The flavonoid 6-hydroxyflavone prevention of cisplatin-induced nephrotoxicity

Inhibitory interaction of flavonoids with organic cation transporter 2 and their structure-activity relationships for predicting nephroprotective effects

Organic cation transporter 2 (OCT2) is mainly responsible for the renal secretion of various cationic drugs, closely associated with drug-induced acute kidney injury (AKI). Screening and identifying potent OCT2 inhibitors with little toxicity in natural products in reducing OCT2-mediated AKI is of great value. Flavonoids are enriched in various vegetables, fruits, and herbal products, and some were reported to produce transporter-mediated drug-drug interactions. This study aimed to screen potential inhibitors of OCT2 from 96 flavonoids, assess the nephroprotective effects on cisplatin-induced kidney injury, and clarify the structure-activity relationships of flavonoids with OCT2. Ten flavonoids exhibited significant inhibition (>50%) on OCT2 in OCT2-HEK293 cells. Among them, the six most potent flavonoid inhibitors, including pectolinarigenin, biochanin A, luteolin, chrysin, 6-hydroxyflavone, and 6-methylflavone markedly decreased cisplatin-induced cytotoxicity. Moreover, in cisplatin-induced renal injury models, they also reduced serum blood urea nitrogen (BUN) and creatinine levels to different degrees, the best of which was 6-methylflavone. The pharmacophore model clarified that the aromatic ring, hydrogen bond acceptors, and hydrogen bond donors might play a vital role in the inhibitory effect of flavonoids on OCT2. Thus, our findings would pave the way to predicting the potential risks of flavonoid-containing food/herb-drug interactions in humans and optimizing flavonoid structure to alleviate OCT2-related AKI.

Salvianolic Acid C Protects against Cisplatin-Induced Acute Kidney Injury through Attenuation of Inflammation, Oxidative Stress and Apoptotic Effects and Activation of the CaMKK-AMPK-Sirt1-Associated Signaling Pathway in Mouse Models

Acute kidney injury (AKI) is a sudden reduction in kidney activity and has a high mortality rate. Salvianolic acid C (SAC), one of the main polyphenolic components of Salvia miltiorrhiza, displays significant pharmacologically active effects. An animal model of cisplatin-induced kidney injury was used to study the potential of SAC to improve AKI. First, SAC was administered intraperitoneally in mice for 10 consecutive days, and then cisplatin was administered intraperitoneally on day 7 to establish a nephrotoxicity mouse model. SAC mitigated renal histological changes, blood creatinine (CRE) and blood urea nitrogen (BUN) production and the levels of inflammatory mediators in the cisplatin-induced AKI. Furthermore, malondialdehyde (MDA) levels were reduced and glutathione (GSH) was increased after intraperitoneal injection (i.p.) administration of SAC. In addition, based on Western blot data, SAC reduced the expression of inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) activation in mouse renal tissues. Finally, SAC diminished the level of TLR-4 expression and enhanced the production of several antioxidative enzymes (superoxidase dismutase (SOD1), glutathione peroxidase (GPx3), catalase, nuclear-factor-erythroid-2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1)), Sirtuin 1 (Sirt1), p-AMP-activated protein kinase (AMPK) and p-Ca²⁺/calmodulin-dependent protein kinase kinase (CaMKK). In addition, Sirt1 inhibition (EX 527) inverted the effect of SAC against cisplatin-induced nephrotoxicity. Collectively, SAC provides a therapeutic target with promising clinical potential after cisplatin treatment by attenuating oxidative stress and inflammation.