Optimization of the traditional processing method for precision detoxification of CaoWu through biomimetic linking kinetics and human toxicokinetics of aconitine as toxic target marker

Abstract

Ethnopharmacological relevanceCaoWu (Aconiti Kusnezoffii Radix), well known for its high toxicity leading to fatal ventricular arrhythmias, is detoxified by HeZi (Terminalia Chebula Retz) decoction to prepare ZhiCaoWu (Aconiti Kusnezoffii Radix Preparata) as one part of ingredients of NaRu-3 pill which is used for the treatment of rheumatoid arthritis (RA). Aconitine (AC) is a highly toxic alkaloid of CaoWu and it is used as toxic target marker for the quality control (QC) of ZhiCaoWu. In the traditional processing method, the vanish of astringent or spicy feeling in tongue is the important detoxification indicator of ZhiCaoWu. However, how CaoWu is detoxified to ZhiCaoWu and whether the appropriate content of AC in ZhiCaoWu can be efficiently perceived after the empirical detoxification still lack factual basis. Aim of the studyThe present study aimed to optimize the traditional processing method for precision detoxification of CaoWu through biomimetic linking kinetics and human toxicokinetics (TK) of AC, with a view of providing insights into the changes of toxic target marker. Materials and methodsCaoWu medicinal slices (Mes) and coarse powder (Cop) were processed by blank HeZi decoction through the soaking method for 7 days. High-performance liquid chromatography (HPLC) was used for the analysis of the samples. The acidity of blank HeZi decoction and HeZi processing decoction was directly determined by pH meter. The non-compartment analysis (NCA) was used to have an intuitive appreciation for AC and pH changes in HeZi processing decoction while the compartment model method was used to build the biomimetic linking kinetics model with the covariate. The inter-species scaling of animal TK parameters was conducted to predict human AC TK profiles. The possible uptake ways of AC (rapid-release or extended-release) for humans were attempted to assess the poisoning risk of AC in NaRu-3 pill. Based on the target content of AC in ZhiCaoWu, the biomimetic linking kinetics model was explored to optimize the traditional processing detoxification method of CaoWu. The assays of determining inflammatory cytokines in lipopolysaccharides (LPS)-induced RAW264.7 cells were performed to investigate the inflammatory modulation effects of AC in vitro. ResultsZhiCaoWu was prepared by eliminating redundant AC in CaoWu through the repeatable replacement of HeZi processing decoction in which its acidity (pH) was affected. AC-pH changes in HeZi processing decoction were adequately depicted by a biomimetic linking kinetics model whose predictive power was determined by comparing the predictions of AC in ZhiCaoWu with the reported data. Rapid-release AC at the converted dose of 111.1 and 417.6 μg (0.011 and 0.042% of AC in NaRu-3 pill) reached maximum blood concentrations of 26.1 and 98.1 ng/mL at 0.3 h, in comparison with minimum human lethal concentration (100 ng/mL). Achieving the target content of AC (0.04%) in ZhiCaoWu or AC (0.011%) in NaRu-3 pill to precisely control the poisoning risk, the potential optimized protocols were that the processing time at 0.2–0.8% of AC in CaoWu was 2.0–4.4 days for Cop and 2.7–6.2 days for Mes. Correspondingly, pH values in HeZi processing decoction were 3.95 and 3.77 for Cop and Mes, respectively. Meanwhile, Lipopolysaccharides (LPS)-induced RAW264.7 cells were exposed to 0, 20, and 200 μM of AC for 12 h and AC at 20 μM enhanced the levels of IL-6, IL-10 and TNF-α. ConclusionsThus, for the first time, a biomimetic linking kinetics model was built to optimize the traditional detoxification method. Moreover, pH changes could be developed as surrogate endpoint for guiding the processing detoxification of CaoWu. Notably, setting the content limit of AC (0.011%) was very rational to control the poisoning risk of NaRu-3 pill. In addition, it was possible that there existed the more complex mechanisms of AC for inflammatory modulation in vitro.