A new oxindole alkaloid named neisosposinine was isolated from the stem bark of Neisosperma oppositifolia and its structure was elucidated as (1) with the aid of spectroscopic data. The C-18 methyl epimer of (1), isocarapanaubine (2) was also isolated along with three indole alkaloids, reserpiline (3), isoreserpiline (4) and ochroposinine (5). © 1989.