A new SEK15-derived polyketide compound, strepolyketide D (1), was isolated from salt-lake-derived Streptomyces sp. DBC5, together with two known analogues (2-3). Their structures were elucidated based on spectroscopic analysis of IR, MS, 1 D and 2 D NMR. Compound 2 elicited moderate antioxidation with IC50 value of 39.26 μg/ml. The results of the study revealed that salt-lake actinomycetes of Lake Dabancheng appear to have immense potential as a source of polyketide compounds.
Keywords: Streptomyces sp.; antioxidant activity; polyketide; strepolyketide D.