Structurally diverse monoterpenoid indole alkaloids from <i>Damnacanthus hainanensis</i> as well as their potential anti-inflammatory and anti-HIV effects

A phytochemical investigation on the stems and leaves of <i>Damnacanthus hainanensis</i> caused the isolation and characterisation of a new monoterpenoid indole alkaloid, damnahainanline (<b>1</b>), as well as seven known analogues (<b>2</b>-<b>8</b>). The molecular structure of <b>1</b> was determined in the light of comprehensive spectroscopic data analyses and the known analogues <b>2</b>-<b>8</b> were determined <i>via</i> comparing their experimental spectroscopic data with the reported spectroscopic data in the literature. The anti-inflammatory effects as well as anti-HIV activities of all isolates <b>1</b>-<b>8</b> <i>in vitro</i> were assessed. As a result, compounds <b>1</b>-<b>8</b> showed remarkable inhibitory effects against nitric oxide (NO) production induced by lipopolysaccharide in mouse macrophage RAW 264.7 cells holding an IC₅₀ values in the range of 0.78 ± 0.06 to 10.89 ± 0.16 <i>μ</i>M. At the same time, compounds <b>1</b>-<b>8</b> displayed remarkable anti-HIV-1 reverse transcriptase (RT) effects with EC₅₀ values ranging from 0.31 to 7.27 <i>µ</i>M.