A NEW ANTHRACYCLINE ANTIBIOTIC, IT-62-B, CONVERTS THE MORPHOLOGY OF RAS-TRANSFORMED CELLS BACK TO NORMAL - TAXONOMY, FERMENTATION, ISOLATION, STRUCTURE ELUCIDATION AND BIOLOGICAL CHARACTERIZATION

A new antibiotic, IT-62-B was isolated from the culture broth of Strep tomyces sp. IT-62 by extraction with acetone and then with ethyl aceta te, followed by conventional column chromatography using silica gel, S ephadex LH-20 and silica ODS. Its structure (C39H47NO15, MW 769) was d etermined by H-1, C-13 NMR, MS, IR and UV spectrometric techniques to be a new member of the baumycin-group anthracyclines. It showed modera te activity against Gram-positive bacteria and had antitumor activity against various tumor cell lines. Further, antibiotic IT-62-B converte d the morphology of ras-transformed NIH3T3 cells and T-cells back to n ormal at concentrations inhibiting cell growth by 30% or more.