Lemon Polyphenols Suppress Diet-induced Obesity by Up-Regulation of mRNA Levels of the Enzymes Involved in β-Oxidation in Mouse White Adipose Tissue

The aim of this study was to investigate the effect of dietary lemon polyphenols on high-fat diet-induced obesity in mice, and on the regulation of the expression of the genes involved in lipid metabolism to elucidate the mechanisms. Mice were divided into three groups and fed either a low fat diet (LF) or a high fat diet (HF) or a high fat diet supplemented with 0.5% w/w lemon polyphenols (LP) extracted from lemon peel for 12 weeks. Body weight gain, fat pad accumulation, the development of hyperlipidemia, hyperglycemia, and insulin resistance were significantly suppressed by lemon polyphenols. Supplementation with lemon polyphenols also significantly up-regulated the mRNA level of the peroxisome proliferator activated receptor-α (PPARα) compared to the LF and HF groups in the liver. Furthermore, the mRNA level of acyl-CoA oxidase (ACO) was up-regulated in the LP group compared to the LF group, but not HF group in the liver, and was also significantly increased in the epididymal white adipose tissue. Thus, feeding with lemon polyphenols suppressed body weight gain and body fat accumulation by increasing peroxisomal β-oxidation through up-regulation of the mRNA level of ACO in the liver and white adipose tissue, which was likely mediated via up-regulation of the mRNA levels of PPARα

Effect on Blood Pressure of Daily Lemon Ingestion and Walking

Background. Recent studies suggest that the daily intake of lemon (Citrus limon) has a good effect on health, but this has not been confirmed in humans. In our previous studies, it was observed that people who are conscious of their health performed more lemon intake and exercise. An analysis that took this into account was required. Methodology. For 101 middle-aged women in an island area in Hiroshima, Japan, a record of lemon ingestion efforts and the number of steps walked was carried out for five months. The change rates (Δ%) of the physical measurements, blood test, blood pressure, and pulse wave measured value during the observation period were calculated, and correlations with lemon intake and the number of steps walked were considered. As a result, it was suggested that daily lemon intake and walking are effective for high blood pressure because both showed significant negative correlation to systolic blood pressure Δ%. Conclusions. As a result of multiple linear regression analysis, it was possible that lemon ingestion is involved more greatly with the blood citric acid concentration Δ% and the number of steps with blood pressure Δ%, and it was surmised that the number of steps and lemon ingestion are related to blood pressure improvement by different action mechanisms

Eriocitrin ameliorates diet-induced hepatic steatosis with activation of mitochondrial biogenesis

application/pdfLemon (Citrus limon) contains various bioactive flavonoids, and prevents obesity and obesity-associated metabolic diseases. We focused on eriocitrin (eriodictyol 7-rutinoside), a powerful antioxidative flavonoid in lemon with lipid-lowering effects in a rat model of high-fat diet. To investigate the mechanism of action of eriocitrin, we conducted feeding experiments on zebrafish with diet-induced obesity. Oral administration of eriocitrin (32 mg/kg/day for 28 days) improved dyslipidaemia and decreased lipid droplets in the liver. DNA microarray analysis revealed that eriocitrin increased mRNA of mitochondrial biogenesis genes, such as mitochondria transcription factor, nuclear respiratory factor 1, cytochrome c oxidase subunit 4, and ATP synthase. In HepG2 cells, eriocitrin also induced the corresponding orthologues, and reduced lipid accumulation under conditions of lipid loading. Eriocitrin increased mitochondrial size and mtDNA content, which resulted in ATP production in HepG2 cells and zebrafish. In summary, dietary eriocitrin ameliorates diet-induced hepatic steatosis with activation of mitochondrial biogenesis.本文/Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics, Mie University Graduate School of Medicine, Mie, Japan11

Eriocitrin ameliorates diet-induced hepatic steatosis with activation of mitochondrial biogenesis

application/pdf内容の要旨・審査結果の要旨 / 三重大学大学院医学系研究科生命医科学専攻ゲノム再生医学講座薬理ゲノミクス分

Difference in Plasma Metabolite Concentration after Ingestion of Lemon Flavonoids and Their Aglycones in Humans

The concentrations of metabolites in human plasma after ingestion of flavanone glycosides (FG) and their aglycones (FA) in lemon were examined. FG consisting abundantly of eriocitrin were prepared from lemon peel and FA consisting abundantly of eriodictyol were prepared from FG by treatment with β-glucosidase. Eriodictyol, homoeriodictyol, and hesperetin in plasma up to 4 h after ingestion of FG with water or FA with water by subjects were not detected in plasma of non-enzyme treatment but in plasma after treatment with β-glucronidase and sulfatase. Metabolites in plasma after ingestion of FG and FA in humans were shown to exist as the glucuro- and/or sulfo-conjugates of eriodictyol, homoeriodictyol, and hesperetin. After ingestion of FA, the concentration of metabolites in plasma exhibited a high maximum peak at 1 h. The AUC (area under the blood concentration time curve) level of metabolites of FA was higher than that of FG. FA were suggested to be absorbed faster and in higher amounts than FG. The AUC of metabolites in subject plasma after ingestion of FG with flavonoid-depleted lemon juice was shown to change to a low level in comparison with that of FG with water. The maximum concentration peak of metabolites in plasma was faster at 0.5 h than FA with water but the AUC level was similar to FA with water, when subjects ingested FA with vodka (40% ethanol). The absorption hour of FG and FA was shown to be affected by the co-existing solution