title: Grape skin phenolics as inhibitors of mammalian α-glucosidase and α-amylase--effect of food matrix and processing on efficacy.
abstract: Type-2 diabetes is continuously increasing worldwide. Hence, there is a need to develop functional foods that efficiently alleviate damage due to hyperglycaemia complications while meeting the criteria for a sustainable food processing technology. Inhibition of mammalian α-amylase and α-glucosidase was studied for white grape skin samples recovered from wineries and found to be higher than that of the drug acarbose. In white grape skins, quercetin and kaempferol derivatives, analysed by UPLC-DAD-MS, and the oligomeric series of catechin/epicatechin units and their gallic acid ester derivatives up to nonamers, analysed by MALDI-TOF-MS were identified. White grape skin was then used for enrichment of a tomato puree (3%) and a flat bread (10%). White grape skin phenolics were found in the extract obtained from the enriched foods, except for the higher mass proanthocyanidin oligomers, mainly due to their binding to the matrix and to a lesser extent to heat degradation. Proanthocyanidin solubility was lower in bread, most probably due to formation of binary proanthocyanin/protein complexes, than in tomato puree where possible formation of ternary proanthocyanidin/protein/pectin complexes can enhance solubility. Enzyme inhibition by the enriched foods was significantly higher than for unfortified foods. Hence, this in vitro approach provided a platform to study potential dietary agents to alleviate hyperglycaemia damage and suggested that grape skin phenolics could be effective even if the higher mass proanthocyanidins are bound to the food matrix.
authors.affiliation: DeFENS, Department of Food, Environmental and Nutritional Sciences, Università degli Studi di Milano, via Celoria 2, 20133 Milano, Italy. vera.lavelli@unimi.it.
authors.forename: V
authors.initials: V
authors.lastname: Lavelli
authors.affiliation: DeFENS, Department of Food, Environmental and Nutritional Sciences, Università degli Studi di Milano, via Celoria 2, 20133 Milano, Italy. vera.lavelli@unimi.it.
authors.forename: P S C
authors.initials: PS
authors.lastname: Sri Harsha
authors.affiliation: Department of Agriculture University of Naples Federico II, 80055 Portici, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Ferranti
authors.affiliation: DeFENS, Department of Food, Environmental and Nutritional Sciences, Università degli Studi di Milano, via Celoria 2, 20133 Milano, Italy. vera.lavelli@unimi.it.
authors.forename: A
authors.initials: A
authors.lastname: Scarafoni
authors.affiliation: DeFENS, Department of Food, Environmental and Nutritional Sciences, Università degli Studi di Milano, via Celoria 2, 20133 Milano, Italy. vera.lavelli@unimi.it.
authors.forename: S
authors.initials: S
authors.lastname: Iametti
mesh_terms: D000818:Animals; D005503:Food Additives / Q000737:chemistry; D005511:Food Handling; D005527:Food, Fortified / Q000032:analysis; D005638:Fruit / Q000737:chemistry*; D065089:Glycoside Hydrolase Inhibitors / Q000737:chemistry; D007700:Kinetics; D010636:Phenols / Q000737:chemistry* / Q000302:isolation & purification; D010936:Plant Extracts / Q000737:chemistry*; D044945:Proanthocyanidins / Q000737:chemistry; D051381:Rats; D013552:Swine; D027843:Vitis / Q000737:chemistry*; D000516:alpha-Amylases / Q000037:antagonists & inhibitors* / Q000737:chemistry; D000520:alpha-Glucosidases / Q000737:chemistry
chemical_list: D005503:Food Additives; D065089:Glycoside Hydrolase Inhibitors; D010636:Phenols; D010936:Plant Extracts; D044945:Proanthocyanidins; C013221:proanthocyanidin; D000516:alpha-Amylases; D000520:alpha-Glucosidases