A new indolinic cryptoalkaloid, mattogrossine, has been isolated from the roots and branches of Strychnos mattogrossensis collected near Manaus. Elucidation of its structure is based mainly on 2D NMR studies. Two other indolinic alkaloids were also obtained: strychnobrasiline and 12-hydroxy- 11 -methoxystrychnobrasiline, and their 13C NMR data are provided. © 1990.