A novel series of furoxan (1,2,5-oxadiazole 2-oxide) (compounds 3, 4a and -b, 13a and -b, and 14a to -f) and benzofuroxan (benzo[c][1,2,5]oxadiazole 1-oxide) (compounds 7 and 8a to -c) derivatives were synthesized, characterized, and evaluated for in vitro activity against promastigote and intracellular amastigote forms of Leishmania amazonensis. The furoxan derivatives exhibited the ability to generate nitric oxide at different levels (7.8% to 27.4%). The benzofuroxan derivative 8a was able to increase nitrite production in medium supernatant from murine macrophages infected with L. amazonensis at 0.75 mM after 48 h. Furoxan and benzofuroxan derivatives showed remarkable leishmanicidal activity against both promastigote and intracellular amastigote forms. Compounds 8a, 14a and -b, and 14d exerted selective leishmanicidal activities superior to those of amphotericin B and pentamidine. In vitro studies at pH 5.4 reveal that compound 8a is stable until 8 h and that compound 14a behaves as a prodrug, releasing the active aldehyde 13a. These compounds have emerged as promising novel drug candidates for the treatment of leishmaniasis.

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In the last years, there is a trend towards the replacement of synthetic colorants by natural ones, mainly due to the increase of consumer demand for natural products. The natural colorants are used to enhance the appearance of pharmaceutical products, food, and different materials, making them preferable or attractive. This review intends to provide and describe a comprehensive overview of the history of colorants, from prehistory to modern time, of their market and their applications, as well as of the most important aspects of the fermentation process to obtain natural colorants. Focus is given to colorants produced by filamentous fungal species, aiming to demonstrate the importance of these microorganisms and biocompounds, highlighting the production performance to get high yields and the aspects of conclusion that should be taken into consideration in future studies about natural colorants.

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A B S T R A C TOver the last few years, synthetic colorants have been increasingly replaced by natural alternatives that cause fewer adverse health effects and can show biological activity. These biocompounds can be produced by fermentative processes using microorganisms such as bacteria and filamentous fungi. However, the biocompounds must be extracted from the fermented broth before industrial application. Thus, the development of effective techniques for the extraction and purification of biocolorants with high recovery is of great interest. The main goal of this study was to evaluate the recovery of natural colorants produced by Talaromyces amestolkiae using aqueous micellar two-phase system (AMTPS) composed of Triton X-114 and Ionic Liquids (ILs) from the imidazolium family as co-surfactants. Preliminary experiments were performed to determine the binodal curves in both presence and absence of fermented broth containing the red colorants. Subsequently, a set of partitioning experiments was performed using the developed systems. Under all conditions, the red colorants were partitioned mainly into the micelle-rich phase. The systems with low concentrations of Triton X-114 and ILs showed high partition coefficients. The system (0.1 wt% [C 10 mim]Cl + 3 wt% Triton X-114) with the highest partition coefficient (K RC = 6.12) was used to study the effect of temperature on partitioning. The partitioning of the red colorants was strongly influenced by the temperature, and K RC increased to 24.71 at 45°C. The results of this study demonstrate that the partitioning of biomolecules can be controlled by the presence of ILs, mainly by electrostatic interactions, or by the proper adjustment of the partitioning temperature.

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Corrigendum to ''The 2 0 ,4 0 -dihydroxychalcone could be explored to develop new inhibitors against the glycerol-3-phosphate dehydrogenase from Leishmania species" [Bioorg. Med. Chem. Lett. 25 (2015) 3564-3568]