STRUCTURE ELUCIDATION OF XANTHONE DERIVATIVES WITH CD4-BINDING ACTIVITY FROM PENICILLIUM-GLABRUM (WEHMER) WESTLING

Fermentations of Penicillium glabrum (Wehmer) Westling produce a compl ex mixture of metabolites with potent CD4-binding activity in an ELISA based on the binding of the monoclonal antibody anti-Leu 3a to solubl e recombinant CD4. On purification this mixture was found to include t he known polyketide metabolites citromycetin and anhydrofulvic acid an d a series of novel xanthone derivatives with CD4-binding activity. Th e structure elucidation of these xanthone derivatives was achieved by a combination of mass spectrometric and NMR spectroscopic techniques i ncluding HMQC, HMBC and ROESY. These new C27/C28 polyketide metabolite s probably arise from a dimerisation of two C-14 polyketides such as t he citromycetin polivione.