Antiretroviral activities of anthraquinones and their inhibitory effects on reverse transcriptase.

Alizarin complexone (AC), alizarin Red S (ARS) and various other anthraquinones were evaluated for their inhibitory effects on Rous-associated virus 2 reverse transcriptase (RAV-2 RT). Some 1,2-dihydroxyanthraquinones were active against this enzyme and AC was the most potent inhibitor among these compounds [50% inhibitory concentration (IC50): 3.8 micrograms/ml]. AC slightly inhibited Rous sarcoma virus RT (RSV RT) and human immunodeficiency virus type 1 RT (HIV-1 RT) (IC50: 100 micrograms/ml and 45 micrograms/ml, respectively). However, AC efficiently inhibited focus formation by Rous sarcoma virus (RSV) and cytopathogenicity of human immunodeficiency virus type 1 (HIV-1). Simultaneous administration of AC with RSV to newborn chickens also delayed tumor induction by RSV.