Antilipidemic, Antidiabetic and Antioxidant Activities of Isabella Grape Pomace Extract: A Design of Experiments Approach

The food processing by-products are considered valuable sources of bioactive compounds with applications in the food, pharmaceutical, cosmetic, and natural colorant industries. are considered valuable sources of bioactive compounds with applications in the food, pharmaceutical, cosmetic, and natural colorant industries. The present study aimed to investigate the phytochemical composition and the pancreatic lipase, cholesterol esterase, and α-glucosidase inhibitory activities of Isabella grape (Vitis labrusca) pomace.Extracts were prepared from Isabella grape pomace using a design of experiments approach. The phenolic content of the extracts was analyzed by RP-HPLC, and the effects of extraction parameters were evaluated. Ethanol concentration, microwave power, and extraction temperature were identified as the most influential factors. A Box-Behnken design was employed to optimize the extraction conditions. The optimized extract was further evaluated for its antioxidant and enzyme inhibitory activities. The results demonstrated that the optimized extract exhibited inhibitory effects against pancreatic lipase, cholesterol esterase, and α-glucosidase enzymes. In addition, strong antioxidant activity was confirmed using CUPRAC, FRAP, and DPPH DPPH radical scavenging assays. These findings indicate that Isabella grape pomace could be considered a promising natural source of bioactive compounds with antioxidant and metabolic enzyme inhibitory potential. Therefore, grape processing by-products may contribute to the development of functional ingredients and nutraceutical candidates targeting oxidative stress and metabolic disorders such as obesity and diabetes.