Application of Plant Extracts in Cosmetics

Application of plant extracts in cosmetics

With the increasing interest in natural, green, healthy and safe cosmetics with plant extracts, the development of active substances from plant resources and pure natural cosmetics has become one of the most active themes in the development of the cosmetics industry. The redevelopment of botanical resources is not simply a matter of restoring history, but rather of developing new types of botanical origin cosmetics, using both traditional Chinese culture and traditional Chinese medicine theories, as well as modern biochemical techniques to provide green raw materials for the development of scientific and safe natural cosmetic products. In addition, plant extracts are widely used in pharmaceuticals, food supplements, functional foods, beverages, cosmetics and other fields.

Plant extracts (PE) are plant products made of small molecules and macromolecules, which are purified by physical, chemical and biological means to isolate one or more active ingredients from plant materials. Compared with traditional cosmetics, cosmetics formulated with plant extracts as active ingredients have many advantages: they overcome the shortcomings of traditional cosmetics, which rely on chemical synthesis, and make the products safer; the natural components are more easily absorbed by the skin, which makes the products more effective; and the functionality is more prominent. In this paper, the application of plant extracts in cosmetics is reviewed in terms of the methods of extracting plant extracts, the factors affecting the extraction rate of extracts and the application properties of plant extracts in cosmetics.

At present, the common methods for extracting plant extracts include solvent extraction, ultrasonic extraction, microwave extraction and enzyme extraction, while supercritical fluid extraction and microwave-assisted extraction are widely used as new extraction techniques.

Solvent extraction method

The solvent extraction method is to extract the active ingredients from solid raw materials with solvents, which must have the property of mutual solubility with the extracted solute. After the plant material is crushed and put into a suitable container, several times the amount of solvent is added, and extraction can be carried out by maceration, percolation, decoction, reflux and continuous extraction.

In the extraction process of solvent extraction, the concentration of solvent, the ratio, the extraction temperature and the extraction time directly affect the extraction rate of the active ingredient. Monte D. Holt et al. used solvent extraction to extract alkylresorcinol from raw and cooked wheat seeds, and showed that the extraction time could be saved by solvent extraction.

Ultrasonic extraction method

Ultrasonic extraction uses the strong vibration and cavitation effect generated by ultrasonic waves to accelerate the release, diffusion and extraction of substances from plant cells, diffusion and At the same time, the structure and biological activity of the extracted substances can be kept unchanged. The principle of ultrasonic extraction is mainly a physical process, and it is a relatively new extraction method that has been gaining attention in recent years. For most of the components, ultrasonic extraction method can significantly shorten the extraction time, consume less solvent and have higher leaching rate than conventional solvent extraction, and therefore has higher extraction efficiency.

Supercritical fluid extraction

Supercritical fluid extraction (*E) is a relatively new extraction and separation technique, which generally uses CO2 as the extractant. The principle of supercritical fluid extraction is to use the unique solubility of supercritical fluids and the solubility of substances in supercritical fluids is very sensitive to changes in pressure and temperature, through the means of temperature and pressure (or both) to separate the dissolved substances in supercritical fluids, to achieve the purpose of separation and purification, it has both distillation and extraction, with the active ingredients are not easy to inactivate, high product quality, and the advantages of simultaneous completion of the extraction and separation process, It is considered as a green and high-tech separation technology, especially suitable for the separation and refinement of unstable natural products and physiologically active substances.

Microwave assisted extraction method

Microwave assistedextraction (MAE) is a new technology that uses microwave energy to improve extraction efficiency. Microwave assisted extraction is a method to selectively extract the target components in the material by using the characteristics of microwave heating, by adjusting the microwave parameters, the target components can be effectively heated to facilitate the extraction and separation of the target components. The principle of microwave-assisted extraction of plants is that the plant sample absorbs a large amount of energy in the microwave field, while the surrounding solvent absorbs less, thus generating thermal stress inside the cells, and the plant cells rupture due to the internal thermal stress, so that the material inside the cells comes into direct contact with the relatively cold extraction solvent, which accelerates the transfer of the target product from the cells to the extraction solvent, thus enhancing the extraction process. 

The microwave-assisted extraction technique uses the same thermal energy as soaking and filtration, but the extraction of plant extracts is much faster than conventional methods, reducing the extraction time while avoiding the destruction and degradation of valuable plant extracts.