Oxachelin, a novel iron chelator and antifungal agent from Streptomyces sp. GW9/1258.

During a screening campaign for new antimicrobial and antifungal secondary metabolites from several thousand actinomycetes, a novel compound, isolated by activity guided fractionation, was oxachelin (1) from the new Streptomyces sp. GW9/1258. Oxachelin shows strong antibiotic activities against several fungi and Gram(+) bacteria.

Design and semisynthesis of novel fredericamycin A derivatives with an improved antitumor profile.

We report the design, semisynthesis, and biological activity of a series of fredericamycin (1) derivatives. Within this series compound 1e combines low nanomolar cytotoxic potency in vitro, increased tumor cell line selectivity, and in vivo activity in a human xenograft model.

Modern methods to produce natural-product libraries.

Natural sources offer a wealth of chemically diverse compounds that have been evolutionary preselected to modulate biochemical pathways. Several industrial and academic groups are accessing this source using advanced technology platforms. Methods have been reported to generate large and diverse natural-product libraries optimised for high-throughput screening and for a fast discovery process.