Antiobesity effect of polyphenolic compounds from molokheiya (Corchorus olitorius L.) leaves in LDL receptor-deficient mice.

BACKGROUND: Dietary supplementation with polyphenolic compounds is associated with reduced diet-induced obesity and metabolic disorders in humans. The antioxidative properties of polyphenolic compounds contribute to their antiobesity effect in animal experiments and human studies. AIM: The aim of the study was to investigate the antiobesity effect of polyphenolic compounds from molokheiya leaves in LDLR-/- mice fed high-fat diet and to elucidate the mechanism of this effect. METHODS: Three groups of LDLR-/- mice were fed with a high-fat diet, supplemented with 0% (control), 1 or 3% molokheiya leaf powder (MLP). Gene expression in the liver associated with lipid and glucose metabolism was analyzed, and physical parameters and blood biochemistry were determined. RESULTS: Compared to controls, mice body weight gain (P = 0.003), liver weight (P = 0.001) and liver triglyceride levels (P = 0.005) were significantly lower in the two MLP groups. Epididymal adipose tissue weight (P = 0.003) was reduced in the 3% MLP group. Liver tissue gene expression of gp91phox (NOX2), involved in oxidative stress, was significantly down-regulated (P = 0.005), and PPARα and CPT1A, related to the activation of ß-oxidation, were significantly up-regulated (P = 0.025 and 0.006, respectively) in the 3% MLP group compared to the control group. CONCLUSIONS: Our results demonstrate an antiobesity effect of polyphenolic compounds from molokheiya leaves and that this effect is associated with reduction in oxidative stress and enhancement of ß-oxidation in the liver. Consumption of molokheiya leaves may be beneficial for preventing diet-induced obesity.

Effect of flavonol glycoside in mulberry (Morus alba L.) leaf on glucose metabolism and oxidative stress in liver in diet-induced obese mice.

BACKGROUND: Mulberry therapies on type 2 diabetic patients or streptozotocin-induced diabetic rats have been reported to improve fasting blood glucose levels. We investigated the effects of dietary consumption of mulberry-leaf powder and purified quercetin 3-(6-malonylglucoside), the quantitatively major flavonol glycoside in mulberry leaves, on glucose and lipid metabolism in high-fat diet-induced obese mice. Male C57BL/6J mice aged 8 weeks were assigned to three groups (control, mulberry leaf powder (MLP), and quercetin 3-(6-malonylglucoside) (Q3MG)) and treated with their respective diets for 8 weeks. RESULTS: We found that dietary supplementation of 10 g MLP kg(-1) or 1 g Q3MG kg(-1) in high-fat diet effectively suppressed blood glucose levels. We also noted increased expression of glycolysis-related genes and suppression of thiobarbituric acid reactive substances concentrations in the liver of Q3MG group compared to control mice. CONCLUSION: Dietary consumption of Q3MG, the quantitatively major flavonol glycoside in mulberry leaves, improved hyperglycemia in obese mice and reduced oxidative stress in the liver.

Screening for antioxidant activity in edible plant products: comparison of low-density lipoprotein oxidation assay, DPPH radical scavenging assay, and Folin-Ciocalteu assay.

Oxidation of low-density lipoprotein (LDL) has been implicated in atherogenesis. Antioxidants that prevent LDL from oxidizing may reduce atherosclerosis. This study investigated LDL antioxidant activity in edible plant products for development of dietary supplementation to prevent atherosclerosis. Fifty-two kinds of edible plants were extracted using 70% aqueous ethanol solution, and the antioxidant activity of the extracts, which inhibit human LDL oxidation induced by copper ion, was determined on the basis of the oxidation lag time and represented as epigallocatechin 3-gallate equivalent. 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and total phenolic content were also measured for comparisons with antioxidant activity in LDL. Plant products showing the greatest activity in LDL oxidation assay were akamegashiwa (Mallotus japonicus) leaf, Japanese privet (Ligustrum japonicum) leaf, green tea [Camellia sinensis (L.) O. Kuntze], and astringent persimmon (Diospyros kaki). The present study revealed high levels of LDL antioxidant activity in plant products for which such activity levels are underestimated in the DPPH radical scavenging assay and Folin-Ciocalteu assay.

Anti-obesity effects of hot water extract from Wasabi (Wasabia japonica Matsum.) leaves in mice fed high-fat diets.

The anti-obesity effects of a hot water extract from wasabi (Wasabia japonica Matsum.) leaves (WLE), without its specific pungent constituents, such as allyl-isothiocyanate, were investigated in high fat-diet induced mice. C57J/BL mice were fed a high-fat diet (control group) or a high-fat diet supplemented with 5% WLE (WLE group). Physical parameters and blood profiles were determined. Gene expression associated with lipid metabolism in liver and white adipose tissue were analyzed. After 120 days of feeding, significantly lower body weight gain, liver weight and epididymal white adipose tissue weight was observed in the WLE group compared to the control group. In liver gene expression within the WLE group, PPARα was significantly enhanced and SREBP-1c was significantly suppressed. Subsequent downstream genes controlled by these regulators were significantly suppressed. In epididymal white adipose tissue of the WLE group, expression of leptin, PPARγ, and C/EBPα were significantly suppressed and adiponectin was significantly enhanced. Acox, related to fatty acid oxidization in adipocytes, was also enhanced. Our results demonstrate that the WLE dietary supplement induces mild suppression of obesity in a high-fat diet induced mice, possibly due to suppression of lipid accumulation in liver and white adipose tissue.