Plant raw materials are widely used in cosmetic products and are favored. Among the new products listed in China in the past five years, plant raw materials such as Asiella sinensis, green tea, licorice, scutellaria skullcap and purslane are common. The 2020 "Beautiful Practice" big data released the top 30 effective ingredients that consumers pay attention to, in addition to tocopherol acetate, niacinamide, sodium hyaluronate, etc., avocado, Asiaticum, Jojoba seed, purslane and other plant ingredients are listed on the list. The plant ingredients that consumers are keen on generally have the following characteristics: familiar, not unfamiliar, strong efficacy, high safety, interpretable, perceptible, transferable, etc. These hot trends present both opportunities and challenges for the use of plant-based ingredients in cosmetics.

Plant raw materials face challenges

First, does natural equal safe? For a long time, people's cognition of natural plants has been double-sided. Because plants and humans live together in nature, most of the plants can also be eaten, and these plant ingredients are safe in the eyes of consumers. But natural is not the same as safe. The composition of plants is actually very complex, and there are uncertainties in terms of safety. We already know that some plant ingredients have definite sensitization and phototoxicity, and perhaps more potentially risky ingredients will be discovered as research progresses and toxicology studies develop. In addition, external environmental pollution will also introduce exogenous unsafe factors. With the increasing application of plant raw materials in cosmetics, the importance of safety is more reflected.

Second, is the claim equivalent? At present, the requirements of young consumer groups and component parties for cosmetics are more rational, and the efficacy should also be safe, and cosmetic developers carefully grasp the balance of safety and efficacy. At the same time, plant raw materials need to have a scientific and logical way of acting to bring about an effect that can be actually felt. However, due to the bottleneck problems encountered in the development of plant cosmetics for a long time, such as the color, taste, stability, cost, resources and many other limitations of plant extracts, plant raw materials do often face the dilemma of separation of claims and effects.

How to address these challenges? The release of new regulations has pointed the way. In June 2020, The State Council announced the Regulations on the Supervision and Administration of Cosmetics, which came into effect on January 1, 2021. Article 9 of the regulations mentions, "encourage and support the use of modern science and technology, combined with China's traditional advantage projects and characteristic plant resources research and development of cosmetics", which said that China's characteristic plant raw materials have a unique advantage. The long-term use history has verified the safety of its application, and the long-term experience accumulation and inheritance have also confirmed its efficacy. The research and application of Chinese characteristic plant raw materials can form Chinese characteristics and help the inheritance of national culture. However, the development and application of characteristic plant raw materials is not a smooth road. In order to meet the four essential elements of quality, stability, safety and efficacy, a balance of many influencing factors needs to be taken into account at the same time, and technological research and innovative breakthroughs are needed.

Modern technology is applied to plant raw materials

The following is the application of three modern technologies in China's characteristic plant raw materials.

The low-temperature microjet technology realizes the complete rupture of cell wall through the impact of high-speed air flow at low temperature, and realizes the efficient extraction technology of fresh plant extraction. Its characteristics are that it can achieve efficient extraction, the extraction rate is higher than the traditional process, and the low temperature extraction can maintain the heat-sensitive components, and make the active extract raw material more active.

Based on the principle of tissue radiation, flash extraction technology is a new extraction technology for soft and hard plant tissue crushing. The principle is to rely on high-speed mechanical shear force and hyperkinetic molecular percolation technology, at room temperature and in the presence of solvents within a few seconds to plant roots, stems, leaves, flowers, fruits, seeds and other materials broken to the appropriate granularity, and the effective components quickly achieve internal and external balance. It is characterized by fast and efficient extraction at room temperature and wide application.

Lyophilized traditional plant raw materials are easy to be oxidized and degraded, which not only reduces the efficacy, but also causes problems such as attenuation of active substances in the formula and the need to add preservatives to increase safety risks. The advantages of freeze-drying technology are low temperature drying, maximum activity, solid state raw materials to maintain a stable state, flexible and convenient application of active substances, to achieve no preservative addition, reduce safety risks.

Innovative development of characteristic plant raw material combination

From the in-depth cultivation of China's characteristic plant raw materials (authentic land, varieties, extraction technology, standards), to the evaluation of the mechanism of active ingredients, the determination of effective concentration, and then to overcome the bottleneck problems such as color, taste, stability, corrosion protection, etc., to add to the formula, and finally achieve perceptible efficacy, each step is hard-won. The ultimate expression of efficacy must be the best combination of ingredients, not a single ingredient that is king. The combination of ingredients is called "Fang" in Chinese medicine. The research of prescription can be screened from the four directions of prescription, effect, test and organization.

There is no prescription in Western medicine, but many people have to eat more than a dozen or even more Western medicines every day, and sometimes it is not prescribed by the same doctor, and there will be interactions and adverse reactions between drugs. In contrast, the compound of Chinese medicine is more concise and efficient, many prescriptions only 4-6 drugs, but can grasp the main contradiction, a comprehensive solution to the problem, the delicacy of the compound also lies in the king and minister, synergistic effect, offset the side effects of each other, can not but make people admire the wisdom of Chinese medicine. Behind the Jingfang is the application of Chinese medical principles, such as Yupingfeng powder for supplementating Qi and strengthening surface for sensitive skin, and Taohong Siwu Decoction for promoting blood circulation and nourishing blood for whitening and removing freckles. The study of Chinese herbal formula can bring a new direction for the application of plant raw materials with Chinese characteristics.

Effective prescription comes from the clinic, verified by a large number of dermatologists, its effectiveness is self-evident. However, it is not easy to transform the effective formula into characteristic plant raw materials for cosmetics, and it may face problems such as unclear basis of the effective material, inconsistent extraction process, influence of the nature of the extract (color, taste, character, uniformity), the actual addition amount of the extract in the formula can not be achieved, and the stability of the extract in the formula. For example, Sanhuang decoction commonly used in hospitals is effective for the treatment of dermatitis and eczema, but its color is very dark. Due to the differences between the pharmaceutical and cosmetic industries, from the hospital prescription to the form of cosmetics available, it is also necessary to achieve a multiple balance of efficacy and safety, stability, and sense of experience. However, the prescription that has been clinically validated saves the time and effort of screening and verification, and can be called a shortcut to effectiveness.

The prescription scattered among the people is mixed in good and bad, with pseudoscience and real pearls. The development of the prescription requires the optimization of extraction technology, in vitro evaluation, hospital clinical testing, safety research and so on. Needless to say, the value of an empirical solution also lies in its effectiveness.

Based on experience in the field of cosmetics/medicine, combinations obtained in the form of project research are called formulations. After rigorous screening, research and design, the formula has higher practicability and feasibility. However, the ultimate manifestation of its efficacy is weaker than the effective formula and the proven formula, and there is uncertainty.

In February 2021, The General Office of the State Council issued Several Policy Measures on Accelerating the Development of TCM Characteristics, proposing that TCM inheritance and innovation must adhere to the "clinical value" orientation. Respect the laws of TCM research and development, make full use of modern technological means such as data science, establish a TCM registration review evidence system that combines TCM theory, human experience, and clinical trials, and actively explore the establishment of a real-world research evidence system for TCM. This can also be used as reference for the innovation and development of China's characteristic plant raw materials. Over the years, the industry for the addition of plant ingredients, stay in the claim, the stagnation caused by many factors. One is a question of thinking. There is a lot of uncertainty in the process of raw material (ingredient) - in vitro efficacy - formulation addition - human testing, because we cannot prejudge the "clinical value" of the raw material. The prescription, the effective prescription and the tested prescription already have "human experience" and "formula theory", and further research is to apply it efficiently, safely and controllably with more scientific "clinical experiments".

The development of the cosmetics industry will inevitably bring about the innovation of product concepts, the optimization of formulas and the appearance of characteristics, and the characteristic plant resources have led such a trend. Combining modern science and technology with China's traditional advantages to create cosmetics with Chinese characteristics will be able to highlight the encircled high-end product market and catch up with international brands in scientific and technological innovation and product quality.

(Excerpt from the Science of Daily Cosmetics, No. 6, 2021)