Of the little investigated genus Malouetia (Apocynaceae) only African Malouetia bequertiana Woods. has been subjected to detailed investigation by Janot, Goutarel and coworkers (1, 2). The French workers succeeded in isolation of eight steroid alkaloids (malouetine, funtuphyllamine B and C, funtumafrine C, malouphyllamine, chinemorphine and malouphyllinine) belonging to the pregnane and conanine series. The presence of funtumafrine C and funtuphyllamine B in South-American Malouetia glandulifers Miers. has been also reported (3). Thus, the presence of alkaloids known as typical of Holarrhena and Funtumia, was also demonstrated in Malouetia. We wish to report the isolation of further steroid bases, including new alkaloids malarborine and malarboreine, from South-American species Malouetia arborea Miers. and Maloustia tamaquaring (Aubl.) A. Dc. which confirms the close relationship between all three genera and extends the number of alkaloid types characteristic of the holarrhimine and conkurchine bases.