Quinacrine, also known as atebrin, atabrine, mepacrine and acrichin, is a 9-alkylaminoacridine (Fig. 1), and was developed as one of a group of potential antimalarial drugs (Mietzsch and Mauss, 1930), apparently patterned after successful antimalarials possessing alkyl side chains as, for example, pamaquine (Goodman and Gilman, 1960; The Acridines, A. Albert, 1966). Quinacrine was introduced clinically in April, 1932 (Mauss and Mietzsch, 1936), but despite rapid professional acceptance, its structure remained masked by inadequate patent disclosure until its degradation and synthesis by Russian scientists (Chelintsev
et al., 1934). Previously, acridines, particularly proflavine (Browning and Gilmour, 1913) and its 10-methyl acridinium derivative, in conjunction known as acriflavine, had been used as antibacterial agents, but only with the advent of quinacrine and additional 9-alkylaminoacridine derivatives, were acridines developed into highly effective antimalarial drugs. During the Second World War, the Allies, separated from their sources of quinine, turned to the synthetic compound, quinacrine, for both prophylaxis and overt therapy of malaria. As a result of the War, of the prevalence of malaria, and of the many cellular and molecular effects of quinacrine, a vast literature has developed, and for detailed knowledge, the reader should consult the very excellent and comprehensive monographs, The Acridines by A. Albert (2nd edition, St Martin’s Press, New York, 1966), Malaria Parasites and Other Haemosporidia, by P.C.C. Garnham (Black-well Scientific Publications, Oxford, 1966), and Chemotherapy and Drug Resistance in Malaria, by W. Peters (Academic Press, London and New York, 1970).