Bioactive constituents from Trichilia dregeana Sond. (Meliaceae)

The chemical investigation of the methanolic leaf extract of Trichilia dregeana Sond. led to the isolation of a hitherto unreported cycloartane-type triterpene, dregeanol (1), together with nine known compounds, (3β,23E)-9,19-cyclolanosta-23,25-dien-3-ol (2), 9,19-cyclolanost-24-en-23-one (3), 6β-hydroxystigmasta-4,22-dien-3-one (4), lyoniresinol (5), maslinic acid (6), asperphernamate (7), mixture of stigmasterol (8) and β-sitosterol (9) and β-sitosterol-3-O-β-D-glucopyranoside (10). The structures of the isolates were elucidated by extensive spectroscopic and spectrometric analyses (1D and 2D NMR, ESI-MS) and by comparison with previously reported data. Compounds 2 and 6 showed significant antibacterial effect against Escherichia coli and Salmonella enteritidis, res-pectively, with MIC value of 31.25 μg/mL, whilst they displayed moderate antifungal effect with MIC value of 62.5 μg/mL against Candida albicans. All the isolates except compound 3 were found to possess a weak antioxidant potential in the DPPH, ABTS and FRAP assays.