Optimization of the extraction process for extract yields, total flavonoid content, radical scavenging activity and cytotoxicity of Curcuma aeruginosa RoxB. rhizome

Abstract

The rhizome of Curcuma aeruginosa RoxB. (RCA) Is used traditionally for several diseases. The flavonoid compounds contained in the RCA that responsible for biological activities. In this study, ethanol, water, and acetone had been used as solvent extraction of RCA and applied the simplex-centroid design to optimize the extraction process. The radical scavenging activity and total flavonoid content were investigated using in vitro assays, while cytotoxicity was evaluated by brine shrimp lethality test. ANOVA suggested a linear model for all responses. The ethanol: acetone extract had the highest extract yield with a value of 25.15%, and this result showed no significant with acetone extract at p  < 0.05 (22.86%). The ethanol extracts confirmed the higher degree of total flavonoid content and cytotoxicity with a value of 17.97 mg QE/g and 140 μg/ml, respectively. The ethanol: water extract, ethanol extract, and water extract (IC₅₀, 100-500 μg/ml) showed moderate radical scavenging activity compared with ascorbic acid (IC₅₀, 7.19 μg/ml). Regarding the correlation analysis, the negative correlation was weakly observed between flavonoid content and IC₅₀ of free radical scavenging activity, which indicates that the flavonoid in RCA contributes not significantly to the antioxidant activity. Introductory studies on the extraction process of the advanced flavonoid extracts exhibited a scavenging and cytotoxic effect of the ethanol extract on C. aeruginosa rhizome.