Study on UPLC fingerprint and multi evaluation method of Schisandra chinensis medicinal materials
South Schisandra chinensis is a plant of the Magnoliaceae family, while Central Schisandra chinensis is a plant of the same family Dried and ripe fruits of et Wils. It is warm in nature, sour and sweet in taste, and has the effects of astringency, tonifying qi and generating fluids, tonifying the kidneys and calming the heart. It is used for symptoms such as chronic cough and wheezing, nocturnal emission, frequent enuresis and urination, persistent diarrhea, spontaneous sweating and night sweats, fluid damage and thirst, internal heat and thirst quenching, palpitations and insomnia. The main chemical components of Schisandra chinensis are triterpenoids and lignans. In recent years, research has shown that Schisandra chinensis has the effects of protecting the liver, calming and hypnotizing, anti-tumor, lowering blood sugar, antioxidant, and enhancing immunity. It has nourishing and strong properties, and has high medicinal and edible value.
The quality of traditional Chinese medicine is directly related to the effectiveness of clinical treatment. Effective control of the quality of traditional Chinese medicine is a prerequisite for ensuring its clinical efficacy. At present, fingerprint technology has been widely applied in the quality control of traditional Chinese medicine. It can comprehensively characterize the chemical components of traditional Chinese medicine and has the characteristics of specificity and comprehensiveness. Combining fingerprint with QAMS to comprehensively control the quality of traditional Chinese medicine from both qualitative and quantitative perspectives is an important way to modernize traditional Chinese medicine. At present, the 2020 edition of the Pharmacopoeia of the People’s Republic of China (hereinafter referred to as the “Chinese Pharmacopoeia”) uses schisandrin methyl as the content determination indicator for the medicinal herb Schisandra chinensis. However, the content determination of a single component can no longer meet the overall quality control concept of traditional Chinese medicine.
At present, there are research reports on the establishment of fingerprint spectra and chemical composition of Schisandra chinensis. Guo et al. used high-performance liquid chromatography (HPLC) to establish fingerprint spectra of Schisandra chinensis and Schisandra chinensis, and combined with chemical pattern recognition analysis, screened out four differential biomarkers that affect the quality of Schisandra chinensis and Schisandra chinensis. Ma et al. established a fingerprint of Schisandra chinensis using HPLC method and quantitatively analyzed seven known components in the fingerprint. Wei et al. established a fingerprint of Schisandra chinensis using UPLC method, and determined the contents of three main active ingredients in Schisandra chinensis, namely Wuweizi Jia, An Wu Zhi Su, and Schisandrin methyl. Compared with ordinary liquid chromatography, the use of ultra-high performance liquid chromatography can shorten the analysis time, improve the separation of chromatographic peaks, and has more obvious advantages in the study of fingerprint spectra. However, the common problem faced by the above studies is the lack of legal reference standards and the increase in cost caused by excessive use of reference standards. The use of one test multiple evaluation method for quality control of Schisandra chinensis medicinal materials has not been reported yet. This study used UPLC fingerprinting and multi evaluation, combined with chemometric analysis methods, to conduct a comprehensive quality control study on 14 batches of Schisandra chinensis medicinal materials. This not only saved reference materials, but also provided a basis for comprehensive, objective, and accurate evaluation of Schisandra chinensis quality.

The 2020 edition of the Chinese Pharmacopoeia stipulates that the medicinal herb Schisandra chinensis should be harvested when the fruit is ripe in autumn. There are literature reports that Li et al. studied the changes in the content of major chemical components in Schisandra chinensis medicinal materials from three production areas in Hubei, Sichuan, and Jiangxi. Through analysis of the measurement results, they found that the accumulation of major chemical components in Schisandra chinensis medicinal materials at different growth stages in the three production areas had certain patterns; The optimal harvesting period for Schisandra chinensis has been preliminarily determined to be mid to late September. Huang et al. used UV spectrophotometry and liquid chromatography to determine the contents of volatile oil, total lignans, schisandrin, and schisandrin in Schisandra chinensis produced in Shaanxi at different harvesting periods. The results showed that the optimal harvesting period for Schisandra chinensis was in early August. In addition, studies have shown that different processing methods in different regions have a significant impact on the content of active ingredients in Schisandra chinensis. This study found that the total content of six lignans in five batches of Schisandra chinensis from Hubei province was the highest, while the content of the remaining nine batches from Shaanxi, Henan, and Shanxi provinces was relatively uniform, with three batches from Shanxi province having the lowest content; In addition, the highest content of protocatechuic acid is found in Henan, followed by Hubei, and the lowest in Shaanxi and Shanxi. This may be related to differences in the origin, harvesting time, and processing methods of medicinal herbs.
This study used UPLC to establish the fingerprint spectrum of Schisandra chinensis medicinal materials, and investigated different mobile phase systems (methanol water, acetonitrile water, and acetonitrile-0.1% phosphoric acid). The results showed that using acetonitrile-0.1% phosphoric acid as the elution system resulted in comprehensive chromatographic peak information and good separation efficiency. A diode array detector (DAD detector) was used to perform full wavelength scanning of the test solution of Schisandra chinensis in the range of 190-350nm, and fingerprint spectra were extracted at different wavelengths (230, 254nm) for comparison. The results showed that at 230nm, the response and capacity of the chromatographic peaks in the fingerprint spectra were good. We also investigated the separation efficiency of different column lengths [Waters ACQUITY HSS T3 (2.1mm × 100mm, 1.8 μ m), Waters ACQUITY HSS T3 (2.1mm × 150mm, 1.8 μ m)] on the fingerprint spectra of Schisandra chinensis medicinal materials. The results showed that the Waters ACQUITY HSS T3 (2.1mm × 150mm, 1.8 μ m) column had better separation efficiency. In addition, through single factor analysis, the effects of extraction solvent, extraction method, and extraction time on the fingerprint spectrum and content determination of Schisandra chinensis were investigated using “total peak area/sample size of fingerprint spectrum” and the content of six lignans as evaluation indicators. The optimal method for preparing the test solution was determined to achieve the highest extraction efficiency of each peak in the fingerprint spectrum.
At present, chemical pattern recognition methods such as fingerprint similarity evaluation, Euclidean distance clustering analysis, and principal component analysis have been widely used in research fields such as the quality, origin differences, and variety identification of Chinese medicinal materials. This study introduces fingerprint similarity evaluation analysis, cluster analysis, and orthogonal partial least squares discriminant analysis to visually measure the similarity and affinity of fingerprint patterns between different batches of Schisandra chinensis samples. The results showed that the similarity between the fingerprint spectra of 14 batches of Schisandra chinensis medicinal materials and the control fingerprint spectra was above 0.95, indicating good consistency among Schisandra chinensis medicinal materials from different origins. Through cluster analysis and orthogonal partial least squares discriminant analysis, the 14 batches of Schisandra chinensis medicinal materials can be divided into 4 categories, showing a certain regularity of origin; A total of 9 differential substances were screened, namely peak 1 (protocatechuic acid), peak 2, peak 4, peak 6, peak 7 (schisandrin ester B), peak 8, peak 9, peak 12, and peak 15, indicating that the above 9 components have a significant impact on the fingerprint of Schisandra chinensis. Further in-depth research is needed. This experiment utilized the structural similarity of lignans in Schisandra chinensis to establish a preliminary determination method using QAMS for the content of six lignans in Schisandra chinensis medicinal materials. The selected components of Schisandrin A, Schisandrin C, Schisandrin B, Amphotericin, Schisandrin A, and Schisandrin D in this study have certain biological activities in Schisandra chinensis medicinal materials, which can reflect the intrinsic quality of the medicinal materials. Among them, Schisandra ester A has stable chemical properties and is representative as an internal reference. By comparing the relative errors of the QAMS method and the external standard method, the results showed that there was no significant difference in the content determination of Schisandra chinensis between the established QAMS method and the external standard method, indicating that the established method has good credibility.
This study used a combination of fingerprint analysis and multiple evaluations to qualitatively and quantitatively evaluate the quality of Schisandra chinensis medicinal materials, which can provide reference for improving the quality standards of Schisandra chinensis medicinal materials.