Bioactive tetrahydrofuran lignans from roots, stems, leaves and twigs of Anogeissus rivularis

Abstract

Four previously undescribed tetrahydrofuran lignans, named anorisols A-D (1-4) and fourteen known compounds (5-18) were isolated from the roots, stems, leaves and twigs of Anogeissus rivularis. The chemical structures were elucidated on the basis of their spectroscopic data and by comparison with the literature data. The absolute configurations of 1-4 were established by comparison of the experimental ECD spectra with the calculated ECD spectra. Some isolated compounds were evaluated for their cytotoxic activity as well as anti-HIV-1 activity employing reverse transcriptase (RT) and syncytium reduction assays using the ^ΔTat/RevMC99 virus in 1A2 cell line systems. Compound 6 displayed the most potent activity in syncytium inhibition assay with effective concentration at 50% (EC₅₀) value of 13.3 μM (SI >3.0). In the reverse transcriptase assay, compound 1 exhibited moderate activity with IC₅₀ value of 213.9 μM.

Keywords: Anogeissus rivularis; Anti-HIV; Combretaceae; Lignans; Tetrahydrofuran.