Griseochelin, a novel carboxylic acid antibiotic from Streptomyces griseus.

Abstract

Griseochelin, C₃₃H₆₀O₇, isolated from an asporogenous strain of Streptomyces griseus represents a novel carboxylic acid antibiotic. The metabolite, which is active against Gram-positive bacteria, forms water-insoluble salts with mono- and divalent cations and binds alkaline-earth metal ions specifically in 2: 1 (x₂M) stoichiometry. Detailed spectral (IR, MS and NMR) studies provide full characterization of its constitution featuring a carboxylic acid function, a substituted tetrahydropyran ring, an allylic OH group which are accomodated within a tetrahydroxylated-octamethyl-C₂₅ diene backbone.