A novel antibiotic CJ-17,572 from a fungus, Pezicula sp.

A new antibiotic, CJ-17,572 (I) was isolated from the fermentation broth of a fungus Pezicula sp. CL11877. The structure of I was determined to be a new equisetin derivative by spectroscopic analyses. The compound inhibits the growth of multi-drug resistant Staphylococcus aureus and Enterococcusfaecalis with IC50s of 10 and 20 microg/ml, respectively.

CJ-15,696 and its analogs, new furopyridine antibiotics from the fungus Cladobotryum varium: fermentation, isolation, structural elucidation, biotransformation and antibacterial activities.

CJ-15,696 and 7 novel furopyridine antibiotics were isolated from the fungus Cladobotryum varium CL12284. Their structures were determined by X-ray crystallography and spectral analysis. Three biotransformed analogs were also prepared from CJ-15,696. CJ-15,696 showed moderate activity against various Gram-positive bacteria including some drug resistant strains such as methicillin resistant Staphylococcus aureus (MRSA).

Thielavins as glucose-6-phosphatase (G6Pase) inhibitors: producing strain, fermentation, isolation, structural elucidation and biological activities.

High-throughput screening of microbial extracts using rat hepatic microsomal glucose-6-phosphatase (G6Pase) led us to find thielavin B as a G6Pase inhibitor with inhibition of glucose output from glucagon-stimulated hepatocytes. Further searching for more potent analogs identified 11 new thielavins F-P in addition to the known thielavins A and B from a fungus Chaetomium carinthiacum ATCC 46463. Thielavin G showed the strongest activity as a G6Pase inhibitor (IC50=0.33 microM), while the IC50 of thielavin B was 5.5 microM. According to the structure-activity relationship, including authentic thielavins C, D and 3 partial hydrolysates from thielavins A and B, 3 benzoic acid-units and carboxylic acid functions are essential for G6Pase inhibition.