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1.
J Nat Prod ; 87(4): 976-983, 2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38438310

RESUMO

Three unique linear oligomeric depsipeptides, designated as cavomycins A-C (1-3), were identified from Streptomyces cavourensis, a gut bacterium associated with the annelid Paraleonnates uschakovi. The structures of these depsipeptides were determined through a combination of spectroscopic methods and chemical derivatization techniques, including methanolysis, the modified Mosher's method, advanced Marfey's methods, and phenylglycine methyl ester derivatization. The unique dipeptidyl residue arrangements in compounds 1-3 indicate that they are not degradation products of valinomycin. Compound 2 and its methylation derivative 2a exhibited antiproliferative activity against PANC-1 pancreatic cancer cells with IC50 values of 1.2 and 1.7 µM, respectively.


Assuntos
Depsipeptídeos , Streptomyces , Streptomyces/química , Depsipeptídeos/farmacologia , Depsipeptídeos/química , Depsipeptídeos/isolamento & purificação , Humanos , Estrutura Molecular , Animais , Ensaios de Seleção de Medicamentos Antitumorais , Antineoplásicos/farmacologia , Antineoplásicos/química , Antineoplásicos/isolamento & purificação
2.
Arch Pharm (Weinheim) ; 356(3): e2200444, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36461683

RESUMO

In the present investigation, we devolved and synthesized a new series of pyrazole-embedded thiazolidin-4-one derivatives (9a-p) with the goal to produce promising antitubercular leads. The in vitro antimycobacterial activity of the synthesized compounds was tested against replicating and nonreplicating Mtb H37Rv strains. With MIC ranging from 3.03 to 22.55 µg/ml, five compounds (9a, 9c, 9d, 9e, and 9f) emerged as promising antitubercular agents. The active molecules were nontoxic to normal Vero cells. All the synthesized compounds were evaluated for in vitro anti-inflammatory studies. Compounds 9a, 9b, 9c, 9h, and 9i exhibited excellent anti-inflammatory efficacy. Docking study was performed to understand the binding pattern of the significantly active compound 9a with 1P44.


Assuntos
Simulação de Dinâmica Molecular , Mycobacterium tuberculosis , Animais , Chlorocebus aethiops , Células Vero , Relação Estrutura-Atividade , Antituberculosos/farmacologia , Antituberculosos/química , Pirazóis/farmacologia , Simulação de Acoplamento Molecular , Estrutura Molecular , Testes de Sensibilidade Microbiana
3.
Bioorg Chem ; 128: 106074, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35987188

RESUMO

The imidazo[1,2-a]pyridine-3-carboxyamides (IAPs) are a unique class of compounds endowed with impressive nanomolar in vitro potency against Mycobacterium tuberculosis (Mtb) as exemplified by clinical candidate Telacebec (Q203). These compounds target mycobacterial respiration through inhibition of the QcrB subunit of cytochrome bc1:aa3 super complex resulting in bacteriostatic efficacy in vivo. Our labs have had a long-standing interest in the design and development of IAPs. However, some of these compounds suffer from short in vivo half-lives, requiring multiple daily dosing or the addition of a cytochrome P450 inhibitor for murine efficacy evaluations. Deuteration has been shown to decrease metabolism as the C-D bond is stronger than the CH bond. Herein we describe our efforts on design and synthesis of potent deuterated IAPs and the effect that deuteration has upon metabolism through microsomal stability studies.


Assuntos
Mycobacterium tuberculosis , Tuberculose , Animais , Antituberculosos/química , Humanos , Camundongos , Piridinas/metabolismo , Piridinas/farmacologia , Tuberculose/microbiologia
4.
Antimicrob Agents Chemother ; 65(8): e0028221, 2021 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-34097493

RESUMO

Anti-infective drug discovery is greatly facilitated by the availability of in vitro assays that are more proficient at predicting the preclinical success of screening hits. Tuberculosis (TB) drug discovery is hindered by the relatively slow growth rate of Mycobacterium tuberculosis and the use of whole-cell-based in vitro assays that are inherently time-consuming, and for these reasons, rapid, noninvasive bioluminescence-based assays have been widely used in anti-TB drug discovery and development. In this study, in vitro assays that employ autoluminescent M. tuberculosis were optimized to determine MIC, minimum bactericidal concentration (MBC), time-kill curves, activity against macrophage internalized M. tuberculosis (90% effective concentration [EC90]), and postantibiotic effect (PAE) to provide rapid and dynamic biological information. Standardization of the luminescence-based MIC, MBC, time-kill, EC90, and PAE assays was accomplished by comparing results of established TB drugs and two ClpC1-targeting TB leads, ecumicin and rufomycin, to those obtained from conventional assays and/or to previous studies. Cumulatively, the use of the various streamlined luminescence-based in vitro assays has reduced the time for comprehensive in vitro profiling (MIC, MBC, time-kill, EC90, and PAE) by 2 months. The luminescence-based in vitro MBC and EC90 assays yield time and concentration-dependent kill information that can be used for pharmacokinetic-pharmacodynamic (PK-PD) modeling. The MBC and EC90 time-kill graphs revealed a significantly more rapid bactericidal activity for ecumicin than rufomycin. The PAEs of both ecumicin and rufomycin were comparable to that of the first-line TB drug rifampin. The optimization of several nondestructive, luminescence-based TB assays facilitates the in vitro profiling of TB drug leads in an efficient manner.


Assuntos
Anti-Infecciosos , Mycobacterium tuberculosis , Tuberculose , Antituberculosos/farmacologia , Antituberculosos/uso terapêutico , Humanos , Testes de Sensibilidade Microbiana , Tuberculose/tratamento farmacológico
5.
J Nat Prod ; 84(10): 2644-2663, 2021 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-34628863

RESUMO

Rufomycin and ilamycin are synonymous for the same class of cyclopeptides, currently encompassing 33 structurally characterized isolates and 9 semisynthetic derivatives. Elucidation of new structures prioritized the consolidation of the names and established the structures of four diastereoisomeric rufomycins with a 2-piperidinone, named rufomycins 4-7, including full 1H/13C NMR assignments. The characteristic HSQC cross-peak for the CH-5, the hemiaminal carbon in amino acid #5, allows assignment of the stereocenters C-4 and C-5 within this ring. Semisynthetic derivatives (rufomycinSS 1, 2, and 3) were prepared from a rufomycins 4 and 6 mixture to validate the structural assignments. Based on the X-ray crystal structures of rufomycins 2 and 4, considering the NMR differences of rufomycins 7 vs 4-6 compared to rufomycinSS 1 vs 2 and 3, and taking into account that two major conformers, A and B, occur in both rufomycinSS 2 and 3, structural modeling was pursued. Collectively, this paper discusses the NMR spectroscopic differences of the stereoisomers and their possible 3D conformers and correlates these with the anti-Mycobacterium tuberculosis activity. In addition, a look at the history prioritizes names and numbering schemes for this group of antibiotics and leads to consolidated nomenclature for all currently known members, natural and semisynthetic derivatives, and serves to accommodate future discoveries.


Assuntos
Oligopeptídeos/química , Peptídeos Cíclicos/química , Antituberculosos/química , Espectroscopia de Ressonância Magnética , Testes de Sensibilidade Microbiana , Estrutura Molecular , Mycobacterium tuberculosis/efeitos dos fármacos , Terminologia como Assunto
6.
J Nat Prod ; 83(3): 657-667, 2020 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-32031795

RESUMO

This study represents a systematic chemical and biological study of the rufomycin (RUF) class of cyclic heptapeptides, which our anti-TB drug discovery efforts have identified as potentially promising anti-TB agents that newly target the caseinolytic protein C1, ClpC1. Eight new RUF analogues, rufomycins NBZ1-NBZ8 (1-8), as well as five known peptides (9-13) were isolated and characterized from the Streptomyces atratus strain MJM3502. Advanced Marfey's and X-ray crystallographic analysis led to the assignment of the absolute configuration of the RUFs. Several isolates exhibited potent activity against both pathogens M. tuberculosis H37Rv and M. abscessus, paired with favorable selectivity (selectivity index >60), which collectively underscores the promise of the rufomycins as potential anti-TB drug leads.


Assuntos
Antituberculosos/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Oligopeptídeos/farmacologia , Streptomyces/química , Cristalografia por Raios X , Testes de Sensibilidade Microbiana , Estrutura Molecular
7.
Mar Drugs ; 17(9)2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31510079

RESUMO

Three new lavandulylated flavonoids, (2S,2''S)-6-lavandulyl-7,4'-dimethoxy-5,2'-dihydroxylflavanone (1), (2S,2''S)-6-lavandulyl-5,7,2',4'-tetrahydroxylflavanone (2), and (2''S)-5'-lavandulyl-2'-methoxy-2,4,4',6'-tetrahydroxylchalcone (3), along with seven known compounds 4-10 were isolated from culture broth of Streptomyces sp. G248. Their structures were established by spectroscopic data analysis, including 1D and 2D nuclear magnetic resonance (NMR), and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS). The absolute configurations of 1-3 were resolved by comparison of their experimental and calculated electronic circular dichroism spectra. Compounds 1-3 exhibited remarkable antimicrobial activity. Whereas, two known compounds 4 and 5 exhibited inhibitory activity against Mycobacterium tuberculosis H37Rv with minimum inhibitory concentration (MIC) values of 6.0 µg/mL and 11.1 µg/mL, respectively.


Assuntos
Antibióticos Antituberculose/farmacologia , Flavonoides/farmacologia , Poríferos/microbiologia , Streptomyces/química , Animais , Antibióticos Antituberculose/química , Antibióticos Antituberculose/isolamento & purificação , Linhagem Celular Tumoral , Dicroísmo Circular , Flavonoides/química , Flavonoides/isolamento & purificação , Espectroscopia de Ressonância Magnética , Testes de Sensibilidade Microbiana , Estrutura Molecular , Mycobacterium tuberculosis/efeitos dos fármacos , Espectrometria de Massas por Ionização por Electrospray , Vietnã
8.
Bioorg Med Chem ; 25(6): 1830-1838, 2017 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-28236509

RESUMO

Rhamnolipids secreted by Pseudomonas aeruginosa are required for the bacteria to form biofilm efficiently and form biofilm with internal structures including pores and channels. In this work, we explore the effect of a class of synthetic analogs of rhamnolipids at controlling (promoting and inhibiting) the biofilm formation activities of a non-rhamnolipid-producing strain - rhlA - of P. aeruginosa. This class of rhamnolipid analogs is known to modulate the swarming motilities of wild-type PAO1 and rhlA mutant, but its effect on biofilm formation of rhlA mutant is unknown. We show that small structural details of these molecules are important for the bioactivities, but do not affect the general physical properties of the molecules. The bioactive synthetic analogs of rhamnolipids promote biofilm formation by rhlA mutant at low concentrations, but inhibit the biofilm formation at high concentrations. To explore the internal structures formed by the biofilms, we first demonstrate that wild-type biofilms are formed with substantial topography (hills and valleys) when the sample is under shaking conditions. Using this observation as a comparison, we found that synthetic analogs of rhamnolipids promoted structured (porous) biofilm of rhlA mutant, at intermediate concentrations between the low ones that promoted biofilm formation and the high ones that inhibited biofilm formation. This study suggests a potential chemical signaling approach to control multiple bacterial activities.


Assuntos
Biofilmes , Glicolipídeos/metabolismo , Mutação , Pseudomonas aeruginosa/metabolismo , Espectroscopia de Prótons por Ressonância Magnética , Pseudomonas aeruginosa/genética , Espectrometria de Massas por Ionização por Electrospray
9.
Chembiochem ; 17(1): 102-11, 2016 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-26511780

RESUMO

Microbes secrete molecules that modify their environment. Here, we demonstrate a class of synthetic disaccharide derivatives (DSDs) that mimics and dominates the activity of naturally secreted rhamnolipids by Pseudomonas aeruginosa. The DSDs exhibit the dual function of activating and inhibiting the swarming motility through a concentration-dependent activity reversal that is characteristic of signaling molecules. Whereas DSDs tethered with a saturated farnesyl group exhibit inhibition of both biofilm formation and swarming motility, with higher activities than rhamnolipids, a saturated farnesyl tethered with a sulfonate group only inhibits swarming motility but promote biofilm formation. These results identified important structural elements for controlling swarming motility, biofilm formation, and bacterial adhesion and suggest an effective chemical approach to control intertwined signaling processes that are important for biofilm formation and motilities.


Assuntos
Dissacarídeos/química , Dissacarídeos/farmacologia , Glicolipídeos/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/fisiologia , Biofilmes/efeitos dos fármacos , Dissacarídeos/síntese química , Glicolipídeos/química
10.
Chembiochem ; 15(10): 1514-23, 2014 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-24944053

RESUMO

We have demonstrated that specific synthetic maltose derivatives activate the swarming motility of a Pseudomonas aeruginosa nonswarming mutant (rhlA) at low concentration, but inhibit it at high concentration. Although these molecules are not microbicidal, active maltose derivatives with bulky hydrocarbon groups inhibited bacterial adhesion, and exhibited biofilm inhibition and dispersion (IC50 ~20 µM and DC50 ~30 µM, respectively). Because the swarming motility of the rhlA mutant is abolished by the lack natural rhamnolipids, the swarming activation suggests that maltose derivatives are analogues of rhamnolipids. Together, these results suggest a new approach of controlling multiple bacterial activities (bacterial adhesion, biofilm formation, and swarming motility) by a set of disaccharide-based molecules.


Assuntos
Antibacterianos/química , Aderência Bacteriana/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Maltose/análogos & derivados , Pseudomonas aeruginosa/efeitos dos fármacos , Antibacterianos/farmacologia , Biofilmes/crescimento & desenvolvimento , Genes Bacterianos , Glicolipídeos/química , Glicolipídeos/metabolismo , Humanos , Maltose/farmacologia , Mutação , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/fisiologia
11.
Bioorg Med Chem ; 22(4): 1313-7, 2014 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-24485124

RESUMO

Both natural and synthetic brominated furanones are known to inhibit biofilm formation by bacteria, but their toxicity to mammalian cells is often not reported. Here, we designed and synthesized a new class of brominated furanones (BBFs) that contained a bicyclic structure having one bromide group with well-defined regiochemistry. This class of molecules exhibited reduction in the toxicity to mammalian cells (human neuroblastoma SK-N-SH) and did not inhibit bacteria (Pseudomonas aeruginosa and Escherichia coli) growth, but retained the inhibitory activity towards biofilm formation of bacteria. In addition, all the BBFs inhibited the production of virulence factor elastase B in P. aeruginosa. To explore the effect of BBFs on quorum sensing, we used a reporter gene assay and found that 6-BBF and 7-BBF exhibited antagonistic activities for LasR protein in the lasI quorum sensing circuit, while 5-BBF showed agonistic activity for the rhlI quorum sensing circuit. This study suggests that structural variation of brominated furanones can be designed for targeted functions to control biofilm formation.


Assuntos
Biofilmes/efeitos dos fármacos , Compostos Bicíclicos com Pontes/química , Furanos/química , Furanos/farmacologia , Pseudomonas aeruginosa/fisiologia , Antibacterianos/síntese química , Antibacterianos/química , Antibacterianos/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Furanos/síntese química , Halogenação , Humanos , Pseudomonas aeruginosa/efeitos dos fármacos , Percepção de Quorum/efeitos dos fármacos
12.
Nat Prod Res ; 37(21): 3623-3630, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-35819993

RESUMO

Phytochemical investigation of Marsypopetalum modestum (Annonaceae) led to the isolation of a new phenylpropanoid glycoside, lyciumphenylpropanoid B (10), along with nine known compounds (1-9) from an aqueous methanolic extract of the stem. Most compounds are reported from this genus for the first time. The structures of the isolated compounds were elucidated using spectroscopic methods including NMR spectroscopy, high-resolution mass spectrometry, and quantum chemical electronic circular dichroism (ECD) calculations. Cytotoxic and antitubercular activities of several isolated compounds were evaluated. Dipyrithione (1) displayed anti-mycobacterial (MIC = 0.23 µM) and cytotoxic (IC50 = 0.8 µM in Hep G2 cells; 4.1 µM in HCT 116 cells) activities. Kelampayoside A (8) showed moderate cytotoxic activity against cancer cells.

13.
Tuberculosis (Edinb) ; 138: 102298, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36580851

RESUMO

Ecumicin and rufomycin 4-7 disrupt protein homeostasis in Mycobacterium tuberculosis by inhibiting the proteolytic activity of the ClpC1/ClpP1/ClpP2 complex. Although these compounds target ClpC1, their effects on the ATPase activity of ClpC1 and proteolytic activity of ClpC1/ClpP1/ClpP2 vary. Herein, we explored the ClpC1 molecular dynamics with these compounds through fluorescence correlation spectroscopy. The effect of these compounds on the ATPase activity of ClpC1-cys, the recombinant protein for fluorescence labeling, and proteolytic activity of ClpC1-cys/ClpP1/ClpP2 were identical to those of native ClpC1, whereas the intermolecular dynamics of fluorescence-labelled ClpC1 were different. Treatment with up to 1 nM ecumicin increased the population of slower diffused ClpC1 components compared with ClpC1 without ecumicin. However, this population was considerably reduced when treated with 10 nM ecumicin. Rufomycin 4-7 treatment resulted in a slower diffused component of ClpC1, and the portion of this component increased in a concentration-dependent manner. Ecumicin can generate an abnormal ClpC1 component, which cannot form normal ClpC1/ClpP1/ClpP2, via two different modes. Rufomycin 4-7 only generates slower diffused ClpC1 component that is inadequate to form normal ClpC1/ClpP1/ClpP2. Overall, we demonstrate that ecumicin and rufomycin 4-7 use different action mechanisms to generate abnormal ClpC1 components that cannot couple with ClpP1/ClpP2.


Assuntos
Mycobacterium tuberculosis , Mycobacterium tuberculosis/genética , Proteínas de Bactérias/metabolismo , Adenosina Trifosfatases/metabolismo , Adenosina Trifosfatases/farmacologia
14.
Phytochemistry ; 216: 113884, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37813133

RESUMO

Six undescribed compounds, uvarirufols D and E, (+)-uvarigranol B, (-)-uvarigranol E, 6-acetoxy-5-hydroxy-7-methoxyflavanone and cherrevenaphthalene D, along with twelve known compounds, including polyoxygenated cyclohexenes, flavonoids, and lignans, were isolated from the methanol extract of Uvaria rufa stems. Their structures were elucidated by spectroscopic analyses and the absolute configurations were determined using electronic circular dichroism. Several isolates were evaluated for cytotoxic, antitubercular and anti-inflammatory potentials. (-)-6-Acetylzeylenol showed moderate inhibitory activity against Mycobacterium tuberculosis, with MIC value of 47.10 µg/mL. Cherrevenaphthalene D exhibited weak antimycobacterial activity and potent inhibitory effect on lipopolysaccharide-induced nitric oxide (NO) production in RAW 264.7 cells (EC50 = 8.54 µM). 8-Hydroxy-5,7-dimethoxyflavanone displayed moderate level of NO inhibition (EC50 = 43.62 µM) with little cytotoxicity. The polyoxygenated cyclohexenes and lignans were inactive against HCT 116 and 22Rv1 cancer cells (IC50 > 100 µM).


Assuntos
Lignanas , Uvaria , Uvaria/química , Estrutura Molecular , Cicloexenos/farmacologia , Cicloexenos/química , Lignanas/farmacologia
15.
ACS Infect Dis ; 9(8): 1593-1601, 2023 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-37450563

RESUMO

For over a century, researchers have cultured microorganisms together on solid support─typically agar─in order to observe growth inhibition via antibiotic production. These simple bioassays have been critical to both academic researchers that study antibiotic production in microorganisms and to the pharmaceutical industry's global effort to discover drugs. Despite the utility of agar assays to researchers around the globe, several limitations have prevented their widespread adoption in advanced high-throughput compound discovery and dereplication campaigns. To address a list of specific shortcomings, we developed the dual-sided agar plate assay (DAPA), which exists in a 96-well plate format, allows microorganisms to compete through opposing sides of a solid support in individual wells, is amenable to high-throughput screening and automation, is reusable, and is low-cost. Herein, we validate the use of DAPA as a tool for drug discovery and show its utility to discover new antibiotic natural products. From the screening of 217 bacterial isolates on multiple nutrient media against 3 pathogens, 55 hits were observed, 9 known antibiotics were dereplicated directly from agar plugs, and a new antibiotic, demethoxytetronasin (1), was isolated from a Streptomyces sp. These results demonstrate that DAPA is an effective, accessible, and low-cost tool to screen, dereplicate, and prioritize bacteria directly from solid support in the front end of antibiotic discovery pipelines.


Assuntos
Antibacterianos , Produtos Biológicos , Antibacterianos/farmacologia , Ágar , Ensaios de Triagem em Larga Escala/métodos , Descoberta de Drogas
16.
RSC Med Chem ; 14(8): 1549-1561, 2023 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-37593576

RESUMO

The phenanthridine core exhibits antitubercular activity, according to reports from the literature. Several 1,2,3-triazole-based heterocyclic compounds are well-known antitubercular agents. A series of twenty-five phenanthridine amide and 1,2,3-triazole derivatives are synthesized and analyzed using ESI-MS, 1HNMR, and 13CNMR on the basis of our earlier findings that phenanthridine and 1,2,3-triazoles shown good antitubercular activity. The synthesized phenanthridine amide and 1,2,3-triazole analogues were tested in vitro against Mycobacterium tuberculosis H37Rv and minimum inhibitory concentration (MIC) values were determined utilizing non-replicating and replicating low-oxygen recovery assay (LORA) and microplate Alamar Blue assay (MABA) methodologies. The phenanthridine amide derivative PA-01 had an MIC of 61.31 µM in MABA and 62.09 µM in the LORA technique, showing intense anti-TB activity. Amongst the phenanthridine triazole derivatives, PT-09, with MICs of 41.47 and 78.75 µM against the tested strain of Mtb in both MABA and LORA was the most active one. The final analogues' drug-likeness is predicted using absorption, distribution, metabolism, excretion, and toxicity (ADMET) studies. The most active compounds PA-01 and PT-09 were further subjected to in silico docking studies. Using the Glide module of Schrodinger, molecular docking analysis was carried out to estimate the plausible binding pattern of PA-01 and PT-09 at the active site of Mycobacterial DNA topoisomerase II (PDB code: 5BS8). Further, molecular dynamics studies of PA-01 and PT-09 were also carried out.

17.
Langmuir ; 28(29): 10797-807, 2012 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-22726240

RESUMO

Single-chain surfactants usually emulsify and stabilize oily substances into droplets in an aqueous solution. Here, we report a coassembly system, in which single types of anionic or non-ionic surfactants emulsify a class of water-soluble nonamphiphilic organic salts with fused aromatic rings in aqueous solutions. The nonamphiphilic organic salts are in turn promoted to form droplets of water-based liquid crystals (chromonic liquid crystals) encapsulated by single-chain surfactants. The droplets, stabilized against coalescence by encapsulated in a layer (or layers) of single chain surfactants, are of both nonspherical tactoid (elongated ellipsoid with pointy ends) and spherical shapes. The tactoids have an average long axis of ∼9 µm and a short axis of ∼3.5 µm with the liquid crystal aligning parallel to the droplet surface. The spherical droplets are 5-10 µm in diameter and have the liquid crystal aligning perpendicular to the droplet surface and a point defect in the center. Cationic and zwitterionic surfactants studied in this work did not promote the organic salt to form droplets. These results illustrate the complex interplay of self-association and thermodynamic incompatibility of molecules in water, which can cause new assembly behavior, including potential formation of vesicles or other assemblies, from surfactants that usually form only micelles. These unprecedented tactoidal shaped droplets also provide potential for the fabrication of new soft organic microcapsules.


Assuntos
Cristais Líquidos/química , Tensoativos/química , Emulsões/química , Estrutura Molecular , Tamanho da Partícula , Solubilidade , Soluções , Propriedades de Superfície , Água/química
18.
Med Sci Monit ; 18(1): CR1-8, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22207113

RESUMO

BACKGROUND: The reaction of vascular endothelial cells to occlusion and heat in Southeast Asian Indians (SAI) compared to Caucasians (C) has not been studied, although genetic differences are found in endothelial cells between the races. MATERIAL/METHODS: Ten C and Ten SAI (<35 years old) male and female subjects participated. There was no difference in the demographics of the subjects except that the SAI group had been in the United States for 6 months; C was natives to the US. Endothelial function was assessed by the response of the circulation (BF) to local heating and the response to vascular occlusion. The effects of local heat on circulation in the skin on the forearm was assessed by applying heat for 6 minutes at temperatures, 38, 40 and 42°C on 3 separate days. On different days, vascular occlusion was applied for 4 minutes to the same arm and skin blood flow was measured for 2 minutes after occlusion; skin temperature was either 31°C or 42°C. RESULTS: When occlusion was applied at a skin temperature of 31°C, the BF response to occlusion was significantly lower in the SAI cohort compared to C (peak BF C = 617 ± 88.2 flux, SAE = 284 ± 73 flux). The same effect was seen at skin temperatures of 42°C. The circulatory response to heat was also significantly less in SAI compared to C at each temperature examined (p<0.05)(for temperatures of 38, 40 and 42°C, peak blood flow for C was 374.7 ± 81.2, 551.9 ± 91.3 and 725.9 ± 107 flux respectively and 248.5 ± 86.2, 361.4 ± 104.3 and 455.3 ± 109.7 flux respectively for SAI. (p<0.05). CONCLUSIONS: Thus there seems to be big differences in these 2 populations in endothelial response to these stressors. The difference may be due to genetic variations between the 2 groups of subjects.


Assuntos
Células Endoteliais/fisiologia , Pele/irrigação sanguínea , População Branca , Adulto , Composição Corporal/fisiologia , California , Feminino , Humanos , Índia/etnologia , Fluxometria por Laser-Doppler , Masculino , Fluxo Sanguíneo Regional/fisiologia , Temperatura Cutânea
19.
Med Sci Monit ; 18(4): CR201-8, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22460091

RESUMO

BACKGROUND: Most studies of the skin and how it responds to local heat have been conducted with either water, thermodes, or dry heat packs. Very little has been accomplished to look at the interaction between air humidity and temperature on skin temperature and blood flow. With variable air temperatures and humidity's around the world, this, in many ways, is a more realistic assessment of environmental impact than previous water bath studies. MATERIAL/METHODS: Eight young and 8 older subjects were examined in an extensive series of experiments where on different days, air temperature was 38, 40, or 42°C. and at each temperature, humidity was either 0%, 25%, 50%, 75%, or 100% humidity. Over a 20 minute period of exposure, the response of the skin in terms of its temperature and blood flow was assessed. RESULTS: For both younger and older subjects, for air temperatures of 38 and 40°C., the humidity of the air had no effect on the blood flow response of the skin, while skin temperature at the highest humidity was elevated slightly. However, for air temperatures of 42°C., at 100% humidity, there was a significant elevation in skin blood flow and skin temperature above the other four air humidity's (p<0.05). In older subjects, the blood flow response was less and the skin temperature was much higher than younger individuals for air at 42°C. and 100% humidity (p<0.05). CONCLUSIONS: Thus, in older subjects, warm humid air caused a greater rise in skin temperature with less protective effect of blood flow to protect the skin from overheating than is found in younger subjects.


Assuntos
Envelhecimento/fisiologia , Ar , Fluxo Sanguíneo Regional/fisiologia , Temperatura Cutânea/fisiologia , Pele/irrigação sanguínea , Temperatura , Adulto , Idoso , Feminino , Antebraço/fisiologia , Humanos , Umidade , Masculino
20.
Curr HIV Res ; 20(3): 255-271, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35549861

RESUMO

BACKGROUND: The necessity for newer anti-HIV and anti-tubercular medications has arisen as a result of the prevalence of opportunistic infections caused by HIV (human immunodeficiency virus). OBJECTIVE: A series of ten new hydrazono 1,3-thiazolidin-4-one derivatives were synthesized in one-pot and evaluated for anti-HIV and anti-tubercular activities. Molecular Docking was accomplished with HIV-1 reverse transcriptase protein (PDB ID: 1REV) and Mycobacterium Tuberculosis (M. tuberculosis) H37Rv protein (PDB ID: 2YES) receptors along with drug-likeness and ADMET properties. METHODS: One-pot synthesis of hydrazono 1,3-thiazolidin-4-one derivatives was carried out by ketones, thiosemicarbazide and ethylchloroacetate with the catalyst of anhydrous sodium acetate. All the synthesized compounds were characterized and evaluated for their in-vitro anti-HIV and also evaluated for their in-vitro anti-tubercular activity against M. tuberculosis H37Rv. In-silico predicted physicochemical parameters were done by MedChem DesignerTM software version 5.5 and ADMET parameters by pkCSM online tool. Furthermore, molecular docking was performed with pyrx 0.8 by autodock vina software. RESULTS: All the synthesized compounds were characterized and evaluated for their in-vitro anti- HIV activity for inhibition of syncytia formation, which shows KTE1 with EC50 47.95 µM and Selectivity Index (SI) of >4.17 and for inhibition of p24 antigen production EC50 was found to be 80.02 µM and SI of >2.49. The compounds were also evaluated for their in-vitro anti-tubercular activity against M. tuberculosis H37Rv, in which KTE1 MIC values of 12.5µg/ml with SI of >4.0 and cytotoxicity against Vero cell lines. In-silico predicted physicochemical parameters for synthesized compounds which were found to be drug-like. Furthermore, docking has shown a good dock score and binding energy with anti-HIV and anti-tubercular receptors. CONCLUSION: From the novel synthesized molecules, none of the molecule is as effective as standards for anti-HIV and anti-tubercular drugs and hence can be further explored for its potential activities. Furthermore, derivatization was made to achieve more potent compounds for anti-HIV and anti-tubercular drugs.


Assuntos
Infecções por HIV , Mycobacterium tuberculosis , Tuberculose , Antituberculosos/química , Antituberculosos/farmacologia , Desenho de Fármacos , Infecções por HIV/tratamento farmacológico , Humanos , Cetonas/farmacologia , Cetonas/uso terapêutico , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Acetato de Sódio/farmacologia , Acetato de Sódio/uso terapêutico , Relação Estrutura-Atividade , Tuberculose/tratamento farmacológico
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