F13459, a new derivative of mycophenolic acid. I. Taxonomy, isolation, and biological properties

In the course of screening for inhibitors of intracellular trafficking of glycoprotein, a new inhibitor, F13459 was isolated from the culture broth of a Penicillium sp. It was purified using solvent extraction, silica gel, Sephadex LH-20 and ODS column chromatography. From structural analysis, F13459 was a derivative of mycophenolic acid, an inhibitor of inosine 5'-monophosphate dehydrogenase. F13459 inhibited hemagglutinin synthesis of NDV at concentrations more than 25 microg/ml. However, syncytium formation as a result of cell surface expression of F-glycoprotein of NDV was inhibited at concentrations of F13459 lower than those required for appreciable inhibition of glycoprotein synthesis.