Four new monacolin analogs from Monascus purpureus-fermented rice.

Four new monacolin analogs, monacolin T (1), monacolin U (2) 6a-O-methyl-4,6-dihydromonacolin L (3), and 6a-O-ethyl-4,6-dihydromonacolin L (4) were isolated from the ethanolic extract of Monascus purpureus-fermented rice. Their structures were determined by a combination of 1D, 2D NMR experiments (H-HCOSY, HSQC, HMBC, and ROESY), and mass spectrometry. In vitro cytotoxic assay, all compounds were inactive at the concentration of 10 µM.