Study on toxicity/efficacy related substances and metabolic mechanism of Tripterygium wilfordii Hook. f based on O2LPS correlation analysis

Tripterygium wilfordii Hook. f (TwHF) has been used as a traditional Chinese medicine for the treatment of rheumatoid arthritis and nephritis for hundreds of years. Although the efficacy of TwHF in the treatment of RA is definite, its serious side effects and toxicity have also received close attention from domestic and international researchers, so the clinical application of TwHF has been controversial. Most of the current TwHF toxicity studies have been conducted with animals in normal body states, but ignore the effects in pathological states. In this study, we aimed to find out the material basis and metabolic mechanism of the "toxicity/effectiveness" of TwHF on rat kidneys in different body states by using two-way orthogonal partial least squares (O2PLS) method. In the present study, TwHF was extracted by reflux extraction method using ethanol as the extraction solvent. Firstly, the effects of TwHF on rat kidneys in different body states were first evaluated by detecting creatinine and urea nitrogen levels and morphological changes in kidney pathology identified the components of TwHF in rats in different body states using UPLC-Q-TOF/MS technique. Serum and urine metabolomics were used to search for biomarkers and metabolic pathways by which TwHF exerts renal injury and protection, and finally, O2PLS correlation analysis was used to correlate the components with renal protective and injury biomarkers. TwHF was found to have a protective effect on the kidney of RA rats and an injurious effect on the kidney of normal rats at a dose of 11.25 g/kg/d. The UPLC-Q-TOF/MS technique was used to identify 34 components in TwHF extracts; 23 components and 57 metabolites were identified in the administered rats. O2PLS screened three substances as both toxic and pharmacodynamic components of TwHF, namely 3,5-dimethoxyphenyl-2-propenl-ol, kaurane-16,19,20-triol, and demethylzeylasteral + O, and found that these three components may exert nephrotoxic effects via the nicotinic acid and nicotinamide metabolic pathways and nephroprotective effects via the tryptophan metabolic pathway. In this study, O2PLS analysis was used for the first time to combine biomarkers and components in vivo and found the material basis and metabolic mechanism of nephrotoxicity and efficacy of TwHF, which provided key clues for further study on the biological mechanism of toxicity and efficacy of TwHF.