Dried and Fermented Powders of Edible Algae ( Neopyropia yezoensis ) Attenuate Hepatic Steatosis in Obese Mice

• Published in: Molecules (Basel, Switzerland) Vol. 27; no. 9; p. 2640
• Main Authors: Nagao, Koji, Inoue, Nao, Tsuge, Keisuke, Oikawa, Akira, Kayashima, Tomoko, Yanagita, Teruyoshi
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 20-04-2022; MDPI
• Subjects: Accumulation; Algae; Animals; Betaine; Betaine - pharmacology; Carnitine; Eicosapentaenoic acid; Eicosapentaenoic Acid - pharmacology; Enzymatic activity; Enzyme activity; Fatty liver; Fatty Liver - drug therapy; Fatty Liver - metabolism; Fermentation; Functional foods & nutraceuticals; Gene expression; hepatic steatosis; Inflammation; Injury prevention; Koji fermentation; Lipids; Liver; Male; Metabolites; Metabolomics; Mice; Mice, Inbred C57BL; Mice, Obese; Neopyropia yezoensis; obese db/db mouse; Porphyra; Powders - metabolism; Rodents; stachydrine; Steatosis; Triglycerides; Triglycerides - metabolism; stachydrine; Koji fermentation; eicosapentaenoic acid; Neopyropia yezoensis; carnitine; obese db/db mouse; betaine; hepatic steatosis
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules27092640

Edible algae
is used as "Nori", its dried sheet product, in Japanese cuisine. Its lipid components reportedly improve hepatic steatosis in obese
/
mice. In this study, we prepared "Nori powder (NP)" and "fermented Nori powder (FNP)" to utilize the functional lipids contained in "Nori" and examined their nutraceutical effects in vivo. Male
/
mice were fed a basal AIN-76 diet, a 10% NP-supplemented diet, or a 10% FNP-supplemented diet for 4 weeks. We detected eicosapentaenoic acid (EPA) present in both NP and FNP in the serum and liver of
/
mice in a dose-dependent manner. The NP diet reduced hepatic triglyceride accumulation (by 58%) in
/
mice by modulating gene expression, which resulted in the inhibition of lipogenic enzyme activity. Additionally, NP intake significantly suppressed the expression of inflammatory genes in the liver and hepatic injury marker levels in the sera (by 26%) of
/
mice. The FNP diet also led to a marked reduction in hepatic triglyceride accumulation (by 50%) and hepatic injury (by 28%) in
/
mice, and the mechanism of these alleviative actions was similar to that of the NP diet. Although the EPA content of FNP was one-third that of NP, metabolomic analysis revealed that bioactive betaine analogs, such as stachydrine, betaine, and carnitine, were detected only in FNP. In conclusion, we suggest that (1) mechanical processing of "Nori" makes its lipid components readily absorbable by the body to exert their lipid-lowering effects, and (2) fermentation of "Nori" produces anti-inflammatory molecules and lipid-lowering molecules, which together with the lipid components, can exert hepatic steatosis-alleviating effects.