Ribbon-like supramolecular structures prepared by the organized aggregation of 4-aryl-4H-1,2,4-triazoles act as optical waveguides that propagate photoluminescence.

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A series of seven 2-amino-4-arylthiazoles were prepared following Hantzsch's modified method under microwave irradiation. A set of 50 derivatives was obtained and the in vitro activity against Giardia intestinalis was evaluated. The results on the biological activity revealed that, in general, the N-(5-bromo-4-arylthiazol-2-yl)-acetamide scaffold showed high bioactivity. In particular, compounds 6e (IC 50 = 0.39 μM) and 6b (IC 50 = 0.87 μM) were found to be more potent than the positive control metronidazole. Citoxicity and acute toxicity tests performed showed low toxicity and high selectivity of the most active compounds (6e SI = 139, 6b SI = 52.3). A QSAR analysis was applied to a data set of 37 obtained 2-amino-4-arylthiazoles derivatives and the best model described a strongly correlation between the anti-giardiasic activity and molecular descriptors as E2M, RDF115m, F10, MATS6v, and Hypnotic-80, with high statistical quality. This finding indicates that N-substituted aminothiazole scaffold should be investigated for the development of highly selective anti-giardial agent.

Trichomoniasis, caused by the protozoan parasite Trichomonas vaginalis, is the most common nonviral sexually transmitted infection worldwide. Although drug treatment is available, unpleasant side effects and increased resistance to the nitroimidazole family have been documented. Hence, there is a need for the identification of new and safe therapeutic agents against T. vaginalis. Antimicrobial activity of anthraquinone compounds has been reported by a number of authors. The genus Morinda is well known for the diversity of anthraquinones with numerous biological activities. A new anthraquinone, lucidin‐ω‐isopropyl ether, was isolated from the roots of Morinda panamensis Seem. The structure of the compound was determined by 1H and 13C Nuclear Magnetic Resonance (NMR) analyses, in addition to comparison with literature reports. Using in vitro susceptibility assay, the half inhibitory concentration (IC50) of lucidin‐ω‐isopropyl ether for T. vaginalis (1.32 μg/mL) was found similar to that of metronidazole concentration tested (6 μM = 1.03 μg/mL). In addition, this anthraquinone was capable of inhibiting the parasite's ability to kill HeLa cells and decreased proteolytic activity of the proteinase TvMP50 from T. vaginalis. This was associated with the decreased expression of the mp50 gene. These results demonstrate the trichomonicidal potential by lucidin‐ω‐isopropyl ether. Further action‐mode studies are necessary to elucidate the antiparasitic mechanism of this new anthraquinone to develop a more potent antitrichomonal agent.