Abstract
Background:
Potassium bromate (KBrO3) is a potent oxidizing agent that can initiate the generation of free radicals through xenobiotic metabolic pathways, according to more research. This chemical disturbs cellular redox balance, causing structural and functional damage to particular tissues and macromolecules.

Aim:
This study explored the therapeutic impact of a blend of Ginkgo biloba extract and metformin, delivered via gold nanoparticles (AuNPs), in reducing the toxicity of KBrO3 in the kidneys.

Methods:
Rats were categorized into eight groups: a control group, a group receiving G. biloba extract with metformin, a group treated with AuNPs, a group with G. biloba extract and metformin delivered via AuNPs, a KBrO3 group, a KBrO3 group combined with G. biloba extract and metformin, and a KBrO3 group treated with both G. biloba extract and metformin on AuNPs.

Results:
KBrO3 administration led to a notable increase in levels of creatinine, urea, and uric acid. KBrO3 caused glomeruli shrinkage, expansion of the capsular space, and tubular damage at the histopathological level, and there was a loss of brush borders in the proximal convoluted tubule, an abundance of vacuoles, and glomerular tubules with irregular basement membranes exhibiting significant thickening at the ultrastructural level. Additionally, it increased malondialdehyde, nitric oxide, and reduced superoxide dismutase, and catalase compared to the normal control group.

Conclusion:
Treatment with G. biloba extract and metformin, and with G. biloba extract and metformin encapsulated in AuNPs reduced the damages caused by KBrO3 in the histopathological and ultrastructural levels of the kidney. Treatment with G. biloba extract and metformin and G. biloba extract and metformin encapsulated in AuNPs improved kidney function tests and kept oxidative stress and antioxidant markers in check. However, G. biloba extract and metformin encapsulated in AuNPs worked better as a treatment option than G. biloba extract and metformin. In conclusion, treatment with G. biloba extract and metformin and with G. biloba extract and metformin encapsulated in AuNPs showed good treatment options against KBrO3induced-nephrotoxicity in the rat model.

Key words: Ginkgo biloba extract, Gold nanoparticles, Metformin, Nephrotoxicity, Potassium bromate