In order to develop a novel variety of shiitake (Lentinula edodes), the progenies obtained by mass mating among the cultivated and wild strains with relatively high content of eritadenine, hypocholesterolemic substance, were subjected to a cultivation test on a saw-dust medium. As a result of the cultivation for screening, strain H44 was selected on the basis of eritadenine content and yield of fruit bodies. In addition, we found that eritadenine content is notably affected by temperature during the growth of fruit bodies, and then we developed a method for the cultivation of eritadenine-enriched shiitake with a five-fold content of eritadenine as compared with that of the normal shiitake. The hypocholesterolemic effect of the eritadenine-enriched shiitake thus obtained was investigated in relation to its influence on lipid metabolisms in rats. Dietary supplementation with eritadenine-enriched shiitake powder (473mg/100g) significantly decreased plasma total cholesterol in a dosedependent manner, where the minimum effective dose was found to be 0.05% in the basal diet. Rats were fed for 2 weeks on the basal diet containing 0.2% shiitake powders with different contents of eritadenine, (0, 107, 194, and 473mg/100g of shiitake powder) to clarify the relationship between eritadenine content and some parameters in lipid metabolism, which are affected by eritadenine. There were significant correlations between eritadenine content and SAM : SAH ratio, PC:PE ratio, or fatty acid composition, i.e., 20:4n-6/18:2n-6 ratio of PC in the liver, in addition to the plasma cholesterol concentration. Dietary supplementation with eritadenine-enriched shiitake powder (473 mg/100g) decreased the plasma total cholesterol and (VLDL+LDL)-cholesterol when rats were fed a diet containing 1% cholesterol, whereas shiitake powder of normal eritadenine content (107mg/100g) did not decrease the plasma cholesterol concentration. Abbreviations: HDL, high density lipoprotein; HPLC, high-performance liquid chromatography; LDL, low density lipoprotein; PC, phosphatidylcholine; PE, phosphatidylethanolamine; PL, phospholipid; SAH, S-adenosylhomocysteine; SAM, Sadenosylmethione; TG, triglyceride; TLC, thin-layer chromatography; VLDL, very low density lipoprotein.
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