Enzymic reduction of 2:4-dinitrophenol by rat-tissue homogenates

Diet aid or aid to die: an update on 2,4-dinitrophenol (2,4-DNP) use as a weight-loss product

During the last decades, we have witnessed unparalleled changes in human eating habits and lifestyle, intensely influenced by cultural and social pressures. Sports practice became strongly implemented in daily routines, and visits to the gym peaked, driven by the indulgence in intensive 'weight-loss programs'. The pledge of boasting a healthy and beautiful body instigates the use of very attractive 'fat burners', which are purportedly advertised as safe products, easily available in the market and expected to quickly reduce body weight. In this context, the slimming properties of 2,4-dinitrophenol (2,4-DNP) galvanised its use as a weight-loss product, despite the drug ban for human consumption in many countries since 1938, due to its adverse effects. The main symptoms associated with 2,4-DNP intoxication, including hyperthermia, tachycardia, decreased blood pressure, and acute renal failure, motivated a worldwide warning, issued by the Interpol Anti-Doping Unit in 2015, reinforcing its hazard. Information on the effects of 2,4-DNP mainly derive from the intoxication cases reported by emergency care units, for which there is no specific antidote or treatment. This review provides a comprehensive update on 2,4-DNP use, legislation and epidemiology, chemistry and analytical methodologies for drug determination in commercial products and biological samples, pharmacokinetics and pharmacodynamics, toxicological effects, and intoxication diagnosis and management.

Synthesis of 2-hydroxypropyl-β-cyclodextrin/pluronic-based polyrotaxanes via heterogeneous reaction as potential Niemann-Pick type C therapeutics

Five polyrotaxanes were synthesized by threading 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) onto a variety of α,ω-ditriethylenediamino-N-carbamoyl-poly-(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic) triblock copolymers using a two-pot strategy under heterogeneous, nonaqueous conditions. The threaded HP-β-CD units were retained on the pseudopolyrotaxane precursors by end-capping the branched diamine termini with sodium 2,4,6-trinitrobenzene sulfonate. Inclusion of the Pluronic copolymers within the HP-β-CD cavities was more favorable in nonpolar solvents, such as diethyl ether and n-hexane, both of which gave better coverage ratios than polar solvents. (1)H NMR and MALDI-TOF were used to estimate the average molecular weights of the purified polyrotaxane products. A globular morphology of aggregated polyrotaxanes was observed by tapping-mode AFM imaging of dried samples. Treatment of Niemann-Pick C (NPC) type 2-deficient fibroblasts with the polyrotaxane derivatives produced substantial reductions in sterol accumulation, as seen by diminished filipin staining in these cells, suggesting that Pluronic-based polyrotaxanes may be promising vehicles for delivery of HP-β-CD to cells with abnormal cholesterol accumulation.

Plasma levels and kinetic disposition of 2,4-dinitrophenol and its metabolites 2-amino-4-nitrophenol and 4-amino-2-nitrophenol in the mouse

Eleven groups of six ICR mice were dosed orally with 22.5 mg/kg 2,4-dinitrophenol. Groups were sacrificed at 0, 0.5, 1, 2, 4, 6, 9, 12, 24, 48, and 96 h post-treatment and plasma was collected for analysis of dinitrophenol, 2-amino-4-nitrophenol, and 4-amino-2-nitrophenol content. Analyses were performed by capillary gas chromatography--mass spectrometry after liquid--liquid extraction of plasma specimens spiked with two internal standards. Quantification was based upon peak-area ratios of base peaks obtained from the three analytes and the trideuterated internal standards 2,4-dinitrophenol and 2-amino-4-nitrophenol. Plasma concentrations for each analyte versus their respective time periods were subjected to pharmacokinetic analysis. Of the two monoamine metabolites, 2-amino-4-nitrophenol was present in the greater amount and had an elimination half-life of 46 h from plasma while that of 4-amino-2-nitrophenol was 26 h.

Metabolism of nitromide in the rat. II. Sites of nitro-reduction

1. Nitromide (3,5-dinitrobenzamide) is reduced to monoamino- and diamino-metabolites in vitro on anaerobic incubation with rat intestinal microflora. This conversion is suppressed by the antibiotics neomycin, tetracycline and bacitracin. 2. Nitromide is also in part reduced to monoamino but not diamino metabolites when incubated aerobically with homogenates of rat liver. 3. Pretreatment of rats with the antibiotics did not decrease their ability to form monoamino metabolites from nitromide, although formation of diamino metabolites was suppressed. 4. An antibiotic regime shown to suppress the methaemoglobinaemia resulting from the administration of nitrobenzene did not significantly reduce the methaemoglobinaemia resulting from the administration of nitromide.