Phenolic Characterization and Neuroprotective Properties of Grape Pomace Extracts

Abstract

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.

Valorization of Grape Pomace and Berries as a New and Sustainable Dietary Supplement: Development, Characterization, and Antioxidant Activity Testing

“…In vitro, grape pomace displays high antioxidant potential [ 72 ], lowers PGE2 levels, and downregulates COX-2 gene expression [ 73 ]. Furthermore, grape pomace polyphenols have proven their efficacy in vivo, by delivering antiglycation agents and preventing the formation of toxic glycation end-products [ 74 ].…”

Food Industry Byproducts as Starting Material for Innovative, Green Feed Formulation: A Sustainable Alternative for Poultry Feeding

“…However, organic solvents are not strictly necessary for these procedures. Indeed, a procedure involving only water was recently optimized for the extraction of grape pomace from the Montepulciano cultivar [ 101 ]. Characterization of this extract was carried out via HPLC and highlighted the presence of gallic acid, caftaric acid, catechin, chlorogenic acid, epicatechin, caffeic and syringic acid.…”

“…This extract also proved to be nontoxic at a concentration of 10 mg/mL in the Daphnia magna toxicity model and showed significant antioxidant and protective properties in HypoE22 cells. The same extract inhibited the H 2 O 2 -induced expression of COX2 in the same cell line, resulting in a lower production of prostaglandin E2 [ 101 ].…”

Antioxidant and Neuroprotective Effect of a Grape Pomace Extract on Oxaliplatin-Induced Peripheral Neuropathy in Rats: Biochemical, Behavioral and Histopathological Evaluation

“…Antioxidant effect of grape pomace extract (GPE) has also been verified to spinal cord neurotoxicity [ 40 ] and to bovine spermatozoa oxidative damage [ 41 ]. Recently, a polyphenol-rich grape pomace extract was found to exert a neuroprotective effect on hypothalamic neurons that were challenged with an oxidative stimulus [ 42 ]. The possible neuroprotective effect of the grape extract against platinum-induced histopathological damage in DRG neurons was tested.…”