Differential Effects of Halofuginone Enantiomers on Muscle Fibrosis and Histopathology in Duchenne Muscular Dystrophy.

Progressive loss of muscle and muscle function is associated with significant fibrosis in Duchenne muscular dystrophy (DMD) patients. Halofuginone, an analog of febrifugine, prevents fibrosis in various animal models, including those of muscular dystrophies. Effects of (+)/(-)-halofuginone enantiomers on motor coordination and diaphragm histopathology in mdx mice, the mouse model for DMD, were examined. Four-week-old male mice were treated with racemic halofuginone, or its separate enantiomers, for 10 weeks. Controls were treated with saline. Racemic halofuginone-treated mice demonstrated better motor coordination and balance than controls. However, (+)-halofuginone surpassed the racemic form's effect. No effect was observed for (-)-halofuginone, which behaved like the control. A significant reduction in collagen content and degenerative areas, and an increase in utrophin levels were observed in diaphragms of mice treated with racemic halofuginone. Again, (+)-halofuginone was more effective than the racemic form, whereas (-)-halofuginone had no effect. Both racemic and (+)-halofuginone increased diaphragm myofiber diameters, with no effect for (-)-halofuginone. No effects were observed for any of the compounds tested in an in-vitro cell viability assay. These results, demonstrating a differential effect of the halofuginone enantiomers and superiority of (+)-halofuginone, are of great importance for future use of (+)-halofuginone as a DMD antifibrotic therapy.

Chemical synthesis of febrifugine and analogues.

The quinazolinone-containing 2,3-disubstituted piperidines febrifugine and isofebrifugine have been the subject of significant research efforts since their occurrence in Dichroa febrifuga and their anti-malarial actions were first described in the late 1940s. Subsequently they have also been shown to be present in other plants belonging to the hydrangea family and various analogues of febrifugine have been prepared in attempts to tune biological properties. The most notable analogue is termed halofuginone and a substantial body of work now demonstrates that this compound possesses potent human disease relevant activities. This review focuses on the literature associated with efforts dedicated towards uncovering the structures of febrifugine and isofebrifugine, the development of practical methods for their synthesis and the syntheses of structural analogues.

Halonium ion triggered rearrangement of unsaturated benzo-annulated bi- and tricyclic sulfonamides.

The halonium ion mediated 1,2-Wagner-Meerwein-type rearrangement of a series of benzo-fused bi- and tricyclic sulfonamides is reported. During this rearrangement the carbon-carbon bond that migrates was selectively set in the intramolecular Mizoroki-Heck (IHR) synthesis of the starting materials. Consequently, this method constitutes a means to access the regioisomeric series of cyclic sulfonamides not observed during the Mizoroki-Heck reaction.