Biochemical, Genotoxic and Somatic responses of Oreochromis Niloticus Exposed to Enalapril Maleate in Water.

Pharmaceutical residues are increasingly detected in aquatic environments; however, information regarding the ecotoxicological effects of antihypertensive drugs such as enalapril maleate remains limited, particularly in fish. This study aimed to evaluate the effects of aqueous exposure to EM on somatic, biochemical, and genotoxic biomarkers in Oreochromis niloticus under controlled laboratory conditions. A 21-day subchronic bioassay was conducted using fish exposed to EM-contaminated water at nominal concentrations of 100, 500, 1000, and 2000 µg/L, alongside a control group. Genotoxic effects were evaluated using the comet assay and micronucleus test, while biochemical biomarkers - including acetylcholinesterase, catalase, glutathione S-transferase, and lipid peroxidation - were assessed to investigate oxidative stress and potential neurotoxicity. Somatic condition was also analyzed as an indicator of overall organism health. The results demonstrated genotoxic effects, evidenced by DNA damage. Biochemical analyses revealed alterations consistent with oxidative stress and potential neurotoxic responses, while somatic indices showed minor but detectable health changes. Although the observed damage levels were relatively low, these findings indicate that continuous exposure to EM and its byproducts can induce sublethal physiological disturbances with potential long-term consequences for aquatic organisms. Overall, this study highlights the relevance of ecotoxicological monitoring of EM in aquatic systems. The observed biological responses underscore its potential ecological risk, and future studies should incorporate preliminary stability assessments and evaluate long-term effects and degradation products to better understand the environmental impact of this antihypertensive drug.