Regulation of Antioxidant Expression in the Liver Tissue of Obese Rats Treated with Coriander Seed Ethanolic Extract: In Silico and In Vivo Studies

Background/Objectives: Obesity increases reactive oxygen species (ROS), thereby triggering oxidative stress. Coriander seeds contain polyphenolic compounds that act as natural antioxidants to reduce oxidative stress. Coriander seed ethanolic extract has been proven to decrease malondialdehyde and increase catalase activity in the liver of high-fat-diet-fed rats. Thus, coriander seeds are thought to protect against obesity-induced oxidative liver damage; however, their molecular mechanism has not been revealed. Nuclear factor erythroid 2-related factor 2 (Nrf2) and Forkhead Box O3 (FOXO3) are transcription factors involved in cellular antioxidant regulation (e.g., superoxide dismutase/SOD, glutathione peroxidase/GPx expression, and reduced glutathione/GSH) that are negatively regulated by Kelch-like ECH-associated Protein 1 (Keap1) and 14-3-3 protein to maintain cellular homeostasis. This study aimed to analyze the regulation of antioxidant expression through in silico and in vivo experiments. Methods: The in silico study assessed the potential of coriander seed ethanolic extract to inhibit Keap1 and 14-3-3 using molecular docking. Then, the drug-likeness, pharmacokinetics, and toxicity of the top three compounds were analyzed. Meanwhile, the in vivo study investigated how the coriander seed ethanolic extract impacted the level of Nrf2, FOXO3, and their downstream effectors (T-SOD, MnSOD, GPx, and GSH). The in vivo study involved five groups of rats with obesity induced by a high-fat diet that were fed with 100 mg/kgBW coriander seed ethanolic extract for 12 weeks. Results: The in silico tests revealed that shionoside b had the highest potential to inhibit Keap1 (ΔG = −8.90 kcal/mol; Ki = 298.01 nM) and 14-3-3 protein (ΔG = −6.85 kcal/mol; Ki = 9.46 µM). The in vivo tests showed that the Nrf2, FOXO3, MnSOD, and GPx mRNA expression was significantly different between the groups (p < 0.05). Meanwhile, T-SOD, MnSOD, GPx, and GSH activity were not significantly different between the groups (p > 0.05). Nrf2 was significantly correlated with FOXO3 as well as the T-SOD, MnSOD, and GPx activity, and FOXO3 was significantly correlated with the T-SOD, MnSOD, GPx, and GSH activity. Conclusions: In obese rats, coriander seeds tend to increase Nrf2 and FOXO3 expression, which is positively correlated with their downstream enzymatic and nonenzymatic antioxidant activity. This is possibly due to the interaction between the coriander seed phytoconstituents and protein inhibitors (Keap1 and 14-3-3), which contribute to the stability and nuclear mobilization of Nrf2 and FOXO3.