Optimization, validation and application of an assay for the activity of HMG-CoA reductase in vitro by LC-MS/MS / 药物分析学报

A stable HMG-CoA reductase (HMGR) reaction in vitro was developed by a sensitive, selective and precise liquid chromatography–tandem mass spectrometry (LC–MS/MS) method. The optimized enzyme reac-tion condition contained 1.5μg of HMGR, 20 nM of NADPH with 50 min of reaction time. The method was validated by several intra-and inter-day assays. The production transitions of m/z 147.0/59.1 and m/z 154.0/59.1 were used to detect and quantify mevalonolactone (MVAL) and MVAL-D7, respectively. The accuracy and precision of the method were evaluated over the concentration range of 0.005–1.000μg/mL for MVAL and 0.010–0.500μg/mL for lovastatin acid in three validation batch runs. The lower limit of quantitation was found to be 0.005μg/mL for MVAL and 0.010μg/mL for lovastatin acid. Intra-day and inter-day precision ranged from 0.95%to 2.39%and 2.26%to 3.38%for MVAL, 1.46%to 3.89%and 0.57% to 5.10% for lovastatin acid, respectively. The results showed that the active ingredients in Xuezhikang capsules were 12.2 and 14.5 mg/g, respectively. This assay method could be successfully applied to the quality control study of Xuezhikang capsule for the first time.

A new monacolin analogue from Xuezhikang capsule / 药学学报

Xuezhikang capsule (ethanol extract of red yeast rice) which produced by Beijing WBL Peking University Biotech Co., Ltd., is a traditional Chinese medication with 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibiting activity. Clinical trials indicated that Xuezhikang with lipid-lowering action could reduce the risk of cardiac events and total mortality of Chinese coronary heart disease patients. To exactly explain the clinical features of Xuezhikang, we undertook a complete study of the chemical constituents of Xuezhikang. This study resulted in the isolation of a new monacolin analogue, named alpha, beta-dehydromonacolin L (1), along with two known compounds: monacolin L (2) and 3-(2, 6-dimethyl-1, 2, 4a, 5, 6, 7, 8, 8a-octahydronaphthalen-1-yl)propanoic acid (3). The chemical structures were determined by extensive 1D and 2D NMR and MS spectroscopic analysis.