Continuing our work on Amaryllidaceae alkaloids, the bulbs of Phaedranassa dubia (H.B. & K.) were studied and found to contain eight alkaloids: pseudolycorine (1), ungeremine (2), zefbetaine (3), haemanthamine (4), sanguinine (5), galanthamine (6), epinorgalanthamine (7) and buphanamine (8). Their structures were established using physical and spectroscopic methods. Each alkaloid was tested against the following parasitic protozoa: Trypanosoma brucei rhodesiense, Trypanosoma cruzi, Leishmania donovani and Plasmodium falciparum. The results showed a good activity of the betaine ungeremine against P. falciparum (IC50=0.09µg/mL). Additionally, haemanthamine presented noteworthy activity against T. brucei rhodesiense (IC50=0.49µg/mL) and P. falciparum (IC50=0.69µg/mL) and pseudolycorine was active against P. falciparum (IC50=0.24µg/mL).
(1)
(2): R1 + R2 =CH2
(4
(5): R1=OH, R2=R4 =H, R3=Me
(8)
(3): R1=H, R2=Me
(6): R1=OH, R2=H, R3=R4=Me
(7): R1=R3=H, R2=OH, R4=Me
Acknowledgements: Edison Osorio thanks the Fundación Carolina for his doctoral fellowship.
