A new inhibitor of melanogenesis, albocycline K3, produced by Streptomyces sp. OH-3984.

The fermentation and isolation of 1 were carried out in the same way as reported previously1}. Astock culture of the producing organism was inoculated into a test tube (i.d. 2x20cm) containing 10ml of seed medium consisting of2% glucose, 0.5% peptone, 0.3% dry yeast, 0.5% meat extract, 0.5% NaCl and 0.3% CaCO3 (pH 7.0 before sterilization). The tube was incubated at 27°C for 72 hours on a reciprocal shaker. Then, 2ml portions of the culture were transferred to a 500-ml Erlenmeyer flask containing 100ml of the seed medium. The flask was incubated at 27°C for 48 hours on a rotary shaker (210rpm), and 400ml of the resulting culture was transferred into a 50-liter fermenter containing 30 liters of the same medium as described above. The fermentation was carried out at 27°C for 96 hours of an agitation rate of 160rpmand an aeration rate of 60 liters per minute. The fermentation broth of Streptomyces sp. OH-3984 (30 liters) was extracted with EtOAc (25 liters), and the EtOAc layer was dried over anhydrous Na2SO4 and