Improving the recovery of phenolics and flavonoids from Coriandrum sativum L. leaves using microwave-enzymatic-assisted extraction

Abstract

This study focused on optimizing the extraction of phenolic compounds and flavonoids from leaves of Coriandrum sativum L. using a sequential green extraction approach based on microwave-enzymatic-assisted extraction (MEAE). Utilizing a glycerol and choline chloride solvent system (composed of Gly–Cho in a molar ratio of 2 : 1, with water), several extraction parameters were systematically investigated to study their influence on total phenolic content (TPC) and total flavonoid content (TFC): solid-to-liquid ratio, water content, microwave power, microwave time, enzyme concentration, and enzyme incubation time. Subsequent optimization established the following conditions: a solid-to-liquid ratio of 1/20 g mL⁻¹, 10% water content in solvent, 1022 W microwave power, 2.6 minutes microwave time, 40 U g⁻¹ enzyme concentration, and 90 minutes enzyme incubation time at 50 °C. Under these optimized parameters, the TPC of the extracts reached 18.15 mg GAE g⁻¹, while the TFC reached 26.36 mg RE g⁻¹. The significance of variables was evaluated using the Plackett–Burman design, while optimal conditions were determined via the Box–Behnken design. Furthermore, the extraction kinetics were modeled using a second-order kinetic model to understand the mechanism. The findings demonstrate that the sequential MEAE technique, optimized via statistical and kinetic models, holds significant promise as an effective green method for enhancing the recovery of antioxidant compounds from Coriandrum sativum L.