These species are known to be very rich in indole alkaloids like aspidospermine and quebrachamine.
Madsen, "Isolation and biological activity of aspidospermine and quebrachamine from an Aspidosperma tree source," Journal of Pharmaceutical and Biomedical Analysis, vol.
Seven tetracyclic alkaloids possessing a free ethyl chain such aspidospermine, showed [IC.sub.50] after incubation for 72 h between 3.2 and 15.4 [micro]M.