Investigation on extraction of bioactive compounds from shiraz grape (Vitis vinifera l.cv. shiraz ) and determination of its bioactive properties

The bioactive properties of grape (Vitis Vinifera L.cv. shiraz ) in terms of total phenol, antioxidant, inhibitory effect on diabetes-relevant enzymes, α-glycosidase and α-amylase, and antimicrobial activity were examined in this study. Four different solvents (water, methanol, ethyl acetat and aceton) were used in the extraction of bioactive compounds. The total polyphenol content of the berry extracts varied from 2,72 to 6,85 mg gallic acid equivalents/g with respect to the solvents used. The highest total phenolics were found in aceton extract.In the determination of antioxidant activity, the free radical scavenging effect (DPPH) of berry extracts ranged from EC50: 0,13 to 5,5 mg/mL, while the reducing power capacity (FRAP) of grape extracts varied from 6,39 to 142,2 mmol trolox equivalents/L. The antioxidant effect of aqueous and aceton extract was found to be the most potent in antioxidant assays. α-glucosidase inhibition varied among extracts, from IC50: 0.21 to 2,52 μg/mL, while the α-amylase inhibition ranged from IC50: 7,28 to 19,67 μg/mL. None of grape fruit extracts show antibacterial activity.