A New Dibenzofuran, Isostrepsilic Acid, Produced by Cultured Mycobiont of the Lichenized Ascomycete Usnea orientalis

Abstract

Two dibenzofurans, isostrepsilic acid and hypostrepsilic acid, were produced in large amounts by the mycobiont of Usnea orientalis cultured on malt-yeast extract medium containing sugar alcohols. These substances were not detected in the natural lichen thalli growing in the field which normally produces usnic acid and salazinic acid. Isostrepsilic acid is a new lichen substance which has been determined to be 3,7-dihydroxy-9-hydroxymethyl-1-methyldibenzofuran-2-carboxylic acid.