Revista:Medicinal Abstract Several cinnamic acid esters were obtained via Fischer esterification of cinnamic acids derivatives with aliphatic alcohols. Cinnamic acids derivatives were synthesized via Knoevenagel reaction between substituted benzaldehydes and malonic acid in aqueous medium assisted by microwave heating. Structures of the products were elucidated by spectroscopic analysis. The synthesized compounds were evaluated for antileishmanial activity against L. panamensis amastigotes and cytotoxic activity against U-937 cells. The compounds 6, 10-12 and 18, were active against Leishmania parasite but toxic for mammalian cells. They are potential candidates for antileishmanial drug development.

A series of styrylcoumarins were obtained via Mizoroki-Heck reactions between 3-bromo-4-methyl-7-(octyloxy)-2H-chromen-2-one or 2-oxo-2H-chromen-7-yl trifluoromethanesulfonate and functionalized styrenes. The structures of the products were elucidated by spectroscopic analysis. All compounds were evaluated against SW480 and CHO-K1 cell lines. A number of hybrids showed good antiproliferative activity. Among the tested compounds, hybrids 6e, 10c and 10d, exhibited the highest activity (IC50-SW480/48h = 6,92; 1,01 and 5,33 µM, respectively) and selectivity (IS48h = >400; 67,8 and 7,2, respectively). In addition, these compounds were able to preserve their activities over time. The results achieved by these hybrids were even better than the lead compounds (coumarin and resveratrol) and the standard drug (5-FU). As regards structure-activity relationship it seems that the location of the styryl group on the coumarin structure and the presence of the hydroxyl group on the phenyl ring were determinant for the activity.

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Twelve hybrids derived from triclosan were obtained via Williamson etherification of O-triclosan alkyl bromide plus chalcone and O-coumarin or O-chromone alkyl bromide plus triclosan, respectively. Structures of the products were elucidated by spectroscopic analysis. The synthesized compounds were evaluated for antileishmanial activity against L. (V) panamensis amastigotes. Cytotoxic activity was also evaluated against mammalian U-937 cells. Compounds 7-9 and 17, were active against Leishmania parasites (EC 50 = 9.4; 10.2; 13.5 and 27.5 µg/mL, respectively) and showed no toxicity toward mammalian cells (>200 µg/mL). They are potential candidates for antileishmanial drug development. Compounds 25-27, were active and cytotoxic. Further studies using OPEN ACCESSMolecules 2014, 19 13252 other cell types are needed in order to discriminate whether the toxicity shown by these compounds is against tumor or non-tumor cells. The results indicate that compounds containing small alkyl chains show better selectivity indices. Moreover, Michael acceptor moieties may modify both the leishmanicidal activity and cytotoxicity. Further studies are required to evaluate if the in vitro activity against Leishmania panamensis demonstrated here is also observed in vivo.

The synthesis, cytotoxicity, anti-leishmanial and anti-trypanosomal activities of twelve triclosan-caffeic acid hybrids are described herein. The structure of the synthesized products was elucidated by a combination of spectrometric analyses. The synthesized compounds were evaluated against amastigotes forms of L. (V) panamensis, which is the most prevalent Leishmania species in Colombia, and against Trypanosoma cruzi, which is the pathogenic species to humans. Cytotoxicity was evaluated against human U-937 macrophages. Eight compounds were active against L. 26 and 28, the remaining compounds were toxic for mammalian cells, yet they have potential to be considered as candidates for anti-trypanosomal and anti-leishmanial drug development. The activity is dependent on the length of the alkyl linker with compound 19, bearing a four-carbon alkyl chain, the most performing hybrid. In general, hydroxyl groups increase both activity and cytotoxicity and the presence of the double bond in the side chain is not decisive for cytotoxicity and anti-protozoal activity.