Synthesis and leishmanicidal activity of cinnamic acid esters: structure–activity relationship

Opuntia ficus-indica (L.) Mill. - anticancer properties and phytochemicals: current trends and future perspectives

Cancer is a leading cause of mortality worldwide, and conventional cancer therapies such as chemotherapy and radiotherapy often result in undesirable and adverse effects. Natural products have emerged as a promising alternative for cancer treatment, with comparatively fewer side effects reported. Opuntia ficus-indica (L.) Mill., a member of the Cactaceae family, contains a diverse array of phytochemicals, including flavonoids, polyphenols, betalains, and tannins, which have been shown to exhibit potent anticancer properties. Various parts of the Opuntia plant, including the fruits, stems/cladodes, and roots, have demonstrated cytotoxic effects against malignant cell lines in numerous studies. This review comprehensively summarizes the anticancer attributes of the phytochemicals found in Opuntia ficus-indica (L.) Mill., highlighting their potential as natural cancer prevention and treatment agents. Bibliometric metric analysis of PubMed and Scopus-retrieved data using VOSviewer as well as QDA analysis provide further insights and niche to be explored. Most anticancer studies on Opuntia ficus-indica and its purified metabolites are related to colorectal/colon cancer, followed by melanoma and breast cancer. Very little attention has been paid to leukemia, thyroid, endometrial, liver, and prostate cancer, and it could be considered an opportunity for researchers to explore O. ficus-indica and its metabolites against these cancers. The most notable mechanisms expressed and validated in those studies are apoptosis, cell cycle arrest (G0/G1 and G2/M), Bcl-2 modulation, antiproliferative, oxidative stress-mediated mechanisms, and cytochrome c. We have also observed that cladodes and fruits of O. ficus-indica have been more studied than other plant parts, which again opens the opportunity for the researchers to explore. Further, cell line-based studies dominated, and very few studies were related to animal-based experiments. The Zebrafish model is another platform to explore. However, it seems like more in-depth studies are required to ascertain clinical utility of this biosustainable resource O. ficus-indica.

Synthetic 2-Nitrocinnamates: Investigation of the Antifungal Action against Candida Species

Derivatives of cinnamic acid have several pharmacological actions, such as antimicrobial activity. Therefore, in the present study, a series of fourteen alkyl and aryl derivatives from (E)-2-nitrocinnamic acid were obtained using Fischer esterification, nucleophilic substitution with halides, and Mitsunobu reaction. Esters were evaluated for antifungal activity against several strains of Candida spp. using nystatin as a positive control. Among the synthetic derivatives obtained, nine are compounds unprecedented in the literature. The characterization of chemical structures was carried out using the techniques of IR, 1H-NMR and 13C-NMR spectroscopy, and high-resolution mass spectrometry. Isopropyl 2-nitrocinnamate (4) was the compound that showed the best antifungal activity (MIC = 513.52 μM) against all fungal strains, followed by compound perillyl 2-nitrocinnamate (14) with MIC = 390.99–781.98 μM.

Phytochemical composition, bioactive properties, and toxicological profile of Tetrapleura tetraptera

The use of medicinal plants has gained renewed wide popularity in Africa, Asia, and most parts of the world because of the decreasing efficacy of synthetic drugs. Thus, natural products serve as a potent source of alternative remedy. Tetrapleura tetraptera is a medicinal plant with cultural and traditional significance in West Africa. In addition to the plant being commonly used as a spice in the preparation of traditional spicy food for postpartum care it is also widely used to constitute herbal concoctions and decoctions for treatment of diseases. This review aimed to provide an up-to-date information on the ethnomedicinal uses, pharmacological activities and phytoconstituents of T. tetraptera. Preclinical studies regarding the plant's toxicity profile were also reviewed. For this updated review, literature search was done on PubMed, Science Direct, Wiley, and Google Scholar databases using the relevant keywords. The review used a total of 106 papers that met the inclusion criteria from January 1989 - February 2022 and summarised the bioactivities that have been reported for the rich phytoconstituents of T. tetraptera studied using various chemical methods. Considering the huge report, the review focused on the antimicrobial and antiinflammatory activities of the plant extracts and isolated compounds. Aridan, aridanin and several bioactive compounds of T. tetraptera have shown pharmacological activities though their mechanisms of action are yet to be fully understood. This study also highlighted the influence of plant parts and extraction solvents on its biological activities. It also presented data on the toxicological profile of the plant extracts using different models. From cultural uses to modern pharmacological research the bioactive compounds of T. tetraptera have proved effective in infectious disease management. We hope that this paper provided a robust summary of the biological activities and toxicological profile of T. tetraptera, thus calling for more research into the pharmacological and pharmacokinetic activities of natural products to help combat the growing threat of drug resistance and provide guidelines for their ethnomedicinal uses.

4-Methoxyphenethyl (E)-3-(o-tolyl)acrylate

4-Methoxyphenethyl (E)-3-(o-tolyl)acrylate (1) was obtained in a good yield by the reaction of 2-methylcinnamic acid, 4-methoxyphenethyl alcohol, 2-methyl-6-nitrobenzoic anhydride, 4-dimethylaminopyridine, and triethylamine at room temperature for 40 min. The structure of 4-methoxyphenethyl (E)-3-(o-tolyl)acrylate (1) was established by FTIR, NMR, and the high resolution of mass spectroscopies. 4-Methoxyphenethyl (E)-3-(o-tolyl)acrylate (1) showed higher α-glucosidase inhibition activity than standard drug acarbose. The molecular docking study exhibited that the title compound 1 had a good affinity for α-glucosidase (PDB ID: 3W37) and formed some interactions with the α-glucosidase active site residue.

Chemopreventive Effect on Human Colon Adenocarcinoma Cells of Styrylquinolines: Synthesis, Cytotoxicity, Proapoptotic Effect and Molecular Docking Analysis

Seven styrylquinolines were synthesized in this study. Two of these styrylquinolines are new and were elucidated by spectroscopic analysis. The chemopreventive potential of these compounds was evaluated against SW480 human colon adenocarcinoma cells, its metastatic derivative SW620, and normal cells (HaCaT). According to the results, compounds 3a and 3d showed antiproliferative activity in SW480 and SW620 cells, but their effect seemed to be caused by different mechanisms of action. Compound 3a induced apoptosis independent of ROS production, as evidenced by increased levels of caspase 3, and had an immunomodulatory effect, positively regulating the production of different immunological markers in malignant cell lines. In contrast, compound 3d generated a pro-oxidant response and inhibited the growth of cancer cells, probably by another type of cell death other than apoptosis. Molecular docking studies indicated that the most active compound, 3a, could efficiently bind to the proapoptotic human caspases-3 protein, a result that could provide valuable information on the biochemical mechanism for the in vitro cytotoxic response of this compound in SW620 colon carcinoma cell lines. The obtained results suggest that these compounds have chemopreventive potential against CRC, but more studies should be carried out to elucidate the molecular mechanisms of action of each of them in depth.

Colorectal Cancer Chemoprevention by S-Allyl Cysteine–Caffeic Acid Hybrids: In Vitro Biological Activity and In Silico Studies

Conventional chemotherapy for colorectal cancer (CRC) gives only a small increase in patient survival, since it is often diagnosed at late stages, when the tumor has disseminated to other organs. Moreover, it is common to observe that malignant cells may acquire resistance to conventional chemotherapies through different mechanisms, including reducing drug activation or accumulation (by enhancing efflux), inducing alterations in molecular targets, and inhibiting the DNA damage response, among other strategies. Considering these facts, the discovery of new molecules with therapeutic potential has become an invaluable tool in chemoprevention. In this context, we previously evaluated two hybrids (SAC-CAFA-MET and SAC-CAFA-PENT) that exhibited selective cytotoxicity against SW480 cells, with better results than the conventional chemotherapeutic agent (5-fluorouracil; 5-FU). Here, we investigated the possible mechanisms of these molecules in greater depth, to identify whether they could be valuable therapeutic scaffolds in the search for new molecules with chemopreventive potential for the treatment of CRC. Both compounds reduced ROS formation, which could be related to antioxidant effects. Further evaluations showed that SAC-CAFA-MET induces cell death independent of caspases and the tumor-suppressor protein p53, but probably mediated by the negative regulation of the pro-apoptotic Bcl-2. In addition, the lack of activation of caspase-8 and the positive regulation of caspase-3 induced by SAC-CAFA-PENT suggest that this compound acts through an apoptotic mechanism, probably initiated by intrinsic pathways. Furthermore, the downregulation of IL-6 by SAC-CAFA-PENT suggests that it also induces a significant anti-inflammatory process. In addition, docking studies would suggest caspase-3 modulation as the primary mechanism by which SAC-CAFA-PENT elicits apoptosis in SW480human colorectal adenocarcinoma cells. Meanwhile, density functional theory (DFT) calculations suggest that both hybrids would produce effects in the modulation of ROS in SW480 cells via the hydrogen atom transfer (HAT) pathway. The present work notes that SAC-CAFA-MET and SAC-CAFA-PENT could be potential candidates for further investigations in the search for potential chemopreventive agents.

Potential of Caffeic Acid Derivatives as Antimalarial Leads

Background:

Background Malaria remained one of the deadliest infectious diseases in 2021. Indeed, this infection, mostly caused by a protozoan called Plasmodium falciparum, is responsible for more than 200 million cases and around 400 000 related deaths annually, mainly in Africa. Despite the availability of efficient drugs, an increase of patients has occurred since 2015, which could be due to the development of resistances from the parasite, but also from its vectors, Anopheles mosquitoes. Consequently, it is necessary to search for new alternative treatments.

Methods:

Methods Polyphenols, and more precisely small phenolic acids, could represent a good starting point for new antimalarials. Indeed, these molecules, including caffeic acid (1), possess several pharmacological activities and an interesting pharmacokinetic profile. Therefore, we have developed several small derivatives of this scaffold to define the potential pharmacophore responsible for the antiplasmodial properties

Results:

Results A good to low activity on Plasmodium falciparum (IC50 = 16-241 µM) was observed, especially for the small ester derivatives (2-6). These molecules were good antiplasmodials compared to their mother compound (IC50 = 80 µM) and showed selectivity against human cells. These structures have also highlighted the need for catechol and carboxyl moieties in the anti-Plasmodium effect.

Conclusion:

Conclusion None of the synthetic caffeate derivatives reported here seemed sufficiently effective to become a potential antimalarial (IC50 < 1 µM). However, the significant increase of their efficacy on the malarial agent and the selectivity to human cells, highlighted their potential as new leads for future developments

4-methoxybenzalacetone, the cinnamic acid analog as a potential quorum sensing inhibitor against Chromobacterium violaceum and Pseudomonas aeruginosa

The continuous increase in the incidence of infectious diseases and the rapid unchecked rise in multidrug-resistance to conventional antibiotics have led to the search for alternative strategies for treatment and clinical management of microbial infections. Since quorum sensing (QS) regulates numerous virulence determinants and pathogenicity in bacteria, inhibition of QS promises to be an attractive target for development of novel therapeutics. In this study, a series of cinnamic acid analogs and benzalacetone analogs were designed and synthesized, and their QS-inhibitory activities explored. We found that, among the test compounds, 4-methoxybenzalacetone (8) exhibited potent anti-quorum sensing property, as evidenced by inhibition of QS-controlled violacein production of Chromobacterium violaceum ATCC12472. The inhibitory activity of such a compound, which was the methyl keto analog of the corresponding cinnamic acid, was not only stronger than the parent cinnamic acid (1), but also superior to that of furanone, the reference drug. Based on our observations, its mechanism of quorum sensing inhibition is likely to be mediated by interference with N-acyl-homoserine lactones (AHL) synthesis. Moreover, 4-methoxybenzalacetone (8) also suppressed the production of pyocyanin, rhamnolipids and swarming motility of Pseudomonas aeruginosa, suggesting a broad spectrum of anti-QS activities of this compound. In terms of structure-activity relationship, the possible chemical substitutions on the scaffold of cinnamic acid required for QS inhibitory activity are also discussed. Since 4-methoxybenzalacetone (8) showed no toxicity to both bacteria and mammalian cells, our findings therefore indicate the anti-QS potential of this compound as a novel effective QS inhibitor.

Alkyl and Aryl Derivatives Based on p-Coumaric Acid Modification and Inhibitory Action against Leishmania braziliensis and Plasmodium falciparum

In low-income populations, neglected diseases are the principal cause of mortality. Of these, leishmaniasis and malaria, being parasitic, protozoan infections, affect millions of people worldwide and are creating a public health problem. The present work evaluates the leishmanicidal and antiplasmodial action of a series of twelve p-coumaric acid derivatives. Of the tested derivatives, eight presented antiparasitic activities 1–3, 8–12. The hexyl p-coumarate derivative (9) (4.14 ± 0.55 μg/mL; selectivity index (SI) = 2.72) showed the highest leishmanicidal potency against the Leishmania braziliensis amastigote form. The results of the molecular docking study suggest that this compound inhibits aldehyde dehydrogenase (ALDH), mitogen-activated kinase protein (MPK4), and DNA topoisomerase 2 (TOP2), all of which are key enzymes in the development of Leishmania braziliensis. The data indicate that these enzymes interact via Van der Waals bonds, hydrophobic interactions, and hydrogen bonds with phenolic and aliphatic parts of this same compound. Of the other compounds analyzed, methyl p-coumarate (64.59 ± 2.89 μg/mL; IS = 0.1) demonstrated bioactivity against Plasmodium falciparum. The study reveals that esters presenting a p-coumarate substructure are promising for use in synthesis of derivatives with good antiparasitic profiles.

Structure-Activity Relationships of Cinnamate Ester Analogues as Potent Antiprotozoal Agents

Protozoal infections are still a global health problem, threatening the lives of millions of people around the world, mainly in impoverished tropical and sub-tropical regions. Thus, in view of the lack of efficient therapies and increasing resistances against existing drugs, this study describes the antiprotozoal potential of synthetic cinnamate ester analogues and their structure-activity relationships. In general, Leishmania donovani and Trypanosoma brucei were quite susceptible to the compounds in a structure-dependent manner. Detailed analysis revealed a key role of the substitution pattern on the aromatic ring and a marked effect of the side chain on the activity against these two parasites. The high antileishmanial potency and remarkable selectivity of the nitro-aromatic derivatives suggested them as promising candidates for further studies. On the other hand, the high in vitro potency of catechol-type compounds against T. brucei could not be extrapolated to an in vivo mouse model.

A Comprehensive QSAR Study on Antileishmanial and Antitrypanosomal Cinnamate Ester Analogues

Parasitic infections like leishmaniasis and trypanosomiasis remain as a worldwide concern to public health. Improvement of the currently available drug discovery pipelines for those diseases is therefore mandatory. We have recently reported on the antileishmanial and antitrypanosomal activity of a set of cinnamate esters where we identified several compounds with interesting activity against L. donovani and T. brucei rhodesiense. For a better understanding of such compounds' anti-infective activity, analyses of the underlying structure-activity relationships, especially from a quantitative point of view, would be a prerequisite for rational further development of such compounds. Thus, quantitative structure-activity relationships (QSAR) modeling for the mentioned set of compounds and their antileishmanial and antitrypanosomal activity was performed using a genetic algorithm as main variable selection tool and multiple linear regression as statistical analysis. Changes in the composition of the training/test sets were evaluated (two randomly selected and one by Kennard-Stone algorithm). The effect of the size of the models (number of descriptors) was also investigated. The quality of all resulting models was assessed by a variety of validation parameters. The models were ranked by newly introduced scoring functions accounting for the fulfillment of each of the validation criteria evaluated. The test sets were effectively within the applicability domain of the best models, which demonstrated high robustness. Detailed analysis of the molecular descriptors involved in those models revealed strong dependence of activity on the number and type of polar atoms, which affect the hydrophobic/hydrophilic properties causing a prominent influence on the investigated biological activities.

Discovery of a Novel Series of Tricyclic Oxadiazine 4a-Methyl Esters Based on Indoxacarb as Potential Sodium Channel Blocker/Modulator Insecticides

Indoxacarb, a commercialized oxadiazine insecticide, nearly irreversibly blocks open/inactivated, but not resting sodium channels. The structure-activity relationships showed that the substituents at the position of the chiral atom in the oxadiazine ring are very important to the biological activity of oxadiazine insecticide. Here we synthesized a series of tricyclic oxadiazine 4a-methyl ester derivatives. The chiral atom in the oxadiazine ring has been epimerized and substituted with either pyrethric acid or cinnamic acid derivatives. Benzene ring in the tricyclic moiety was substituted with a chlorine, fluorine, or bromine atom, and nitrogen-linked benzene ring was substituted with a trifluoromethyl or trifluoromethoxy group. Toxicity of these compounds against Spodoptera litura F. was evaluated. Diastereoisomers of most toxic compounds J7 and J9 with pyrethric acid moiety were separated by flash column chromatography. The more polar diastereoisomers, J7-L-Rf and J9-L-Rf, and compounds J24 and J26 with cinnamic acid moiety exhibited highest insecticidal activities. We further used Monte Carlo energy minimizations to dock compound J7 and J24 in the NavMs-based homology model of the open cockroach sodium channel. In the low-energy binding modes, the compound interacted with residues in the inner pore and domain interfaces, which previously were proposed to contribute to receptors of pyrethroids and sodium channel blocker insecticides. Our results define compound J7 and J24 as a potentially useful optimized hit for the development of multiple sites sodium channel blocker or modulator.

Design, Bioactivity and structure-activity of 3-Arylpropionate Derivatives as Potential High-Efficient Acaricides against Psoroptes Cuniculi

A series of 3-aryl propionic esters and their analogues were designed and evaluated for acaricidal activity in vitro against Psoroptes cuniculi, a mange mite. The structure–activity relationship (SAR) was also discussed. The results showed that 6 compounds possessed the excellent activity (LC₅₀ = 0.17–0.24 mM, LT₅₀ = 1.5–2.9 h), superior to ivermectin (LC₅₀ = 0.28 mM, LT₅₀ = 8.9 h) (P < 0.05), a standard drug. Furthermore, 7 compounds showed the good activity (LC₅₀ = 0.25–0.37 mM, LT₅₀ < 3.9 h), slightly lower or close to that of ivermectin. One compound displayed super-fast acaricidal property, far superior to ivermectin. SAR analysis found that the ester group is vital for the activity and the small steric hindrance adjacent to the ester group is advantageous for the high activity. The <C4 linear alcohol esters can give the higher activity. The substituents on the 3-phenyl ring or replacement of the 3-phenyl with heterocyclic aryl generally decreases the activity. The position of the ester group in the ester chain also influences the activity, where the 3-phenyl propionate and the benzoate had the highest and lowest activity, respectively. Thus, 3-arylpropionates emerged as new and promising high-efficient acaricide candidates.

Triclosan-caffeic acid hybrids: Synthesis, leishmanicidal, trypanocidal and cytotoxic activities

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. (V) panamensis (18-23, 26 and 30) and eight of them against T. cruzi (19-22, 24 and 28-30) with EC₅₀ values lower than 40 μM. Compounds 19-22, 24 and 28-30 showed higher activities than benznidazole (BNZ). Esters 19 and 21 were the most active compounds for both L. (V) panamensis and T. cruzi with 3.82 and 11.65 μM and 8.25 and 8.69 μM, respectively. Compounds 19-22, 24 and 28-30 showed higher activities than benznidazole (BNZ). Most of the compounds showed antiprotozoal activity and with exception of 18, 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.

Bioactivity and structure-activity relationship of cinnamic acid derivatives and its heteroaromatic ring analogues as potential high-efficient acaricides against Psoroptes cuniculi

A series of cinnamic acid derivatives and its heteroaromatic ring analogues were synthesized and evaluated for acaricidal activity in vitro against Psoroptes cuniculi, a mange mite. Among them, eight compounds showed the higher activity with median lethal concentrations (LC₅₀) of 0.36-1.07mM (60.4-192.1µg/mL) and great potential for the development of novel acaricidal agent. Compound 40 showed both the lowest LC₅₀ value of 0.36mM (60.4µg/mL) and the smallest median lethal time (LT₅₀) of 2.6h at 4.5mM, comparable with ivermectin [LC₅₀=0.28mM (247.4µg/mL), LT₅₀=8.9h], an acaricidal drug standard. SAR analysis showed that the carbonyl group is crucial for the activity. The type and chain length of the alkoxy in the ester moiety and the steric hindrance near the ester group significantly influence the activity. The esters were more active than the corresponding thiol esters, amides, ketones or acids. Replacement of the phenyl group of cinnamic esters with α-pyridyl or α-furanyl significantly increase the activity. Thus, a series of cinnamic esters and its heteroaromatic ring analogues with excellent acaricidal activity emerged.

Bioactivity and structure-activity relationship of cinnamic acid esters and their derivatives as potential antifungal agents for plant protection

A series of cinnamic acid esters and their derivatives were synthesized and evaluated for antifungal activities in vitro against four plant pathogenic fungi by using the mycelium growth rate method. Structure−activity relationship was derived also. Almost all of the compounds showed some inhibition activity on each of the fungi at 0.5 mM. Eight compounds showed the higher average activity with average EC₅₀ values of 17.4–28.6 μg/mL for the fungi than kresoxim-methyl, a commercial fungicide standard, and ten compounds were much more active than commercial fungicide standards carbendazim against P. grisea or kresoxim-methyl against both P. grisea and Valsa mali. Compounds C1 and C2 showed the higher activity with average EC₅₀ values of 17.4 and 18.5 μg/mL and great potential for development of new plant antifungal agents. The structure−activity relationship analysis showed that both the substitution pattern of the phenyl ring and the alkyl group in the alcohol moiety significantly influences the activity. There exists complexly comprehensive effect between the substituents on the phenyl ring and the alkyl group in the alcohol moiety on the activity. Thus, cinnamic acid esters showed great potential the development of new antifungal agents for plant protection due to high activity, natural compounds or natural compound framework, simple structure, easy preparation, low-cost and environmentally friendly.

Antiprotozoal activity of (E)-cinnamic N-acylhydrazone derivatives

A series of 14 (E)-cinnamic N-acylhydrazone derivatives, designed through molecular hybridization between the (E)-1-(benzo[d][1,3]dioxol-5-yl)-3-(4-bromophenyl)prop-2-en-1-one and (E)-3-hydroxy-N'-((2-hydroxynaphthalen-1-yl)methylene)-7-methoxy-2-naphthohydrazide, were tested for in vitro antiparasitic activity upon axenic amastigote forms of Leishmania donovani and bloodstream forms of Trypamosoma brucei rhodesiense. The derivative (2E)-3-(4-hydroxy-3-methoxy-5-nitrophenyl)-N'-[(1E)-phenylmethylene]acrylohydrazide showed moderate antileishmanial activity (IC₅₀ = 6.27 µM) when compared to miltefosine, the reference drug (IC₅₀ = 0.348 µM). However, the elected compound showed an excellent selectivity index; in one case it was not cytotoxic against mammalian L-6 cells. The most active antitrypanosomal compound, the derivative (E)-N'-(3,4-dihydroxybenzylidene)cinnamohydrazide (IC₅₀ = 1.93 µM), was cytotoxic against mammalian L-6 cells.

Synthesis, leishmanicidal and cytotoxic activity of triclosan-chalcone, triclosan-chromone and triclosan-coumarin hybrids

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 (EC50=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 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.