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1.
IUBMB Life ; 2024 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-38348962

RESUMO

Ferroportin (FPN) is a transmembrane protein and is the only known iron exporter that helps in maintaining iron homeostasis in vertebrates. To maintain stable iron equilibrium in the body, ferroportin works in conjunction with a peptide called hepcidin. In this study, we have identified an alternatively spliced novel isoform of the human SLC40A1 gene, which encodes for the FPN protein and is found to be expressed in different tissues. The novel transcript has an alternate last exon and encodes 31-amino acid long peptide sequence that replaces 104 amino acids at C-terminal in the novel transcript. Molecular modelling and molecular dynamics (MD) simulation studies revealed key structural features of the novel isoform (FPN-N). FPN-N was predicted to have 12 transmembrane domains similar to the reported isoform (FPN), despite being much smaller in size. FPN-N was found to interact with hepcidin, a key regulator of ferroportin activity. Also, the iron-binding sites were retained in the novel isoform as revealed by the MD simulation of FPN-N in bilipid membrane. The novel isoform identified in this study may play important role in iron homeostasis. However, further studies are required to characterize the FPN-N isoform and decipher its role inside the cell.

2.
Bioorg Med Chem Lett ; 41: 128029, 2021 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-33839254

RESUMO

Inflammatory bowel diseases (IBD) are continuous idiopathic inflammation of GIT. Ulcerative colitis, inflammation of the colonic or rectal mucosa has no known medical cure and its treatment is aimed at reducing the signs and symptoms associated with the disorders, induction and maintenance of remission. In this study, we have reported the synthesis of mesalamine and coumarin linked together by a diazo group. The compound was characterized by various spectroscopic methods. Therapeutic potential of the synthesized compound was investigated through acetic acid induced ulcerative rat model. Pharmacokinetic properties were predicted for the compounds by ADMET related descriptors. Molecular docking studies were conducted with four proteins (COX-2, MMP-9, TNF-α and MPO) to examine the interaction of mesalamine (MS) and mesalamine coumarin derivative (MS-CU). Moreover, molecular dynamic simulations were carried out to study the dynamics and stability of the complexes in solvent system. The binding energy of MS-CU with MPO, COX-2, MMP-9 and TNF-α was found to be -9.5, -10.4, -9.2 and -8.4 kcal/mol respectively. MS-CU exhibited higher binding affinity towards all tested proteins than MS. Molecular dynamic simulation reveals that both MS and MS-CU formed a stable complex with all test proteins in aqueous system. Overall binding energy of MS-CU was more than MS showing stronger affinity towards the test portions. In conclusion, Mesalamine-coumarin derivative reduces colonic damage in acetic acid induced ulcerative colitis in rat model, and therefore may prove to be effective in the management of IBD.


Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Cumarínicos/farmacologia , Desenho de Fármacos , Doenças Inflamatórias Intestinais/tratamento farmacológico , Mesalamina/farmacologia , Ácido Acético , Animais , Anti-Inflamatórios não Esteroides/síntese química , Anti-Inflamatórios não Esteroides/química , Cumarínicos/química , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Feminino , Doenças Inflamatórias Intestinais/induzido quimicamente , Doenças Inflamatórias Intestinais/metabolismo , Masculino , Mesalamina/química , Modelos Moleculares , Estrutura Molecular , Ratos , Ratos Wistar , Relação Estrutura-Atividade
3.
Biofouling ; 35(9): 1026-1039, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31778072

RESUMO

The emergence and spread of multidrug-resistant (MDR) pathogenic bacteria is a clinical problem that requires novel anti-infective agents. Targeting pathogenic biofilms is considered a promising strategy to control bacterial infections. In this study, bioactive extracts of Carum copticum were investigated for their anti-biofilm efficacy against extended spectrum ß-lactamase (ESßL) producing MDR enteric bacteria. Thymol was also tested for its anti-biofilm properties, as gas chromatography-mass spectrometry revealed a high content (65.8%) of this phytochemical in the C. copticum methanolic extract. Biofilm inhibition was assessed in microtitre plates and further validated by light, electron and confocal laser microscopy. Sub-inhibitory concentrations of bioactive extracts of C. copticum and thymol significantly prevented biofilm development, ranging from 78.6 to 83.9% reductions. Microscopic analysis revealed that biofilms made by ESßL producing MDR enteric bacteria had a weakened structure, scattered microcolonies, and reduced cell density and thickness after exposure to the bioactive extracts and thymol.


Assuntos
Biofilmes/efeitos dos fármacos , Carum/química , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Microbioma Gastrointestinal/efeitos dos fármacos , Extratos Vegetais/farmacologia , Timol/farmacologia , Inibidores de beta-Lactamases/farmacologia , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Testes de Sensibilidade Microbiana
4.
Drug Chem Toxicol ; 41(3): 358-367, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29411658

RESUMO

Spices and herbs are recognized as sources of natural antioxidants and thus play an important role in the chemoprevention of diseases and aging. Piper cubeba is one among them and known for its medicinal properties for decades. Various biological activities are associated with its extract and phytocompounds. However, the anti-mutagenic activity of antioxidant rich extract is less explored. In this study, we performed the fraction-based antioxidant activity of P. cubeba using four different assays and evaluated the anti-mutagenic activity of most potent antioxidant fraction using Salmonella typhimurium tester strains against four mutagens (methyl methanesulfonate [MMS], sodium azide [SA], benzo(a)pyrene, and 2-aminoflourene) respectively. Among all tested fractions at 25-200 µg/ml, ethanolic extract revealed highest antioxidant activity and significant anti-mutagenicity against both direct and indirect acting mutagens at least one tester strain. Phytochemical analysis by gas chromatography-mass spectrometry (GC/MS) revealed the presence of various phytocompounds including copaene, isocaryophyllene, α-cubebene, etc. Molecular docking studies on DNA binding interactions of GC/MS detected phytocompounds highlight the possible mode of binding. In summary, these in vitro studies have provided the scientific basis for validation of using this plant in the traditional system of medicine and highlighted the need for exploring the role of various compounds for therapeutic efficacy. On the other hand, synergistic interaction among phytocompounds is to be explored to optimize or standardize the extracts for the exploitation in modern phytomedicine.


Assuntos
Antimutagênicos/farmacologia , Antioxidantes/farmacologia , Piper , Extratos Vegetais/farmacologia , Frutas , Cromatografia Gasosa-Espectrometria de Massas , Simulação de Acoplamento Molecular , Piper/química
5.
J Biomol Struct Dyn ; 42(2): 935-947, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-37098813

RESUMO

Hyperglycaemia accelerates the aging process significantly. Diabetes problems can be mitigated by inhibiting glycation. To learn more about glycation and antiglycation mediated by methyl glyoxal and baicalein, we studied human serum albumin as a model protein. A Methylglyoxal (MGO) incubation period of seven days at 37 degrees Celsius induced glycation of Human Serum Albumin.s Hyperchromicity, decreased tryptophan and intrinsic fluorescence, increased AGE-specific fluorescence, and reduced mobility were all seen in glycated human serum albumin (MGO-HSA) in sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Fourier transform infrared spectroscopy (FT-IR) and then far ultraviolet dichroism were used to detect secondary and tertiary structural perturbations (CD). The Congo red assay (CR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) all verified the presence of amyloid-like clumps. Structure (carbonyl groups on ketoamine moieties) (CO), physiological problems including diabetes mellitus, and cardiovascular disease, etc. are linked to the structural and functional changes in glycated HSA, as proven by these studies.Communicated by Ramaswamy H. Sarma.


Assuntos
Flavanonas , Produtos Finais de Glicação Avançada , Reação de Maillard , Humanos , Produtos Finais de Glicação Avançada/química , Espectroscopia de Infravermelho com Transformada de Fourier , Óxido de Magnésio , Albumina Sérica/química , Albumina Sérica Humana/química
6.
J Biomol Struct Dyn ; : 1-13, 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38715440

RESUMO

Various serum proteins, like Human Serum Albumin (HSA) and others, are susceptible to glycation and the formation of Advanced Glycation End Products (AGEs). Diabetes and other diseases are associated with AGE development. Recently, isoflavones have been studied for their therapeutic benefits. In the present study, we glycated HSA with Methylglyoxal (MGO) with and without the test compound, i.e., Biochanin A (BCA), to test its antiglycating capacity. We studied the biochemical and biophysical effects of glycation on HSA with and without BCA and also took the help of the in silico technique. Analytical methods included intrinsic and extrinsic fluorescence, polyacrylamide gel electrophoresis (PAGE), UV spectroscopy, far UV circular dichroism, and others. For structural comprehension, TEM and SEM were used. Molecular docking and simulation were employed to observe BCA-HSA's site-specific interaction. Since HSA is a therapeutically relevant protein involved in many disorders, this study's findings are important.Communicated by Ramaswamy H. Sarma.

7.
J Biomol Struct Dyn ; 41(1): 67-80, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-34842044

RESUMO

Albumin, an important serum protein, is continuously exposed to various oxidizing/nitrating and glycating agents. Depending upon the nature/concentration of reactive species present, the protein may be glycated, oxidized/nitroxidized or glyco-nitro-oxidized. Peroxynitrite is a powerful nitroxidant and has been reported to damage a wide array of macromolecules. On the other hand, methylglyoxal is a very strong reactive dicarbonyl and a potent precursor for the formation of advanced glycation end products under pathological conditions. In certain pathological conditions albumin may be modified by peroxynitrite and methylglyoxal simultaneously. There is dearth of literature suggests that structural/conformational and functional alteration in albumin upon glycation and oxidation/nitroxidation, however the alterations produced by glyco-nitro-oxidation has not yet been explored. Therefore, in this study, simultaneous effect of glycation and nitroxidation on the structure and conformation, vis-a-vis function of albumin was explored. Glyco-nitro-oxidized albumin showed decreased free amino acid content together with decreased affinity of albumin towards cobalt. Molecular docking model and molecular dynamic simulations showed close interaction and formation of stable complexes between methylglyoxal, peroxynitrite and albumin. Formation of carboxymethyl lysine and 3-nitrotyrosine in glyco-nitro-oxidized albumin were confirmed by MALDI-TOF MS and UP-LC MS. Aggregate formation in glyco-nitro-oxidized albumin was visualized by transmission electron microscopy. On the basis of these results, it may be speculated that, albumin modified with endogenously generated methylglyoxal and peroxynitrite might be a driving factor in the progression of heightened inflammatory autoimmune responses. The work presents a ground to study the role of glyco-nitro-oxidized albumin in the pathogenesis and progression of various autoimmune diseases including rheumatoid arthritis. Communicated by Ramaswamy H. Sarma.


Assuntos
Aldeído Pirúvico , Albumina Sérica Humana , Humanos , Aldeído Pirúvico/química , Ácido Peroxinitroso , Simulação de Acoplamento Molecular , Albuminas , Produtos Finais de Glicação Avançada/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
8.
J Biomol Struct Dyn ; 41(18): 9134-9142, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36326451

RESUMO

Arsenic contamination is highly prevalent in food chain, soil and groundwater. Continuous exposure to elevated levels of this environmental toxin is a global concern. Studies have reported enriched accumulation of arsenic in the eyes compared to other body organs leading to various eye diseases. Here, the impact of arsenic exposure on the enzymatic eye ζ-crystallin has been investigated. Arsenic inhibited the activity of the enzyme with an IC50 value of 35 µM. It decreased the free thiol group content of ζ-crystallin due to protein oxidation. The binding of arsenic with ζ-crystallin was explored using biophysical and computational tools. The enzyme undergoes some conformational changes upon arsenic binding. The binding constant (Kb) was determined to be 1.2 × 102 M-1. Thermodynamic parameters were determined by isothermal titration calorimetry (ITC) and the binding energy (ΔG) was calculated to be -3.52 kcal/mol. Molecular docking studies helped in visualizing the amino acid residues (especially Cys165) of the enzyme involved in binding with arsenic. Continuous arsenic exposure is expected to increase the eye crystallin-related abnormalities, elevating the risk of cataractogenesis. Therefore, proper measures need to be taken by authorities to control the contamination of arsenic in the environment and groundwater.Communicated by Ramaswamy H. Sarma.

9.
J Biomol Struct Dyn ; 41(3): 765-777, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-34861809

RESUMO

Natural product such as flavonoids and their derivatives have a discernible capability to inhibit tumor formation and the growth of cancer cell, which have a vital link between diet and chronic disease prevention. Several plants and spices that contain flavonoid derivatives have been used in traditional medicine as disease preventative and therapeutic agents. Therefore, flavonoids could be used as chemotherapeutic drugs, indicating their potential clinical utility in cancer treatment. The purpose of this research was to discover and produce innovative pharmaceuticals from natural sources by introducing structural changes into flavonoids' backbones and changing their structures to improve biological activity and anticancer effects. In the current study, it was expected that the percent unbound values for the 15 compounds in human plasma would be low, ranging between 0.188 and 0.391. However, all compounds have a safe range and are not toxic to the brain. Compounds 2, 10, and 13 were shown to be permeable to the CNS (log PS > -3), but all other compounds had difficulty penetrating the CNS. Furthermore, all compounds had a low total clearance, ranging from 0.038 to 1.216 ml/min/kg, indicating that these compounds have a long half-life. None of the compounds caused skin sensitization (SS), and only compounds 1, 11, and 12 are expected to be AMES-positive, suggesting that the other compounds are not mutagenic. The result of the study showed based on the Drug-likeness and ADMET studies, only 3 compounds, including 3, 4, and 15, have a good pharmacokinetics propriety, the lowest toxicity, and good binding affinity towards Caspase 3 V266APDB (ID: 5I9B) as potential inhibitor candidates for the HeLa cell line, they have a low total clearance property and no AMES mutagenicity or hERG inhibition properties. These compounds (3,4,15) were examined to act as new cytotoxic drug candidates and would have an interest as starting point for designing compounds against the HeLa cell line.Communicated by Ramaswamy H. Sarma.


Assuntos
Produtos Biológicos , Humanos , Células HeLa , Simulação de Acoplamento Molecular , Produtos Biológicos/farmacologia , Produtos Biológicos/química , Simulação de Dinâmica Molecular , Flavonoides
10.
Acta Chim Slov ; 69(2): 489-506, 2022 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-35861093

RESUMO

The present study deals with the in silico of 45 indolyl-aryl-sulfones known as anti-HIV1. The data were collected from recent previously reported inhibitors and divided into a sub-set of 33 compounds as the training set and the remaining 12 compounds were kept in the test set. The selected pharmacophore-ADRRR-yielded a statistically significant 3D-QSAR model containing high confidence scores (R2 = 0.930, Q2 = 0.848, and RMSE = 0.460). The predictive power of the established pharmacophore model was validated with an external test (r2 = 0.848). A systematic virtual screening workflow shows an enrichment factor and has revealed a high predictive power. Then the model was used to screen the filtered PubChem database mapping all chemical features of model pharmacophore. The recognized hits were further assessed by in silico ADMET studies. Molecular dynamics also used to explore the stability of obtained complexes. Finally, these selected compounds are probably to become a good lead molecule for the development of effective anti-HIV-1 drugs.


Assuntos
Simulação de Dinâmica Molecular , Relação Quantitativa Estrutura-Atividade , Simulação de Acoplamento Molecular , Sulfonas
11.
J Biomol Struct Dyn ; 40(21): 11264-11273, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34315340

RESUMO

Main protease (Mpro) of SARS-CoV-2 is a key CoV enzyme that plays a pivotal role in mediating viral replication and transcription, making it an attractive drug target for SARS-CoV-2 the new strain of coronavirus. In this study, we evaluated biologically active compounds present in medicinal plants as potential SARS-CoV-2 Mpro inhibitors, using a molecular docking study with Autodock Vina software. Top seven compounds Afzelin, Phloroglucinol, Myricetin-3-O- rutinosid Tricin 7-neohesperidoside, Silybin, Kaempferol and Silychristin among 50 molecules of natural Origin (Algerian Medicinal plants) were selected which had better and significantly low binding energy as compared to the reference molecule with binding affinities of -9.3, -9.3, -9, -8.9, -8.5, 8.3 and -8.3 kcal mol-1 respectively. Then, we analyzed the ADME properties of the best 7 ligands using the Web server SwissADME. Two of small molecules have been shown to be the ideal candidates for further drug development. Finally, the stability of the both compounds complexed with Mpro was validated through molecular dynamics (MD) simulation, they displayed stable trajectory (RMSD, RMSF) and molecular properties with consistent interaction profile in molecular dynamics simulations, moreover, Silybin could form more stable complex with Mpro than Silychristin.Communicated by Ramaswamy H. Sarma.


Assuntos
Inibidores de Proteases , SARS-CoV-2 , Silibina , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Inibidores de Proteases/farmacologia , SARS-CoV-2/efeitos dos fármacos , Silibina/farmacologia
12.
J Biomol Struct Dyn ; 40(19): 8615-8629, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-33908318

RESUMO

Coronavirus disease 2019 (COVID-19) is an ongoing pandemic instigated by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) which changed the daily train of the world's population and cause several dead. Despite the significant efforts made in developing vaccines and therapeutic drugs, there is currently no available effective treatment against this new coronavirus infection, hence the need to continue research which is aimed at limiting the progression of this virus. The present study which has as objective to carry out in silico studies on the metabolites of some Cameroonian medicinal plants of the Asteraceae family with a view to propose potential molecules to fight against COVID-19. The selected plants are commonly used to treat respiratory infectious diseases, and for this reason they may contain some constituents which could exhibit an antiviral activity against SARS-CoV-2. In this work, a set of 74 naturally occurring compounds are computed with SARS-CoV-2 main protease protein (PDB ID: 6lu7) and spike protein (PDB ID: 6m0j) for their affinity and stability using binding energy analysis and molecular docking. Chrysoeriol-7-O-ß-D-glucuronopyranoside (compound 16) has showed promising results including excellent Absorption, Distribution, Metabolism and Excretion (ADME) parameters as well as insignificant toxicity. Finally, the stability of this compound is complex with the two proteins validated through molecular dynamics (MD) simulation, they displayed stable trajectory and molecular properties with consistent interaction profile in molecular dynamics simulations. These findings call for further in vitro and in vivo challenges of phytoconstituents against the COVID-19 as a potential agent to fight the spread of this dramatic pandemic.Communicated by Ramaswamy H. Sarma.


Assuntos
COVID-19 , Plantas Medicinais , SARS-CoV-2 , Simulação de Acoplamento Molecular , Antivirais/farmacologia , Antivirais/uso terapêutico , Simulação de Dinâmica Molecular , Inibidores de Proteases/farmacologia , Inibidores de Proteases/uso terapêutico
13.
J Biomol Struct Dyn ; 40(21): 10753-10762, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34278954

RESUMO

Since the first appearance of a novel coronavirus pneumonia (NCP) caused by a novel human coronavirus, and especially after the infection started its rapid spread over the world causing the COVID-19 (coronavirus disease 2019) pandemics, a very substantial part of the scientific community is engaged in the intensive research dedicated to finding of the potential therapeutics to cure this disease. As repurposing of existing drugs represents the only instant solution for those infected with the virus, we have been working on utilization of the structure-based virtual screening method to find some potential medications. In this study, we screened a library of 646 FDA approved drugs against the receptor-binding domain of the SARS-CoV-2 spike (S) protein and the main protease of this virus. Scoring functions revealed that some of the anticancer drugs (such as Pazopanib, Irinotecan, and Imatinib), antipsychotic drug (Risperidone), and antiviral drug (Raltegravir) have a potential to interact with both targets with high efficiency. Further we performed molecular dynamics simulations to understand the evolution in protein upon interaction with drug. Also, we have performed a phylogenetic analysis of 43 different coronavirus strains infecting 12 different mammalian species.Communicated by Ramaswamy H. Sarma.


Assuntos
COVID-19 , Animais , Humanos , SARS-CoV-2 , Filogenia , Reposicionamento de Medicamentos/métodos , Simulação de Acoplamento Molecular , Antivirais/farmacologia , Antivirais/química , Simulação de Dinâmica Molecular , Inibidores de Proteases/química , Mamíferos
14.
J Biomol Struct Dyn ; 38(3): 722-732, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-30821650

RESUMO

Cromolyn sodium (CS), an anti-inflammatory drug is used in the treatment of allergic disorders. Bovine serum albumin (BSA) a blood plasma protein is used as a model protein for studying protein folding and ligand binding mechanism as it is the main transporter protein which decides the disposition and pharmacodynamics of numerous drugs. In this study, interaction of CS with BSA was investigated using isothermal titration calorimetry, UV-vis, fluorescence, circular dichroism (CD) spectroscopy and molecular docking techniques. Steady state fluorescence data revealed that BSA-CS complex formation occurred through static mode of quenching. Negative values of Gibbs free energy change and enthalpy change showed that BSA-CS complexation was spontaneously favorable and enthalpy driven. CS preferentially interacted at Sudlow's site I (sub-domain IIA) of BSA and the finding was further substantiated by molecular docking study. The binding of CS induced changes in secondary motif of BSA resulting decrease of α-helical content as evident from CD. We explored detailed thermodynamic and structural parameters of interaction of CS to BSA that will be helpful for understanding the more precise binding mechanism of the drug at molecular level.Communicated by Ramaswamy H. Sarma.


Assuntos
Cromolina Sódica/química , Simulação de Acoplamento Molecular , Soroalbumina Bovina/química , Análise Espectral , Animais , Sítios de Ligação , Calorimetria , Bovinos , Transferência Ressonante de Energia de Fluorescência , Cinética , Ligação Proteica , Desnaturação Proteica , Espectrofotometria Ultravioleta , Temperatura
15.
Toxicol Res (Camb) ; 8(4): 568-579, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31741732

RESUMO

Oxidative stress performs an imperative role in the onset and progression of diabetes. Metabolic enzymes and cellular organelles are detrimental to increased levels of free radicals and the subsequent reduction in anti-oxidant defence. Pyridoxamine (vitamin B6) is an indispensible nutrient for humans and is considered to be an important food additive too. The aim of this research was to examine the effect of vitamin B6 in a diabetic environment. This study reports the effects of pyridoxamine supplementation in alloxan induced diabetic rats. Diabetes was induced by the single intra peritoneal dose of alloxan (120 mg per kg body weight). Diabetic rats were treated with pyridoxamine (10 and 15 mg per kg body weight) and compared with a control set of diabetic rats without supplementation. Pyridoxamine treatment showed dose dependent recovery in all parameters. A notable decline in oxidative stress parameters and ROS production with reductions in fasting blood glucose levels along with normal patterns of the glucose tolerance test has been reported here. Histological studies reveal damage recovery in the liver as well as kidney tissues. A notable amount of recovery was observed in cellular DNA distortion and damage. It is thus advocated that pyridoxamine might help in reducing problems associated with diabetes. A probable mechanism pertaining to the action of pyridoxamine is proposed as well.

16.
Saudi J Biol Sci ; 26(7): 1848-1855, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31762667

RESUMO

The widespread occurrence of extended spectrum ß-lactamases (ESßLs) producing enteric bacteria and their co-resistance with flouroquinolones has impaired the current antimicrobial therapy. This has prompted the search for new alternatives through synergistic approaches with herbal extracts. In this study Carum copticum (seeds) was extracted first in methanol and then subsequently extracted in different organic solvents. MIC of plant extracts, ciprofloxacin and thymol was determined by broth micro-dilution method using TTC. Synergism between plant extracts and ciprofloxacin was assayed by the checkerboard method. Chemical constituents of active extracts were analyzed by GC-MS. Methanolic, hexane and ether extract of Carum copticum exhibited significant antibacterial activity with MIC values ranged from 0.25 mg/ml to 2.0 mg/ml. Synergy analysis between Carum copticum extracts and ciprofloxacin combinations revealed FIC index in the range of 0.093-0.25. About 81% ciprofloxacin resistant ESßL producing enteric bacteria were re-sensitized in the presence of 15.6-250 µg/ml of methanolic extract of Carum copticum. Moreover, ciprofloxacin showed 8 to 64 folds reduction in MIC in presence of 250 and 500 µg/ml of hexane extract. Whereas, 4-32 folds reduction in MIC of ciprofloxacin was achieved in the presence of 31.25 and 62.5 µg/ml of ether extract, indicating synergistic enhancement of drug activity. The chemical analysis of hexane and ether extracts by GC-MS revealed the common occurrence of one or more phenolic hydroxyl at different locations on benzene ring. This study demonstrated the potential use of herbal extract of Carum copticum in combination therapy against ESßL producing bacteria.

17.
Toxicol Res (Camb) ; 7(2): 156-171, 2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30090571

RESUMO

Considering the ethnopharmacological importance of Syzygium cumini's seed and the lack of information on the antimutagenic and DNA-protecting mechanisms, a fraction-based study was conducted. Four different (hexane, chloroform, ethyl acetate, and aqueous) fractions were obtained from the sequential extraction of the methanolic extract of the seed. The most active antioxidant fraction (ethyl acetate) contained significant amount of phenolics and flavonoids. LC-qTOF-MS analysis of the ethyl acetate fraction revealed the presence of rutin, myricetin, naringin, cuscohygrin, and epoxycarryophyllone as constituent phytocompounds. The ethyl acetate fraction (100 µg ml-1) and a selected compound (rutin, 40 µg ml-1) showed remarkable decrease in the revertants frequency range from 74-77% and 66-84%, respectively, against both the mutagens (sodium azide (NaN3) and methyl methane sulfonate (MMS)) in the Salmonella typhimurium tester strains. All the statistical analyses were at a significance level of 0.05 between the different treatment groups. Moreover, the underlying mechanism of antimutagenicity using different treatment regime for rutin was explored. MMS-mediated DNA fragmentation and oxidation in lymphocytes were also shown to be decreased significantly when treated with the ethyl acetate fraction and rutin. Oxidative damage to pBR322 plasmid DNA was also reduced when incubated with different concentration of the ethyl acetate fraction and rutin. Biophysical (UV, fluorescence, ITC, etc.) and computational methods were employed to obtain a closer look at the DNA-rutin interaction. The data obtained clearly revealed that the ethyl acetate fraction exhibited promising antimutagenic and DNA-protective activity and its flavonoid constituents, including rutin, contribute significantly to the observed activity.

18.
J Biomol Struct Dyn ; 36(3): 795-809, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-28276274

RESUMO

Riboflavin (RF) plays an important role in various metabolic redox reactions in the form of flavin adenine dinucleotide and flavin mononucleotide. Human serum albumin (HSA) is an important protein involved in the transportation of drugs, hormones, fatty acid and other molecules which determine the biodistribution and physiological fate of these molecules. In this study, we have investigated the interaction of riboflavin RF with HSA under simulative physiological conditions using various biophysical, calorimetric and molecular docking techniques. Results demonstrate the formation of riboflavin-HSA complex with binding constant in the order of 104 M-1. Fluorescence spectroscopy confirms intermediate strength having a static mode of quenching with stoichiometry of 1:1. Experimental results suggest that the binding site of riboflavin mainly resides in sub-domain IIA of HSA and that ligand interaction increases the α-helical content of HSA. These parameters were further verified by isothermal titration calorimetry ITC which confirms the thermodynamic parameters obtained by fluorescence spectroscopy. Molecular docking was employed to suggest a binding model. Based on thermodynamic, spectroscopic and computational observations it can be concluded that HSA-riboflavin complex is mainly stabilized by various non-covalent forces with binding energy of -7.2 kcal mol-1.


Assuntos
Complexos Multiproteicos/química , Riboflavina/química , Albumina Sérica Humana/química , Termodinâmica , Sítios de Ligação , Dicroísmo Circular , Humanos , Ligantes , Modelos Moleculares , Simulação de Acoplamento Molecular , Ligação Proteica , Espectrometria de Fluorescência
19.
J Biomol Struct Dyn ; 36(10): 2530-2542, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28753123

RESUMO

Titanium dioxide nanoparticles (TiO2-NPs) interaction with human serum albumin (HSA) and DNA was studied by UV-visible spectroscopy, spectrofluorescence, circular dichroism (CD), and transmission electron microscopy (TEM) to analyze the binding parameters and protein corona formation. TEM revealed protein corona formation on TiO2-NPs surface due to adsorption of HSA. Intrinsic fluorescence quenching data suggested significant binding of TiO2-NPs (avg. size 14.0 nm) with HSA. The Stern-Volmer constant (Ksv) was determined to be 7.6 × 102 M-1 (r2 = 0.98), whereas the binding constant (Ka) and number of binding sites (n) were assessed to be 5.82 × 102 M-1 and 0.97, respectively. Synchronous fluorescence revealed an apparent decrease in fluorescence intensity with a red shift of 2 nm at Δλ = 15 nm and Δλ = 60 nm. UV-visible analysis also provided the binding constant values for TiO2-NPs-HSA and TiO2-NPs-DNA complexes as 2.8 × 102 M-1 and 5.4 × 103 M-1. The CD data demonstrated loss in α-helicity of HSA and transformation into ß-sheet, suggesting structural alterations by TiO2-NPs. The docking analysis of TiO2-NPs with HSA revealed its preferential binding with aromatic and non-aromatic amino acids in subdomain IIA and IB hydrophobic cavity of HSA. Also, the TiO2-NPs docking revealed the selective binding with A-T bases in minor groove of DNA.


Assuntos
DNA/química , DNA/metabolismo , Nanopartículas/química , Conformação de Ácido Nucleico , Albumina Sérica Humana/química , Albumina Sérica Humana/metabolismo , Titânio/química , Dicroísmo Circular , Humanos , Simulação de Acoplamento Molecular , Nanopartículas/ultraestrutura , Ligação Proteica , Domínios Proteicos , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Difração de Raios X
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