Antiplasmodial activity, in silico ADME and mammalian cell cytotoxicity of a synthetic protoberberine alkaloid, coralyne

Coralyne is a synthetic protoberberine alkaloid with anticancer activity and selectivity superior to that of berberine, its congener. As berberine is gifted with antiplasmodial activity, this study assessed the antiplasmodial activity of coralyne against erythrocytic stages of the malaria parasite in culture. Parasites were cultured by adopting the method described by Trager and Jensen in 1976. Following this, parasites were exposed at ring stage to increasing doses of coralyne to enable us compute the IC50. Further, given that berberine is a substrate of the efflux transporter permeability glycoprotein (P-gp), in silico techniques were used to study the pharmacokinetics of oral coralyne. Coralyne showed excellent potency (IC50Pf3D7: 0.52 µg/ml) against chloroquine sensitive strain and a little less potency (IC50PfINDO: 1.15 µg/ml) against the chloroquine resistant malaria parasite strain (Resistance index: 2.21). Further, with CC50HEK: >100 µg/ml, it was non-toxic to mammalian cells. However, in silico absorption, distribution, metabolism and excretion (ADME) studies predicts that like berberine, coralyne may also have poor oral bioavailability thus limiting its usefulness as an orally deliverable antimalarial agent. Given the negative impact of low bioavailability in the development of protoberberine alkaloids as antimalarials, synthesizing analogues of coralyne with nanomolar potency against the malaria parasite and improved oral pharmacokinetics may be a good strategy for the future.

 Nekpen Erhunse and Dinkar Sahal