Alpiniamides E-G from the Saline Lake-Derived Streptomyces sp. QHA48 and Their Lipid Accumulation Inhibitory Activity.

Alpiniamides E-G, three previously unreported linear polyketide derivatives, along with two known compounds, were isolated from Streptomyces sp. QHA48, which was isolated from the saline lakes of Qinghai-Tibet Plateau. The structures of these compounds were determined through analysis of their spectroscopic data, as well as density functional theory prediction of NMR chemical shifts, application of the DP4+ algorithm and electronic circular dichroism (ECD) calculations. In a cell-based lipid-lowering assay, all five alpiniamides exhibited significant inhibition of lipid accumulation in HepG2 cells without inducing cytotoxic effects at a concentration of 27 µM.