Plant-derived and semi-synthetic calanolide compounds with in vitro activity against both human immunodeficiency virus type 1 and human cytomegalovirus

Plant-derived and semi-synthetic calanolide compounds with anti-human immun odeficiency virus type 1 (HIV-1) activity were tested for antihuman cytomeg alovirus (HCMV) activity in both cytopathic effect inhibition and plaque re duction assays. The results indicated that the anti-HCMV activity of calano lide compounds does not correlate with their activity against HIV-1. The se mi-synthetic 12-keto derivatives tended to be more active against HCMV than the corresponding 12-OH congeners, which were more active against HIV-1. I t appeared that the 7,8-unsaturated double bond in the chromene ring played a certain role in maintaining activities against both HCMV and HIV-1. Satu ration of the double bond increased the EC50 values against both viruses, w ith concomitant increase in toxicity. The calanolide compounds reported her e are the first non-nucleoside analogues capable of inhibiting both HIV-1 a nd HCMV and, therefore, may be useful chemoprophylactic agents for HCMV in HIV-infected people or vice versa.