mannich-bases and melamine

A new and simple spectrophotometric method has been developed and validated for measuring the contamination of melamine in different milk products. The method is based upon measuring the absorption of the complex formed from melamine, 4-hydroxyacetophenone (Hap) and 1-pyrene carboxaldehyde (Pcd), which was adapted from the Mannich reaction. Quantitative analysis was done at a wavelength of 236 nm within a few minutes. The reaction was optimized by focusing on both obtaining high performance of the method and to concern the volatility and toxicity of used reagents. This method provided a linear dynamic range, limit of detection and limit of quantification of 0.100-3.78, 0.08 and 0.14 mg L(-1), respectively. The relative standard deviation (RSD) was 3.6% (n=10). The recoveries of melamine spiked liquid milk samples, with melamine concentrations of 0.63, 1.26, 1.89 and 2.52 mg L(-1), were 87.7±3.7%, 91.1±8.8%, 89.2±4.4% and 90.6±3.6% (n=3), respectively.

Topics: Absorption; Animals; Calibration; Mannich Bases; Milk; Naphthalenes; Pyrenes; Reproducibility of Results; Spectrophotometry; Triazines

A series of unsaturated Mannich bases possessing two electrophilic sites was recently identified as irreversible inhibitors of trypanothione reductase from Trypanosoma cruzi. New derivatives were synthesized by modifying the substitution pattern on the aromatic ring and by incorporating the melamine motif of melarsoprol. Their affinity to P2 transporter and their trypanocidal properties have been studied using three strains expressing various purine transporters. While the melamine derivatives showed some affinity to the P2 transporter, unsaturated Mannich bases without the melamine motif showed excellent potencies against pentamidine-resistant strains of T. brucei brucei suggesting alternative drug uptake routes. The Michael acceptor properties of the three most active compounds towards glutathione correlated with the observed trypanocidal activities.

Topics: Adenosine; Animals; Antiparasitic Agents; Glutathione; Humans; Mannich Bases; Membrane Transport Proteins; NADH, NADPH Oxidoreductases; Triazines; Trypanosoma brucei brucei; Trypanosomiasis