Tehran University of Medical Sciences Acta Biochimica Iranica 0001-5261 1 2 2023 11 11 90 95 Farideh Jafari-Hafshejani Department of Biochemistry, Islamic Azad University of Falavarjan, Falavarjan, Iran Kahin Shahanipour Department of Biochemistry, Islamic Azad University of Falavarjan, Falavarjan, Iran Mansoureh Kazemipiur Faculty of literature and human sciences, Islamic Azad University of Shushtar, Shushtar, Iran. Faezeh Seif Department of Basic sciences, Shoushtar Faculty of Medical sciences, Shoushtar, Iran. Alireza Jafari Hyperlipidemia Research Center, Department of Clinical Biochemistry, Faculty of Medicine, Ahvaz Jundishapur University of Medical, Ahvaz, Iran Mojgan Noor Behbahani Hyperlipidemia Research Center, Department of Clinical Biochemistry, Faculty of Medicine, Ahvaz Jundishapur University of Medical, Ahvaz, Iran Hossein Babaahmadi-Rezaei Hyperlipidemia Research Center, Department of Clinical Biochemistry, Faculty of Medicine, Ahvaz Jundishapur University of Medical, Ahvaz, Iran 2023 11 11 Objectives: The endothelium constitutes a significant part of the vasculature. Oxidative stress, an imbalance between the generation of reactive oxygen species (ROS) and the antioxidant defense system, contributes to the impairment of endothelial function. ROS regulate several signaling pathways, such as transforming growth factor β (TGF-β) and nuclear factor kappa B (NF-κB). This study aimed to investigate the effects of curcumin, a polyphenol with antioxidant properties, on these two molecules in endothelial cells treated with hydrogen peroxide (H2O2). Methods: Cultured Bovine aortic endothelial cells (BAECs) were treated with different concentrations of H2O2 (20 µM, 40 µM, and 200μM) for 1 and 24 hours in the absence and presence of curcumin. TGF-β expression was detected by quantitative real-time PCR analysis, and phosphorylation of NF-κB-p65 was examined by western blot. Results: H2O2 up-regulates TGF-β mRNA expression and induces the phosphorylation of the p65 subunit of NF-kB in a dose-dependent manner in BAECs. Curcumin inhibited both H2O2-stimulated TGF-β expression and phosphorylation of NF-κB-p65 in these cells. Conclusion: The findings demonstrate that curcumin reduces TGF-β mRNA expression and inhibits NFκB-p65 phosphorylation in endothelial cells. https://abi.tums.ac.ir/index.php/abi/article/view/33 https://abi.tums.ac.ir/index.php/abi/article/download/33/20