Isolation and Structural Determination of Eriobofuran, A New Dibenzofuran Phytoalexin from Leaves of Loquat, Eriobotrya japonica L.

Abstract

An antimicrobial substance, named as eriobofuran (Ia) was isolated from loquat leaves [Eriobotrya japonica L. (Rosaceae)] inoculated with Entomosporium eriobotryae, a host-pathogenic fungus. The structure of eriobofuran was deduced to be 2, 4-dimethoxy-3-hydroxy-dibenzofuran by spectroscopic, chemical evidence and biosynthetic considerations. Its structure was confirmed by direct comparison with a synthetic specimen of eriobofuran ethyl ether. Eriobofuran inhibited strongly the spore germination and germ tube growth of Pestalotia funerea, a host-pathogenic fungus of loquat tree.