Precursor-Directed Biosynthesis of Neoantimycin Derivatives with Selective Cytotoxicity.

A precursor-directed biosynthesis approach led to the accumulation of seven new neoantimycin derivatives ( 1 - 7 ) from Streptomyces conglobatus RJ2. Structure elucidation was conducted using NMR and HRESIMS analysis, and the absolute configuration was determined by advanced Marfey's method, Mosher's analysis, and ECD analysis. The obtained compounds revealed selective and significant cytotoxicity, specifically against colorectal cancer cells bearing the K-ras mutation, with IC 50 values ranging from 40 nM to 3.5 μM.