Sesquiterpenoids from <em>Dysoxylum acutangulum</em> Miq. Twigs and Their Antibiofilm Activity Against <em>Streptococcus mutans</em>

Sesquiterpenoids are terpenoid-derived compounds with diverse biological activities and are commonly found in plants of the Dysoxylum genus (Meliaceae). This study aimed to isolate and characterize sesquiterpenoids from the n-hexane extract of Dysoxylum acutangulum Miq. and to evaluate their antibiofilm activity against Streptococcus mutans. The extract was separated using various chromatographic tech-niques to yield one tricyclic sesquiterpenoid and one mixture of epimeric sesquiterpenoids. Structural elucidation was performed using spectroscopic analyses, including MS, IR, and NMR, and by comparison with reported data. The isolated com-pounds were identified as spathulenol (1), 10-oxo-isodauc-3-en-15-al (2a, mayor), and sinulin A (2b, minor). In vitro testing showed weak antibiofilm activity (MBIC 250–500 µg/mL) and no significant inhibition at 62.5 µg/mL compared to chlorhexidine. Molecular docking against Sortase A and GtfB revealed moderate binding affinities consistent with the experimental trend. The slightly better activity of the epimeric mixture suggests a possible additive effect. Overall, these findings provide preliminary structure–activity insights into sesquiterpenoids from D. acutangulum as potential antibiofilm candidates, warranting further mechanistic and combination-based investigations.