Synthesis of deep eutectic solvents for natural antioxidants extracted from medicinal plant, Coleus aromaticus

Abstract

Antioxidant is a basic requirement for maintaining good health. However, due to toxicity of synthetic antioxidant, hence, demand of natural antioxidant are high. In this research, natural antioxidant are extracted from C. aromaticus by using different types of DES synthesized. Firstly, powder of C. aromaticus are immersed in DES at different condition (temperature, duration, solid to solvent ratio) to find out the optimum condition for extraction. After that, the extract are undergoing total phenolic content assay, DPPH radical scavenging assay and total flavonoid content assay. Finally, HPLC assay is used to check the present of target compound. From the result obtained, the best DES is ChCl : glycerol with 1:4 ratio and the optimum condition are 100 oC, 2.5 hour and 1.10 g/ml solid to solvent ratio with 251.25 μg/ml of total phenolic content extracted which are 2.6 fold higher than that of before optimization which is 97.25 μg/ml. And the bioactive compound that is successfully identified through HPLC assay and FTIR assay are Rosmarinic acid, Caffeic acid, Gallic acid and Quercetin. This shows DES is a potential green solvent to extract the bioactive compound present in medicinal plant.