Unveiling the antimicrobial efficacy of madras thorn (Pithecellobium dulce): A promising natural weapon against Staphylococcus aureus infections

Abstract

The escalating global health crisis of antimicrobial resistance (AMR), driven by the overuse of conventional antibiotics, has intensified the emergence of multidrug-resistant pathogens, with Staphylococcus aureus posing a significant threat due to its association with severe hospital-acquired infections. This study investigates the potential of Pithecellobium dulce, a medicinal plant abundant in Tamil Nadu, India, as a natural antimicrobial agent. Leaves, stems, and pods of P. dulce were collected, air-dried, and pulverized, followed by extraction using ethanol, hexane, and water to isolate a broad spectrum of bioactive compounds. Antimicrobial activity was assessed against S. aureus (ATCC 25923) using disk diffusion and broth microdilution methods, with ciprofloxacin as a positive control. The ethanolic extract exhibited the highest efficacy, with a mean inhibition zone of 15±0.5 mm and a minimum inhibitory concentration (MIC) of 12.5 mg/mL, compared to hexane (8±0.3 mm, 25 mg/mL) and aqueous (5±0.2 mm, 50 mg/mL) extracts. Phytochemical screening confirmed the presence of alkaloids, flavonoids, saponins, tannins, and terpenoids in the ethanolic extract, while GC-MS analysis identified key compounds such as pyrogallol (27.51%), 5-hydroxymethylfurfural (24.48%), and furfural (4.44%), contributing to its antibacterial effects through oxidative stress and cell wall disruption. The study demonstrates the synergistic antimicrobial potential of P. dulce, validating its traditional use as a sustainable therapeutic agent in microbiology. Further research on optimization and testing against multidrug-resistant strains like MRSA is essential.