Isolation, Structure Elucidation and Antifungal Activity of Angucycline Antibiotics from Streptomycete cellulosae

Streptomyces species are the major producers of antibiotics, and not many bioactive substances and antibiotics have been found in Streptomyces cellulosae. Two angucycline antibiotics were isolated from the ethyl acetate extract of the fermentation broth of the strain S. cellulosae YIM PH20352, they were identified as urdamycinone B (1) and dehydroxyaquayamycin (2) based on extensive spectroscopic analyses. Four root-rot pathogens of the Panax notoginseng including Alternaria panax, Plectosphaerella cucumerina, Fusarium oxysporum, and Fusarium solani were used for their antagonistic activity test. Compound 1 exhibited the most potent antifungal activity against A. panax and P. cucumerina with the MIC values at 16 and 64 & mu;g/mL, respectively; compound 2 exhibited antifungal activity against A. panax with the MIC value at 64 & mu;g/mL.