New polyesters from Talaromyces flavus

Six new polyesters, talapolyesters A-F (1-4, 14, and 16), together with 11 known ones 15G256 nu (5), 15G256 nu-me (6), 15G256 pi (7), 15G256 beta-2 (8), 15G256 alpha-2 (9), 15G256 alpha-2-me (10), 15G256 iota. (11), 15G256 beta (12), 15G256 alpha (13), 15G256 alpha-1 (15), and 15G256 omega (17), were isolated from the wetland soil-derived fungus Talaromyces flavus BYD07-13, and their structures were determined by NMR and MS spectroscopic data. Among them, 1-4 and 16 were assembled in a different manner from that of the known 256 polyesters. All the polyesters are composed of (R)-2,4-dihydroxy-6-(2-hydroxypropyl)benzoic acid and (R)-3-hydroxybutyric acid/(S)-3,4-dihydroxybutyric acid residues. The absolute configurations of the residues were determined by alkaline hydrolysis. The cytotoxicity against five tumor cell lines of these compounds was examined, and a tight structure-activity relationship is proposed. (C) 2014 Elsevier Ltd. All rights reserved.