Acute Kaempferol Stimulation Induces AKT Phosphorylation in HepG2 Cells.

Type 2 diabetes mellitus (T2DM) stands as a prevalent global public health issue caused by deficiencies in the action of insulin and/or insulin production. In the liver, insulin plays an important role by inhibiting hepatic glucose production and stimulating glycogen storage, thereby contributing to blood glucose regulation. Kaempferitrin (KP) and kaempferol (KM), flavonoids found in Bauhinia forficata, exhibit insulin-mimetic properties, showing promise in managing T2DM. In this study, we aimed to assess the potential of these compounds in modulating the insulin signaling pathway and/or glucose metabolism. Cell viability assays confirmed the non-cytotoxic nature of both compounds toward HepG2 cells at the concentrations and times evaluated. Theoretical molecular docking studies revealed that KM had the best docking pose with the IR ß subunit when compared to the KP. Moreover, Langmuir monolayer evaluation indicated molecular incorporation for both KM and KP. Specifically, KM exhibited the capability to increase AKT phosphorylation, a key kinase in insulin signaling, regardless of insulin receptor (IR) activation. Notably, KM showed an additional synergistic effect with insulin in activating AKT. In conclusion, our findings suggest the potential of KM as a promising compound for stimulating AKT activation, thereby influencing energy metabolism in T2DM.

Employing "Red Flags" to Fight the Most Neglected Diseases: Nitroaromatic as Still Suitable Tools to Treat Human and Veterinary Parasitosis.

Nitroaromatic compounds have been used for treating parasitic diseases since the 1960s. Pharmacological alternatives to treat them are under observation. However, for the most neglected diseases, such as those caused by worms and less known protozoans, nitro compounds are still among the drugs of choice, despite their well-known collateral effects. In this review, we describe the chemistry and the uses of the still most employed nitroaromatic compounds for treating parasitosis caused by worms or lesser-known protozoans. We also describe their application as veterinary drugs. The most accepted mechanism of action seems to be the same, leading to collateral effects. For this reason, a special session was dedicated to discussing toxicity, carcinogenicity, and mutagenesis, as well as the most acceptable aspects of the known structure-activity/toxicity relationships involving nitroaromatic compounds. It employed the SciFindern search tool from the American Chemical Society in the search for the most relevant bibliography within the field, exploring keyword expressions such as "NITRO COMPOUNDS" and "BIOLOGICAL ACTIVITY" (within Abstracts or Keywords) and concepts related to parasites, pharmacology and toxicology. The results were classified according to the chemical classes of nitro compounds, being the most relevant studies regarding journal impact and interest of the described results chosen to be discussed. From the found literature, it is easy to notice that nitro compounds, especially the nitroaromatic ones, are still widely used in antiparasitic therapy, despite their toxicity. They also are the best starting point in the search for new active compounds.

Nifuroxazide as JAK2 inhibitor: A binding mode proposal and Hel cell proliferation assay.

Nifuroxazide has been employed as an anti-diarrheic agent since 1966, but in the last decade has brought to the research spotlight again due to its recently described antitumoral activity through the JAK2 inhibitory potential. Since 2008, more than 70 papers have been published about the issue and more are expected to the following years. Herein we discuss the findings of molecular modelling studies which were performed to elucidate the potential binding mode of this drug into the JAK2 ATP recognition site and also into the allosteric region near the catalytic site. Molecular modelling followed by dynamics simulations indicated the NFZ could bind at both sites, such as a Type II kinase inhibitor since residues from both ATP and modulatory site would exhibit contacts with the drug when in a stable complex. Synthesis of NFZ and its sulfur bioisosteric analogue GPQF-63 were performed and experimental assays against HEL cells indicate the potential of NFZ and, mainly of its analogue GPQF-63 in acting as inhibitors of cell growth. HEL-cells present the JAK2 V617F mutation which leads to an enhanced JAK/STAT pathway and they have never been tested by the NFZ activity before. A mechanistic approach was also performed and revealed that both compounds induce cell apoptosis.Taken together, both the theoretical and experimental approaches point out the N-acylhydrazones as good starting points in the search for JAK2 modulatory small molecules which could then, be studied as promising leads toward new alternatives to control the JAK-STAT pathway related pathologies. This is the first study, as far as we have known, to propose a potential binding mode for NFZ as well as reporting the activity of this drug against HEL cells, which are a usual cellular model to human erythroleukemia and other myeloproliferative diseases.

Exposure to sub-inhibitory ciprofloxacin and nitrofurantoin concentrations increases recA gene expression in uropathogenic Escherichia coli: The role of RecA protein as a drug target.

Sub-inhibitory concentrations (sub-MIC) of antimicrobial agents can lead to genetic changes in bacteria, modulating the expression of genes related to bacterial stress and leading to drug resistance. Herein we describe the impact of sub-MIC of ciprofloxacin and nitrofurantoin on three uropathogenic Escherichia coli strains. Disk-diffusion assays with different antimicrobial agents were tested to detect phenotype alterations, and quantitative real-time PCR (qRT-PCR) was performed to analyze the expression of ompF and recA genes. Significant reduction on the susceptibility to ciprofloxacin and nitrofurantoin was detected on disk diffusion test. The qRT-PCR results revealed a 1.2-4.7 increase in recA expression in all E. coli studied, while the ompF expression varied. Because RecA was pointed as an important component to the development of drug resistance, molecular docking studies were performed with three experimentally known inhibitors of this enzyme. These studies aimed to understand the inhibitory binding mode of such compounds. The results confirmed the ADP/ATP binding site as a potential site of inhibitor recognition and a binding mode based on π-stacking interactions with Tyr103 and hydrogen bonds with Tyr264. These findings can be useful for guiding the search and design of new antimicrobial agents, mainly concerning the treatment of infections with resistant bacterial strains.

N-Myristoyltransferases as antileishmanial targets: a piggyback approach with benzoheterocyclic analogues

Leishmaniasis is one of the neglected diseases that remain in need for pharmacological alternatives. In this context, N-Myristoyltransferases (NMT) arise as interesting targets to explore since they are involved in the co/post-translational processing of peptides which are responsible for host cell invasion. Studies that consider these enzymes as targets point out the potential of benzoheterocyclic compounds as inhibitors of Candida albicans's N-myristoyltransferase. Here we applied a combination of comparative binding site analysis and molecular docking studies based on a Piggyback approach in the search for new Leishmania major NMT ligands. Our results revealed that NMT enzymes from both pathogens present enough structural similarity to allow extrapolation of the knowledge available from C. albicans studies to develop new L. major NMT inhibitors. Molecular docking studies with benzoheterocyclic analogues indicate the potential of benzothiazole derivatives as L. major NMT ligands, giving rise to a completely new class of chemical compounds to be explored in the development of antileishmanial drugs.

4-Phenyl-1,3-thiazole-2-amines as scaffolds for new antileishmanial agents.

BACKGROUND: There is still a need for new alternatives in pharmacological therapy for neglected diseases, as the drugs available show high toxicity and parenteral administration. That is the case for the treatment of leishmaniasis, particularly to the cutaneous clinical form of the disease. In this study, we present the synthesis and biological screening of eight 4-phenyl-1,3-thiazol-2-amines assayed against Leishmania amazonensis. Herein we propose that these compounds are good starting points for the search of new antileishmanial drugs by demonstrating some of the structural aspects which could interfere with the observed activity, as well as suggesting potential macromolecular targets. METHODS: The compounds were easily synthesized by the methodology of Hantzsch and Weber, had their purities determined by Gas Chromatography-Mass spectrometry and assayed against the promastigote forms of Leishmania amazonensis as well as against two white cell lines (L929 and THP-1) and the monkey's kidney Vero cells. PrestoBlue® and MTT viability assays were the methodologies applied to measure the antileishmanial and cytotoxic activities, respectively. A molecular modeling target fishing study was performed aiming to propose potential macromolecular targets which could explain the observed biological behavior. RESULTS: Four out of the eight compounds tested exhibited important anti-promastigote activity associated with good selectivity indexes when considering Vero cells. For the most promising compound, compound 6, IC50 against promastigotes was 20.78 while SI was 5.69. Compounds 3 (IC50: 46.63 µM; SI: 26.11) and 4 (IC50: 53.12 µM; SI: 4.80) also presented important biological behavior. A target fishing study suggested that S-methyl-5-thioadenosine phosphorylase is a potential target to these compounds, which could be explored to enhance activity and decrease the potential toxic side effects. CONCLUSIONS: This study shows that 4-phenyl-1,3-thiazol-2-amines could be good scaffolds to the development of new antileishmanial agents. The S-methyl-5-thioadenosine phosphorylase could be one of the macromolecular targets involved in the action.

Flavones-bound in benzodiazepine site on GABAA receptor: Concomitant anxiolytic-like and cognitive-enhancing effects produced by Isovitexin and 6-C-glycoside-Diosmetin.

Increasing evidence suggests that flavones can modulate memory and anxiety-like behaviour. However, these therapeutic effects are inconsistent and induce of adverse effects, which have been associated with interactions at the Benzodiazepine (BZ)-binding site. To improve our understanding of flavone effects on memory and anxiety, we employed a plus-maze discriminative avoidance task. Furthermore, we evaluated the potential of the compounds in modulating GABAA receptors via BZ-binding site using molecular modelling studies. Adult male Wistar rats were treated 30 min before training session with Vicenin-2 (0.1 and 0.25 mg/kg), Vitexin (0.1 and 0.25 mg/kg), Isovitexin (0.1 and 0.25 mg/kg) and 0.1 mg/kg 6-C-glycoside-Diosmetin, vehicle and a GABAA receptor agonist. The analysis of the time spent in the non-aversive vs aversive enclosed arms during the test session and percentage of time in the open arms within the training session revealed that treatment with Isovitexin and 6-C-glycoside-Diosmetin had memory-enhancing and anxiolytic-like effects (P < 0.001). In contrast, treatment with a higher dose of Diazepam impaired short-and long-term memory when it alleviated anxiety level. Docking studies revealed that flavones docked in a very similar way to that observed to the Diazepam, except by a lack of interaction in residue α1His101 in the BZ-binding site on GABAA receptors, which may be related to memory-enhancing effect. The occurrence of the α1His101 interaction could justify the memory-impairing observed following Diazepam treatment. These findings provide the first evidence that Isovitexin and 6-C-glycoside-Diosmetin could exert their memory-enhancing and anxiolytic-like effects via GABAA receptor modulation, which likely occurs via their benzodiazepine-binding site.

4-Phenyl-1, 3-thiazole-2-amines as scaffolds for new antileishmanial agents

There is still a need for new alternatives in pharmacological therapy for neglected diseases, as the drugs available show high toxicity and parenteral administration. That is the case for the treatment of leishmaniasis, particularly to the cutaneous clinical form of the disease. In this study, we present the synthesis and biological screening of eight 4-phenyl-1,3-thiazol-2-amines assayed against Leishmania amazonensis. Herein we propose that these compounds are good starting points for the search of new antileishmanial drugs by demonstrating some of the structural aspects which could interfere with the observed activity, as well as suggesting potential macromolecular targets. Methods: The compounds were easily synthesized by the methodology of Hantzsch and Weber, had their purities determined by Gas Chromatography-Mass spectrometry and assayed against the promastigote forms of Leishmania amazonensis as well as against two white cell lines (L929 and THP-1) and the monkey's kidney Vero cells. PrestoBlue® and MTT viability assays were the methodologies applied to measure the antileishmanial and cytotoxic activities, respectively. A molecular modeling target fishing study was performed aiming to propose potential macromolecular targets which could explain the observed biological behavior. Results: Four out of the eight compounds tested exhibited important anti-promastigote activity associated with good selectivity indexes when considering Vero cells. For the most promising compound, compound 6, IC50 against promastigotes was 20.78 while SI was 5.69. Compounds 3 (IC50: 46.63 µM; SI: 26.11) and 4 (IC50: 53.12 µM; SI: 4.80) also presented important biological behavior. A target fishing study suggested that S-methyl-5-thioadenosine phosphorylase is a potential target to these compounds, which could be explored to enhance activity and decrease the potential toxic side effects. Conclusions: This study shows that 4-phenyl-1,3-thiazol-2-amines could be good scaffolds to the development of new antileishmanial agents. The S-methyl-5-thioadenosine phosphorylase could be one of the macromolecular targets involved in the action.(AU)

Molecular modeling approach to predict a binding mode for the complex methotrexate-carboxypeptidase G2.

Carboxypeptidase G(2) (CPG(2)) is a zinc-metalloenzyme employed in a range of cancer chemotherapy strategies by activating selectively nontoxic prodrugs into cytotoxic drugs in tumor as well as in the treatment of intoxication caused by high-doses of the anticancer drug methotrexate (MTX). CPG(2) catalyzes the hydrolytic cleavage of C-terminal of glutamate moiety from folic acid and analogues. Regardless of its extensive application, its mechanism of catalysis has not yet been determined and, so far, no co-crystallized complex has been published. So, in this study, molecular docking and a short molecular dynamics (MD) simulation sampling scheme, as a function of temperature, were performed to investigate a possible binding mode for MTX, a recognized substrate of CPG(2). The findings suggested that MTX interacts possibly in quite specific points of the CPG(2) active site, which are probably responsible for the molecular recognition and cleavage procedures. The MTX substrate fits well in the catalytic site by accommodating the pteridine moiety in an adjacent pocket to the active site whereas a glutamate moiety is pointed toward the protein surface. Additionally, a glutamate residue can interact with a crystallization water molecule in the active site, supporting its activation as a nucleophilic group.

New antitumoral agents I: In vitro anticancer activity and in vivo acute toxicity of synthetic 1,5-bis(4-hydroxy-3-methoxyphenyl)-1,4-pentadien-3-one and derivatives.

This paper describes a new method for the preparation of 1,5-bis(4-hydroxy-3-methoxyphenyl)-1,4-pentadien-3-one 1 and its derivatives 2-5. This set of synthetic compounds exhibited high antitumoral activities regarding in vitro screening against several human tumor cell lines as lung carcinoma NCI-460, melanoma UACC-62, breast MCF-7, colon HT-29, renal 786-O, ovarian OVCAR-03 and ovarian expressing the resistance phenotype for adriamycin NCI-ADR/RES, prostate PC-3, and leukemia K-562. Compounds were also tested against murine tumor cell line B16F10 melanoma and lymphocytic leukemia L1210 as well as to their effect toward normal macrophages. Specific activity against colon cancer cells HT-29 was observed for all tested compounds and suggests further studies with models of colon cancer. Compounds 1, 2, and 4 showed significant cytotoxic activity with IC(50) values 2.3 microM for all human cancer cell lines. Intraperitoneal acute administration of compound 1 and 2 showed very low toxicity rate.

New antitumoral agents I in vitro anticancer activity and in vivo acute toxicity of synthetic 15 bis(4-hydroxy-3-methoxyphenyl)14pentadien 3 one and derivatives

This paper describes a new method for the preparation of 1,5-bis(4-hydroxy-3-methoxyphenyl)-1,4-pentadien-3-one 1 and its derivatives 2–5. This set of synthetic compounds exhibited high antitumoral activities regarding in vitro screening against several human tumor cell lines as lung carcinoma NCI-460, melanoma UACC-62, breast MCF-7, colon HT-29, renal 786-O, ovarian OVCAR-03 and ovarian expressing the resistance phenotype for adriamycin NCI-ADR/RES, prostate PC-3, and leukemia K-562. Compounds were also tested against murine tumor cell line B16F10 melanoma and lymphocytic leukemia L1210 as well as to their effect toward normal macrophages. Specific activity against colon cancer cells HT-29 was observed for all tested compounds and suggests further studies with models of colon cancer. Compounds 1, 2, and 4 showed significant cytotoxic activity with IC50 values ⩽2.3 ìM for all human cancer cell lines. Intraperitoneal acute administration of compound 1 and 2 showed very low toxicity rate.

Antiproliferative and antimetastatic activity of DM-1, sodium 4-[5-(4-hydroxy-3-methoxyphenyl)-3-oxo-penta-1,4-dienyl]-2-methoxy-phenolate, in B16F10 melanoma

Melanoma causes 75% of skin cancer deaths mainly due to its high potential to progress to metastasis and by its recognized resistance to conventional therapies. Compound DM-1, sodium 4-[5-(4-hydroxy-3-methoxyphenyl)-3-oxo-penta-1,4-dienyl]-2-methoxy-phenolate, presents structural and biological similarity to curcumin, exhibiting properties such as potent antitumoral and antioxidant activities. In this work, the antitumoral and antiproliferative effects of this compound in in vitro assays with tumor and normal cell lines have been evaluated. Also evaluated was the in vivo antitumoral potential against B16F10 melanoma-bearing mice. Normal and tumor cells were treated with different concentrations of compound DM-1 and the cellular viability was determined by MTT colorimeter assay. The half maximal inhibitory concentration (IC50) found was 30 ìg/mL in B16F10 melanoma cells, while no toxic activity was verified against normal human fibroblastic cells. When DM-1 was administrated by intraperitoneal and endovenous routes to melanoma-bearing animals the survival rate increased by 40% when compared to the control group. Tumor load was reduced by 84% when administered via endovenous and by 54% via intraperitoneal. In conclusion, compound DM-1 acts as selective antitumoral agent inducing cytotoxicity in B16F10 melanoma cells, reducing the tumor load in the treated animals, as well as increasing the survival rate of the animal bearing this neoplasia.

Prodrugs for the treatment of neglected diseases.

Recently, World Health Organization (WHO) and Medicins San Frontieres (MSF) proposed a classification of diseases as global, neglected and extremely neglected. Global diseases, such as cancer, cardiovascular and mental (CNS) diseases represent the targets of the majority of the R&D efforts of pharmaceutical companies. Neglected diseases affect millions of people in the world yet existing drug therapy is limited and often inappropriate. Furthermore, extremely neglected diseases affect people living under miserable conditions who barely have access to the bare necessities for survival. Most of these diseases are excluded from the goals of the R&D programs in the pharmaceutical industry and therefore fall outside the pharmaceutical market. About 14 million people,mainly in developing countries, die each year from infectious diseases. From 1975 to 1999,1393 new drugs were approved yet only 1% were for the treatment of neglected diseases[3]. These numbers have not changed until now, so in those countries there is an urgent need for the design and synthesis of new drugs and in this area the prodrug approach is a very interesting field. It provides, among other effects, activity improvements and toxicity decreases for current and new drugs, improving market availability. It is worth noting that it is essential in drug design to save time and money, and prodrug approaches can be considered of high interest in this respect. The present review covers 20 years of research on the design of prodrugs for the treatment of neglected and extremely neglected diseases such as Chagas' disease (American trypanosomiasis), sleeping sickness (African trypanosomiasis), malaria, sickle cell disease, tuberculosis, leishmaniasis and schistosomiasis.

Quimioterápicos potencialmente ativos em endemias tropicais e tuberculose: estudos de QSAR na série de 5-nitroderivados benzidrazídicos e o planejamento de pró-fármacos de ação prolongada / Chemotherapeutic agents potentially active in tropical endemic and tuberculosis: QSAR studies in the series of 5-nitro-benzhydrazide derivatives and the design of prolonged action prodrugs

Malária, doença de Chagas e leishmaniose, consideradas doenças negligenciadas, e tuberculose, infecção bacteriana reemergente, que grassa em diversas regiões do mundo, constituem-se grandes desafios médico-sociais para os países acometidos. Nitroderivados são substâncias utilizadas na terapêutica como antimicrobianos de amplo espectro. O mecanismo de ação proposto para estes compostos engloba a redução do grupo nitro por nitrorredutases inespecíficas, levando à produção de radicais livres. Estes, altamente reativos, reagiriam, por sua vez, com macromoléculas, organelas, membranas e mesmo ácidos nucléicos danificando-os irreversivelmente e levando o microrganismo bactérias e parasitos - à morte. No caso particular da doença de Chagas, a redutase envolvida na redução seria a tripanotiona redutase, que poderia ser inibida por estes compostos...

Use of N-methylene phosphonic chitosan to obtain an isoniazid prodrug

Tuberculosis (TB) is one of the most neglected health problems and has out of control in many areas of the world. Since new antituberculous alternatives, including controlled classical drug delivery systems, are urgently needed to face this serious situation, the purpose of the present work was the sysnthesis and characterization of a prolonged action prodrug of isoniazid. The N-methylene phosphonic chitosan (NMPC), a hydrosoluble derivative of chitosan was the synthesis and characterization of a prolonged action prodrug of isoniazid. The N-methylene phosphonic chitosan (NMPC), a hydrosoluble derivative of chitosan was used as drug carrier. This analog, as well as its precursor, exhibits simulatory activity on macrophages, host cells of Mycobacterium tuberculosis...