The basic principle of ultrasonic action, the application of ultrasound in the extraction of active components of natural products, and the application and research progress of ultrasonic in the extraction of active components of natural products were reviewed. It points out that ultrasonic extraction has the advantages of high yield, fast speed and no change in the structure of active components, discusses the problems that should be paid attention to in ultrasonic extraction, and systematically expounds the application of ultrasonic in the extraction of polysaccharide, glycosides, flavonoids, alkaloids and other components. Research progress. It provides a reference for the research on the extraction of active ingredients of Chinese medicine.
The chemical composition of traditional Chinese medicine is very complex. Extracting its active ingredients is an important content in the field of traditional Chinese Medicine research. The active ingredient of traditional Chinese medicine generally refers to a chemical substance with a clear chemical structure and physical constant. If the concentration of the active ingredient is not high, the dose will be increased. At the same time, due to the presence of invalid or low-utility parts, Chinese medicine will be easy to absorb moisture. Metamorphic, difficult to preserve, Therefore, it is necessary to extract and separate the active ingredients of Chinese medicine. Many of the effective chemical components in traditional Chinese medicine are intracellular components that require broken cells or cell membranes when extracted, and existing chemical and mechanical methods of cell fragmentation are often difficult to achieve the desired crushing effect, which affects the extraction results. Due to its unique extraction mechanism and ideal extraction effect, ultrasonic extraction has shown obvious advantages in the extraction of chemical components of traditional Chinese medicine. Ultrasonic assisted extraction technology uses ultrasonic strong vibration, high acceleration, strong cavitation effect, and strong stirring to shorten the time when the active components of natural products enter the solvent, speed up the extraction process, improve the extraction rate, and effectively avoid the destruction of the effective components at high temperatures. In recent years, with the development of natural product modernization and ultrasonic technology, many researchers have said that ultrasonic extraction technology has been introduced into the process of extraction of active components, an important part of natural product production. This paper briefly introduces the basic principle of ultrasonic action, introduces the application of ultrasound in extraction of active components of natural products, and summarizes the application and research progress of ultrasonic in extraction of active components of natural products. It is pointed out that ultrasonic extraction has the advantages of high yield, fast speed and not changing the structure of active components. The problems that should be paid attention to in ultrasonic extraction are discussed. The application of ultrasonic in the extraction of polysaccharide, glycosides, flavonoids, alkaloids and other components is systematically described. Research progress. It provides a reference for the research on the extraction of active ingredients of Chinese medicine.
Basic Principles of Ultrasonic Extraction
In the process of product component extraction, the cell wall can be broken and the cell contents can be extracted efficiently and quickly. Since the generation of ultrasound in 1830 *, it has been widely used in many fields such as food, medical care, and home appliances, including ultrasound extraction, ultrasonic drying, ultrasound sterilization, ultrasound filtration, and ultrasound cleaning. The ultrasonic extraction method is a method that uses ultrasonic cavitation, mechanical action, and thermal effect to increase the frequency and speed of the material's molecular motion and increase the solvent penetration, thereby improving the leaching rate of the target components. It has the advantages of time saving, energy saving and high extraction efficiency. It is a fast and efficient extraction method, and there is no heating process in the extraction. It can avoid changes in the structure of drug components caused by heating factors and can be used for the extraction of heat-sensitive components. Ultrasonic extraction method has been widely used in sample processing of Chinese medicine quality inspection. In recent years, its application in the extraction process of Chinese medicine preparations has also received more and more attention and important progress has been made. Ultrasonic waves used in plant sample extraction are generally generated by magnetic materials via converters, and the effective frequency is generally in the range of 20-50 kHz. It is believed that its cavitation, heat effect and mechanical action are the three theoretical bases of ultrasonic technology in the extraction of traditional Chinese medicine.
1.1 Air role
There are often some vacuum or small bubbles containing a small amount of gas or steam in the liquid. These small bubbles are of different sizes. When a certain frequency of ultrasound acts on the liquid, resonance occurs only in small bubbles of suitable size. Small bubbles larger than the resonance size are driven out of the liquid and smaller than the resonance size gradually become larger under ultrasound. When approaching the resonance size, the sparse phase of the sound wave causes the vesicle to swell rapidly; In the compression phase of sound waves, the vesicles are suddenly compressed by adiabatic heat until annihilation. During the annihilation process, the temperature in the hole can reach 5000 K or more(equivalent to the temperature of the sun's surface), the pressure reaches 1.013 × 105 kPa or more(equivalent to the pressure at the bottom of the ocean), and the temperature change rate reaches 109K/s, resulting in the so-called "hot spot". The above phenomenon is called cavitation. When the small bubble is swollen, due to friction, charge can be generated, discharge and luminescence can be generated during the annihilation process, and liquid microjets with speeds of up to 1000m/ns can be generated. Airization is used to clean, atomize, emulsify, and promote chemical reactions.
1.2 Thermal effects
Due to the absorption of ultrasonic waves and the consumption of internal friction, the molecules produce violent vibrations, and the mechanical energy of ultrasonic waves is converted into the internal energy of the medium, causing the temperature of the medium to rise. The greater the intensity of the ultrasonic wave, the stronger the thermal effect it produces. Controlling ultrasonic strength can instantly increase the temperature inside the drug tissue, accelerate the dissolution of the active ingredient, and do not change the nature of the component.
1.3 Mechanical effects
Ultrasound is the propagation of mechanical vibration energy. It can form effective agitation and flow in liquids, destroy the structure of the medium, crush the particles in liquids, and achieve the effect that ordinary low-frequency mechanical agitation can not achieve. Mechanical effects are often used for crushing, cutting, and condensation. Ultrasound can cause chemical reactions that can not occur at room temperature and pressure to occur under cavitation, and even make very hard solids crushed. Controlling a certain ultrasonic frequency and intensity, the great pressure generated by cavitation causes the rupture of the biological cell wall and the entire organism, and the entire crushing process is completed instantaneously. At the same time, the vibration generated by ultrasound enhances the release, diffusion, and dissolution of intracellular substances.. The biological activity of the extracted material remains unchanged at the moment it is broken, and the breakage speed and extraction rate are increased.
2 Advantages of ultrasonic extraction
2.1 High extraction efficiency
The physical characteristics of ultrasonic alone caused the plant cell tissue to break or deform, so that the effective components of traditional Chinese medicine were extracted more fully, and the extraction rate was significantly increased by 50-500 % compared with the traditional technology.
2.2 Short extraction time
Ultrasonic enhanced Chinese medicine extraction can usually be obtained in 24-40 minutes. The extraction time is greatly shortened by more than 2/3 compared with the traditional method, and the raw materials of medicinal materials are treated in large quantities.
2.3 Low extraction temperature
The * temperature of ultrasonic extraction of Chinese herbal medicines is 40-60 °C, which has a protective effect on the active ingredients in herbal medicines that are unstable, easily hydrolyzed or oxidized, and at the same time greatly saves energy;
2.4 Wide adaptability
Ultrasonic extraction of Chinese herbal medicines is not limited by component polarity and molecular weight, and is suitable for the extraction of most kinds of Chinese herbal medicines and various components.
2.5 Other advantages
There are few impurities in the extract liquid, and the active ingredients are easy to be separated and purified. The operation cost of the extraction process is low and the comprehensive economic benefits are significant. Easy operation, easy to maintain and maintain equipment; Protect active ingredients.
3. Purpose
Can be used for biological and plant cell fragmentation; Extraction of biological and plant active ingredients; Low temperature extraction of active ingredients of Chinese herbal medicine; BCR element morphology extraction; Low energy state activates bacteria; High energy state can kill dead and alive bacteria; Can be used for DNA extraction and DNA shear;
Application of Ultrasonic Extraction in Extraction of Chemical Components of Traditional Chinese Medicine
Ultrasonic extraction technology is widely used in the extraction of Chinese herbal medicines. Almost all kinds of active ingredients extraction of Chinese herbal medicines involve ultrasonic extraction technology. At present, the study of ultrasonic extraction technology used in Chinese medicine extraction focuses on the study of its process conditions. The factors affecting the efficiency of ultrasonic extraction are: immersion time, extraction time, number of extraction times, type and amount of solvent extracted, extraction temperature, ultrasonic frequency, sound strength, crushed granularity of medicinal materials, and empty ratio. The main experimental design method for the study of process conditions is orthogonal experimental method. Acoustics parameters such as ultrasonic frequency, sound intensity, and empty ratio that affect ultrasonic extraction efficiency are the unique factors that affect the extraction efficiency of this technology.