Biochemical effects and theoretical study of a metformin in the carp (Cyprinus carpio) fry

Pharmaceutical chemicals are frequently detected in wastewater, and metformin, an oral hypoglycemic agent, is among the most common. In this study, the effects of metformin on biochemical (total protein, glycogen, lipid) and antioxidant (malondialdehyde (MDA), glutathione (GSH), glutathione S-transferase (GST), catalase (CAT)) parameters were investigated in carp ( Cyprinus carpio ) fry. Fish were exposed to 40 and 80 µg/L metformin for 96 h, 14 and 21 days. No mortalities occurred in any group. At 80 µg/L for 21 days, total protein activity and lipid levels significantly decreased. Glycogen activity showed no significant differences compared to controls. Antioxidant parameters measured spectrophotometrically revealed that MDA levels, CAT and GST activities decreased with time but increased with dose, while GSH levels rose with time yet decreased with dose. Overall, significant time- and dose-dependent effects ( p < 0.05) were observed. In silico analyses were also performed. The activity of metformin against antioxidant proteins was evaluated, and molecular dynamics simulations confirmed strong interactions with the most active protein. ADME/T analysis provided pharmacokinetic insights, and Gaussian-based quantum chemical calculations (EHOMO, ELUMO, ΔE, dipole, etc.) characterized electronic and structural properties. These combined results indicate that metformin alters key biochemical pathways in carp fry and has significant reactivity toward antioxidant proteins. Findings suggest potential ecotoxicological risks in aquatic systems and relevance to pharmacological profiling.