Polyphenol extract and essential oil of Amomum tsao-ko equally alleviate hypercholesterolemia and modulate gut microbiota

This study explored the effects of polyphenol extract (TKP) and essential oil (TKO) from Amomum tsao-ko Crevost et Lemaire (tsao-ko) on plasma total cholesterol and gut microbiota. Four groups of hamsters (n = 8 each) were fed one of four diets, respectively, namely a high-cholesterol diet (HCD) containing 0.1% cholesterol, a HCD containing 0.5% cholestyramine (PCD), a HCD with daily oral administration of 1000 mg per kg body weight TKP, and a HCD with daily oral administration of 200 mg per kg body weight TKO for 6 weeks. TKP and TKO equally lowered plasma total cholesterol (TC) by 13-18% via increasing the fecal elimination of total acidic sterols by 50-191%. This might be due to up-regulation of liver cholesterol 7α-hydroxylase (CYP7A1) at both transcriptional and translational levels. At a family level, TKP and TKO diets favorably modified the relative abundance of Ruminococcaceae, Erysipelotrichaceae, and Desulfovibrionaceae associated with acidic sterols and CYP7A1. It was therefore concluded that TKP and TKO were equally effective in alleviating hypercholesterolemia in hamsters via the interaction between gut microbiota and bile acid metabolism.