HONGOQUERCINS, NEW ANTIBACTERIAL AGENTS FROM THE FUNGUS LL-23G227 - FERMENTATION AND BIOLOGICAL-ACTIVITY

Two new antibiotics, hongoquercins A and B, were isolated from ferment ation extracts of the unidentified fungus LL-23G227. In the optimum me dium, titers of the A and B components reached approximately 2.1 g/lit er and 0.02 g/liter, respectively. The optimum temperature for antibio tic production was approximately 22 degrees C. Growth was delayed at 1 5 degrees C but appeared to teach higher levels than was observed at 2 2 degrees C. Addition of dextrose to growth media increased hongoquerc in B production. Hongoquercin A exhibited moderate activity against Gr am-positive bacteria. Mechanistic studies conducted in an E. coli imp strain suggested membrane damage as the primary mode of bactericidal a ction. These compounds also lysed human red blood cells, suggesting a similar mode of action on eukaryotic cells.