Comparative study of the antibacterial activity of Azadirachta indica A. Juss. and Piper betle L. against Streptococcus mutans, an oral pathogenic bacterium

The present study aimed to evaluate and compare the antibacterial activity of Azadirachta indica A. Juss. (Neem) and Piper betle L. (Betel) against Streptococcus mutans, a key oral pathogen associated with dental caries. Fresh and dried leaf and stem samples of both plants were collected, shade-dried, powdered and subjected to solvent extraction using methanol and distilled water. The antibacterial potential was assessed using the agar well diffusion method, with gentamicin serving as the positive control and plain solvents as negative controls. The results demonstrated that all plant extracts exhibited varying degrees of antibacterial activity. Notably, fresh methanol extract of A. indica stem showed the highest zone of inhibition (10.5 mm), followed by the leaf extract of P. betle leaf (8 mm). In general, dried extracts were less effective than fresh ones and methanol proved to be a more efficient solvent than water for extracting bioactive compounds. These findings underscored the potential of these traditionally used medicinal plants as natural alternatives for oral hygiene management and supported the development of plant-based mouthwashes or dental formulations. Further in vivo studies and clinical trials were recommended to validate these in vitro findings and to identify the active constituents responsible for the antibacterial effects.