Objectives : This study was performed to find best extraction solvent for application of Ulmi cortex to food or herbal medicine as an antioxidant only using water, ethanol and their mixtures.
Methods : The Ulmi cortex extracts were prepared using water and 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% and 100% (v/v) ethanol, and were evaluated yields, total polyphenol contents, DPPH and ABTS radical scavenging activities, lipid peroxidation activities, and catechin and epicatechin contents.
Results : Among the Ulmi cortex extracts, the yield was highest in water extract (8.9%) and lowest in ethanol extract (3.8%). The yield of 30% ethanol extract (8.5%) also was very high to similar with water extract. The total polyphenol content was highest in the 30% ethanol extract (253.6 μg /mg extract) and lowest in water extract (109.0 μg /mg extract). The DPPH radical scavenging activity was highest in ethanol extract (IC50, 8.53 μg/ml), ABTS radical scavenging activity was highest in 60% ethanol extract (IC50, 3.08 μg/ml), and the inhibition of lipid peroxidation was highest in 70% ethanol extract (IC50, 7.96 μg/ml). As ethanol content of extraction solvent increased from 0% to 30%, the antioxidant activities were remarkably increased whereas from 30% to 100%, the antioxidant activities were increased or decreased a little.
Conclusions : The findings of the present study suggest that 30% ethanol is best solvent for extraction of Ulmi cortex, considering yield, polyphenol content, and antioxidant activities with extraction cost.