Effects of Extraction Solvents on the Total Phenolic Content, Total Flavonoid Content, and Antioxidant Activity in the Aerial Part of Root Vegetables

Abstract

The present study aimed to investigate the total phenolics, total flavonoids, and antioxidant activity in terms of the DPPH scavenging, reducing power, and H2O2 scavenging of the aerial parts of onion, white radish, red radish, carrot, and beet as affected by different extraction solvents. Generally, the aerial part of these vegetables has high antioxidant properties. Samples were extracted with methanol (100 and 70%), ethanol (100 and 70%), and water. Total phenolic content was highest when the samples were extracted using 100% methanol, while extraction with 100% ethanol yielded the highest total flavonoids. The highest DPPH activity and H2O2 scavenging values were obtained by extraction of the aerial plant parts with 70% ethanol, and the 70% methanol extract had the highest reducing power. Partial least regression (PLS) was performed to validate the optimum solvent for extraction of the antioxidants and their activity in each plant. The PLS indicated that there was a variation in the validation of the different extracts for each plant. The high antioxidant capacity of root vegetables, which is natural, indicates that they may have health and dietetic advantages for consumers.