The Use of Ultrasound in the Extraction of Biologically Active Compounds from Plant Raw Materials, Used or promising for Use in Medicine (Review)

Introduction. This review examines the current state of technology for ultrasonic isolation of biologically active components from medicinal vegetal raw materials. The main emphasis is placed on "green" technologies that intensify the processes of isolation of components such as flavonoids.Text. Modern technologies imply the use of combined methods, including, in addition to ultrasound, significant grinding of raw materials before the extraction process, the use of supercritical solvents (liquefied gases) under excessive pressure. The effect of ultrasound power and temperature on the output of the extracted components was also considered.Conclusion. 1. To increase the yield of biologically active compounds from plant raw materials among various physical methods of extraction intensification, the use of ultrasound dominates. 2. Ultrasonic extraction can be divided into several main types: extraction in an ultrasonic bath, the use of submersible ultrasonic emitters, as well as the combination of ultrasonic extraction with additional types of influence. 3. In the literature, examples of the use of ultrasonic extraction for the isolation of phenolic compounds are most fully presented, it being noted that the parameters need to be selected individually for each individual plant. 4. The power of ultrasound and the nature of the extractant can affect the course of oxidative processes in the extract, and such phenomena are characteristic not only for too high capacities, but also for low ones. 5. Ultrasound can significantly increase the yield of biologically active compounds even in aqueous extraction of fresh raw materials. 6. The spectrum of extractants selection for ultrasonic extraction of plant raw materials is quite large. Both organic solvents (ethanol, methanol, ethyl acetate, acetone) and water can be used, as well as mixtures of various extractants.