Evaluation of New Processing Techniques for Pinellia ternata Based on Quality Consistency Before and After Processing
Pinellia Rhizoma (PR) is a dried tuber of Pinellia ternata (Thunb.) Breit, a plant in the Araceae family. It has the effects of drying dampness, resolving phlegm, reducing nausea and vomiting, and dispersing lumps. It is one of the commonly used traditional Chinese medicines in clinical practice. Pinellia Rhizoma Praeparatum cum Aluminum (PRPA) is a processed medicinal herb made by soaking or boiling Pinellia ternata in alum, which enhances its ability to dispel cold and phlegm compared to raw Pinellia ternata. The quality transfer relationship between the two can be summarized as follows: after processing raw Pinellia ternata, the content of free organic acids increases, while the content of total sugars, total alkaloids, and some nucleosides and proteins decreases. However, there are few reports on the changes of single components in organic acids and nucleosides, and there is a lack of systematic analysis on the changes in the main components of Pinellia ternata and Pinellia ternata.
The preparation method of Pinellia ternata is relatively fixed. In the 2015 edition of the Pharmacopoeia of the People’s Republic of China (hereinafter referred to as the “Chinese Pharmacopoeia”), Pinellia ternata was soaked in an 8% alum solution. The 2020 edition of the Pharmacopoeia added boiling Pinellia ternata on this basis. But currently, in addition to soaking and boiling with alum to produce Qingbanxia decoction pieces, there are also companies attempting to use alum steaming to improve the production process of Qingbanxia decoction pieces.
The high-temperature steaming method is favored as an emerging processing technique due to its controllable process, time-saving and labor-saving, and good detoxification effect on toxic medicinal materials. According to research, there is no record of steaming method in the processing methods of Pinellia ternata throughout history. Currently, some scholars have studied the steaming method of Pinellia ternata processing. Mo, Li, and others have established a stable high-pressure steaming process for processing Pinellia ternata; Xiao processed Qingbanxia using steaming method, and compared with soaking Qingbanxia, its total organic acid content increased, the content of calcium oxalate needle crystals significantly decreased, and the limit of alum met the pharmacopoeia standards. However, there are still many questions that need to be answered regarding the steaming method, such as the stability of the quality of Qingbanxia obtained by steaming, the efficacy of Qingbanxia obtained by steaming, and the consistency of the quality of Qingbanxia obtained by steaming with that of soaked and boiled Qingbanxia.
This study processed Pinellia ternata medicinal materials from different origins into Qingbanxia decoction pieces by soaking, boiling, and steaming methods. Using the content determination method established by the team in the early stage, the quality transfer relationship between raw Pinellia ternata and Qingbanxia was analyzed from the aspects of extracts, organic acids, polysaccharides, nucleosides, and proteins. The consistency of Qingbanxia obtained by steaming, soaking, and boiling methods in terms of quality was explored, laying a foundation for further research on the pharmacological and detoxification mechanisms of Qingbanxia.

ANXIA
Starting from the transmission of quality components, this study compared the differences among three processing methods of Pinellia ternata and evaluated the steaming method as a new processing technique. Based on the exploration of the influencing factors of quality transfer mentioned above, the key step that distinguishes steaming from immersion and boiling methods should be steaming. The high temperature and lack of direct contact with water in the steaming step directly lead to the retention and increase of extracts, oxalic acid, and polysaccharides. Based on all the testing indicators and multiple analysis methods, it can be seen that the steaming method has a significant impact on the internal quality of the processed products, resulting in significant differences from traditional Qingbanxia. Whether the processed products can be called “Qingbanxia” remains to be discussed.
However, the quality indicators of Banxia and Qingbanxia have not been determined yet, and the 2020 edition of the Chinese Pharmacopoeia only uses extracts as quality testing indicators. Citric acid, L-malic acid, adenine, and other components that are positively correlated with the content of the extract are also important positive components of the first and second principal components in principal component analysis. This result suggests the possibility of using citric acid, L-malic acid, adenine and other components to evaluate the quality of raw Pinellia ternata. At the same time, according to the currently established quality evaluation method, steaming method shows better quality than soaking and boiling method for processed products. Moreover, by comparing the yield of decoction pieces and the limit of alum, the steaming method has significant advantages over the boiling method in terms of production efficiency and safety.
The consistency of quality transfer between decoction pieces processed by soaking and boiling methods is good, but there is a significant difference in quality between decoction pieces processed by steaming method. However, there is currently no comparison of the clinical effects of the three processing methods on the processed products. The cooking method is included in the local Chinese herbal medicine decoction standards (such as Beijing, Inner Mongolia, Jilin, Henan, etc.) and the 1963 edition of the Chinese Pharmacopoeia, but there are few reports on the steaming method, and it has not been included in the pharmacopoeia or local standards. According to the results of this study, steaming method has advantages in terms of its component content and stability, and whether it can be used as a formal processing method for loading still needs further in-depth research.
Steaming method can be used to shorten the processing time due to high temperature, and in this study, it showed a more stable trend of content change rate, which has great potential in saving time and labor. The next step is to further optimize the steaming process: can the soaking time be shortened, and can high-temperature steam be used simultaneously to achieve a penetrating effect. In addition, the inherent content of steamed processed products differs from traditional techniques. Based on these differences in ingredients, the pharmacological effects and clinical efficacy of Qingbanxia processed products can be compared with traditional Qingbanxia processed products to explore the pharmacological mechanism of Qingbanxia and provide a basis for elucidating the scientific nature of processing.