Toxicological profile and hepatotoxic mechanism of Caulis sinomenii for safe application in chickens

Caulis sinomenii (C. sinomenii) has been widely used to treat rheumatoid arthritis and multiple types of kidney diseases and has the potential to treat and prevent avian gout, but its safety has not been fully evaluated. In this study, the ethanol extract of C. sinomenii (CS) was obtained via an optimized method, and its composition, bioactive constituents and plasma concentration were investigated via high-performance liquid chromatography (HPLC). The toxicological profile of CS in chickens was investigated via acute and subacute toxicity experiments, including daily examination, blood tests and histopathological evaluation. The toxicity mechanism was analysed via network toxicology. Under the optimized conditions of 70.35% ethanol, a 20.26:1 ml/g liquid‒solid ratio, an extraction temperature of 81.61°C and an extraction time of 154.71 min, 203.04 mg/g of CS was obtained from C. sinomenii. Seven bioavailable components among the 13 compounds detected in the CS entered the bloodstream. The median lethal dose (LD50) of CS was 1018.83 mg/kg, with a safe dose of ≤ 127.35 mg/kg and a toxic dose of ≥ 254.71 mg/kg after oral administration. Structural and functional damages to the intestinal tract and liver were the main toxic effects, which might be attributed to 16‑epi-isositsirikine, magnograndiolide and michelenolide acting on Toll-like receptors and the MAPK, gap junction and apoptosis signalling pathways via the key targets HTR2A, NTRK1 and TLR7. In summary, C. sinomenii is hypotoxic after oral administration and has a favourable safety profile in chickens. However, excessive (≥ 254.71 mg/kg) and long-term administration should be avoided, as multiple components that act on multiple signalling pathways can cause structural and functional damage to the liver.