Hit-to-Lead Optimization of a Novel Class of Potent, Broad-Spectrum Trypanosomacides.

The parasitic trypanosomes Trypanosoma brucei and T. cruzi are responsible for significant human suffering in the form of human African trypanosomiasis (HAT) and Chagas disease. Drugs currently available to treat these neglected diseases leave much to be desired. Herein we report optimization of a novel class of N-(2-(2-phenylthiazol-4-yl)ethyl)amides, carbamates, and ureas, which rapidly, selectively, and potently kill both species of trypanosome. The mode of action of these compounds is unknown but does not involve CYP51 inhibition. They do, however, exhibit clear structure-activity relationships, consistent across both trypanosome species. Favorable physicochemical parameters place the best compounds in CNS drug-like chemical space but, as a class, they exhibit poor metabolic stability. One of the best compounds (64a) cleared all signs of T. cruzi infection in mice when CYP metabolism was inhibited, with sterile cure achieved in one mouse. This family of compounds thus shows significant promise for trypanosomiasis drug discovery.

Microwave-assisted synthesis and bioevaluation of some semicarbazones.

In continuation to our efforts in finding potential therapeutic agents, a variety of biologically significant semicarbazones were synthesized by the reaction of different carbonyl compounds with phenyl semicarbazides through microwave irradiation. Initially, 18 semicarbazones were studied for their antimicrobial, antitumor, and antioxidant potential. None of the tested compounds showed any antibacterial activity; however, some compounds showed significant antifungal activity. Interestingly, all compounds showed antitumor activity when tested against tumors grown on potato discs. These compounds were also tested for their effect on OH radical-induced oxidative DNA damage. All the compounds showed DNA protection to varying extent. Based on the promising results of antitumor and antioxidant activities, another set of 24 semicarbazones was synthesized, and all of these semicarbazones were evaluated for their antioxidant potential. The results showed that the semicarbazones derived from 2-nitrobenzaldehyde and acetophenone were the most active 2,2-diphenyl-1-picrylhydrazyl 9 (DPPH) free radical scavengers. The overall results have led to the identification of some interesting compounds which seem to have great potential to be developed into effective anticancer drugs.