Discovery of dual-action phenolic 4-arylidene-isoquinolinones with antioxidant and α-glucosidase inhibition activities.

A multicomponent-derived synthesis of arylidene isoquinolinones decorated with phenolic moieties is described. The series demonstrated good DPPH trapping and, in the case of sinapic acid-containing analogs, excellent activity against lipoperoxidation; EPR also demonstrated that one derivative scavenged hydroxyl radicals. In addition, some compounds showed excellent inhibition of α-glucosidase activity and, according to both Lineweaver-Burk plots and molecular docking, they act as non-competitive or mixed inhibitors. In vitro assay also demonstrated that two compounds significantly reduced the plasma glucose levels after sucrose administration. In summary, the studied isoquinolinones become novel compounds with dual action (antioxidant and α-glucosidase inhibition) against diabetes and related metabolic diseases, whose optimization would lead to more potent candidates.

Synthesis, antibiofilm activity and molecular docking of N-acylhomoserine lactones containing cinammic moieties.

We prepared a series of cinnamoyl-containing furanones by an affordable and short synthesis. The nineteen compounds hold a variety of substituents including electron-donating, electron-withdrawing, bulky and meta-substituted phenyls, as well as heterocyclic rings. Compounds showed antibiofilm activity in S. aureus, K. pneumoniae and, more pronounced, against P. aeruginosa. The disruption of quorum sensing (QS) was tested using the violacein test and molecular docking predicted the antagonism of LasR as a plausible mechanism of action. The trimethoxylated and diene derivatives showed the best antibiofilm and anti-QS properties, thus becoming candidates for further modifications.

A regioselective synthesis of 3,4-diaryl-1H-pyrazoles through a 1,3-dipolar cycloaddition of tosylhydrazones and nitroalkenes.

A procedure for the selective synthesis of 3,4-diaryl-1H-pyrazoles through a 1,3-dipolar cycloaddition is reported. The transformation occurred under mild conditions using affordable tosylhydrazones and nitroalkenes commencing from benzaldehydes/heteroaromatic aldehydes as starting materials. Due to the versatility of this protocol, we prepared a vast collection of 3,4-diaryl-1H-pyrazoles, which included the incorporation of heterocyclic rings at the pyrazole core. Two-dimensional NMR techniques (2D-NOESY and HMBC) confirmed the regioselectivity of the transformation and correlated well with DFT calculations. Accordingly, the analysis of the transition states indicated that the 3,4-diaryl product corresponded to the product with the lowest activation energy and led to the most stable product. Finally, the series was evaluated against three cancer cell lines, with compound 8f being the most remarkable analog in terms of activity and extraordinary selectivity towards PC-3 compared to the other cell lines (including COS-7).

Expanding the structure-activity relationship of cytotoxic diphenyl macrocycles.

Twenty-four biaryl tetrapeptide macrocycles were synthesized as an extension of our previous work. Two groups of compounds were constructed for establishing a structure-activity relationship: one having an aromatic substituent at α-position of one exo-peptide and the other group with a variation in the size of the lipophilic chain. Compound 13t had the best cytotoxicity from all the compounds tested (in a panel of six human cancer cell lines) and low toxicity on one healthy cell line. The study identified the lipophilic chain as the main structural moiety for improving the biological activity, being the seven-carbon chain the optimal length. On the other hand, the aromatic rings at α-position did not enhance the cytotoxicity.

Multicomponent synthesis and anti-proliferative screening of biaryl triazole-containing cyclophanes.

We report a practical two-step approach involving a Ugi 4-CR/ azide-alkyne cycloaddition for the synthesis of biaryl-containing cyclophanes. The series represents an extension of our previously reported macrocycles as an effort to enhance the anti-proliferative activity of this scaffold. In this variant, we incorporate a biphenyl moiety in the framework, thus enhancing the macrocycle size, lipophilicity, and structural diversity. Macrocycles were tested against different cell lines, being more cytotoxic against prostate (PC-3 and DU-145) and breast (MCF-7) tumor cells. Gratifyingly, the most active compound showed a significative enhancement of PC-3 growth inhibition with respect to our previous series, reaffirming the potential anti-proliferative activity of this kind of cyclophanes.

Multicomponent synthesis and preliminary anti-inflammatory activity of lipophilic diphenylamines.

Non-Steroidal Anti-inflammatory Drugs (NSAIDs) are some of the most prescribed medications for pain but the incidence of adverse effects -especially during chronic treatment- points out the requirement of new analgesics. In this study, we showed an efficient two-steps synthesis of diphenylamine-containing dipeptides consisting of a multicomponent process followed by a Buchwald-Hartwig cross-coupling reaction. We prepared 16 diphenylamine derivatives and evaluated their in vivo anti-inflammatory activity through an ear edema model using 12-O-tetradecanoylpholbol-13-acetate. Furthermore, the toxicity of the more potent compounds in the Artemia salina model and their cell viability using murine RAW 264.7 cells is reported. The fluorinated compound 10k becomes a reliable candidate since it reduced the TPA-induced edema to 92%, lacked cytotoxicity against murine macrophages, and had minimal toxicity in Artemia salina.

Discovery of Benzopyrrolizidines as Promising Antigiardiasic Agents.

Current treatments for giardiasis include drugs with undesirable side effects, which increase the levels of therapeutic desertion and promote drug resistance in the parasites. Herein, we describe the antigiardiasic evaluation on Giardia lamblia trophozoites of a structurally diverse collection of 74 molecules. Among these scaffolds, we discovered a benzopyrrolizidine derivative with higher antigiardiasic activity (IC50 = 11 µM) and lower cytotoxicity in human cell cultures (IC50 = 130 µM) than those displayed by the current gold-standard drugs (metronidazole and tinidazole). Furthermore, this compound produced morphologic modifications of trophozoites, with occasional loss of one of the nuclei, among other changes not observed with standard giardicidal drugs, suggesting that it might act through a novel mechanism of action.

Synthesis of diphenylamine macrocycles and their anti-inflammatory effects.

A collection of fourteen diphenylamine macrocyclic derivatives containing a peptide chain with different substituents was synthesized using a protocol of two Ugi four component reactions (Ugi-4CR) and a Buchwald-Hartwig macrocyclization. Their anti-inflammatory effects were assayed with an ear edema model using 12-O-tetradecanoylphorbol-13-acetate, while the activity of myeloperoxidase was determined to evaluate the index of leukocyte infiltration. Compound 5e had an ID50 of 0.18 µM per ear with a potency higher than that of the reference drugs indomethacin and celecoxib (0.24 and 0.91 µM per ear, respectively). Moreover, the cytotoxicity of the macrocycles was determined in two healthy cell lines, showing a low percentage of toxicity.

A Two-Step Multicomponent Synthetic Approach and Anti-inflammatory Evaluation of N-Substituted 2-Oxopyrazines.

Inflammation is widely reported as a main factor for the development of chronic diseases such as cancer, diabetes, and even metabolic syndrome. Thus, the search for novel anti-inflammatory compounds is required. Herein we describe the synthesis of a collection of peptidic pyrazinones by a convenient approach involving a multicomponent isocyanide-based reaction followed by a tandem deprotection/oxidative cyclization step. This series of compounds were tested for their potential anti-inflammatory capacity in an in vivo murine model, and four compounds were identified to inhibit tetradecanoylphorbol acetate (TPA)-induced edema by more than 75 %. The two most active compounds, N-benzyl-2-(4-hydroxy-3,5-dimethoxyphenyl)-2-[2-oxopyrazin-1(2H)-yl]acetamide (10 o) and N-cyclohexyl-2-[2-oxopyrazin-1(2H)-yl]-2-[4-(trifluoromethyl)phenyl]acetamide (10 x), with methyl and trifluoromethyl groups, were also able to decrease myeloperoxidase activity and leukocyte infiltration. Moreover, 10 x decreased the thickness of TPA-treated mouse ears, as observed in histological analysis of the tissues.

Acute and subacute antidiabetic studies of ENP-9, a new 1,5-diarylpyrazole derivative.

OBJECTIVES: To explore the antihyperglycaemic and antidiabetic effects and to determine the acute toxicity of 5-(4-chlorophenyl)-1-(2,4-dichloro-phenyl)-4-methyl-N-(piperidin-1-yl)-1H-pyrazole-3-carboxamide (ENP-9). METHODS: The antihyperglycaemic effect of ENP-9 (50 mg/kg) was determined by oral glucose tolerance test (OGTT). Also, the acute (16, 50 and 160 mg/kg) and subacute (50 mg/kg/day for 10 days) antidiabetic effects of ENP-9 were determined. After subacute treatment, blood samples were analysed to determine glucose and lipid profiles. Also, an acute toxicity determination of ENP-9 was conducted followed the OECD recommendation. Molecular docking was performed using AutoDock 4.2.6 at human cannabinoid receptor 1 (PDB code 5TGZ). KEY FINDINGS: Acute Administration of ENP-9 showed significant antidiabetic effect and decreased the maximum OGTT peak, compared to the control group (P < 0.05). Moreover, the 10 days treatment induced a decrease in plasma glucose levels, being significant at the end of the experiments (P < 0.05); however, triacylglycerols and cholesterol were not modified. Finally, LD50 of ENP-9 was estimated to be greater than 2000 mg/kg. Molecular docking suggests that ENP-9 may act as rimonabant does. CONCLUSIONS: ENP-9 showed significant antihyperglycaemic and antidiabetic properties and also was demonstrated to be safety in the studied doses, which might allow future studies for its potential development as antidiabetic agent.

Cytotoxic Activity and Structure-Activity Relationship of Triazole-Containing Bis(Aryl Ether) Macrocycles.

Cancer continues to be a worldwide health problem. Certain macrocyclic molecules have become attractive therapeutic alternatives for this disease because of their efficacy and, frequently, their novel mechanisms of action. Herein, we report the synthesis of a series of 20-, 21-, and 22-membered macrocycles containing triazole and bis(aryl ether) moieties. The compounds were prepared by a multicomponent approach from readily available commercial substrates. Notably, some of the compounds displayed interesting cytotoxicity against cancer (PC-3) and breast (MCF-7) cell lines, especially those bearing an aliphatic or a trifluoromethyl substituent on the N-phenyl moiety (IC50 <13 µm). Additionally, some of the compounds were able to induce apoptosis relative to the solvent control; in particular, (Z)-N-cyclohexyl-7-oxo-6-[4-(trifluoromethyl)phenyl]-11 H-3,10-dioxa-6-aza-1(4,1)-triazola-4(1,3),9(1,4)-dibenzenacyclotridecaphane-5-carboxamide (12 f) was the most potent in this regard (22.7 % of apoptosis).

Diversity-oriented synthesis and cytotoxic activity evaluation of biaryl-containing macrocycles.

Synthesis of biaryl-containing macrocycles has been carried out through a four-step approach comprising two Ugi four component reactions and a Suzuki-Miyaura macrocyclization. This protocol allowed the synthesis of 12- and 14-membered macrocycles. Cytotoxic activity evaluation showed that some of the molecules were effective against leukemia, glioblastoma and lung cancer cell lines (IC50 = 4.0, 5.9 and 7.6, respectively).

Antidiabetic, antidyslipidemic and toxicity profile of ENV-2: A potent pyrazole derivative against diabetes and related diseases.

Diabetes is a major health problem and a predisposition factor for further degenerative complications and, therefore, novel therapies are urgently needed. Currently, cannabinoid receptor 1 (CB1 receptor) antagonists have been considered as promissory entities for metabolic disorders treatment. Accordingly, the purpose of this work was the evaluation of the sub-acute antidiabetic, anti-hyperglycemic, antidyslipidemic and toxicological profile of ENV-2, a potent hypoglycemic and antioxidant CB1 receptor antagonist. In this study, ENV-2 showed a pronounced anti-hyperglycemic effect even at a dose of 5mg/kg (P<0.05) in a glucose tolerance test on normoglycemic rats. Moreover, after administration of ENV-2 (16mg/kg) to diabetic rats, a prominent antidiabetic activity was observed (P<0.05), which was higher than glibenclamide. Sub-acute treatment (10 days) of ENV-2 resulted in a significant reduction of plasma glucose (P<0.05). Also, the levels of peripheral lipids were improved; blood triacylglycerols (TG) and cholesterol (CHOL) were diminished (P<0.05). In addition, it was found that ENV-2 reduced IL-1ß and IL-18 mRNA expression in adipose tissue (P<0.05). Due to the satisfactory outcomes, we were interested in evaluating the toxicity of ENV-2 in both acute and sub-chronic approaches. Regarding the acute administration, the compound resulted to be non-toxic and was grouped in category 5 according to OECD. It was also found that sub-chronic administration did not increase the size of the studied organs, while no structural damage was observed in heart, lung, liver and kidney tissues. Finally, neither AST nor ALT damage hepatic markers were augmented.

Practical synthesis and cytotoxic evaluation of the pyrazino[1,2-b]-isoquinoline ring system.

A practical three-step protocol for the synthesis of pyrazino[1,2-b]isoquinolines is reported. This approach includes a one-pot parallel cyclization/cyclization parallel process followed by a non-common 6-endo Heck cyclization that transformed previously constructed Ugi adducts into diversely decorated tricyclic systems. Compounds bearing a t-butyl or 2,6-dimethylphenyl substituent showed significant cytotoxic activity. The most active analogue (6p) showed significant activity against HCT-15 and K562 (IC50 = 41.8 ± 3.3 and 57.7 ± 2.1 µM, respectively) with no cytotoxicity against human gingival fibroblasts.

Synthesis and molecular docking of N'-arylidene-5-(4-chlorophenyl)-1-(3,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carbohydrazides as novel hypoglycemic and antioxidant dual agents.

Herein, the design and synthesis of 10 novel N'-arylidene pyrazole-3-carbohydrazides are described. Compounds were pretended to act as dual agents against diabetes and oxidative stress, two correlated pathologies involved in metabolic syndrome development and progression. The antioxidant capacity was evaluated by means of DPPH and FRAP in vitro assays. It was found that compounds bearing a hydroxyl group at 4-position of the hydrazone moiety are potent antioxidant entities, being compound 3g (a syringaldehyde derivative) the most active compound. In addition, the in vivo hypoglycemic effect of the analogues was determined. With regard to the above, the cinnamaldehyde derivatives showed a scarce biological activity, while the 4-hydroxy analogues showed the higher glycemia reduction at 7h after administration. Interestingly, the most potent antioxidants 3b and 3g also were of the most active compounds in reducing the plasma glucose, reaching 80% of reduction in the case of 3g. Molecular docking binding poses conducted to a plausible interpretation of the biological outcomes and a possible interaction between a hydroxy group and Asn287 of CB1R was proposed as an important feature for enhancing the observed activity.

Multicomponent/Palladium-Catalyzed Cascade Entry to Benzopyrrolizidine Derivatives: Synthesis and Antioxidant Evaluation.

A versatile and efficient protocol for the synthesis of highly substituted benzopyrrolizidines (tetrahydro-3H-pyrrolo[2,1-a]isoindol-3-ones) is reported. The strategy consisted of an Ugi four-component reaction/elimination methodology to afford dehydroalanines containing trans-cinnamic acid derivatives and different substituted 2-bromobenzylamines, followed by a palladium-catalyzed 5-exo-trig/5-exo-trig cascade carbocyclization process. Gratifyingly, benzopyrrolizidines were obtained in moderate to good yields (42-77%) with a Z geometry due to the structural requirements for syn-ß-hydride elimination. The prepared heterocyclic scaffolds are decorated with several substituents and incorporate a benzopyrrolizidine-fused system, along with an embedded cinnamic acid derivative, two privileged medicinal chemistry scaffolds. Additionally, since some of the compounds are derived from the well-known antioxidants ferulic and sinapinic acids, they were tested for their in vitro antioxidant capacity. The data suggested that compounds having a p-hydroxyl group showed moderate 2,2-diphenyl-1-picrylhydrazyl-radical-scavenging activity and were effective antioxidants in preventing lipoperoxidation in a thiobarbituric acid reactive substances assay.

Ugi-derived dehydroalanines as a pivotal template in the diversity oriented synthesis of aza-polyheterocycles.

Various readily available, Ugi-derived dehydroalanines were used as pivotal templates to easily and efficiently assemble diverse pharmacologically important polyheterocyclic systems through cascade palladium-catalyzed C-C bond formation processes. Allyl, homoallyl and propargylamine led to the formation of benzopyrrolizidinones, benzoindolizidinones and pyrazinoisoquinolines, respectively, while benzylamines and o-bromobenzylamines were used as precursors of tetracyclic-fused systems and pyrazionoisoquinolindiones.

1,5-Diarylpyrazole and vanillin hybrids: Synthesis, biological activity and DFT studies.

Herein, we report the design and synthesis of 13 diarylpyrazole hybrids with vanillin constructed as dual compounds against oxidative stress and diabetes. Compounds were tested in two different antioxidant assays. It was found that all compounds showed an important antioxidant activity in both DPPH and ORAC models and the activity was even more remarkable than vanillin. In addition, the hypoglycemic effect of compounds 1, 2, 4 and 12 was evaluated. Interestingly, compound 1 had the most potent hypoglycemic effect with a glycemia reduction of 71%, which was higher than rimonabant. Finally, a DFT study to propose a reasonable antioxidant mechanism is detailed. Both thermodynamic and kinetic studies indicated that the most feasible mechanism consists in the HAT abstraction of the phenolic hydrogen due to the formation of an stable transition state through the most rapid and exergonic path, while the SPLET mechanism is the most significant at higher pH values.

ENP11, a potential CB1R antagonist, induces anorexia in rats.

Over the past decade, pharmacological manipulation of cannabinoid 1 receptor (CB1R) has become an interesting approach for the management of food ingestion disorders, among other physiological functions. Searching for new substances with similar desirable effects, but fewer side-effects we have synthesized a SR141716A (a cannabinoid receptor inverse agonist also called Rimonabant) analog, 1-(2,4-Difluorophenyl)-4-methyl-N-(1-piperidinyl)-5-[4-(trifluoromethyl)phenyl]-1H-pyrazole-3-carboxamide, ENP11, that so far, as we have previously shown, has induced changes in glucose availability, i.e. hypoglycemia, in rats. In this study we tested the effects, if any, of ENP11 (0.5, 1.0, and 3.0mg/kg) in food ingestion, core temperature, pain perception and motor control in adult Wistar rats. Results showed that ENP11 reduced food ingestion during the first hour immediately after administration. Likewise, ENP11 (1.0mg/kg) blocked anandamide (AEA)-induced hyperphagia during the first 4h of the dark phase of the light-dark cycle, and it also blocked AEA-induced hypothermia. However, none of the ENP11 doses used affected pain perception or motor control. We believe that ENP11 is a potential useful CB1R antagonist that reduces food ingestion and regulates core temperature.

Synthesis, hypoglycemic activity and molecular modeling studies of pyrazole-3-carbohydrazides designed by a CoMFA model.

Diabetes and obesity are two universal health problems that constitute a research objective of several groups due to the lack of efficient and safe drug treatment. In this sense, cannabinoid receptor 1 (CB1) has attracted interest because of its role in food intake and metabolic balance, two targets in the control of metabolic syndrome. In this work, novel 1,5-diaryl pyrazole derivatives were synthesized in accordance with the pKi prediction of a previously reported CoMFA model by our group. To further investigate the biological activity of these compounds in metabolic disorders, their hypoglycemic activity in an in vivo model was tested. Interestingly, a high degree of correlation was observed between the predicted pKi and hypoglycemic effect 7 h after administration. Compounds 4, 9 and 13 showed the most significant plasma glucose reduction with decreases of 60%, 64% and 60% respectively. This result not only surpasses the activity of the lead rimonabant, but also that of the reference drug glibenclamide. Moreover, PASS prediction and molecular docking in an excellent validated homology model of CB1 suggest that these compounds would probably act as CB1 antagonists/inverse agonists and therefore, anti-obesity agents. The ligand-receptor complexes demonstrate that 1,5-diaryl pyrazole derivatives bind to the proposed binding site where a hydrophobic moiety interacts with the phenyl rings in the pyrazole nucleus and Lys192 forms a hydrogen bond with the oxygen of the carbonyl group. Dynamics simulations were also carried out to study the stability of the ligand-receptor complexes where the most active compounds showed smaller ΔG values and more hydrogen bonds throughout the simulation. These compounds are considered useful leads for further optimization in the treatment of such metabolic illnesses.