Optimization of Ultrasonic‐Assisted Extraction of Quercetin and Cyanidin from Pyracantha Coccinea and Their Scavenging Effect on Free Radicals

The response surface method was used to optimize the quercetin and cyanidin content experimental parameters for the ultrasonic‐assisted extraction of phenolics from Pyracantha coccinea. The optimal conditions were an extraction time of 97 and 93 min, ethanol concentration of 71 and 79% (v/v), HCl concentration of 1.55 and 1.52 mol/L, liquid–solid ratio of 12.2 and 12.6 mL/g for determining the quercetin and cyanidin contents, respectively. The predicted quercetin and cyanidin contents were 2.30 and 4.01 mg/g, respectively. The experimental values agreed with those predicted at the 95% confidence level, which indicates the response surface method was suitable for optimizing the ultrasound‐assisted extraction of phenolics from P. coccinea. The scavenging effects of cyanidin and quercetin in P. coccinea extract, which extracted at optimum conditions, on free radicals were investigated using the Fenton oxidation. It was also demonstrated that cyanidin had more effective free radical scavenging activity than quercetin. PRACTICAL APPLICATIONS: The phenolic compounds differ in polarity, acidity, number of both hydroxyl groups and aromatic rings, concentration and matrix complexity, specific extractions techniques must be designed and optimized for each phenolic compound. Response surface methods have been used widely to produce and optimize different industrially important biotechnological and biochemical products. A central composite design was used to optimize the parameters for P. coccinea extractions based on the quercetin and cyanidin content. The study results indicate the ultrasonic‐assisted extraction is an economical and efficient method for extracting quercetin and cyanidin from P. coccinea. The free radical scavenging effects of the two phenolic compounds investigated in this study. They act as free scavengers and inhibit free radical production. This study indicates P. coccinea can be considered a good source of naturally occurring antioxidant compounds.