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.