Isolation and structure of vanitaracin A, a novel anti-hepatitis B virus compound from Talaromyces sp

Two new tricyclic polyketides, vanitaracin A (1) and B (2), together with three novel compounds 3, 4 and 5, were isolated from a culture broth of a fungus, Talaromyces sp. The chemical structures of these compounds were determined from spectroscopic data (1D/2D NMR, MS and IR). The five isolated compounds were then tested for anti-hepatitis B virus (HBV) activity and vanitaracin A was found to exhibit an IC50 value of 10.5 μM using a HBV-susceptible cell line. By contrast, the derivative 2 displayed weak anti-HBV action, which suggested that the substituents at C-9 in 1 are likely to be important for its antiviral activity. We believe the two vanitaracin derivatives constitute a new class of anti-HBV agents.