Three monoterpenoid indole alkaloids (MIAs), tabernabovines A-C (1-3), were isolated from Tabernaemontana bovina. They were elucidated by spectroscopic data and computational calculations. Unlike precursors of MIAs, strictosidine and alstrostine A, alkaloid 1 consists of tryptamine and secologanin in a 2:1 ratio. Alkaloid 2 is a cage compound, and 3 possesses a bridged ring. Tabernabovine A exhibited inhibitory activity against NO production with IC(50) 44.1 muM compared to l-NMMA with IC(50) of 48.6 muM.