Synthesis and Biological Evaluation of 4-Aminoantipyrine Analogues.

OBJECTIVES: The aim of the present study is to carry out a simple synthesis of aminoantipyrine analogues and exploration of their antibacterial, cytotoxic, and anticonvulsant potential. METHODS: The compounds were characterized employing multi-spectroscopic methods. The in vitro pharmacological response of a series of bacteria was screened employing serial dilution method. The derivatives were screened against maximal electro-shock for their anticonvulsant activity. Molecular docking was carried out to optimize the interaction of the compounds with HPV16-E7 receptors. Further, the in vitro cytotoxicity was tested against human cervical cancer (SiHa) cell lines. RESULTS: The compounds show protection against maximal electroshock, esp. 3-nirto- and 4- methyl-3-nitrobenzamido derivatives. In addition, they reveal appreciable DNA cleavage activities and interactions with HPV16-E7 protein receptors, esp. 3,5-dinitro- and 4-methyl-3-nitrobenzamido derivatives. Furthermore, they show potent activity against cervical cancer cells (LD50 value up to 1200 in the case of 4-methyl-3-nitrobenzamido derivative and an inhibition of a maximum of ~97% of cells). CONCLUSION: The simply synthesized aminoantipyrine derivatives show a variety of biological activities like antibacterial and anticancer effects. In addition, this is the first study demonstrating that 4-aminoantipyrine derivatives show an anticonvulsant activity.

Adaptive changes of extracellular amino acid concentrations in mouse dorsal striatum by 4-AP-induced cortical seizures.

The striatum is a major target of cerebral cortical output. The cortico-striatal projection has been well described, however, the neurochemical changes that occur in the striatum after prolonged cortical hyperactivation remain to be investigated. In this study, extracellular levels of glutamate, GABA, and alanine levels were measured in the dorsal striatum using microdialysis in anesthetized mice at resting condition and during 4-aminopyridine (4-AP)-induced cortical seizures. After topical application of 4-AP on the primary motor cortex that induced cortical seizures, the extracellular level of striatal GABA increased by 40% in 60 min. By contrast, the extracellular level of striatal glutamate decreased by 20%. Moreover, the surface amounts of striatal glutamate/aspartate transporter (GLAST) and glutamate transporter 1 (GLT-1), the major astrocytic high-affinity glutamate transporters, tended to increase by cortical seizures in 60 min, suggesting a recruitment of the glutamate transporters from internal stores. 4-AP also resulted in a steady increase of alanine levels which are thought to reflect glutamate and pyruvate metabolism in neurons and astrocytes. These observations possibly delineate adaptive changes of striatal metabolism by severe cortical seizures.

Insights into potentially toxic effects of 4-aminoantipyrine on the antioxidant enzyme copper-zinc superoxide dismutase.

4-Aminoantipyrine (AAP) is scarcely administered as an analgesic drug because of side effects. The residue of AAP in the environment is potentially harmful. To evaluate the toxicity of AAP from molecular level, the effects of AAP on the important antioxidant enzyme copper-zinc superoxide dismutase (Cu/ZnSOD) were explored using spectroscopic and molecular modeling methods. AAP can spontaneously bind with Cu/ZnSOD with one binding site to form AAP-Cu/ZnSOD complex through hydrogen bond and van der Waals forces. The molecular docking simulation revealed that AAP bound into the Cu/ZnSOD interface of two subdomains, which induced some conformational and microenvironmental changes of Cu/ZnSOD and further caused the inhibition of Cu/ZnSOD activity. The present study provides important insights into toxic mechanism of AAP with Cu/ZnSOD. The estimated research route can be applied to characterize interactions of enzyme systems and other pollutants and drugs.

Molecular interaction between 4-aminoantipyrine and catalase reveals a potentially toxic mechanism of the drug.

4-Aminoantipyrine (AAP) is scarcely administered as an analgesic drug because of the potential side effects. The residue of AAP in the environment possesses a potential threat to human health. In this article, the binding mode of AAP with the important antioxidant enzyme catalase (CAT) was investigated using spectroscopic and molecular docking methods. AAP can interact with CAT to form an AAP-CAT complex. The binding constant, number of binding sites and thermodynamic parameters were measured, which indicated that AAP could spontaneously bind with CAT through electrostatic forces with one binding site. Molecular docking results revealed that AAP bound into the CAT central cavity. UV-visible absorption, synchronous fluorescence and circular dichroism (CD) results provide data concerning conformational and some microenvironmental changes of CAT. Furthermore, the binding of AAP can inhibit CAT activity in erythrocytes. The present study provides direct evidence at a molecular level to show that exposure to AAP could induce changes in the enzyme CAT structure and function. The estimated methods in this work can be applied to characterize interactions of enzyme systems and other pollutants and drugs.

The interaction between 4-aminoantipyrine and bovine serum albumin: multiple spectroscopic and molecular docking investigations.

4-Aminoantipyrine (AAP) is widely used in the pharmaceutical industry, in biochemical experiments and in environmental monitoring. AAP as an aromatic pollutant in the environment poses a great threat to human health. To evaluate the toxicity of AAP at the protein level, the effects of AAP on bovine serum albumin (BSA) were investigated by multiple spectroscopic techniques and molecular modeling. After the inner filter effect was eliminated, the experimental results showed that AAP effectively quenched the intrinsic fluorescence of BSA via static quenching. The number of binding sites, the binding constant, the thermodynamic parameters and binding subdomain were measured, and indicated that AAP could spontaneously bind with BSA on subdomain IIIA through electrostatic forces. Molecular docking results revealed that AAP interacted with the Glu 488 and Glu 502 residues of BSA. Furthermore, the conformation of BSA was demonstrably changed in the presence of AAP. The skeletal structure of BSA loosened, exposing internal hydrophobic aromatic ring amino acids and peptide strands to the solution.

Spectroscopic investigation on the toxicological interactions of 4-aminoantipyrine with bovine hemoglobin.

The effects of 4-aminoantipyrine (AAP) on bovine hemoglobin (BHb) were investigated by fluorescence spectroscopy, synchronous fluorescence spectroscopy, ultraviolet-visible absorption spectroscopy and circular dichroism spectroscopy (CD) under simulated physiological conditions. The experimental results showed that AAP effectively quenched the intrinsic fluorescence of BHb via static quenching. The number of binding sites, the binding constant K(a), and the thermodynamic parameters (DeltaH(o), DeltaS(o) and DeltaG(o)) were measured at two different temperatures. Van der Waals' interactions and hydrogen bonds were the predominant intermolecular forces in stabilizing the BHb-AAP complex. The experiment results confirmed micro-environmental and conformational changes of BHb in the presence of AAP. The alpha-helix content decreased, indicating that AAP destroys some of the hydrogen bonding networks in the polypeptide chain.

Photodegradation study of three dipyrone metabolites in various water systems: identification and toxicity of their photodegradation products.

The photochemical behaviour of three relevant metabolites of the analgesic and antipyretic drug dipyrone, 4-methylaminoantipyrine (4-MAA), 4-formylaminoantipyrine (4-FAA) and 4-acetylaminoantipyrine (4-AAA), was evaluated under simulated solar irradiation (Suntest system). For 4-MAA, different aqueous solutions (synthetic seawater, freshwater and Milli-Q water) as well as different operational conditions were compared. According to the experimental results, 4-MAA resulted as being an easily degraded molecule by direct photolysis, with half-life times (t1/2) ranging from 0.12 to 0.58 h, depending on the irradiation conditions. Faster degradation was observed in synthetic waters, suggesting that the photolysis was influenced by the salt composition of the waters. However, no effect on the degradation rate was observed by the presence of natural photosensitizers (dissolved organic matter, nitrate ions). 4-FAA and 4-AAA showed slower photodegradation kinetics, with t1/2 of 24 and 28 h, respectively. A study of photoproduct identification was carried out by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-time-of-flight mass spectrometry (LC-TOF-MS) (ESI positive mode), which allowed us to propose a tentative photodegradation pathway for 4-MAA and the identification of persistent by-products in all the cases. Finally, the application of an acute toxicity test (Daphnia magna) showed an increase in toxicity during the photolytic process, a consequence of the formation of toxic photoproducts.

Mutagenicity of 4-aminoantipyrine and 4-nitrosoantipyrine, the C-nitroso derivative of antipyrine.

The drug antipyrine and its 4-substituted analogs, 4-aminoantipyrine, 4-dimethylaminoantipyrine (aminopyrine) and 4-nitrosoantipyrine were tested for mutagenicity against the screening array of Salmonella typhimurium tester strains TA100, TA98, TA97, TA102 and TA104. Antipyrine and aminopyrine were nonmutagenic to all 5 tester strains even in the presence of S9. 4-Aminoantipyrine was directly mutagenic to TA97 only and the presence of S9 slightly increased its activity. 4-Nitrosoantipyrine was directly mutagenic to all tester strains used and S9 decreased its activity except with strain TA102. The possible long-term hazards of C-nitroso compounds derived from drugs and dietary constituents are discussed in view of their pluripotent direct genotoxicity.