Anti-HIV-1 activities of constituents from the rhizomes of Boesenbergia thorelii

A new lignan, thoreliin A (1), and a new bisnorlignan, thoreliin B (2), were isolated from a MeOH extract of the rhizomes of Boesenbergia thorelii. In addition, the known bisnorlignans 3 and 4, neolignan 5, phenylpropanoids 6–15, as well as benzenoids 18–21 were also obtained from the same source. The structures were elucidated based on their spectroscopic data. By single crystal X-ray analysis, the relative stereochemistry of 1 was confirmed. All isolated compounds were evaluated for anti-HIV-1 activities. Among them, thoreliin A (1) exhibited anti-HIV-1 activities on both HIV-1 reverse transcriptase (41.43% inhibition at 200 μg/mL) and syncytium reduction assays (EC₅₀ 20.6 μM, SI 3.7), while compounds 3–6, 9 and 11–21 showed anti-HIV-1 activity only in the anti-syncytium assay (EC₅₀ 6.6–454.1 μM, SI >1.32–7.75).