Steroidal alkaloids from Cryptolepis obtusa

Two novel diglycosylated steroidal alkaloids of 5Δ-pregnene nucleus, named obtusine-20(R)-O-[β-thevetopyranosyl-(1→4)-β-cymaropyranoside] and obtusolactam-20(R)-O-[β-thevetopyranosyl-(1→4)-β-cymaropyranoside], together with the known β-sitosteryl-3-O-β-glucopyranoside were isolated from the roots of Cryptolepis obtusa N. E. Br.
We thank Mr. Daniel Zunguza of the Faculty of Bi- ology, Eduardo Mondlane University, Mozambique, for his kindly collaboration in plant collection; Mrs. J. Hawkes of the Intercollegiate NMR Service Unit, Department of Chemistry, King's College London; Mr. Peter Haycock of the NMR Service of Queen Mary and West®eld College, London and Mr. Mark Domin of the Mass Spectrometry Service of School of Pharmacy, London. We want also to acknowledge INVOTAN-Portugal for a Ph.D. grant (13/A/94/PO) to Alexandra Paulo.