Research on the Re extraction Process and Whitening Activity of Wen’e Medicine Residue
Wen E Shu is the dried main root stem of Curcuma wenyujin Y.H. Chen et C. Ling, a plant in the ginger family. It has various pharmacological effects such as antioxidant, anti-inflammatory, antibacterial, anti rheumatic, anti-tumor, improving immune system function, and antiviral. It is a traditional Chinese medicine with wide application value. The main components of Curcuma zedoaria are volatile oil, curcumin, polysaccharides, phenolic acids, and alkaloids, with volatile oil accounting for 1% to 2.5%. It is one of the main medicinal substances of Curcuma zedoaria and has been extracted and applied in clinical practice. However, many pharmaceutical factories often use steam distillation to extract the oil from the fermentation process, which has low efficiency in extracting volatile oils, resulting in a large amount of fermentation residue accumulation after oil extraction. Due to the lack of effective utilization methods and high treatment costs, hundreds or thousands of tons of fermentation residue can only be discarded as waste every year, seriously causing resource waste and environmental pollution. However, some scholars have analyzed the chemical composition of the residue left after the extraction of volatile oil from Curcuma zedoaria by steam distillation, and found that there are still various active ingredients such as curcumin compounds and curcumin diketones in the residue of Curcuma zedoaria. Curcumin compounds have been proven to have biological activities such as antibacterial, antioxidant, and whitening, indicating that there is still great feasibility in the secondary development and utilization of Curcuma zedoaria medicinal residue.
The extract of Wen Yu Jin has been included in the 2021 edition of the “Catalogue of Used Cosmetic Raw Material Names”, but there are no relevant research literature reports on its use in the cosmetics field. Whitening, as one of the most common efficacy claims of cosmetics, has gradually gained popularity in recent years, and skin color is mainly determined by melanin. When cells are stimulated by endogenous factors such as alpha MSH, they induce the expression of microphthalmia related transcription factors (MIFT) through various signaling pathways, thereby activating tyrosinase and promoting melanin production. In addition, reactive oxygen species (ROS) also play a very important role in the process of melanin production. ROS is the initiator and reactant in the tyrosinase catalyzed oxidation process, which induces the expression of melanin synthesis genes through the action of related proteins, leading to an increase in melanin content. Therefore, inhibiting tyrosinase activity and antioxidant activity are currently recognized as two key targets for whitening.
Therefore, the aim of this study is to explore the potential value of Curcuma frutescens extract in the field of cosmetics. Using the total curcumin yield as the indicator of its whitening active ingredient, the response surface methodology is used to optimize the optimal extraction process of Curcuma frutescens extract. At the same time, the effects of Curcuma frutescens extract on DPPH, ABTS free radical scavenging, and melanin synthesis and tyrosinase activity in rat melanoma B16 cells under the optimal extraction process conditions are investigated. To provide scientific basis for expanding the utilization of plant resources in the field of cosmetics and promoting the secondary development and utilization of traditional Chinese medicine residue resources in various industries, thereby promoting further development of local economy and industry.

The optimal extraction process for the extract of Curcuma zedoaria medicinal residue was optimized using response surface methodology, with a liquid to material ratio of 22mL/g, 82% ethanol ultrasonic extraction, and ultrasonic time of 55min. The average yield of total curcumin was 6.38mg/g. The process conditions are simple, the operation is convenient and stable, and it can provide reference for the secondary utilization of curcumin compounds in the residual residue after extracting volatile oil from Curcuma zedoaria.
In addition, the extract of the medicinal residue of Wenzhe, prepared by the optimal process, has good scavenging effects on DPPH and ABTS free radicals, with IC50 values of 24.99 and 49.72 μ g/mL, respectively. The results of cell experiments showed that the experimental groups of extracts from the residue of Curcuma zedoaria at concentrations of 50-800 μ g/mL could effectively reduce the content of melanin in melanoma B16 cells and inhibit tyrosinase activity.
Curcumin compounds have relatively stable properties in acidic and neutral environments, and are easily soluble in organic solvents but not easily soluble in water. The traditional reflux extraction method for curcumin compounds is time-consuming, has low extraction rates, and is not conducive to ensuring the biological activity of curcumin compounds. At the same time, the detection method for curcumin compound content is also complex. Therefore, this experiment improved the literature method by using ultraviolet spectrophotometry to determine the total curcumin compounds, studied the effects of different liquid to material ratios, ethanol concentrations, and ultrasound time on their yield, and optimized the extraction process through response surface modeling. After optimization, the extraction rate of total curcumin in the medicinal residue of Curcuma zedoaria increased by 14.42%. This method is stable, feasible, and has good repeatability. It also provides a theoretical basis for the optimization, determination, and secondary utilization of curcumin compounds in the residue of Curcuma zedoaria.
The DPPH method and ABTS method are two commonly used in vitro antioxidant evaluation tests, widely used to evaluate the antioxidant properties of plant extracts. This experiment found that the extract of Curcuma zedoaria medicinal residue showed good antioxidant effects, and further verification through cell experiments revealed that it had a good inhibitory effect on melanin production and the activity of its key rate limiting enzyme tyrosinase. In the future, further research can be conducted on the whitening mechanism of the extract of Curcuma zedoaria medicinal residue at the cellular and molecular levels, or to isolate and purify it to obtain safer and more effective antioxidants or tyrosinase inhibitors, providing a scientific theoretical basis for the development of Curcuma zedoaria medicinal residue.
With the rapid development of the traditional Chinese medicine industry, a large amount of traditional Chinese medicine residue has also been produced in production. Adhering to the concept of green and sustainable development and resource reuse in China, traditional Chinese medicine residue has gradually become a hot research topic in recent years. Currently, traditional Chinese medicine residue has been widely used as feed, additives, fuels, adsorbents, fertilizers, etc., with great potential for development. Therefore, this experiment also lays the foundation for accelerating the secondary development and utilization of traditional Chinese medicine residue resources in various industries and achieving sustainable utilization of traditional Chinese medicine residue.