Louisianins A, B, C and D: non-steroidal growth inhibitors of testosterone-responsive SC 115 cells. I. Taxonomy, fermentation, isolation and biological characteristics.

In the course of screening for non-steroidal growth inhibitors of testosterone-responsive Shionogi carcinoma 115 cells, louisianins A, B, C and D, were isolated from fermentation broth of Streptomyces sp. WK-4028. Louisianin A remarkably inhibited the growth of SC 115 cells in the presence of 10(-7) M testosterone at an IC50 value of 0.6 microgram/ml, whereas, no inhibition was observed on the other cell lines. Furthermore, inhibitory activity of testosterone 5 alpha-reductase and antimicrobial activity have not been observed at a concentration of 50 micrograms/ml and 1,000 micrograms/ml, respectively.