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1.
Br J Cancer ; 128(8): 1491-1502, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36759727

RESUMO

BACKGROUND: Chaperon-mediated autophagy (CMA) has taken on a new emphasis in cancer biology. However, the roles of CMA in hypoxic tumours are poorly understood. We investigated the anti-tumour effects of the natural product ManA through the activation of CMA in tumour progression under hypoxia. METHODS: The effect of ManA on CMA activation was assessed in mouse xenograft models and cells. The gene expressions of HIF-1α, HSP90AA1, and transcription factor EB (TFEB) were analysed using The Cancer Genome Atlas (TCGA) datasets to assess the clinical relevance of CMA. RESULTS: ManA activates photoswitchable CMA reporter activity and inhibits Hsp90 chaperone function by disrupting the Hsp90/F1F0-ATP synthase complex. Hsp90 inhibition enhances the interaction between CMA substrates and LAMP-2A and TFEB nuclear localisation, suggesting CMA activation by ManA. ManA-activated CMA retards tumour growth and displays cooperative anti-tumour activity with anti-PD-1 antibody. TCGA datasets show that a combined expression of HSP90AA1High/HIF1AHigh or TFEBLow/HIF1AHigh is strongly correlated with poor prognosis in patients with lung cancer. CONCLUSIONS: ManA-induced CMA activation by modulating Hsp90 under hypoxia induces HIF-1α degradation and reduces tumour growth. Thus, inducing CMA activity by targeting Hsp90 may be a promising therapeutic strategy against hypoxic tumours.


Assuntos
Autofagia Mediada por Chaperonas , Neoplasias Pulmonares , Camundongos , Animais , Humanos , Hipóxia , Proteínas de Choque Térmico HSP90/metabolismo , Chaperonas Moleculares , Autofagia/genética
2.
Chemistry ; 29(29): e202300262, 2023 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-36867738

RESUMO

Cruentaren A is a natural product that exhibits potent antiproliferative activity against various cancer cell lines, yet its binding site within ATP synthase remained unknown, thus limiting the development of improved analogues as anticancer agents. Herein, we report the cryogenic electron microscopy (cryoEM) structure of cruentaren A bound to ATP synthase, which allowed the design of new inhibitors through semisynthetic modification. Examples of cruentaren A derivatives include a trans-alkene isomer, which was found to exhibit similar activity to cruentaren A against three cancer cell lines as well as several other analogues that retained potent inhibitory activity. Together, these studies provide a foundation for the generation of cruentaren A derivatives as potential therapeutics for the treatment of cancer.


Assuntos
Antineoplásicos , Neoplasias , Humanos , Estrutura Molecular , Microscopia Crioeletrônica , Linhagem Celular , Antineoplásicos/farmacologia , Antineoplásicos/química , Trifosfato de Adenosina , Relação Estrutura-Atividade
3.
Chem Rec ; 22(11): e202200186, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35959940

RESUMO

Plastics have been an indispensable material of choice in automobiles with wide range of applications such as interior, exterior, under the hood, and lighting/wiring applications. The prime motive of inclusion of these materials is increase in fuel efficiency and reduction in carbon footprint by replacing the energy intensive metallic counterparts. The current decade i. e., the 2020s has seen a recent surge in the sales of electronic vehicles. Although these numbers are promising, the growth in the rest of the parts of the world is not encouraging. It is primarily due to the skepticism involving battery life and efficiency, profitability, and environmental footprint when compared to conventional and hybrid vehicles. Also, a more concerted effort is needed in the lagging areas in order to install the required infrastructure. The emergence of plastics in the development and acceptance of e-vehicles is going to be pivotal especially when the efficiency and profitability are considered as they give the required freedom to the engineers for the design and development of various parts and sizes by replacing the bulkier and more dense materials. Also, the research on bionanocomposites has received great interest from the research community due to their versatility in application along with their eco-friendly nature throughout the lifecycle starting from feedstock up to end-of-life treatment. This review paper will be one of its kind to present a critical review of the recent developments of polymers suitable for use in e-vehicles. Also, a comprehensive discussion comprising of newer research areas for polymers in their use for e-vehicles will be presented.


Assuntos
Automóveis , Polímeros , Eletricidade , Fontes de Energia Elétrica , Plásticos
4.
J Org Chem ; 87(15): 9940-9956, 2022 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-35894845

RESUMO

The 90 kDa heat shock protein (Hsp90) belongs to a group of molecular chaperones that regulate homeostasis via the folding of nascent polypeptides into their biologically active proteins, many of which are involved in cancer development and progression. As a result, inhibition of Hsp90 is an exciting area of research for the treatment of cancer. However, most of the 18 Hsp90 N-terminal inhibitors evaluated in clinical trials exhibited deleterious side effects and toxicities. Cruentaren A is a natural product that manifests potent anticancer activity against various human cancer cell lines via disruption of interactions between Hsp90α and F1FO ATP synthase, which does not induce the pro-survival, heat shock response, a major limitation associated with current Hsp90 inhibitors. However, the development of cruentaren A as a new anticancer agent has been hindered by its complex structure. Herein, we systematically removed the functionalities present in fragment 2 of cruentaren A and incorporated some key structural modifications from previous work, which produced 12 simplified analogues. Our studies determined that all functional groups present in fragment 2 are essential for cruentaren A's anticancer activity.


Assuntos
Antineoplásicos , Neoplasias , Antineoplásicos/farmacologia , Proteínas de Choque Térmico HSP90/química , Proteínas de Choque Térmico HSP90/metabolismo , Humanos , Macrolídeos/farmacologia , Neoplasias/tratamento farmacológico
5.
Ann Hum Biol ; 49(7-8): 332-341, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36343161

RESUMO

BACKGROUND: Owing to its high copy number and its small size, mtDNA analysis is the most reliable choice when biological materials from crime scenes are degraded or have mixed STR profiles. AIM: To examine the occurrence of heteroplasmy along with its frequency and pattern in both HV1 and HV2 regions of the mtDNA among unrelated individuals from India. SUBJECTS AND METHODS: Mitochondrial DNA control region [hypervariable region one (HV1) and hypervariable region two (HV2)] were analysed in blood and buccal tissues of 104 unrelated individuals from the Indian state of Gujarat. RESULTS: A high frequency of point heteroplasmy (PH) and length heteroplasmy (LH) was revealed. PH was detected in 7.69% of the population, with a higher frequency observed in blood than in buccal samples. However, there were no statistically significant differences in PH between the two tissues (Chi-square = 0.552, p ≥ 0.05). A total of six PH positions were detected: three at HV1, and another three at HV2. The studied population showed 46.15% LH in the HV1 and HV2 regions of both tissues. The LH positions observed in the Gujarat population were the same as those previously reported at HV1 np16184-16193 and HV2 np303-315. CONCLUSIONS: Our findings suggest that differences in the pattern of heteroplasmy found in different tissues can complicate the forensic analysis, on the other hand, the probability of a match between the questioned and reference samples increases when the heteroplasmy is identical in both tissues. Variability of PH among persons and even within tissues recommends analysing multiple tissue samples before drawing a conclusion in forensic mtDNA analyses.


Assuntos
DNA Mitocondrial , Heteroplasmia , Humanos , DNA Mitocondrial/genética , DNA Mitocondrial/análise , Índia , Análise de Sequência de DNA
6.
Mol Pharm ; 18(10): 3843-3853, 2021 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-34519511

RESUMO

In addition to activity, successful biological drugs must exhibit a series of suitable developability properties, which depend on both protein sequence and buffer composition. In the context of this high-dimensional optimization problem, advanced algorithms from the domain of machine learning are highly beneficial in complementing analytical screening and rational design. Here, we propose a Bayesian optimization algorithm to accelerate the design of biopharmaceutical formulations. We demonstrate the power of this approach by identifying the formulation that optimizes the thermal stability of three tandem single-chain Fv variants within 25 experiments, a number which is less than one-third of the experiments that would be required by a classical DoE method and several orders of magnitude smaller compared to detailed experimental analysis of full combinatorial space. We further show the advantage of this method over conventional approaches to efficiently transfer historical information as prior knowledge for the development of new biologics or when new buffer agents are available. Moreover, we highlight the benefit of our technique in engineering multiple biophysical properties by simultaneously optimizing both thermal and interface stabilities. This optimization minimizes the amount of surfactant in the formulation, which is important to decrease the risks associated with corresponding degradation processes. Overall, this method can provide high speed of converging to optimal conditions, the ability to transfer prior knowledge, and the identification of new nonlinear combinations of excipients. We envision that these features can lead to a considerable acceleration in formulation design and to parallelization of operations during drug development.


Assuntos
Produtos Biológicos/administração & dosagem , Composição de Medicamentos/métodos , Aprendizado de Máquina , Teorema de Bayes , Produtos Biológicos/uso terapêutico , Avaliação Pré-Clínica de Medicamentos/métodos , Humanos , Sistemas de Liberação de Fármacos por Nanopartículas/administração & dosagem
7.
Anal Bioanal Chem ; 412(8): 1769-1784, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32043201

RESUMO

Simultaneous speciation of benzenediol isomers (BDIs), 1,2-benzenediol (catechol, CC), 1,3-benzenediol (resorcinol, RS), and 1,4-benzenediol (hydroquinone, HQ), was investigated by differential pulse voltammetry (DPV) using a graphite paste electrode (GPE) modified with Prussian blue-polyaniline nanocomposite. The modified GPE showed good stability, sensitivity, and selectivity properties for all the three BDIs. Prussian blue-doped nanosized polyaniline (PBNS-PANI) was synthesized first by using mechanochemical reactions between aniline and ferric chloride hexahydrate as the oxidants and then followed by the addition of potassium hexacyanoferrate(II) in a solid-state and template-free technique. The material was characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The DPV measurements are performed in phosphate electrolyte solution with pH 4.0 at a potential range of - 0.1 to 1.0 V. The proposed modified electrode displayed a strong, stable, and continuous three well-separated oxidation peaks towards electrooxidation at potentials 0.20, 0.31, and 0.76 V for HQ, CC, and RS, respectively. The calibration curves were linear from 1 to 350.5 µM for both HQ and CC, while for RS, it was from 2 to 350.5 µM. The limit of detection was determined to be 0.18, 0.01, and 0.02 µM for HQ, CC, and RS, respectively. The analytical performance of the PBNS-PANI/GPE has been evaluated for simultaneous determination of HQ, CC, and RS in creek water, commercial hair dye, and skin whitening cream samples with satisfactory recoveries between 90 and 106%. Overall, we demonstrated that the presence of NS-PANI and PB resulted in a large redox-active surface area that enabled a promising analytical platform for simultaneous detection of BDIs. Graphical abstract.


Assuntos
Compostos de Anilina/química , Derivados de Benzeno/análise , Ferrocianetos/química , Nanoestruturas/química , Derivados de Benzeno/química , Calibragem , Eletrodos , Humanos , Concentração de Íons de Hidrogênio , Isomerismo , Cinética , Limite de Detecção , Espectroscopia de Infravermelho com Transformada de Fourier
8.
Anal Chem ; 91(15): 10116-10124, 2019 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-31250649

RESUMO

Recently, a plethora of ecofriendly methods have been developed for the synthesis of AuNPs using a multitude of biogenic agents. Polyphenols from plants are particularly attractive for producing AuNPs because in addition to helping with the synthesis of AuNPs, the polyphenol capping of the NPs can be used as a platform for versatile applications. Polyphenol-capped AuNPs could also make the detection of AuNPs possible, should they be released into the environment. Because polyphenols are redox-active, they can be used as a probe to detect AuNPs using electrochemical techniques. In this work, we have developed an MWCNT-rGO nanocomposite electrode for the sensitive detection of AuNPs capped with gallic acid (GA, a green-tea-derived polyphenol) using differential pulse voltammetry (DPV). The reduction of gallic acid-capped AuNPs was used as the quantification signal, and the calibration curve displayed a detection limit of 2.57 pM. Using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), we have shown that the modification of the electrode surface with an MWCNT-rGO hybrid nanocomposite resulted in a 10-fold increase in current response leading to the sensitive detection of GA-AuNPs compared to unmodified electrodes. We have also demonstrated the applicability of the electrochemical sensor in detecting GA-AuNPs in various analytical matrixes such as human serum and natural creek water (Highland Creek, ON) with good recovery.

9.
Mikrochim Acta ; 186(12): 844, 2019 11 25.
Artigo em Inglês | MEDLINE | ID: mdl-31768658

RESUMO

A "detect and destroy" strategy is reported for the spectroscopic determination and photocatalytic degradation of Malachite Green (MG) in aqueous solutions. The intensity of the reflection peak maxima from the TiO2-coated 2D-photonic crystal (PhC) at 633 nm wavelength undergoes a gradual decrease with increasing concentrations of MG. The determination of MG was readily achieved in the nanomolar range due to the quenching of the reflection intensity of the peak, measured using a fiber optic probe. The assay works in the 1.0 nM to 10 µM MG concentration range with a detection limit of 1.3 nM. The same TiO2-coated 2D-PhC surface can photocatalytically degrade MG in aqueous solutions under UV irradiation. The photocatalytic degradation in the presence of TiO2-coated 2D-PhC becomes evident as the blue color of MG changes to colorless with increasing irradiation time. The decrease in absorption is detected at 617 nm. It was found that the photocatalytic efficiency of TiO2 was synergistically enhanced in the presence of 2D-PhCs. It is concluded that each component of the TiO2-coated 2D-PhC system plays a key role in the detection and degradation of MG. Graphical abstractSchematic representation for reflectometric detection and photocatalytic degradation of hazardous Malachite Green dye using TiO2-coated two-dimensional photonic crystals.


Assuntos
Corantes de Rosanilina/análise , Corantes de Rosanilina/efeitos da radiação , Espectrofotometria Ultravioleta/métodos , Titânio/química , Catálise/efeitos da radiação , Desinfetantes/análise , Desinfetantes/efeitos da radiação , Água Potável/análise , Água Doce/análise , Limite de Detecção , Estudo de Prova de Conceito , Titânio/efeitos da radiação , Raios Ultravioleta , Águas Residuárias/análise , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/efeitos da radiação
10.
J Assoc Physicians India ; 67(3): 19-21, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31304699

RESUMO

AIM: Trichosporon species are the major emerging opportunistic pathogen in immunocompromised patients. Its diverse refractoriness to conventional antifungal drugs and association with high mortality rate is worrisome. The present study aims to determine the risk factors, treatment outcome and antifungal susceptibility pattern of Trichosporon species in blood stream infections. MATERIAL AND METHODS: All patients with blood culture positive for Trichosporon species from January 2012 to August 2016 at PD Hinduja National Hospital and research centre were evaluated retrospectively. Species identification and antifungal susceptibility by broth microdilution method for various drugs was determined using Vitek2 compact automated system. RESULTS: 12 patients were found to have Trichosporon blood stream infection. 9 isolates that were speciated all were T. asahii. All patients had central venous catheter and received prior antibiotics. Overall mortality rate was 50%. CONCLUSION: Higher mortality was associated with central venous catheter and voriconazole should be used as drug of choice for treatment. Identification of Trichosporon species along with its sensitivity and proper treatment of patients is of utmost importance.


Assuntos
Bacteriemia/epidemiologia , Trichosporon , Tricosporonose/epidemiologia , Bacteriemia/terapia , Humanos , Testes de Sensibilidade Microbiana , Estudos Retrospectivos , Tricosporonose/terapia , Voriconazol/uso terapêutico
11.
Analyst ; 143(16): 3890-3899, 2018 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-30033476

RESUMO

Dye effluents are one of the main causes of water pollution. Azo dyes, the most widely applied colorants, are particularly difficult to degrade. Exposure of such dyes to the aquatic environment is hazardous to human health and biota due to their intrinsic harmful mutagenic and carcinogenic properties. Congo Red (CR) is an anionic and synthetic diazo dye, which is recalcitrant to the biodegradative process and metabolizes to produce a potential carcinogen. Research on the interaction of this toxic dye with serum albumin, as a transport protein, is of paramount significance because the physiological and toxicological behaviours of the dye in vivo are associated with its interactive characteristics with the proteins. In this regard, a detailed binding profile of CR with human serum albumin (HSA) was studied using isothermal titration calorimetry (ITC) along with various spectroscopic and microscopic methods. The thermodynamic results from ITC indicated that the CR-HSA non-covalent interaction occured primarily due to favorable entropy and unfavorable enthalpy with a Ka of 106 M-1 at lower concentrations and 105 M-1 at higher concentrations. Steady-state fluorescence data revealed that the intrinsic fluorescence of HSA was quenched in the presence of CR via the static quenching mechanism. Using Förster's non-radioactive energy transfer theory (FRET), the specific binding distance r (2.73 nm) between the donor (Trp-214 from HSA) and the acceptor (CR) was calculated. Our preliminary results indicated that CR had a high affinity to HSA, which can have significant implications in the distribution and elimination of this toxic dye upon exposure.


Assuntos
Compostos Azo/química , Calorimetria , Albumina Sérica Humana/química , Espectrometria de Fluorescência , Sítios de Ligação , Humanos , Ligação Proteica , Termodinâmica
12.
Biomed Chromatogr ; 32(5): e4165, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29228469

RESUMO

A selective, sensitive and rapid ultra-performance liquid chromatography tandem mass spectrometry method was developed and validated for the simultaneous determination of etonogestrel (ENG) and ethinyl estradiol (EE) in human plasma. The analytes and their deuterated internal standards, ENG-d7 and EE-d4, were extracted from plasma samples by solid-phase extraction on HyperSep™ Retain PEP cartridges. The chromatographic analysis was performed on an Acquity UPLC HSS Cyano column, 100 Å (50 × 2.1 mm, 1.8 µm), column using gradient mobile phase, acetonitrile and 2.0 mm ammonium trifluoroacetate at 0-1.7 min (65:35, v/v) and 1.8-2.7 min (95:5, v/v) with 0.250 mL/min flow rate. Analytes and IS protonated precursor → product ion transitions (ENG, m/z 325.2 → 257.2; EE, m/z 530.2 → 171.2; ENG-d7, m/z 332.2 → 263.2; EE-d4, m/z 534.2 → 171.2) were monitored on a Triple Quadrupole Mass spectrometer (TQMS), operating in multiple reaction monitoring and positive ionization mode. The calibration curves were established at 10.00-2500 pg/mL for ENG and 1.500-150.0 pg/mL for EE with a correlation coefficient (r2 ) ≥0.9996 for both. The validated method was successfully applied to support a bioequivalence study of 0.15 mg ENG and EE 0.03 mg tablet formulation, administered in 24 healthy Indian females. Method reliability was assessed by reanalysis of 94 incurred study samples.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Desogestrel/sangue , Desogestrel/farmacocinética , Etinilestradiol/sangue , Etinilestradiol/farmacocinética , Espectrometria de Massas em Tandem/métodos , Desogestrel/química , Etinilestradiol/química , Feminino , Humanos , Limite de Detecção , Modelos Lineares , Reprodutibilidade dos Testes
13.
Biomed Chromatogr ; 31(9)2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28178366

RESUMO

A novel, precise, sensitive and accurate ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method has been developed for the simultaneous determination of a novel drug combination, candesartan (CAN) and chlorthalidone (CHL), in human plasma. Chromatographic separation was achieved on Waters Acquity UPLC BEH C18 (50 × 2.1 mm, 1.7 µm). Mobile phase consisting of 1 mm ammonium acetate in water-acetonitrile (20:80 v/v) was used. The total chromatographic runtime was 1.9 min with retention times for CAN and CHL at 0.7 and 1.1 min respectively. Ionization and detection of analytes and internal standards was performed on a triple quadrupole mass spectrometer, operating in the multiple reaction monitoring and negative ionization mode. Quantitation was done to monitor protonated precursor → product ion transition of m/z 439.2 → 309.0 for CAN, 337.0 → 189.8 for CHL and 443.2 → 312.1 for candesartan D4 and 341.0 → 189.8 for chlorthalidone D4. The method was validated over a wide dynamic concentration range of 2.0-540.0 ng/mL for candesartan and 1.0-180.0 ng/mL for chlorthalidone. The validated method was successfully applied for the assay of CAN and CHL in healthy volunteers.


Assuntos
Benzimidazóis/sangue , Clortalidona/sangue , Cromatografia Líquida de Alta Pressão/métodos , Espectrometria de Massas em Tandem/métodos , Tetrazóis/sangue , Adolescente , Adulto , Benzimidazóis/química , Benzimidazóis/farmacocinética , Compostos de Bifenilo , Clortalidona/química , Clortalidona/farmacocinética , Combinação de Medicamentos , Estabilidade de Medicamentos , Humanos , Limite de Detecção , Modelos Lineares , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Tetrazóis/química , Tetrazóis/farmacocinética , Adulto Jovem
14.
J Assoc Physicians India ; 65(9): 14-16, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29313570

RESUMO

INTRODUCTION: Antibiotic treatment of Urinary Tract Infections (UTI) is becoming increasingly difficult due to emergence of multi-drug resistant (ESBLs, AmpC, CRE) uropathogens. Fosfomycin is an old antibiotic that has evoked renewed interest with unique properties of not sharing any structural similarity and lack of cross-resistance with other antimicrobial agents. Our aim is to evaluate in-vitro activity of Fosfomycin against urinary tract Enterobacteriaceae. MATERIAL & METHODS: The study period was March 2014 to September 2015. All 72 isolates were identified using conventional biochemical tests. Antimicrobial susceptibility testing was performed using the automated broth microdilution system Vitek 2 (bio- Mérieux, Inc., Durham, NC). Fosfomycin susceptibility was determined by the E-test (bioMérieux, Inc., Durham, NC) method. Interpretive criteria from the Clinical and Laboratory Standards Institute (CLSI) for fosfomycin susceptibility are not available for the Enterobacteriaceae other than Escherichia coli. Therefore, results were interpreted according to criteria for E. coli (i.e., susceptible at a MIC of ≤ 64 µg/ml), as has been reported previously. RESULTS: Overall, 79.16% (57/72) isolates were susceptible to fosfomycin w i t h 92.00% (23/25) susceptibility in ESBL producing enterobacteriaceae and 72.34% (34/47) in CRE. One CRE isolate has developed resistant while on treatment. There was not much difference in number of susceptible isolates CLSI:EUCAST = 57:53,but number of resistant isolates was more with EUCAST (CLSI:EUCAST = 10:19). CONCLUSION: Study demonstrate that, a considerable proportion (79.16%) of the multidrug-resistant Enterobacteriaceae with diverse resistance mechanisms, including ESBL and CRE, found susceptible to fosfomycin. Consequently, fosfomycin may currently be considered a useful antibiotic agent in the treatment armamentarium of UTIs.


Assuntos
Antibacterianos/uso terapêutico , Infecções por Enterobacteriaceae/tratamento farmacológico , Fosfomicina/uso terapêutico , Infecções Urinárias/tratamento farmacológico , Infecções Urinárias/microbiologia , Humanos , Testes de Sensibilidade Microbiana
15.
J Comput Chem ; 37(16): 1425-41, 2016 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-27013141

RESUMO

We have developed and implemented pseudospectral time-dependent density-functional theory (TDDFT) in the quantum mechanics package Jaguar to calculate restricted singlet and restricted triplet, as well as unrestricted excitation energies with either full linear response (FLR) or the Tamm-Dancoff approximation (TDA) with the pseudospectral length scales, pseudospectral atomic corrections, and pseudospectral multigrid strategy included in the implementations to improve the chemical accuracy and to speed the pseudospectral calculations. The calculations based on pseudospectral time-dependent density-functional theory with full linear response (PS-FLR-TDDFT) and within the Tamm-Dancoff approximation (PS-TDA-TDDFT) for G2 set molecules using B3LYP/6-31G*(*) show mean and maximum absolute deviations of 0.0015 eV and 0.0081 eV, 0.0007 eV and 0.0064 eV, 0.0004 eV and 0.0022 eV for restricted singlet excitation energies, restricted triplet excitation energies, and unrestricted excitation energies, respectively; compared with the results calculated from the conventional spectral method. The application of PS-FLR-TDDFT to OLED molecules and organic dyes, as well as the comparisons for results calculated from PS-FLR-TDDFT and best estimations demonstrate that the accuracy of both PS-FLR-TDDFT and PS-TDA-TDDFT. Calculations for a set of medium-sized molecules, including Cn fullerenes and nanotubes, using the B3LYP functional and 6-31G(**) basis set show PS-TDA-TDDFT provides 19- to 34-fold speedups for Cn fullerenes with 450-1470 basis functions, 11- to 32-fold speedups for nanotubes with 660-3180 basis functions, and 9- to 16-fold speedups for organic molecules with 540-1340 basis functions compared to fully analytic calculations without sacrificing chemical accuracy. The calculations on a set of larger molecules, including the antibiotic drug Ramoplanin, the 46-residue crambin protein, fullerenes up to C540 and nanotubes up to 14×(6,6), using the B3LYP functional and 6-31G(**) basis set with up to 8100 basis functions show that PS-FLR-TDDFT CPU time scales as N(2.05) with the number of basis functions. © 2016 Wiley Periodicals, Inc.

16.
Biomed Chromatogr ; 30(3): 447-58, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26189757

RESUMO

The objective of the present work was to carry out systematic evaluation to eliminate matrix effect owing to plasma phospholipids as observed during sample preparation and to develop a cross-talk-free sensitive, selective and rapid bioanalytical method for the simultaneous determination of zolmitriptan (ZT) and N-desmethyl zolmitriptan (DZT) in human plasma by liquid chromatography-tandem mass spectrometry using naratriptan as internal standard (IS). The analytes and IS were quantitatively extracted from 200 µL human plasma by solid phase extraction. No cross-talk was found between ZT and DZT having identical product ions. Quantitation was performed on a triple quadrupole mass spectrometer employing electrospray ionization technique, operating in multiple reaction monitoring and positive ion mode. The total chromatographic run time was 2.5 min. The method was fully validated for sensitivity, selectivity, specificity, linearity, accuracy, precision, recovery, matrix effect, dilution integrity and stability studies. The method was validated over a dynamic concentration range of 0.1-15 ng/mL for ZT and DZT. The method was successfully applied to a bioequivalence study of 2.5 mg ZT tablet formulation in 18 healthy Indian male subjects under fasting conditions. Assay reproducibility was assessed by reanalysis of 62 incurred samples.


Assuntos
Cromatografia Líquida/métodos , Oxazolidinonas/sangue , Oxazolidinonas/farmacocinética , Espectrometria de Massas em Tandem/métodos , Triptaminas/sangue , Triptaminas/farmacocinética , Humanos , Modelos Lineares , Masculino , Oxazolidinonas/química , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Extração em Fase Sólida , Triptaminas/química
17.
Bioorg Med Chem ; 23(18): 6125-37, 2015 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-26320664

RESUMO

Methicillin resistant Staphylococcus aureus (MRSA) is a major drug resistant bacteria that persists in both community and clinical settings due to growing resistance to current drug regimens. Thus, there is a continued need for novel compounds that are active against this organism. Previously, we reported that various rhodanine derivatives inhibited the supercoiling activity of DNA gyrase. In this study, we determined the effect of new phenylalanine-derived (Z)-5-arylmethylidene rhodanines (which are efficacious against MRSA) on the activity of the two type II bacterial topoisomerases, DNA gyrase and topoisomerase IV (Topo IV). Compounds 1 and 9 showed the greatest efficacy against DNA gyrase with a minimal inhibitory concentration (MIC) of 5 µM while compounds 2 and 3 were the most efficacious against Topo IV with MIC values of 0.75 µM and 0.5 µM, respectively. Induced fit docking, using the crystallographic structures of the target enzymes, indicated that these rhodanine derivatives bind to the ATPase domain of gyrB and ParE subunits on DNA gyrase and Topo IV, respectively. These new compounds were efficacious against both DNA gyrase and Topo IV. The increased efficacy of these new rhodanine compounds, as compared to other rhodanine derivatives, results from their dual inhibition of DNA gyrase and Topo IV, thereby making them good candidates for further drug design and development.


Assuntos
Antibacterianos/química , DNA Girase/química , DNA Topoisomerase IV/antagonistas & inibidores , Rodanina/química , Staphylococcus aureus/enzimologia , Inibidores da Topoisomerase II/química , Sequência de Aminoácidos , Antibacterianos/farmacologia , Sítios de Ligação , Domínio Catalítico , DNA Girase/metabolismo , DNA Topoisomerase IV/metabolismo , Desenho de Fármacos , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Dados de Sequência Molecular , Fenilalanina/química , Rodanina/farmacologia , Alinhamento de Sequência , Staphylococcus aureus/efeitos dos fármacos , Inibidores da Topoisomerase II/farmacologia
18.
Arch Pharm (Weinheim) ; 348(1): 10-22, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25449674

RESUMO

In continuation of our efforts to develop new derivatives as hepatitis C virus (HCV) NS5B inhibitors, we synthesized novel 5-arylidene-4-thiazolidinones. The novel compounds 29-42, together with their synthetic precursors 22-28, were tested for HCV NS5B inhibitory activity; 12 of these compounds displayed IC50 values between 25.3 and 54.1 µM. Compound 33, an arylidene derivative, was found to be the most active compound in this series with an IC50 value of 25.3 µM. Molecular docking studies were performed on the thumb pocket-II of NS5B to postulate the binding mode for these compounds.


Assuntos
Antivirais/síntese química , Antivirais/farmacologia , Desenho de Fármacos , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacologia , Hepacivirus/efeitos dos fármacos , Tiazolidinas/síntese química , Tiazolidinas/farmacologia , Proteínas não Estruturais Virais/antagonistas & inibidores , Antivirais/metabolismo , Sítios de Ligação , Linhagem Celular Tumoral , Desenho Assistido por Computador , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/metabolismo , Hepacivirus/enzimologia , Ensaios de Triagem em Larga Escala , Humanos , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Estrutura Molecular , Conformação Proteica , Relação Estrutura-Atividade , Tiazolidinas/metabolismo , Proteínas não Estruturais Virais/metabolismo
19.
Water Sci Technol ; 71(9): 1293-300, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25945844

RESUMO

The present study was aimed towards the effective bio-treatment of actual industrial effluent containing as high as 42,000 mg/L COD (chemical oxygen demand), >28,000 ADMI (American Dye Manufacturers Institute) color value and four heavy metals using indigenous developed bacterial consortium TSR. Mineral salt medium supplemented with as low as 0.02% (w/v) yeast extract and glucose was found to remove 70% ADMI, 69% COD and >99% sorption of heavy metals in 24 h from the effluent by consortium TSR. The biodegradation of effluent was monitored by UV-vis light, HPLC (high performance liquid chromatography), HPTLC (high performance thin layer chromotography) and FTIR (Fourier transform infrared spectroscopy) and showed significant differences in spectra of untreated and treated effluent, confirming degradation of the effluent. Induction of intracellular azoreductase (107%) and NADH-DCIP reductase (128%) in addition to extracellular laccase (489%) indicates the vital role of the consortium TSR in the degradation process. Toxicity study of the effluent using Allium cepa by single cell gel electrophoresis showed detoxification of the effluent. Ninety per cent germination of plant seeds, Triticum aestivum and Phaseolus mungo, was achieved after treatment by consortium TSR in contrast to only 20% and 30% germination of the respective plants in case of untreated effluent.


Assuntos
Corantes/isolamento & purificação , Metais Pesados/isolamento & purificação , Consórcios Microbianos , Eliminação de Resíduos Líquidos/métodos , Biodegradação Ambiental , Análise da Demanda Biológica de Oxigênio , Cromatografia Líquida de Alta Pressão , Resíduos Industriais/efeitos adversos , Lacase/metabolismo , Phaseolus , Quinona Redutases/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier , Triticum
20.
Chembiochem ; 15(1): 157-69, 2014 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-24288265

RESUMO

Multidrug resistance caused by ATP binding cassette transporter P-glycoprotein (P-gp) through extrusion of anticancer drugs from the cells is a major cause of failure in cancer chemotherapy. Previously, selenazole-containing cyclic peptides were reported as P-gp inhibitors and were also used for co-crystallization with mouse P-gp, which has 87 % homology to human P-gp. It has been reported that human P-gp can simultaneously accommodate two to three moderately sized molecules at the drug binding pocket. Our in silico analysis, based on the homology model of human P-gp, spurred our efforts to investigate the optimal size of (S)-valine-derived thiazole units that can be accommodated at the drug binding pocket. Towards this goal, we synthesized varying lengths of linear and cyclic derivatives of (S)-valine-derived thiazole units to investigate the optimal size, lipophilicity, and structural form (linear or cyclic) of valine-derived thiazole peptides that can be accommodated in the P-gp binding pocket and affects its activity, previously an unexplored concept. Among these oligomers, lipophilic linear (13) and cyclic trimer (17) derivatives of QZ59S-SSS were found to be the most and equally potent inhibitors of human P-gp (IC50 =1.5 µM). As the cyclic trimer and linear trimer compounds are equipotent, future studies should focus on noncyclic counterparts of cyclic peptides maintaining linear trimer length. A binding model of the linear trimer 13 within the drug binding site on the homology model of human P-gp represents an opportunity for future optimization, specifically replacing valine and thiazole groups in the noncyclic form.


Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/antagonistas & inibidores , Desenho de Fármacos , Oligopeptídeos/síntese química , Peptídeos Cíclicos/química , Tiazóis/química , Valina/análogos & derivados , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Animais , Sítios de Ligação , Transporte Biológico/efeitos dos fármacos , Compostos de Boro/química , Células HeLa , Humanos , Camundongos , Simulação de Acoplamento Molecular , Oligopeptídeos/metabolismo , Oligopeptídeos/farmacologia , Peptídeos Cíclicos/metabolismo , Peptídeos Cíclicos/farmacologia , Peptidomiméticos , Fotodegradação/efeitos dos fármacos , Ligação Proteica , Estrutura Terciária de Proteína , Relação Estrutura-Atividade , Tiazóis/metabolismo , Valina/química , Valina/metabolismo
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