Plant fermented cosmetics(PFC) are the extension of natural cosmetics. Generally, natural plant raw materials are slowly fermented by microorganisms to release active substances in plants, and then the structure is deconstructed, transformed or decomposed by microbial enzymes to further obtain valuable bioactive substances which are beneficial to skin absorption and improve skin care efficacy. Research on the domestic cosmetic market has shown that the enterprises of cosmetic development and manufacturing are developing the plant fermented cosmetics, and various plant fermented cosmetics have appeared in the market. Plant fermented cosmetics are the typical representatives of natural and green cosmetics, which have perfect product properties and broad market prospects, and have become the new trend in the future development of the cosmetics industry.

1. Definition

Plant fermented cosmetics are cosmetics that adopt the fermentation filtrate produced by microbial fermenting plant materials as the main functional ingredients, which are natural plant active substances. Although the microorganisms used in plant fermented cosmetics and probiotic skin care products are usually lactic acid bacterium and microzyme, there are essential differences between the two types of cosmetics. The functional ingredients of plant fermented cosmetics are mainly natural plant active substances, and the functional ingredients of probiotic skin care products are mainly probiotic lysate or metabolite secreted by probiotic bacterium.

2. Advantages

2.1 Enriched with the active ingredients in plants for better skin care

There are many active substances in natural plants, such as polysaccharide, polypeptide, flavone, polyphenol, amino acid, etc. The traditional process is to extract active ingredients from plants by using organic solvents or aqueous solutions, but the content of the obtained active ingredients is low, and sometimes it is difficult to meet the expected efficacy. Studies have shown that plant raw materials can be enriched with active ingredients after fermentation. For example, more or stronger whitening substances can be extracted from Tricholoma matsutake by fermenting it with Lactobacillus acidophilus, and the whitening effect of Tricholoma matsutake fermentation solution is better compared to the aqueous extract and alcohol extract of Tricholoma matsutake [5].

2.2 Reduced side effects and safer use

China is rich in plant resources, and the planting environment varies greatly in different regions, the active substances in plants are complex, and a few plant ingredients may have certain side effects, which will limit the effective utilization of some plant resources. It has been reported that skin sensitization of fermented red ginseng is significantly lower than that unfermented, so is the toxicity of fermented red ginseng at a high doses. In addition, the contents of alkaloids, lactones, glycosides, toxoproteins, aristolochic acids, anthraquinones, tannins and heavy metals in plants can be reduced by microbial fermentation technology.

2.3 Generate new active substances and improve skin care efficacy

After the fermentation of Panax notoginseng root by Bacillus subtilis, ginsenoside Rh4, which  exists only in the stems and leaves of ginseng, is generated. The ginsenoside Rh4 has anti-aging effect and can improve the skin care efficacy of fermented raw pulp.

3. R&D of raw pulp of plant fermented cosmetics

The active ingredients of plant fermented cosmetics are mainly located in the fermentation raw pulp, which is used as the raw material of plant fermented cosmetics after centrifugation and filtration. Most of the methods for preparing raw pulp of plant fermented cosmetics in the literature are based on the slow fermentation of edible plant raw materials under liquid conditions by fermenting microorganisms such as lactic acid bacteria, lactobacillus or microzyme and aspergillus oryzae, rhizopus oryzae commonly used in the food industry, Aspergillus oryzae and rice rhizinase, etc. such as rice bran, selenium-rich mung bean, rice raw materials, plant leaves, etc, or plant raw materials with medicinal value, such as ganoderma lucidum, purslane, rhodiola rosea, ophiopogon root, ginseng, pseudo-ginseng, etc., the fermented raw pulp of plants obtained after fermentation has the effects of whitening, moisturizing or anti-aging (see Table 1). The research and development of plant fermented cosmetics have yielded a great number of positive results in China. The research and development of plant fermentation raw pulp has been further strengthened, and the plant fermentation raw pulp with multiple effects and stronger skin care efficacy has been developed, which will be beneficial to improve the development and market share of domestic plant fermented cosmetics.

4. Market Situation of plant fermented cosmetics

Cosmetics that focus on fermentation concept have successfully entered the mainstream of cosmetics industry, and have a high degree of penetration among consumers. Plant fermented cosmetics have become a trend in cosmetics industry due to their green, environmental friendly, biodegradability and higher safety. According to the statistical data of Mintel (see Fig 1 and Fig 2), the new cosmetics made by fermentation or fermentation raw materials have shown a year-on-year growth trend in recent 5 years (see Fig 1). Among them, the Chinese market has the fastest growth rate in the number of new products released of fermented cosmetics. By 2020, it has become the region with the largest number of new products released of fermented cosmetics in China mainland.

Fig.1  The Top 5 countries of new products released for fermented cosmetics (from:GNPD)

The rapid growth in the number of new products of fermented cosmetics in China depends on the increase of enterprises related to the development and production of fermented cosmetics, with growth driven by consumer preference for fermented cosmetics and the improvement of product safety and efficacy by scientific and technological progress. According to the published raw materials of fermented cosmetics, the new fermented cosmetics are mainly plant/herbal fermented cosmetics, and most of the new fermented cosmetics have nourishing/moisturizing effect, which is consistent with the current demand trend of consumers, see Figure 2.

Table 1 The fermented raw materials and the efficacy of fermented raw pulp of plant fermented cosmetics in the literature

Fig. 2 Propaganda-orientation of new fermented cosmetics (from: GNPD)

Many domestic and international cosmetics companies have launched plant fermented cosmetics. Searching the plant fermented cosmetics on the network platform, where the mainstream products are fermented water, fermented cream, fermented essence, cleanser and mask, etc. Most plant fermented cosmetics are compounded and fermented by multiple plant raw materials, which have the effects of moisturizing, anti-wrinkle, wrinkle reduction, whitening, soothing or skin repairing. With the development of plant fermented raw materials and fermented microorganisms, more types and efficacy of plant fermented cosmetics will emerge in the cosmetics market.

5. Conclusion

At present, the popular plant fermented cosmetics in the market usually take the plant fermented raw pulp as the main functional active ingredient, and still contain a large number of chemical ingredients. The development of plant emulsifiers, plant preservatives, etc., and the gradual use of plant active ingredients and tissue components instead of the chemical components in cosmetics will be the future development trend of plant fermented cosmetics, in order to realize the phytocosmetics, which is called "six-no products" in some literature, i.e. "no preservatives, no chemical additives, no chemical oils, no animal fats, no essence and no dilution," which will greatly improve the safety of plant fermented cosmetics and meet the consumers' demand for green, safe and healthy cosmetics.