Herb pairs containing Curcumae Rhizoma (Ezhu): A review of bio-active constituents, compatibility effects and t-copula function analysis

Ethnopharmacological relevance: An herbal pair is a classic form of clinical dispensing in Traditional Chinese Medicine (TCM), often used in prescriptions to enhance the effect or reduce potential side effects. It is the smallest component unit of Chinese medicine prescription and an essential bridge between Chinese medicine and prescription. Curcumae Rhizoma (called Ezhu in Chinese) is a representative TCM herb that promotes blood circulation and removes blood stasis. It has been used in Chinese medicine for thousands of years. Ezhu is generally used in clinical applications as a part of a "drug pair" to treat heartburn, stomach pain, tumour, amenorrhea and abdominal pain caused by blood stasis, qi stagnation and injury. Aims of the review: This review aims to summarize the latest and comprehensive situation of the biological ac-tivity and clinical application of drug pairs containing Ezhu, find the law of Ezhu compatibility application, and discuss the rationalization of Ezhu drug compatibility. For Ezhu, herb pairs to provide a theoretical basis for clinical research in TCM and serve as a research foundation for developing new drugs. Materials and methods: Using a self-built prescription database and Apriori algorithm for association rule mining. A systematic search for studies on herb pairs containing Ezhu was carried out by using the internet databases of PubMed, CNKI, Baidu Scholar, Google Scholar and Web of Science, as well as other relevant textbooks, reviews and documents (e.g. Chinese Pharmacopoeia, 2020 edition, Chinese herbal classic books and PhD and MSc theses, etc.). Among them with keywords including "Curcumae Rhizoma", "Ezhu", "herb pairs", "clinical application", etc. and their combinations. Moreover, the t-copula function was used to analyse the dose-coupling effect of five drug pairs, including Ezhu. Results: The preliminary statistical analysis retrieved Ezhu prescriptions from self-built prescription database and internet databases. The results showed that the compatibility frequency of Ezhu with the other five Chinese medicines was high. Most of these selected herbal combinations are used to treat internal diseases. In this paper, the progress of the ethnopharmacology of Ezhu was reviewed, emphasizing the changes in bioactive components and compatibility of Chinese traditional medicine combinations such as Ezhu and Astragalus Curcuma (Spar-ganium stoloniferum Buch.-Ham; called Sanleng in Chinese), Ezhu and Astragali Radix (Astragalus membranaceus (Fisch.) Bge. var. mongholicus (Bge.) Hsiao, Astragalus membranaceus (Fisch.) Bge.; called Huangqi in Chinese). Some other varieties, such as Ezhu and Rhizoma Chuanxiong (Ligusticum chuanxiong Hort.; called Chuanxiong in Chinese), Trionycis Carapax (Trionyx sinensis Wiegmann; called Biejia in Chinese), and Coptidis Rhizoma (Coptis chinensis Franch., Coptis deltoidea C. Y. Cheng et Hsiao, Coptis teeta Wall.; called Huanglian in Chinese), are also recorded in ancient books but rarely researched. The dose of Ezhu is strongly correlated with the amount of Sanleng, Huangqi, Biejia, Chuanxiong and Huanglian, respectively. Furthermore, there was a positive correlation between them. Conclusions: The bioactive components and compatibility effects of Ezhu herb pairs were studied in detail using data mining and t-copula function analysis. Ezhu and Astragalus Curcuma (Sanleng) mainly treat gynecological disorders by activating blood circulation and relieving congestion. Ezhu and Astragali Radix (Huangqi) drug pair and Ezhu and Trionycis Carapax (Biejia) drug pair are all commonly used in the clinical treatment of tumors, the former is mainly used clinically for the treatment of digestive tract-related inflammation and tumors, liver cancer and gynecological tumors, and the latter is commonly used for the treatment of malignant tumors, such as liver cancer and mammary cancer.