Comparative antibacterial and anti-biofilm activities of hot and cold pandan leaf extracts against Streptococcus mutans with cytotoxicity assessment

This study investigated the effects of hot and cold pandan leaf extracts on antibacterial activity, biofilm formation inhibition, and acid production of Streptococcus mutans (S. mutans). The cytotoxicity of both extracts on oral fibroblasts was also evaluated. The chemical compositions of the extracts were identified using liquid chromatography-mass spectrometry. The hot extract contained fewer compounds, such as tetraphyllin B, rhizocticin A and gabapentin with a slightly lower match score for compound identification. In contrast, the cold extract included a wider variety of compounds, including crotanecine, Quinoline alkaloid and metaraminol, with higher match scores indicating more accurate identification. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of both extracts (hot and cold pandan leaf extracts) against S. mutans were determined. The MICs of hot and cold pandan extracts were 200 mg/mL and 125 mg/mL, respectively, while the MBCs were greater than 500 mg/mL for the hot extract and 400 mg/mL for the cold extract. Both extracts significantly inhibited biofilm formation at their respective MICs. Moreover, both extracts effectively reduced acid production at MIC, 1/2 MIC, and 1/4 MIC concentrations. Importantly, neither extract affected the survival of human gingival fibroblasts (HGFs), indicating their safety at 200 mg/mL for the hot pandan extract and 125 mg/mL for the cold pandan leaf extract. Overall, both hot and cold pandan leaf extracts exhibited bacteriostatic and bactericidal effects against S. mutans, with the cold extract demonstrating greater efficacy in inhibiting biofilm formation and acid production. These findings suggest the potential of pandan leaf extracts as safe natural alternatives for oral health management.