Simultaneously screening multiple UGT1A1 inhibitors from Polygonum multiflorum root using ultrafiltration LC–MS

Liver injury induced by Polygonum multiflorum root (PMR) is an immediate issue requiring global attention. UDP-glucuronosyltransferase 1A1 (UGT1A1) inhibitors are suspected to additively contribute to the hepatotoxicity of PMR. This study was deliberately designed to simultaneously screen UGT1A1 inhibitors from PMR, and their co-contribution to hepatotoxicity was determined. Using ultrafiltration coupled to LC–MS method, four compounds, namely cis-2,3,5,4′-tetrahydroxystilbene-2-O-β-glucoside, trans-2,3,5,4′-tetrahydroxystilbene-2-O-β-d -glucoside, emodin-8-O-β-d -glucoside, and emodin, were screened, exhibiting the in vitro inhibitory activities against UGT1A1 with IC₅₀ values of 76.23, 18.70, 62.18, and 34.02 μM, respectively. The varying activities of the screened UGT1A1 inhibitors were demonstrated by performing a molecular docking simulation. Finally, zebrafish larvae and mice assays demonstrated that the UGT1A1 inhibitors co-contributed to the hepatotoxicity of PMR. These findings are conducive to understand the role of UGT1A1 inhibitors in PMR-induced hepatotoxicity.