Chemical constituents from a soil-derived actinomycete, Actinomadura miaoliensis BCRC 16873, and their inhibitory activities on lipopolysaccharide-induced tumor necrosis factor production.

An investigation on the secondary metabolites from the BuOH extract of the fermentation broth of the thermotolerant polyester-degrading actinomycete Actinomadura miaoliensis BCRC 16873 was carried out. One previously undescribed α-pyrone (=pyran-2-one) derivative, designated as miaolienone (1), and a new butanolide, miaolinolide (2), together with 13 known compounds, 3-15, were obtained. Their structures were established on the basis of extensive 1D- and 2D-NMR analyses in combination with HR-MS experiments. In addition, the isolated compounds 1-15 were evaluated for the inhibitory effects of the isolates on the production of tumor necrosis factor (TNF-α) induced by lipopolysaccharide (LPS). Among the isolates, 1 and 2 significantly inhibited TNF-α production in U937 cells in vitro, and the IC(50) values were 0.59 and 0.76 μM, respectively. Compounds 3-5 displayed moderate inhibitory activities on LPS-induced TNF-α production.