Physicochemical characteristics and antioxidant activities of solvent fractions from ethanol extract of Wasabia koreana Nakai leaf

This study was conducted to investigate the physicochemical properties and antioxidant activity of the solvent fractions obtained from 80% ethanol extracts of Wasabia koreana Nakai leaves. From the ethanol extracts, hexane, chloroform, ethyl acetate, and n-butanol fractions were sequentially extracted and collected, and further used for the investigation. The highest yield was obtained in the water fraction and its pH was 4.25. The total polyphenol, total flavonoid and total pectin contents in the ethyl acetate fraction were 56.24 mgGAE/g, 97.29 mgNE/g and 108.8 mg/g, respectively. This indicated that the extraction yields of the phenolic compounds and pectin in the solvent fractions obtained from the Wasabi leaves and petiole were significantly different. Analysis of the taste components of the ethyl acetate and water fractions was carried out using an electronic tongue sensor. A negative concentration-dependent population for the ethyl acetate fraction and a positive population for the water fraction, corresponding to DF1 (83.96%) in the discriminant function analysis (DFA) plot, were confirmed from the analysis. In the ethyl acetate fraction, the IC50 values ​​of 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical scavenging activity and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid(ABTS) radical scavenging activity were 899.88 ppm and 276.63 ppm, respectively. Therefore, the ethanol extracts and fractions from Wasabia koreana Nakai leaf have low utilization, which will be beneficial for the development of high value-added products via improvement in the taste components and antioxidant activity.