Helioxanthin 8-1, an analogue of helioxanthin, exhibits significant in vitro anti-HBV/HCV/HSV-1/HIV activity with EC50 of >5/10/1.4/15 μM.

The cyclic hydrazide 28(Helioxanthin 8-1) showed the most potent anti-HBV activity among those helioxanthin analogues tested. In addition, compound 28 exhibited moderately potent activity against HIV. It would therefore be promising to study helioxanthin analogues that contain a six-membered ring instead of the five-membered ring found in the lactam [1]. 8-1 exhibited effective inhibition on DHBV replication. The combination of 8-1 with 3TC resulted in the additional anti-DHBV activity. Viral induced cells displayed higher susceptibility to 8-1 treatment than non-induced cells. HBV X protein might not be an essential factor in the initiation of the biological activity of 8-1, as demonstrated by its absence in DHBV [2].