Propagule Powder of Japanese Yam (Dioscorea Japonica) Reduces High‐Fat Diet‐Induced Metabolic Stress in Mice through the Regulation of Hepatic Gene Expression

• Published in: Molecular nutrition & food research 2020-09, Vol.64 (17), p.e2000284-n/a
• Main Authors: Shinozaki, Fumika, Kamei, Asuka, Watanabe, Yuki, Yasuoka, Akihito, Shimada, Kousuke, Kondo, Kaori, Arai, Soichi, Kondo, Takashi, Abe, Keiko
• Format: Article
• Language: English
• Subjects: Amino acids; Biosynthesis; Carbohydrate metabolism; Carbohydrates; Catabolism; Cholesterol; Deoxyribonucleic acid; Diet; Dioscorea japonica; DNA; DNA chips; DNA microarrays; Fat metabolism; food functionality; Functional foods & nutraceuticals; Gene expression; Genes; Gluconeogenesis; Glycogen; Glycogens; Glycolysis; High fat diet; Immune system; Ingestion; Japanese yam propagule; Lipid metabolism; Lipids; Liver diseases; metabolic stress; Metabolism; Oxidation; Physiology; Propagules; Pyruvic acid; Quotients; Respiratory quotient; transcriptome
• ISSN: 1613-4125; 1613-4133
• DOI: 10.1002/mnfr.202000284

Scope Japanese yam propagules are supposed to have high potential as a functional food. However, there are almost no studies examining their physiological function. This study aims to elucidate the physiological function of Japanese yam propagules that are heated, freeze‐dried, and powdered. Methods and results A high‐fat diet with Japanese yam propagules is administered to mice for 4 weeks. High‐fat loading induces a decline in respiratory quotient, and a high‐fat diet with propagules reduces it more. This result suggests that propagules increase fat oxidation, indicating fat utilization. The hepatic transcriptome is analyzed using a DNA microarray. Some of the genes affected by high‐fat loading are reversed by simultaneous ingestion of propagules. Such genes are mainly involved in the immune system and fat metabolism. High‐fat loading induces hepatic inflammation, which is repressed by simultaneous ingestion of propagules. For lipid metabolism, propagules repress an increase in cholesterol biosynthesis and catabolism by high‐fat loading. Regarding carbohydrate metabolism, propagules decrease glycolysis and glycogen synthesis and increase gluconeogenesis. Moreover, amino acids are converted into pyruvate and then used for gluconeogenesis. Conclusion Propagules act to delay the occurrence of hepatic disease by suppressing carbohydrate and fat metabolism disorders in high‐fat loaded mice. A high‐fat diet with Japanese yam propagules is administered to mice. Hepatic transcriptome reveals that simultaneous administration of propagules and high‐fat diet reverse some differential expressed genes (DEGs) which are affected by high‐fat loading. The reversed DEGs are related to lipid and carbohydrate metabolism. These results indicate that propagules may have the modulating functions of lipid and carbohydrate in liver.