P-glycoprotein (P-gp) plays a crucial role in the protection of susceptible organs, by significantly decreasing the absorption/distribution of harmful xenobiotics and, consequently, their toxicity. Therefore, P-gp has been proposed as a potential antidotal pathway, when activated and/or induced. Knowing that xanthones are known to interact with P-gp, the main goal was to study P-gp induction or/and activation by six new oxygenated xanthones (OX 1-6). Furthermore, the potential protection of Caco-2 cells against paraquat cytotoxicity was also assessed. The most promising compound was further tested for its ability to increase P-gp activity ex vivo, using everted intestinal sacs from adult Wistar-Han rats. The oxygenated xanthones interacted with P-gp in vitro, increasing P-gp expression and/or activity 24 h after exposure. Additionally, after a short-incubation period, several xanthones were identified as P-gp activators, as they immediately increased P-gp activity. Moreover, some xanthones decreased PQ cytotoxicity towards Caco-2 cells, an effect prevented under P-gp inhibition. Ex vivo, a significant increase in P-gp activity was observed in the presence of OX6, which was selectively blocked by a model P-gp inhibitor, zosuquidar, confirming the in vitro results. Docking simulations between a validated P-gp model and the tested xanthones predicted these interactions, and these compounds also fitted onto previously described P-gp induction and activation pharmacophores. In conclusion, the in vitro, ex vivo, and in silico results suggest the potential of some of the oxygenated xanthones in the modulation of P-gp, disclosing new perspectives in the therapeutics of intoxications by P-gp substrates.
P-糖蛋白(P-gp)在保护易受损害器官方面发挥着关键作用,通过显著降低有害异物的吸收/分布,从而降低其毒性。因此,当P-gp被激活和/或诱导时,已被提议作为潜在的解毒途径。鉴于黄酮类化合物已知与P-gp相互作用,主要目标是研究六种新的含氧黄酮类化合物(OX 1-6)对P-gp的诱导和/或激活。此外,还评估了Caco-2细胞对百草枯细胞毒性的潜在保护作用。最有前途的化合物进一步被测试其在体外增加P-gp活性的能力,使用成年Wistar-Han大鼠的转出肠囊。这些含氧黄酮类化合物在体外与P-gp相互作用,增加P-gp表达和/或活性,在暴露后24小时。此外,在短时间培养后,几种黄酮类化合物被确定为P-gp激活剂,因为它们立即增加了P-gp活性。此外,一些黄酮类化合物减少了对Caco-2细胞的百草枯细胞毒性,这种效应在P-gp抑制下被阻止。在体外实验中,存在OX6时P-gp活性显著增加,这种增加被一种模型P-gp抑制剂zosuquidar选择性地阻断,从而证实了体外实验结果。通过验证的P-gp模型和被测试的黄酮类化合物之间的对接模拟预测了这些相互作用,这些化合物也符合先前描述的P-gp诱导和激活药效团。总之,体外、体内和计算机模拟结果表明,一些含氧黄酮类化合物在调节P-gp方面具有潜力,揭示了P-gp底物中毒治疗中的新视角。