Calofrasolide A, a new pyranocoumarin from the stem bark of Calophyllum fraseri M.R.Hend. & Wyatt-Sm. and their antimicrobial and antibiofilm activities.

A new pyranocoumarin, Calofrasolide A (1), was isolated from the stem bark of Calophyllum fraseri, together with the known constituents β-sitosterol, stigmasterol, friedelin, and lupeol. The structure of the new compound was established through comprehensive spectroscopic analyses and confirmed by comparison with reported data. Compound 1 was evaluated for antimicrobial and antibiofilm activities using microdilution and crystal-violet assays. It exhibited notable antimicrobial activity, with MIC values of 62.5 μg/mL against Candida albicans and Streptococcus mutans. In the antibiofilm assays, compound 1 demonstrated pronounced inhibitory effects, suppressing C. albicans biofilm formation by 30.25 ± 1.04 % and S. mutans biofilms by 78.37 ± 0.22 %. Molecular docking studies supported the experimental findings, revealing favourable binding (LBE = -8.5 kcal/mol) within the active sites of ERG11 (5TZ1) and GtfB (8FK4). These findings highlight Calofrasolide A as a promising pyranocoumarin scaffold with potential antimicrobial and antibiofilm relevance, particularly against oral pathogenic infections.