Antimalarial alkaloids from a Bhutanese traditional medicinal plant Corydalis dubia.
BACKGROUND
Corydalis dubia is used in Bhutanese traditional medicine as a febrifuge and for treating infections in the blood, liver and bile which correlate to the signs and symptoms of malarial and microbial infections.


OBJECTIVE
To validate the ethnopharmacological uses of the plant and to discover potential new therapeutic drug leads.


METHODS
C. dubia was collected from Bhutan and the alkaloids were obtained using acid-base fractionation and separation by repeated column and preparative plate chromatography. The alkaloids were identified from analysis of their physiochemical and spectroscopic data and were tested for antiplasmodial, antimicrobial and cytotoxicity activities.


RESULTS
A systematic extraction and isolation protocol yielded one new natural product, dubiamine, and seven known isoquinoline alkaloids, scoulerine, cheilanthifoline, protopine, capnoidine, bicuculline, corydecumbine and hydrastine. Among the four alkaloids tested, scoulerine showed the best antiplasmodial activity with IC(50) values of 5.4μM and 3.1μM against the antifolate sensitive and the multidrug resistant P. falciparum strains: TM4/8.2 and K1CB1, respectively. None of the alkaloids tested showed significant antimicrobial or cytotoxicity activities.


CONCLUSIONS
The antiplasmodial test results, of the isolated alkaloid components, are commensurated with the ethnopharmacological uses of this plant.
School of Chemistry, University of Wollongong, Wollongong, NSW 2522, Australia.
Phurpa
P
Wangchuk
Paul A
PA
Keller
Stephen G
SG
Pyne
Anthony C
AC
Willis
Sumalee
S
Kamchonwongpaisan
D000470:Alkaloids / Q000302:isolation & purification* / Q000494:pharmacology*; D000962:Antimalarials / Q000302:isolation & purification / Q000494:pharmacology*; D001600:Berberine Alkaloids / Q000302:isolation & purification / Q000494:pharmacology*; D001631:Bhutan; D031311:Corydalis / Q000737:chemistry*; D004351:Drug Resistance / Q000187:drug effects; D020128:Inhibitory Concentration 50; D007546:Isoquinolines / Q000494:pharmacology*; D008519:Medicine, Traditional; D010936:Plant Extracts / Q000494:pharmacology*; D010963:Plasmodium falciparum / Q000187:drug effects*
D000470:Alkaloids; D000962:Antimalarials; D001600:Berberine Alkaloids; D007546:Isoquinolines; D010936:Plant Extracts; C576824:dubiamine; C010941:discretamine