Comparative Studies on Microwave and Ultrasound and Their Combined Use in the Extraction of Resveratrol from Plants

Background: Resveratrol is a polyphenolic compound found in plants such as Polygo-num cuspidatum, Veratrum nigrum L. and Gnetum montanum Markgr. It has unique functions and biological activities. It has important physiological effects such as anti-cancer, anti-bacterial, lipid-lowering, and prevention of cardiovascular and cerebrovascular diseases. At present, resveratrol is a new type of medicinal and healthcare-active substance, with the potential to develop into a new anti-cancer drug and a new ingredient for healthcare products. Objective: The purpose of this study is to seek the optimal extraction process for resveratrol from the root of Veratrum nigrum L. Methods: The microwave-assisted extraction method (MAE) was used to extract resveratrol from the root of Veratrum nigrum L. and orthogonal experiments were conducted to optimize the extrac-tion process. The results of the microwave-assisted extraction, ultrasonic extraction, and their com-bined use methods were compared with those of the conventional heating reflux method. At the same time, the extraction data of four plants, including Polygonum cuspidatum, Veratrum nigrum L., Gnetum montanum Markgr. and Blueberry, were compared. Results: Under the optimized microwave-assisted extraction conditions, the best process conditions for the root of Veratrum nigrum L were a solid-liquid ratio of 1:20 (g/mL), at a microwave power of 600W, affording an extraction rate as high as 2.7130 (mg/g), within an extraction time of 10 minutes. It is higher than the extraction rate of 2.2911 (mg/g) obtained by the conventional heating reflux method. Conclusion: This study indicates that microwave-assisted extraction is an efficient method with a high extraction rate of resveratrol during short extraction time. It is a green and environmentally friendly extraction technique, and it is recommended for the extraction of active substances such as resveratrol from plants.