achieving complete eradication of at 25 µg·mL under light exposure. Scanning electron microscopy (SEM) revealed morphological damage in irradiated bacterial cells, confirming lapachol's bactericidal effect. This research underscores lapachol's potential as a novel photosensitizer in antimicrobial photodynamic therapy, addressing a critical need in combating antibiotic resistance.