LAUSR

Abstract Daily ingestion of aronia juice is known to reduce serum low density lipoprotein cholesterol levels. However, the mechanism is not clear. In this study, the effect of aronia juice on the activity of human β-hydroxy-β-methylglutaryl-coenzyme A (HMG-CoA) reductase, the enzyme mediating the rate-determining step of cholesterol biosynthesis, was studied. Aronia juice inhibited the reductase activity by 57%. Using reverse-phase chromatography, two fractions (F1 and F2) showing significant inhibitory activity against the reductase were obtained from the juice. Liquid chromatography electrospray ionization tandem mass spectrometry analysis and sugar analysis of these fractions suggested the presence of delphinidin-arabinoside in fraction F1 and petunidin-glycoside-arabinoside in fraction F2, respectively. Since fraction F2 contained only petunidin glycoside as obtained using the total ion chromatogram, petunidin-glycoside-arabinoside seemed to inhibit the activity of HMG-CoA reductase.