Quantitative analyses of sennosides A and B in eight ethical bofutsushosan extract products.

Aim: Currently, no information regarding the sennosides A and B content is provided on bofutsushosan extract products for ethical use. In this study, sennosides A and B in bofutsushosan extract products from eight different pharmaceutical companies and those in bofutsushosan decoction were quantitatively analyzed. Additionally, since it has been reported that sennoside A is unstable to heat, the relationship between the different decoction times of Rhubarb and the total extracted amounts of sennosides A and B was investigated. Finally, nuclear magnetic resonance (NMR)‐based metabolomics analysis was performed on Rhubarb extracts to evaluate the variability in the quality of Rhubarb. Methods: Solutions of bofutsushosan extract products, bofutsushosan decoction, and Rhubarb decoction were subjected to solid‐phase extraction, and then were analyzed using HPLC. The five Rhubarb extracts prepared from five different lots were subjected to NMR‐based metabolomics analysis. Results: The quantities of sennosides A and B varied among the bofutsushosan extract products, with a maximum interproduct variation of approximately five‐fold. Sennosides A and B were not significantly unstable to heat up to 60 min. The five Rhubarb samples were classified into three independent clusters. Conclusion: It is recommended that the quantities of sennosides A and B in Kampo extract products, including Rhubarb, be described in the package insert. When preparing Rhubarb‐containing Kampo medicines, sennosides A and B decomposition can be ignored for decoction times of up to 60 min. Further studies on the biological activity of secondary metabolites other than sennosides A and B are necessary for Rhubarb quality control. [ABSTRACT FROM AUTHOR]