Optimization of Microwave-Assisted Extraction of Bioactive Compounds from Veronica Persica Using Response Surface Methodology

Background: The current study aimed to optimize microwave-assisted extraction (MAE) for the recovery of bioactive compounds from Veronica Persica and to enhance extraction yield through ultrasonic pretreatment as an emerging technique. Methods: The MAE was optimized in terms of microwave power, solid-to-solvent ratio, and irradiation time through response surface methodology (RSM) for maximum extraction yield. The extraction yield was further enhanced by using ultrasonic pretreatment with different levels of ultrasound power, temperature, and sonication time. The total phenolic content and radical scavenging activity were determined through the Folin-Ciocalteu method and DPPH and OH free radicals scavenging activity assays, respectively. Results: The optimal conditions for maximizing extraction yield were 211 W microwave power, 14 min irradiation time, and 1:33.5 g/mL solid-to-solvent ratio. Under the optimal conditions, the predicted extraction yield was 12.12%. The results confirmed that ultrasonic pretreatment effectively enhanced the release of bioactive compounds from aerial parts of V. persica. Moreover, scanning electron microscopy images indicated a positive effect of ultrasonic pretreatment on enhancing bioactive compound recovery through damage to the cell structure of the treated samples. Conclusion: The results indicated that using ultrasonic and microwave energy can speed up the extraction process and increase the quality of the extracted biomass.