Mechanisms of Pesticide Toxicity in Fish: Insights Into the Ameliorative Role of Plant-Derived Compounds—A Review

Pesticide contamination in aquatic environments poses severe risks to fish health, causing oxidative stress, immunosuppression, endocrine disruption, and neurotoxicity. These effects result from the accumulation of reactive oxygen species (ROSs), enzyme inhibition, and damage to physiological systems. Plant-derived compounds and phytochemicals, such as polyphenols, flavonoids, alkaloids, saponins, and terpenoids, offer a sustainable strategy to mitigate these toxic effects due to their antioxidative, anti-inflammatory, immunomodulatory, and detoxifying properties. Phytochemicals protect fish by scavenging ROS, upregulating antioxidant enzymes (i.e., superoxide dismutase, catalase, and glutathione peroxidase), and enhancing detoxification pathways (i.e., cytochrome P450 enzymes and glutathione-S-transferase). They also reduce inflammation by inhibiting pro-inflammatory cytokines and NF-κB signaling and restore immune function by improving phagocytic activity and lymphocyte proliferation. Additionally, phytochemicals counter endocrine disruption and neurotoxicity by stabilizing hormone levels and preventing the accumulation of acetylcholine in neural pathways. Incorporating plant-derived compounds into fish diets can reduce oxidative damage, strengthen immune responses, and enhance fish resilience to pesticide exposure. This review emphasizes the potential of phytochemicals to promote safer, more sustainable aquaculture practices. Further research on dosage and application methods could lead to significant advancements in aquatic toxicology and fish health management.