New monoterpenoid indole alkaloids from the stems of Tabernaemontana bovina Lour (Apocynaceae).

Two new monoterpenoid indole alkaloids, named taberibogines E and F (1 and 2), together with three known ones (3–5) were isolated from the stems of Tabernaemontana bovina Lour (Apocynaceae). Their structures including absolute configurations were elucidated from a combination of NMR and HRESIMS data and NMR calculations as well as DP4+ probability analyses. Compounds 1 and 2 exhibited inhibitory effects on LPS-induced nitric oxide (NO) production in RAW 264.7 macrophages. [ABSTRACT FROM AUTHOR]