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1.
J Nanosci Nanotechnol ; 20(2): 840-851, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31383079

RESUMO

A mixture of Cu (10%) and Fe (1 to 9%) was deposited on multiwalled carbon nanotubes (MWCNTs) and mesoporous carbon (MC). The catalytic activity was investigated in a reaction between carboxylic acids/esters and aromatic amines. The physico-chemical properties of the materials were characterized by different analytical techniques such as powder XRD (X-ray diffraction), BET (brunauer emmett teller) surface area, XPS (X-ray photoelectron spectroscopy), TPD-NH3 (thermal desorption spectroscopy), SEM-EDS (scanning electron microscopy-energy dispersive spectroscopy) and TEM (transmission electron microscopy). The catalytic activity was investigated in the synthesis of aliphatic and aromatic amides from aliphatic/aromatic carboxylic acids and esters with aniline/benzyl amine. The yields of the product/s were in the range 30 to 92% with 100% selectivity. The percentage yield of amides from esters was found to be less than that of corresponding acids. Cu along with 5% of Fe supported on MWCNTs was found to be a better catalyst than when supported on MC, with respect to the isolated yield of the product/s and recyclability. The catalytic activity of the materials had a good correlation with their surface acidity. A plausible reaction mechanism has been proposed.

2.
J Nanosci Nanotechnol ; 18(1): 202-214, 2018 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-29768832

RESUMO

Sulphate ion modified multiwalled carbon nanotubes (S-CNTs), mesoporous carbon (S-MC), zirconia (S-ZrO2), alumina (S-Al2O3) and silica (S-SiO2) were prepared by wet impregnation technique. The physico-chemical properties of the prepared materials were investigated by Powder-XRD, BET-Surface area and SEM-EDS analysis. Surface acidity of the materials was analyzed using TPD-NH3 and n-butyl amine titration methods. Catalytic activity of these materials was investigated in liquid phase transesterification of diethyl malonate with benzyl alcohol. Effect of various reaction parameters on product yield as well as recyclability of the catalysts was investigated. Kinetics of the reactions was studied and activation energy was evaluated. All the catalysts investigated in this reaction were found to be catalytically active except S-Al2O3, for the formation of transester products; benzyl ethyl malonate (BEM) and dibenzyl malonate (DBM). S-ZrO2 and S-MC resulted good % yield (70 and 73% respectively) of total transester products where as S-CNTs showed 100% selectivity towards the formation of only BEM. Acid sites with moderate acid strength are found to be catalytically active for the transesterification reaction. The catalysts were recyclable up to 5 times without significant loss in their catalytic activity except in the case of S-MC. The reaction followed first order kinetics and the energy of activation of the reaction with different catalysts was in the range of 12-58 kJ mol-1.

3.
J Nanosci Nanotechnol ; 18(1): 426-433, 2018 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-29768864

RESUMO

Sulphate modified multiwalled carbon nanotubes (S-MWCNT) and Mesoporous carbon (S-MC) catalysts were prepared by wet impregnation method. These materials were characterized by different analytical techniques such as Powder-XRD, BET surface area analysis, SEM-EDS and TEM analysis to evaluate their bulk and surface properties. Surface acidity of the catalyst was measured by TPD-NH3 technique, as well as n-butyl amine titration. The estimated surface acidity of S-MWCNT and S-MC using n-butyl amine titration was found to be 0.82 and 1.75 mmol/g respectively. The catalytic activity of these materials was investigated in the synthesis of acetamide derivatives using aromatic acids with substituted aromatic amines in a liquid phase reaction. The reaction conditions were optimized to achieve good % yield of the products. In general S-MC catalyst exhibited good catalytic activity and gave higher % yield of the respective acetamides than S-MWCNT. This is attributed to higher surface acidity of S-MC, however the catalyst was found to be non-recyclable. S-MWCNT exhibited moderate % yield and 100% selectivity towards the formation of products. S-MWCNT catalyst was recycled up to 5 times with a consistent % yield of the respective acetamide derivatives. The synthesized acetamide derivatives were analyzed by M.P, 1HNMR techniques.

4.
Eur J Med Chem ; 139: 454-460, 2017 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-28818769

RESUMO

Efforts were made to synthesize a series of substituted methoxybenzyl-sulfonyl-1H-benzo[d]imidazole derivatives (8a-l) and investigate their anti-ulcer therapeutics. Prior to evaluating antiulcer potentials of 8a-l, a preliminary binding assay against H+/K+-ATPase from goat gastric mucosa was carried out, since it plays an important role in the ulcer development. In order to get more insight into the binding mode of the compounds to H+/K+-ATPase, a molecular docking study was carried out and the best binding affinities were unveiled. Many of the substituted methoxybenzyl-sulfonyl-1H-benzo[d]imidazole derivatives (8a-l) were active for the proposed activity. The key finding was that, least inhibitory constant (ki) values of 8a-l were found between 0.02 and 1.8 µM in the molecular docking study. Almost the same range was reflected/correlated in the H+/K+-ATPase inhibition assay (IC50 0.14-1.29 µM). Remarkably, compounds 8a-l showed a relative activity percentage range of 72-92%. Efficient HRBC membrane stabilization activity of 8a-l ensured the non-harm/safety and the suitability/alternative towards anti-ulcer therapy.


Assuntos
Antiulcerosos/farmacologia , Benzimidazóis/farmacologia , ATPase Trocadora de Hidrogênio-Potássio/metabolismo , Inibidores da Bomba de Prótons/farmacologia , Úlcera Gástrica/tratamento farmacológico , Animais , Antiulcerosos/síntese química , Antiulcerosos/química , Benzimidazóis/síntese química , Benzimidazóis/química , Relação Dose-Resposta a Droga , Cabras , Estrutura Molecular , Inibidores da Bomba de Prótons/síntese química , Inibidores da Bomba de Prótons/química , Úlcera Gástrica/metabolismo , Relação Estrutura-Atividade
5.
Biotechnol Lett ; 29(9): 1333-9, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-17541759

RESUMO

Recombinant human platelet-derived growth factor-BB (rhPDGF-BB) is used to treat full-thickness diabetic ulcers and is being investigated for use in other chronic ulcers, non-healing wounds, and periodontal defects. A simple, novel method for expression and purification of rhPDGF-BB from Escherichia coli is now described. This method produces the dimeric protein in high yield (10-12 mg/g wet cell mass) and with a purity >95%. rhPDGF-BB was exclusively found in inclusion bodies (IBs) representing approx. 30% of the total cell proteins. The IBs were extracted and the monomer purified by RP-HPLC. The purified rhPDGF-B monomer was then refolded using Tris buffer and subsequently dimerized to produce biologically active rhPDGF-BB. This product was composed of two polypeptide chains, each approx. 12 kDa. The final product exhibited specific activity in a fibroblast proliferation assay indistinguishable from that of the WHO reference standard.


Assuntos
Fibroblastos/efeitos dos fármacos , Engenharia de Proteínas/métodos , Becaplermina , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Clonagem Molecular/métodos , Escherichia coli/genética , Escherichia coli/metabolismo , Fibroblastos/citologia , Fibroblastos/fisiologia , Melhoramento Genético/métodos , Humanos , Fator de Crescimento Derivado de Plaquetas/administração & dosagem , Fator de Crescimento Derivado de Plaquetas/química , Fator de Crescimento Derivado de Plaquetas/genética , Fator de Crescimento Derivado de Plaquetas/metabolismo , Proteínas Proto-Oncogênicas c-sis , Proteínas Recombinantes/metabolismo
6.
J Ethnopharmacol ; 85(1): 169-72, 2003 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12576217

RESUMO

Different doses of ethanolic fraction of fruits of Terminalia pallida were evaluated for hypoglycemic and antihyperglycemic activity in normal and alloxan diabetic rats. The oral administration of ethanolic extract at a dosage of 0.5 g/kg body weight exhibited a significant antihyperglycemic activity in alloxan diabetic rats, whereas in normal rats no hypoglycemic activity was observed.


Assuntos
Diabetes Mellitus Experimental/tratamento farmacológico , Hipoglicemiantes/uso terapêutico , Fitoterapia , Terminalia , Administração Oral , Animais , Glicemia/análise , Relação Dose-Resposta a Droga , Etanol , Frutas , Masculino , Extratos Vegetais/uso terapêutico , Ratos , Ratos Wistar
7.
Anc Sci Life ; 15(1): 15-20, 1995 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22556715

RESUMO

The paper deals with the folklore use of twentyone plant species occurring in Rayalaseema region of Andhra Pradesh for curing dental aliments.

8.
Membr Biochem ; 9(3): 227-37, 1990 Jul-Sep.
Artigo em Inglês | MEDLINE | ID: mdl-2135304

RESUMO

Plasma membranes were isolated from the cerebral cortex of control and chronic ethanol-treated rat brains. Analysis of protein composition by SDS-PAGE and by two-dimensional gel electrophoresis (IEF-SDS-PAGE) revealed significant differences in the membrane protein patterns between control and ethanol-treated rat cerebral cortices, indicating the loss of several proteins in membranes from ethanol-treated rat brains. Plasma membrane-associated protein species are categorized into ethanol-sensitive and -insensitive proteins, based on their response to ethanol. This study reports that ethanol depletes certain intrinsic proteins of membranes that might be responsible for plasma membrane disruption by ethanol.


Assuntos
Alcoolismo/metabolismo , Córtex Cerebral/metabolismo , Proteínas de Membrana/metabolismo , Animais , Peso Corporal , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/ultraestrutura , Ingestão de Alimentos , Eletroforese em Gel Bidimensional , Eletroforese em Gel de Poliacrilamida , Etanol/farmacologia , Feminino , Masculino , Ratos , Ratos Endogâmicos
9.
J Ethnopharmacol ; 29(2): 137-58, 1990 May.
Artigo em Inglês | MEDLINE | ID: mdl-2374428

RESUMO

An ethnobotanical survey of Rayalaseema of Andhra Pradesh was carried out during 1985-1988. One hundred and thirty-one useful plants currently used by the tribal and non-tribal inhabitants for treating different ailments are presented. Most of the uses of the plants reported by herbalists appear not to have been recorded hitherto. The study reveals some interesting information about the mode of plant use in various ailments either singly or in combination. It has been observed that though the tribes studied live under the same environment and use the same plant species for treating diseases, their prescriptions are quite different. This indicates that these tribes still retain their own traditions so far as treatments are concerned.


Assuntos
Plantas Medicinais/análise , Botânica , Cultura , Índia , Medicina Ayurvédica
10.
Anc Sci Life ; 9(1): 31-5, 1989 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22557673

RESUMO

The paper deals with the folk-lore use of 26 antidiabetic plant species occurring in Rayalaseema region of Andhra Pradesh. The methods of preparation and dose of administration of crude drugs as suggested by tribal and non - tribal herbalists are recorded in the study. Also the known chemical constituents(s) of these plants are included in the communication.

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