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ANTIDIABETIC POTENTIAL OF MICROWAVE-ASSISTED AQUEOUS GRAPE SKIN EXTRACTS FROM SELECTED WHITE TABLE GRAPE CULTIVARS
Domagoj Šubarić
; Josip Juraj Strossmayer University of Osijek, Faculty of Agrobiotechnical Sciences Osijek, Vladimira Preloga 1, 31000 Osijek, Croatia
Maja Karnaš Babić
; Josip Juraj Strossmayer University of Osijek, Faculty of Agrobiotechnical Sciences Osijek, Vladimira Preloga 1, 31000 Osijek, Croatia
*
Toni Kujundžić
; Josip Juraj Strossmayer University of Osijek, Faculty of Agrobiotechnical Sciences Osijek, Vladimira Preloga 1, 31000 Osijek, Croatia
Mato Drenjančević
; Josip Juraj Strossmayer University of Osijek, Faculty of Agrobiotechnical Sciences Osijek, Vladimira Preloga 1, 31000 Osijek, Croatia
Dejan Agić
; Josip Juraj Strossmayer University of Osijek, Faculty of Agrobiotechnical Sciences Osijek, Vladimira Preloga 1, 31000 Osijek, Croatia
Vesna Rastija
; Josip Juraj Strossmayer University of Osijek, Faculty of Agrobiotechnical Sciences Osijek, Vladimira Preloga 1, 31000 Osijek, Croatia
* Dopisni autor.
Sažetak
Type 2 diabetes mellitus is one of the fastest-growing metabolic disorders worldwide, increasing the demand for naturally occurring compounds capable of improving postprandial glycaemic control. Grape skins represent an abundant source of biologically active phytochemicals, including polyphenols and other antioxidant constituents, which may contribute to antidiabetic activity. In the present study, the antioxidant capacity and inhibitory activities against α-amylase and α-glucosidase of aqueous microwave-assisted extracts obtained from the skins of ten white table grape cultivars were evaluated. Grape skin extracts were prepared using microwave-assisted extraction with acidified water as an environmentally friendly extraction solvent. Antioxidant activity was determined by the ferric reducing antioxidant power (FRAP) assay, whereas antidiabetic activity was assessed through inhibition of α-amylase and α-glucosidase. Significant differences among cultivars were observed for all analysed parameters. Sonja exhibited the highest ferric reducing antioxidant capacity, whereas the strongest inhibition of α-amylase and α-glucosidase was recorded for Fanny and Sonja, respectively. Interestingly, antioxidant activity did not correspond to enzyme inhibitory activity, indicating that the antidiabetic potential of grape skin extracts cannot be predicted solely from their overall reducing capacity. These findings suggest that the qualitative composition of phytochemicals rather than total antioxidant capacity plays a dominant role in digestive enzyme inhibition. Microwave-assisted aqueous extraction proved to be an efficient green extraction technique for obtaining biologically active grape skin extracts, supporting the utilisation of grape-processing by-products as valuable ingredients for functional foods and nutraceuticals.
Ključne riječi
white table grape; grape skin; microwave-assisted extraction; antioxidant activity; FRAP; α-amylase; α-glucosidase; functional foods
Hrčak ID:
349982
URI
Datum izdavanja:
31.7.2026.
Posjeta: 0 *