Effects of the Combined Extracts of Grape Pomace and Omija Fruit on Hyperglycemia and Adiposity in Type 2 Diabetic Mice

Phenolic Characterization and Neuroprotective Properties of Grape Pomace Extracts

Vitis vinifera (grape) contains various compounds with acknowledged phytochemical and pharmacological properties. Among the different parts of the plant, pomace is of particular interest as a winemaking industry by-product. A characterization of the water extract from grape pomace from Montepulciano d’Abruzzo variety (Villamagna doc) was conducted, and the bioactive phenolic compounds were quantified through HPLC-DAD-MS analysis. HypoE22, a hypothalamic cell line, was challenged with an oxidative stimulus and exposed to different concentrations (1 µg/mL⁻¹ mg/mL) of the pomace extract for 24, 48, and 72 h. In the same conditions, cells were exposed to the sole catechin, in a concentration range (5–500 ng/mL) consistent with the catechin level in the extract. Cell proliferation was investigated by MTT assay, dopamine release through HPLC-EC method, PGE₂ amount by an ELISA kit, and expressions of neurotrophin brain-derived neurotrophic factor (BDNF) and of cyclooxygenase-2 (COX-2) by RT-PCR. The extract reverted the cytotoxicity exerted by the oxidative stimulus at all the experimental times in a dose-dependent manner, whereas the catechin was able to revert the oxidative stress-induced depletion of dopamine 48 h and 72 h after the stimulus. The extract and the catechin were also effective in preventing the downregulation of BDNF and the concomitant upregulation of COX-2 gene expression. In accordance, PGE₂ release was augmented by the oxidative stress conditions and reverted by the administration of the water extract from grace pomace and catechin, which were equally effective. These results suggest that the neuroprotection induced by the extract could be ascribed, albeit partially, to its catechin content.

Grape pomace reduces the severity of non-alcoholic hepatic steatosis and the development of steatohepatitis by improving insulin sensitivity and reducing ectopic fat deposition in mice

While non-alcoholic fatty liver disease (NAFLD) represents the common cause of chronic liver disease, specific therapies are currently unavailable. The wine industry produces millions of tons of residue (pomace), which contains high levels of bioactive phytochemicals. The aim of this study was to clarify the potential benefits of grape pomace for the treatment of NAFLD at different levels of severity, and to clarify the mechanism of action. C57Bl/6 mice were given high fat diet (HFD) or western diet (WD) as models of obesity and hepatic steatosis or steatohepatitis, respectively, with or without pomace supplementation (50-250 mg/day). Pomace inhibited food intake, and reduced serum leptin and body weight gain. Ectopic fat deposition was reduced, while white adipose tissue mass was preserved. In addition, pomace improved glucose tolerance and insulin sensitivity, prevented the development of adipose tissue inflammation, and reduced hepatic steatosis. Higher expression of genes involved in fatty acids transport and oxidation was observed in adipose tissue, while lipogenic genes were attenuated in the liver of pomace-treated mice. In WD-fed mice, pomace reduced the severity of hepatic steatosis and inflammation and improved blood lipid profile, but was ineffective in reversing hepatic damage of advanced NASH. In conclusion, pomace improved insulin sensitivity and reduced ectopic fat deposition, leading to a healthier metabolic profile. Pomace may hold the potential as a supplement with beneficial health outcomes for the prevention and treatment of hepatic steatosis and other obesity-related pathologies.

Targeting interleukin-β by plant-derived natural products: Implications for the treatment of atherosclerotic cardiovascular disease

Inflammation is the main contributing factor to atheroma formation in atherosclerosis. Interleukin-1 beta (IL-1β) is an inflammatory mediator found in endothelial cells and resident leukocytes. Canakinumab is a selective monoclonal antibody against IL-1β which attenuates inflammation and concurrently precipitates fatal infections and sepsis. Natural products derived from medicinal plants, herbal remedy and functional foods are widely used nowadays. Experimental and clinical trial evidence supports that some natural products such as curcumin, resveratrol, and quercetin have potential effects on IL-1β suppression. In this review, we tried to document findings that used medicinal plants and plant-based natural products for treating atherosclerosis and its related diseases through the suppression of IL-1β.

Low-dose grape pomace and omija fruit extract is more effective than high-dose in lowering oxidative stress and fat-pad mass in db/db mice

Previous studies have shown that the mixture of extracts of grape pomace and omija (GO) improved oxidative stress and obesity in mice. This study first investigated the dose-response effects of GO on oxidative stress and fat-pad mass. Male C57BL/KsJ-db/db mice were fed the following three experimental diets for 7 weeks: a normal control, high-dose grape pomace plus omija (HGO; 0.5% grape pomace plus 0.05% omija fruit, w/w), and low-dose grape pomace plus omija (LGO; 0.3% grape pomace plus 0.05% omija fruit, w/w). The LGO significantly decreased white adipose tissues weights, as well as ameliorated the plasma lipid profiles. The antioxidant effects of LGO led to a significant decrease in the erythrocytic H₂O₂ and thiobarbituric acid-reactive substance levels, while LGO increased erythrocytic antioxidant activities. These results suggest that LGO is more effective than HGO in lowering oxidative stress and body fat mass in db/db mice.