Isolation of new xanthones and evaluation of antioxidant, antibacterial activities, and molecular docking of Calophyllum soulattri Burm.f. Stem bark

Abstract

Six new xanthones (1-6), along with eight known xanthones (7-14) were isolated from C. soulattri stem bark. Their structures were elucidated using 1D and 2D NMR, FTIR, and MS analyses. The phytochemical profiling, antioxidant, and antibacterial evaluations were conducted on the extracts, and the interaction of new compounds with PBP was explored through molecular docking analysis. Among the extracts, ethyl acetate and chloroform exhibited the highest TPC and TFC, respectively, whereas the methanol extract portrayed the highest antioxidant activity (IC50 7.97 μg/mL). In the antibacterial assay, the chloroform and ethyl acetate extracts exhibited the most significant inhibitory activity against all tested A. baumannii strains (MIC 0.225-0.440 mg/mL). Molecular docking study revealed that compound 6 displayed the strongest binding energy (-14.2 kJ/ mol) towards penicillin-binding protein compared to the other isolated compounds.