Potential of green extraction using edible deep eutectic solvents on the bioactivities from Curcuma aromatica rhizome extracts for food application

Abstract

Curcuma aromatica (CA) rhizomes are abundant in medicinal phytochemicals and have been reported to promote a variety of health conditions. Deep eutectic solvents (DESs) are an alternative system of liquid at room temperature with advantageous features. The purpose of this study was to evaluate the extraction process, preliminary phytochemical content, bioactivities, anti-inflammatory activity on RAW 264.7 cells and HPLC analysis of edible DESs extracts of CA rhizomes. DESs extracts had extraction yields of total phenolic content ranging from 2.67 ± 0.17 to 19.36 ± 0.26 mg GAE/g extract and total flavonoid content ranging from 30.27 ± 1.36 to 259.19 ± 1.13 mg QE/g extract. The IC50 values of free radical scavenging by DPPH assay, lipid peroxidation inhibition and tyrosinase inhibition of DESs extracts were 20.60 ± 5.50, 11.02 ± 3.56 and 11.18 ± 0.02 mg/ml, respectively. The DESs extracts exhibited nitric oxide radical scavenging ranging from 3.62 ± 1.94 to 48.86 ± 4.30 % and hyaluronidase inhibition ranging from 29.41 ± 0.41 to 40.13 ± 0.56 %. The extracts containing lactic acid and glucose (D2), citric acid and fructose (D5) and citric acid and glucose (D6) exhibited no cytotoxic effects at concentrations ranging from 0.03 to 3.91 μg/ml. The IC50 values of these extracts on anti-inflammatory activity were 0.64 ± 0.01 to 1.25 ± 0.35 μg/ml. In HPLC analysis, D2, D5 and D6 had the content of curcumin per extract at 74.05 ± 0.86, 13.76 ± 0.46 and 31.08 ± 0.72 μg/g, respectively. This study demonstrated the potential application of green extraction using edible DESs on medicinal plants for the further development of novel health care products.