Lentinus (L.) edodes (shiitake mushroom) is used as a traditional medicine in Asia. One of the components of L. edodes, eritadenine (an adenosine analog alkaloid), has been shown to reduce cholesterol levels. The hypocholesterolemic action of eritadenine appears to be achieved through the modification of hepatic phospholipid metabolism. In the present study, the effects of L. edodes in a mouse model of hypercholesterolemia were investigated. Hypercholesterolemia was induced by the consumption of a high-fat diet (HFD). The animals were divided into six groups, which were fed a normal diet, HFD alone, HFD containing eritadenine [10 mg/kg of body weight (BW)] or HFD with 5, 10 or 20% L. edodes, respectively, for 4 weeks (from 5 to 9 weeks of age). The mice in the six groups had similar BW gains. Total serum cholesterol (T-CHO), low-density lipoprotein (LDL) and triglyceride (TG) levels were increased in the HFD-fed group compared with those in the normal diet group. However, the levels of high-density lipoprotein (HDL) were not significantly altered. In mice treated with L. edodes (5, 10 or 20%), the T-CHO, LDL and TG serum levels were reduced in a dose-dependent manner. The mRNA expression of cholesterol 7-α-hydroxylase 1 (CYP7A1) was decreased in hypercholesterolemic mice and increased by eritadenine and L. edodes (5, 10 and 20%) supplementation. In liver tissues, it was observed that lipid accumulation was reduced by treatment with eritadenine and L. edodes. In addition, it was revealed that the formation of atherosclerotic plaques due to the HFD was also suppressed by eritadenine and L. edodes. The results of the study indicated that the consumption of an HFD may inhibit CYP7A1 expression in the liver by increasing serum T-CHO, LDL and TG levels. L. edodes may help regulate lipid metabolism, suggesting that this fungus ameliorates hypercholesterolemia in mice by regulating CYP7A1 expression in the liver.
Keywords: CYP7A1; Lentinus edodes; eritadenine; hypercholesterolemia.