Effect of combined mulberry leaf and fruit extract on liver and skin cholesterol transporters in high fat diet-induced obese mice

1,2,3,4,6 penta-O-galloyl-β-D-glucose ameliorates high-fat diet-induced nonalcoholic fatty liver disease and maintains the expression of genes involved in lipid homeostasis in mice

Non-alcoholic fatty liver disease (NAFLD) is currently the most frequently occurring liver disorder in the world. However, a specific drug for the treatment of patients with NAFLD is not available. Therefore, the discovery of novel compounds for the treatment of NAFLD and elucidation of the underlying mechanisms of therapeutic drugs that can be used to treat this disease are urgently needed. 1,2,3,4,6 penta-O-galloyl-β-d-glucose (PGG) is known to exert anti-inflammatory, antidiabetic, and hepatoprotective effects. However, little is known about the therapeutic potential of PGG in NAFLD. In this study, we investigated the effects of PGG on a high-fat diet (HFD)-induced mouse model of NAFLD. PGG was co-administered along with an HFD to C57BL/6 mice. After eight weeks of treatment, serum biochemistry, liver steatosis, and lipid metabolism-related genes were examined. The results showed that PGG treatment significantly reduced HFD-induced gain in body weight, liver steatosis, and leukocyte infiltration in a dose-dependent manner. Furthermore, PGG treatment markedly reduced serum triglyceride and glucose levels in HFD mice. Moreover, alterations in the mRNA expression of genes involved in lipid metabolism, including Hmgcr, Acc1, Abca1, Mttp, and Cd36, observed in the livers of HFD-treated mice were significantly reversed by PGG treatment. PGG significantly reduced HFD-induced protein expression of CD36, which is associated with fatty acid uptake, insulin resistance, hyperinsulinemia, and increased hepatic steatosis, in the liver of HFD mice. These results suggest that PGG inhibits HFD-induced hepatic steatosis and reverses HFD-induced alterations of gene expression in lipid metabolism. PGG has been shown to be well tolerated; therefore, it has potential uses in NAFLD treatment.

Beneficial Effect of Pachyrhizus erosus Fiber as a Supplemental Diet to Counteract High Sugar-Induced Fatty Liver Disease in Mice

Background and aims: Edible fiber isolated from the tuber of yam bean (Pachyrhizus erosus, Leguminosae) has been suggested to prevent the development of metabolic diseases caused by excessively consuming sugary foods. However, it is unclarified whether P. erosus fiber (PEF) is also capable of preventing liver diseases. This study aimed to determine the effectivity of PEF in counteracting the development of non-alcoholic fatty liver disease (NAFLD) caused by excessive intake of high-sugar diet (HSD).

Material and method: 25% of PEF in HSD (w/w) was fed in BALB/c mice for eight weeks followed by subsequent morphological and histological examinations of the liver at the end of treatment in comparing with HSD alone.

Results: We found that supplementation of 25% PEF sustained the normal morphological feature of the liver in HSD-fed mice. Moreover, PEF also prevented the development of microvesicles in the liver tissue, nuclear shrinkage, and hepatolysis as indicators of liver disease. Macrophages infiltration as a marker of liver inflammation was also less observed in PEF-treated mice.

Conclusions: PEF could effectively elicit a beneficial effect against NAFLD caused by HSD. Hence, PEF is suggested to be used as a potent supplemental diet to preclude the metabolic diseases caused by HSD.

Effects of unaltered and bioconverted mulberry leaf extracts on cellular glucose uptake and antidiabetic action in animals

Background

Mulberry is a Korean medicinal herb that shows effective prevention and treatment of obesity and diabetes. Bioconversion is the process of producing active ingredients from natural products using microorganisms or enzymes.

Methods

In this study, we prepared bioconverted mulberry leaf extract (BMLE) with Viscozyme L, which we tested in insulin-sensitive cells (i.e., skeletal muscle cells and adipocytes) and insulin-secreting pancreatic β-cells, as well as obese diabetic mice induced by co-administration of streptozotocin (100 mg/kg, IP) and nicotinamide (240 mg/kg, IP) and feeding high-fat diet, as compared to unaltered mulberry leaf extract (MLE).

Results

BMLE increased the glucose uptake in C2C12 myotubes and 3 T3-L1 adipocytes and increased glucose-stimulated insulin secretion in HIT-T15 pancreatic β-cells. The fasting blood glucose levels in diabetic mice treated with BMLE or MLE (300 and 600 mg/kg, PO, 7 weeks) were significantly lower than those of the vehicle-treated group. At the same concentration, BMLE-treated mice showed better glucose tolerance than MLE-treated mice. Moreover, the blood concentration of glycated hemoglobin (HbA_1C) in mice treated with BMLE was lower than that in the MLE group at the same concentration. Plasma insulin levels in mice treated with BMLE or MLE tended to increase compared to the vehicle-treated group. Treatment with BMLE yielded significant improvements in insulin resistance and insulin sensitivity.

Conclusion

These results indicate that in the management of diabetic condition, BMLE is superior to unaltered MLE due to at least, in part, high concentrations of maker compounds (trans-caffeic acid and syringaldehyde) in BMLE.

Electronic supplementary material

The online version of this article (10.1186/s12906-019-2460-5) contains supplementary material, which is available to authorized users.

Mulberry leaves ameliorate obesity through enhancing brown adipose tissue activity and modulating gut microbiota

The increased prevalence of obesity significantly affects human health worldwide.

Effects of mulberry leaf on experimental hyperlipidemia rats induced by high-fat diet

Hypercholesterolemia is a major risk factor for cardiovascular disease. Mulberry leaf (ML) is a Traditional Chinese Medicine used to treat hyperlipidemia in clinical settings. The aim of the present study was to identify the potential effect and possible target of ML in anti-hypercholesterolemia. Male Sprague-Dawley rats were fed with a high-fat diet and treated with ML for 5 weeks. Blood lipid levels, total cholesterol (TC) and total bile acid (TBA) in the liver and feces were measured to assess the effects of ML on hypercholesterolemia. Harris's hematoxylin staining and oil red O staining was applied to observe the pathological change and lipid accumulation in the liver. Immunohistochemical assay was performed to observe the location of expressions of scavenger receptor class B type I and low-density lipoprotein (LDL) receptor (-R), and western blotting was applied to determine the protein expression of ATP-binding cassette transporter G5/G8 (ABCG5/8), nuclear transcription factor peroxisome proliferator-activated receptor-α (PPARα), farnesoid-X receptor (FXR) and cholesterol 7α-hydroxylase 1 (CYP7A1). The results demonstrated that ML treatment reduced serum TC and LDL-cholesterol levels, and liver TC and TBA contents; increased serum HDL-C levels, and fecal TC and TBA contents; and alleviated hepatocyte lipid degeneration. In addition, ML treatment inhibited liver LDL-R, PPARα and FXR protein expression, promoted protein expression of CYP7A1, and maintained the ratio of ABCG5/ABCG8. The findings of the present study provide a positive role of ML on cholesterol clearance via promoting cholesterol and TBA execration via FXR- and CYP7A1-mediated pathways; RCT regulation may be a potential mechanism of ML on anti-hypercholesterolemia.

Mulberry fruit prevents LPS-induced NF-κB/pERK/MAPK signals in macrophages and suppresses acute colitis and colorectal tumorigenesis in mice

Here, we investigated the impact of mulberry fruit (MBF) extracts on lipopolysaccharide (LPS)-induced inflammatory responses in RAW 264.7 macrophages, and the therapeutic efficacy of MBF diet in mice with dextran sulfate sodium (DSS)-induced acute colitis and MUC2^−/− mice with colorectal cancer. In vitro, LPS-induced nitric oxide (NO) production was significantly inhibited by MBF extracts via suppressing the expression of proinflammatory molecules, including inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin-1 beta (IL-β) and IL-6. Particularly, a dose-dependent inhibition on LPS-induced inflammatory responses was observed following treatment with MBF dichloromethane extract (MBF-DE), in which linoleic acid and ethyl linolenate were identified as two active compounds. Moreover, we elucidated that MBF-DE attenuated LPS-induced inflammatory responses by blocking activation of both NF-κB/p65 and pERK/MAPK pathways. In vivo, DSS-induced acute colitis was significantly ameliorated in MBF-fed mice as gauged by weight loss, colon morphology and histological damage. In addition, MBF-fed MUC2^−/− mice displayed significant decrease in intestinal tumor and inflammation incidence compared to control diet-fed group. Overall, our results demonstrated that MBF suppressed the development of intestinal inflammation and tumorgenesis both in vitro and in vivo, and supports the potential of MBF as a therapeutic functional food for testing in human clinical trials.

Dietary fat and carbohydrate modulate the effect of the ATP-binding cassette A1 (ABCA1) R230C variant on metabolic risk parameters in premenopausal women from the Genetics of Atherosclerotic Disease (GEA) Study

Background

Although the R230C-ATP-binding cassette A1 (ABCA1) variant has been consistently associated with HDL-C levels, its association with diabetes and other metabolic parameters is unclear. Estrogen and dietary factors are known to regulate ABCA1 expression in different tissues. Thus, we aimed to explore whether gender, menopausal status and macronutrient proportions of diet modulate the effect of this variant on various metabolic parameters.

Methods

One thousand five hundred ninety-eight controls from the GEA study were included (787 men, 363 premenopausal women and 448 menopausal women), previously assessed for anthropometric and biochemical measurements and visceral to subcutaneous abdominal fat (VAT/SAT) ratio on computed tomography. Taqman assays were performed for genotyping. Diet macronutrient proportions were assessed using a food frequency questionnaire validated for the Mexican population. Multivariate regression models were constructed to assess the interaction between the proportion of dietary macronutrients and the R230C polymorphism on metabolic parameters.

Results

All significant interactions were observed in premenopausal women. Those carrying the risk allele and consuming higher carbohydrate/lower fat diets showed an unfavorable metabolic pattern [lower HDL-C and adiponectin levels, higher VAT/SAT ratio, homeostasis model assessment for insulin resistance (HOMA-IR) and higher gamma-glutamyl transpeptidase (GGT) and alkaline phosphatase (ALP) levels]. Conversely, premenopausal women carrying the risk allele and consuming lower carbohydrate/higher fat diets showed a more favorable metabolic pattern (higher HDL-C and adiponectin levels, and lower VAT/SAT ratio, HOMA-IR, GGT and ALP levels).

Conclusion

This is the first study reporting a gender-specific interaction between ABCA1/R230C variant and dietary carbohydrate and fat percentages affecting VAT/SAT ratio, GGT, ALP, adiponectin levels and HOMA index. Our study confirmed the previously reported gender-specific ABCA1-diet interaction affecting HDL-C levels observed in an independent study. Our results show how gene-environment interactions may help further understand how certain gene variants confer metabolic risk, and may provide information useful to design diet intervention studies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12986-015-0040-3) contains supplementary material, which is available to authorized users.

Mulberry fruit extract protects pancreatic β-cells against hydrogen peroxide-induced apoptosis via antioxidative activity

Among the many environmental stresses, excessive production of reactive oxygen species (ROS) and the ensuring oxidative stress are known to cause significant cellular damage. This has clinical implications in the onset of type 1 diabetes, which is triggered by the destruction of pancreatic β-cells and is associated with oxidative stress. In this study, we investigated the protective and antioxidative effects of mulberry extract (ME) in insulin-producing pancreatic β-cells. We found that ME protects pancreatic β-cells against hydrogen peroxide (H₂O₂)-induced oxidative stress and the associated apoptotic cell death. ME treatment significantly reduced the levels of H₂O₂-induced 2-diphenyl-1-picrylhydrazyl (DPPH) radicals, and lipid peroxidation and intracellular ROS accumulation. In addition, ME inhibited DNA condensation and/or fragmentation induced by H₂O₂. These results suggest that ME protects pancreatic β-cells against hydrogen peroxide-induced oxidative stress.