SCYTALOL-A, SCYTALOL-B, SCYTALOL-C, AND SCYTALOL-D AND OTHER MODULATORS OF MELANIN BIOSYNTHESIS FROM SCYTALIDIUM SP.-36-93

From submerged cultures of Scytalidium sp. 36-93, tell metabolites wer e isolated hue to their effects on dihydroxynaphthalene (DHN) or DDPA melanin biosynthesis. Four of the compounds, scytalols A (1a), B (1b), C (2), and D (3), are new secondary metabolites, the structures of wh ich were determined by spectroscopy, while the other compounds are kno wn. Scytalols A (1a) and D (3) are selective inhibitors of DHN melanin biosynthesis and exhibit no antifungal or cytotoxic activities. Nectr iapyrone, 6-methoxymellein and 4-chloro-6-methoxymellein stimulated th e formation of DOPA melanin in B16-F1 melanoma cells in the absence of melanin-stimulating hormone.