Feasibility of vinegar processing of toxic herbs in Shi-Zao-Tang: toxicity reduction, efficacy preservation in malignant ascites rats and underlying pharmacodynamic mechanisms.

Background: Shi-Zao-Tang (SZT), a classical formula of Traditional Chinese Medicine orally used for treating malignant ascites effusion (MAE), is made by mixing the powder of Kansui Radix (KR), Euphorbiae Pekinensis Radix (EPR) and fried Genkwa Flos with the decoction of Jujubae Fructus. According to Chinese Pharmacopoeia, vinegar-processed KR and EPR should be used in oral administration. However, toxicity and efficacy of SZT containing vinegar-processed KR and EPR (VSZT) versus SZT in MAE rats, and the potential mechanisms of VSZT against MAE, remain unknown. Here, we comparatively studied the quality, toxicity and efficacy of SZT and VSZT, and explored the potential mechanisms of VSZT against MAE.

Methods: Main components in SZT and VSZT were quantified by liquid chromatographic coupled with triple quadrupole tandem mass spectrometry. The intestinal toxicity and efficacy of SZT and VSZT were comparatively investigated in MAE rats. Specially, intestinal toxicity was evaluated by intestinal barrier function, histopathology and oxidative damage. The efficacy was investigated by amount of ascites, indices in excretion, intestinal motility and inflammation. The potential mechanisms of VSZT treats MAE were explored through integration of metabolomics, 16S rRNA and Western blotting analysis.

Results: VSZT contains less 3-O-EZ and more ingenol than SZT. VSZT showed reduced intestinal toxicity than SZT in MAE rats. Both SZT and VSZT indiscriminately decreased the amount of ascites and ascitic inflammatory cytokines, promoted urination and defecation, increased fecal water content and intestinal motility. VSZT reversed endogenous metabolism and gut microbiota disorders, down-regulated colonic cAMP, PKA, p-CREB/CREB and AQP3, as well as mesenteric p-VEGFR2/VEGFR2, p-SRC/SRC, and p-VE-cadherin/ VE-cadherin in MAE rats.

Conclusion: VSZT preserved the efficacy of SZT on MAE with lower intestinal toxicity. VSZT increased water excretion and decreased MAE formation to alleviate MAE through regulating gut microbiota, restoring tryptophan and tyrosine metabolism disorders, and affecting cAMP-PKA-CREB-AQP3 and VEGFA-VEGFR2-SRC-VE-cadherine pathway.