Investigation of the detoxification mechanism of ZhiCaoWu-HeZi compatibility via CYP450 enzyme modulation

Junxuan ZhuMing AnWeiting WangJingjing GuoMengting ChenLonglong FangCen WangDong Zhang^*Guodong Wu^*

• Baotou Medical College, Baotou, China

Background: CaoWu (Aconiti kusnezoffii Radix) and HeZi (Terminalia chebula Retz) are widely used herbs in Mongolian medicine. Owing to the high toxicity of CaoWu, HeZi is frequently co-administered to mitigate its toxic effects, particularly in CaoWu-containing formulations. While the detoxification mechanisms of the CaoWu–HeZi combination have been extensively investigated, its modulation of cytochrome P450 (CYP450) enzymes remains largely unexplored. Aim: This study aimed to investigate the effects of ZhiCaoWu (Aconiti kusnezoffii Radix Preparata)–HeZi compatibility on CYP450 enzyme activity and its potential detoxification mechanism, both in vivo and in vitro. Methods: The effects of ZhiCaoWu–HeZi compatibility on CYP450 enzyme activity were evaluated using the cocktail probe drug method and quantitative reverse transcription PCR (RT-qPCR). These analyses were conducted in conjunction with pathological and biochemical indices to elucidate the detoxification mechanism. Results: Pathological and biochemical indices demonstrated that HeZi mitigated ZhiCaoWu hepatotoxicity, with the most pronounced attenuation observed in the 1:3 ZhiCaoWu–HeZi combination. The in vivo results indicated that ZhiCaoWu inhibited CYP1a2, CYP2d2, CYP3a1, and CYP2c11 activities as evidenced by an increase in AUC(0-t), AUC(0-∞)) and Cmax of theophylline, metoprolol, testosterone, and diclofenac. Additionally, ZhiCaoWu prolonged the t1/2 z and reduced the CLz/F of these substances. Following co-administration with HeZi, the AUC(0-t), AUC(0-∞), and Cmax values of these substrates were significantly reduced, whereas the t1/2 z values were notably shorter and the CLz/F values significantly higher. These findings suggest that the combination of HeZi and ZhiCaoWu can induce the activities of CYP1a2, CYP2d2, CYP3a1, and CYP2c11. The metabolizing clearance rates of theophylline, metoprolol, testosterone, and diclofenac were reduced. However, after pairing with HeZi, the metabolic clearance rates of these substrates were significantly enhanced, suggesting that HeZi-ZhiCaoWu compatibility induces these CYP450 enzymes. These in vitro findings were consistent with the in vivo results. RT-qPCR analysis of liver tissues showed that the mRNA expression levels of CYP1a2, CYP2d2, CYP3a1, and CYP2c11 were downregulated in the ZhiCaoWu group. However, after co-administration with HeZi, the mRNA expression was upregulated, aligning with the previous pharmacokinetic findings. Conclusions: HeZi may facilitate detoxification through dose-dependent induction of CYP1A2, CYP2D6, CYP3A4, and CYP2C9, thereby accelerating toxic substance metabolism in CaoWu.