Chemical constituents from branches of Maytenus gonoclada (Celastraceae) and evaluation of antimicrobial activity

Six pentacyclic triterpenes were isolated from branches of Maytenus gonoclada (Celastraceae) and all NMR data of a new compound 3-oxo-12α,29-dihydroxyfriedelane are herein reported. The stereochemistry of the new friedelane was established by bidimensional NMR (HSQC, HMBC and NOESY) data, and its molecular weight confirmed by ESI mass spectrometry. Antimicrobial activity assays using the method of disk diffusion and macrodilution were carried out against the bacteria Escherichia coli, Citrobacter freundii, and Bacillus cereus, and against the fungi Candida albicans. The triterpene 3-oxo-12α-hydroxyfriedelane showed positive result against C. albicans

Improvement of genistein content in solid genistein/-cyclodextrin complexes β

Genistein:β-cyclodextrin complexes with high drug loading (19.22%) were prepared by freeze-drying and characterized by differential scanning calorimetry and hydrogen nuclear magnetic resonance spectroscopy. The spatial configuration of the complex was proposed by means of 2D-NOESY experiment combined with molecular modeling. According to the results obtained, the interaction of genistein with β -cyclodextrin in a 1:1 complex is supposed to occur mainly through the insertion of the guest A-ring in cyclodextrin cavity, without rule out the possibility of inclusion through the B-ring, as previously reported in the literature

Artigo IMPROVEMENT OF GENISTEIN CONTENT IN SOLID GENISTEIN/β-CYCLODEXTRIN COMPLEXES

Recebido em 17/3/09; aceito em 7/9/09; publicado na web em 23/2/10 Genistein:β-cyclodextrin complexes with high drug loading (19.22%) were prepared by freeze-drying and characterized by differential scanning calorimetry and hydrogen nuclear magnetic resonance spectroscopy. The spatial configuration of the complex was proposed by means of 2D-NOESY experiment combined with molecular modeling. According to the results obtained, the interaction of genistein with β-cyclodextrin in a 1:1 complex is supposed to occur mainly through the insertion of the guest A-ring in cyclodextrin cavity, without rule out the possibility of inclusion through the B-ring, as previously reported in the literature

Antidiarrheal activity of extracts from Maytenus gonoclada and inhibition of Dengue virus by lupeol

ABSTRACT Diarrhea is an infectious disease caused by bacterial, virus, or protozoan, and dengue is caused by virus, included among the neglected diseases in several underdeveloped and developing countries, with an urgent demand for new drugs. Considering the antidiarrheal potential of species of Maytenus genus, a phytochemical investigation followed by antibacterial activity test with extracts of branches and heartwood and bark of roots from Maytenus gonoclada were conducted. Moreover, due the frequency of isolation of lupeol from Maytenus genus the antiviral activity against Dengue virus and cytotoxicity of lupeol and its complex with β-cyclodextrins were also tested. The results indicated the bioactivity of ethyl acetate extract from branches and ethanol extract from heartwood of roots of M. gonoclada against diarrheagenic bacteria. The lupeol showed potent activity against Dengue virus and low cytotoxicity in LLC-MK2 cells, but its complex with β-cyclodextrin was inactive. Considering the importance of novel and selective antiviral drug candidates the results seem to be promising

Interaction between bradykinin potentiating nonapeptide (BPP9a) and beta-cyclodextrin: A structural and thermodynamic study

Herein, we demonstrate the physical and chemical characterizations of the supramolecular complex formed between beta-cyclodextrin (beta CD) and bradykinin potentiating nonapeptide (BPP9a), an endogenous toxin found in Bothrops jararaca. Circular dichroism results indicate a conformational change in the BPP9a secondary structure upon its complexation with beta CD. Nuclear magnetic resonance results, mainly from NOESY experiments, and theoretical calculations showed a favorable interaction between the tryptophan residue of BPP9a and the beta CD cavity. Thermodynamic inclusion parameters were investigated by isothermal titration calorimetry, demonstrating that beta CD/BPP9a complex formation is an exothermic process that results in a reduction in entropy. Additionally, in vitro degradation study of BPP9a against trypsin (37 degrees C, pH 7.2) showed higher stability of peptide in presence of beta CD. This beta CD/BPP9a complex, which presents new chemical properties arising from the peptide inclusion process, may be useful as an antihypertensive drug in oral pharmaceutical formulations. (C) 2011 Elsevier B.V. All rights reserved.Fundacao de Amparo a Pesquisa do Estado de Minas Gerais (FAPMIG)Fundacao de Amparo a Pesquisa do Estado de Minas Gerais (FAPMIG)Fundacao de Amparo a Pesquisa do Estado Sao Paulo (FAPESP)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)COINFAR Pesquisa e Desenvolvimento LtdaCOINFAR Pesquisa e Desenvolvimento LtdaNCTNanobiofar (MCTCNPqFAPEMIG)NCT-Nanobiofar (MCT-CNPq-FAPEMIG

Quercetin/β-Cyclodextrin Solid Complexes Prepared in Aqueous Solution Followed by Spray-drying or by Physical Mixture

The present study was designed to investigate the influence of operating conditions (temperature, stirring time, and excess amount of quercetin) on the complexation of quercetin with β-cyclodextrin using a 23 factorial design. The highest aqueous solubility of quercetin was reached under the conditions 37°C/24 h/6 mM of quercetin. The stoichiometric ratio (1:1) and the apparent stability constant (Ks = 230 M−1) of the quercetin/β-cyclodextrin complex were determined using phase-solubility diagrams. The semi-industrial production of a 1:1 quercetin/β-cyclodextrin solid complex was carried out in aqueous solution followed by spray-drying. Although the yield of the spray-drying process was adequate (77%), the solid complex presented low concentration of quercetin (0.14%, w/w) and, thus, low complexation efficiency. The enhancement of aqueous solubility of quercetin using this method was limited to 4.6-fold in the presence of 15 mM of β-cyclodextrin. Subsequently, an inclusion complex was prepared via physical mixture of quercetin with β-cyclodextrin (molar ratio of 1:1 and quercetin concentration of 23% (w/w)) and characterized using infrared spectroscopy, differential scanning calorimetry, nuclear magnetic resonance spectroscopy, and scanning electron microscopy analyses. The enhancement of aqueous solubility of quercetin using this method was 2.2-fold, similar to that found in the complex prepared in aqueous solution before the spray-drying process (2.5-fold at a molar ratio of 1:1, i.e., 6 mM of quercetin and 6 mM of β-cyclodextrin)