MR304A, a new melanin synthesis inhibitor produced by Trichoderma harzianum.

In the screening for new melanin synthesis inhibitors, we found a novel isonitrile inhibitor, MR304Afrom the culture broth of Trichoderma harzianum. There were someisonitrile antibiotics that were reported to have been isolated from Trichoderma sp. 1 ~ 4) and trichoviridin, one of these isonitriles, showed a melanin biosynthesis inhibitory activity5). In this paper we described the fermentation, isolation, physico-chemical properties, structure determination and biological activities of MR304A. The producing microorganism, strain MR304,was isolated from a soil collected in Taejon, Korea. The fungus was identified as Trichoderma harzianum on the basis of its cultural properties and has been deposited with Korean Collection for Type Cultures, KCTC 0123BP.