Comparison of Antioxidant and Antidiabetic Activities of Jeju Crops Extracts according to Extraction Conditions

In this study, Jeju dried radish leaves (Raphanus sativus L.), tartary buckwheat (Fagopyrum tataricum Gaertner), common buckwheat (Fagopyrum esculentum Moench), and bitter melon (Momordica charanitia L.) were used to discover materials with antioxidant and antidiabetic effects. These samples were extracted under different conditions using 70% ethanol and hydrothermal as the extraction solvent. The extracts were then filtered, centrifuged, concentrated, and freeze-dried. The total polyphenol content, DPPH radical scavenging activity, ABTS radical scavenging activity, Ferric reducing antioxidant power and α-Glucosidase inhibition activity of each freeze-dried sample diluted to various concentrations were analyzed. The results of various antioxidant and antidiabetic analyses showed that the 70% ethanol extract had significantly higher activity than the hydrothermal extract (p<0.05). Antioxidant activity was the highest in radish leaves, and antidiabetic activity was the highest in tartary buckwheat. Therefore, we determined that radish and tartary buckwheat extracts have relatively high utilization potential and can be used as blood sugar-regulating material.