Simultaneous administration of 2-aminoethyl diphenylborinate and chloroquine reverses chloroquine resistance in malaria parasites.

A nearly complete reversal of chloroquine (CQ) resistance in the CQ-resistant Plasmodium falciparum K-1 strain, with a significant decrease in the mean ± standard deviation (SD) 50% inhibitory concentration (IC50) from 1,050 ± 95 nM to 14 ± 2 nM, was achieved in vitro by the simultaneous administration of 2-aminoethyl diphenylborinate (2-APB). The CQ resistance-reversing activity of 2-APB, which showed the same efficacy as verapamil, was also observed in an in vivo mouse infection model with the CQ-resistant Plasmodium chabaudi AS(30CQ) strain.