Aristolochic acid I (AAI)是一种已经被证实的肾毒素和人类致癌物质。细胞质NAD(P)H醌氧还酶1（NQO1）在亚硝基还原过程中发挥着重要作用，导致产生aristoloactam和AA-DNA加合物。强效的NQO1抑制剂双香豆素的应用受到其作为抗凝剂的危及生命的副作用和随之而来的出血并发症的限制。由于市场上依然存在含有AAI的传统药物，迫切需要新型NQO1抑制剂来减轻AAI暴露的毒性。在本研究中，我们采用全面的二维NQO1生物色谱法筛选能够与NQO1蛋白结合的候选化合物。从黄芩中筛选出了四种化合物，即黄芩黄酮II（SFII）、儿茶素A、黄芩素和异黄酮。其中，SFII是最有前途的NQO1抑制剂，具有结合亲和力（KD = 4.198μmol/ L）和抑制活性（IC50 = 2.87μmol/ L）。在人正常肝细胞系L02和人肾近曲小管上皮细胞系HK-2中，SFII显著减轻了AAI引起的DNA损伤和细胞凋亡。在成年小鼠中，口服SFII剂量依赖性地改善了AAI引起的肾纤维化和功能障碍。在幼年小鼠中，口服SFII抑制了AAI引起的肝细胞癌发生。此外，对成年小鼠进行SFII给药在短期内并不影响凝血功能。总之，SFII已被确认为一种新型NQO1抑制剂，可以阻止AAI对肾和肝的风险，而不会产生明显的副作用。© 2023。作者（通过上海中医药大学中国科学院和中国药理学学会独家许可）。

Aristolochic acid I (AAI) is a well established nephrotoxin and human carcinogen. Cytosolic NAD(P)H quinone oxidoreductase 1 (NQO1) plays an important role in the nitro reduction of aristolochic acids, leading to production of aristoloactam and AA-DNA adduct. Application of a potent NQO1 inhibitor dicoumarol is limited by its life-threatening side effect as an anticoagulant and the subsequent hemorrhagic complications. As traditional medicines containing AAI remain available in the market, novel NQO1 inhibitors are urgently needed to attenuate the toxicity of AAI exposure. In this study, we employed comprehensive 2D NQO1 biochromatography to screen candidate compounds that could bind with NQO1 protein. Four compounds, i.e., skullcapflavone II (SFII), oroxylin A, wogonin and tectochrysin were screened out from Scutellaria baicalensis. Among them, SFII was the most promising NQO1 inhibitor with a binding affinity (KD = 4.198 μmol/L) and inhibitory activity (IC50 = 2.87 μmol/L). In human normal liver cell line (L02) and human renal proximal tubular epithelial cell line (HK-2), SFII significantly alleviated AAI-induced DNA damage and apoptosis. In adult mice, oral administration of SFII dose-dependently ameliorated AAI-induced renal fibrosis and dysfunction. In infant mice, oral administration of SFII suppressed AAI-induced hepatocellular carcinoma initiation. Moreover, administration of SFII did not affect the coagulation function in short term in adult mice. In conclusion, SFII has been identified as a novel NQO1 inhibitor that might impede the risk of AAI to kidney and liver without obvious side effect.© 2023. The Author(s), under exclusive licence to Shanghai Institute of Materia Medica, Chinese Academy of Sciences and Chinese Pharmacological Society.