The <i>In Vitro</i> Study of the Synergistic Antibacterial Effect of Hydroalcoholic <i>Mentha </i>Extract with Alum on the Growth of <i>Streptococcus mutans</i>

Abstract

Antimicrobial resistance poses a significant global health challenge, necessitating the search for novel therapeutic approaches. Streptococcus mutans, a key etiological agent in dental caries, requires innovative strategies due to its biofilm-forming ability and resistance to conventional antibiotics. Natural plant-derived compounds have garnered attention as potential antimicrobial agents with a low risk of resistance development. In this study, we investigated the synergistic antibacterial effect of a hydroalcoholic Mentha extract combined with alum against Streptococcus mutans (PTCC 16836). The well diffusion assay demonstrated that alum exhibited a larger inhibition zone diameter (12.04 ± 2.02 mm) compared to the hydroalcoholic Mentha extract (10.33 ± 1.53 mm). However, the minimum inhibitory concentration (MIC) values for the hydroalcoholic Mentha extract (8.20 ± 5.57 mg/mL) and alum (0.35 ± 0.20 mg/mL) were comparable. The minimum bactericidal concentration (MBC) for the hydroalcoholic Mentha extract was 10 mg/mL, while the MBC for alum was 0.625 ± 0.006 mg/mL. The combination of these substances demonstrated a synergistic effect, indicating enhanced antibacterial activity against Streptococcus mutans.