γ-Pyrone derivatives, kojic acid methyl ethers from a marine-derived fungusaltenaria sp

Abstract
Kojic acid dimethyl ether (1), and the known kojic acid monomethyl ether (2), kojic acid (3) and phomaligol A (4) have been isolated from the organic extract of the broth of the marine-derived fungusAltenaria sp. collected from the surface of the marine green algaUlva pertusa. The structures were assigned on the basis of comprehensive spectroscopic analyses. Each isolate was tested for its tyrosinase inhibitory activity. Kojic acid (3) was found to have significant tyrosinase inhibitory activity, but compounds1,2, and4 were found to be inactive.