Study on the processing transformation law of CATR and ATR in Xanthii Fructus and the metabolomics mechanism of their transformation products in LO2 cells

The thermal processing of Xanthii Fructus is known to attenuate its hepatotoxicity. Carboxyatractyloside (CATR) and atractyloside (ATR), the primary toxic constituents, exhibit differential toxicity, with CATR being more potent. While the conversion of CATR to the less toxic ATR during processing is believed to underlie this toxicity reduction, the precise conversion dynamics and associated molecular mechanisms remain to be fully elucidated. This study aimed to elucidate the mechanisms responsible for the reduced hepatotoxicity of Xanthii Fructus following sand-frying. We employed an integrated approach combining ultra-high-performance liquid chromatography (UHPLC), metabolomics, and network pharmacology to investigate the differences in chemical composition and toxicological pathways between the crude and processed herb. The UHPLC method was used to establish fingerprint of Xanthii Fructus from different origins before and after processing, and the contents of CATR and ATR were determined. The thermal conversion and comparative toxicity of these compounds were subsequently evaluated. Cellular metabolomics was performed to identify differential metabolites and perturbed pathways, while network pharmacology and molecular docking were used to predict and validate primary protein targets and their binding affinities. The attenuated hepatotoxicity was primarily attributed to the thermal conversion of CATR to ATR. Metabolomic analysis revealed that CATR significantly impacted alanine, aspartate, and glutamate metabolism and the TCA cycle, whereas ATR predominantly affected pyrimidine, arginine, and proline metabolism. Glutathione metabolism was a common pathway for both. Molecular docking simulations showed that CATR exhibited a stronger binding affinity than ATR towards key protein targets (DSS, DESG2, and ENTPD1), which is consistent with its greater toxicity. • Processing reduces toxicity by converting the more toxic CATR into its less toxic analog, ATR, mitigating hepatotoxicity. • Metabolomics shows CATR disrupts alanine/aspartate/glutamate and TCA; ATR affects pyrimidine/arginine/proline pathways. • Glutathione metabolism is a shared pathway for both CATR and ATR, indicating oxidative stress injury in hepatotoxicity. • Molecular docking shows CATR binds key proteins more strongly than ATR, explaining its higher toxicity.