Quinolidomicins A1, A2 and B1, novel 60-membered macrolide antibiotics. I. Taxonomy, fermentation, isolation, physico-chemical properties and biological activity.

Three novel macrolide antibiotics, quinolidomicins A1, A2 and B1, were isolated from the fermentation broth of Micromonospora sp. JY16. Quinolidomicin A1 inhibited the growth of various tumor cells including multidrug-resistant cells. Quinolidomicin B1 was similarly cytotoxic, while quinolidomicin A2 was inactive against these tumor cells.