New biflavonoid and other flavonoids from the leaves of Chimarrhis turbinata and their antioxidant activities

A new biflavonol, named chimarrhoside (1), and eight known flavonol glycosides (2-9), were isolated from the leaves of Chimarrhis turbinata. Their structures were established on the basis of 1D and 2D NMR experiments as quercetin-3-O-rutinoside (2), kaempferol-3-O-rutinoside (3), kaempferol-3-O-α-L-rhamnopyranosyl-(1→6)-β-D-galactopyranoside (4), quercetin-3-O-α-L-rhamnopyranosyl-(1→6)-β-D- galactopyranoside (5), 6-hydroxy-rutin (6), kaempferol-3-O-D-galactopyranoside (7), kaempferol-3-O-D-glucopyranoside (8) and kaempferol-3-O-α- Lrhamnopyranosyl-(1→6)-α-L-rhamnopyranosyl-(1→4) -β-D-glucopyranoside (9). In addition, catechin (10) and catechin-(4α→8)-catechin-procyanidin B-3) (11) were isolated. The crude extract, fractions and isolated compounds were evaluated for their antioxidative properties using an autographic assay based on β-carotene bleaching on TLC plates, and spectrophotometric detection by reduction of the stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical. Flavonoids 2, 5, 6, 10 and 11 displayed strong free radical scavenging activity, when compared with the standards BHT and rutin. ©2005 Sociedade Brasileira de Química.

New bioactive metabolites produced by Phomopsis cassiae, an endophytic fungus in Cassia spectabilis

Two new metabolites, ethyl 2,4-dihydroxy-5,6-dimethylbenzoate (1) and phomopsilactone (2) were isolated from Phomopsis cassiae, an endophytic fungus in Cassia spectabilis. Their structures were elucidated by 1D and 2D NMR, MS and IR spectral data. Compounds 1 and 2 displayed strong antifungal activity against the phytopatogenic fungi Cladosporium cladosporioides and C. sphaerospermum, as well as cytotoxicity against human cervical tumor cell line (HeLa), in in vitro assays. ©2005 Sociedade Brasileira de Química.

New flavone from the leaves of Neea theifera (Nyctaginaceae)

Neea theifera Oerst. (Nyctaginaceae) is widely used in Brazilian folk medicine for the treatment of gastric ulcers and inflammation. Phytochemical investigation of the leaves of Neea theifera afforded the isolation of the new flavone luteolin-7-O-[2″-O-(5‴-O-feruloyl)-β-D-apiofuranosyl]- β-D-glucopyranoside (1) besides the eight-known compounds vitexin, isovitexin, isoorientin, orientin, vicenin-2, chrysoeriol, apigenin and luteolin. Their chemical identification was established by NMR spectroscopic methods including 2D-NMR, as well as UV and ESI-MS analyses. ©2007 Sociedade Brasileira de Química.

Myeloperoxidase inhibitory and radical scavenging activities of flavones from Pterogyne nitens

Two new flavone glucosides, nitensosides A and B (1, 2), together with four known compounds, sorbifolin (3), sorbifolin 6-O-β-glucopyranoside (4), pedalitin (5), and pedalitin 6-O-β-glucopyranoside (6) were isolated from Pterogyne nitens. Their structures were elucidated from 1D and 2D NMR analysis, as well as by high resolution mass spectrometry. All the isolated flavones were evaluated for their myeloperoxidase (MPO) inhibitory activity. The most active compound, pedalitin, exhibited IC 50 value of 3.75 nM on MPO. Additionally, the radical-scavenging capacity of flavones 1-6 was evaluated towards ABTS and DPPH radicals and compared to standard compounds quercetin and Trolox®. © 2008 Pharmaceutical Society of Japan.

Fungos endofíticos: Uma fonte inexplorada e sustentável de novos e bioativos produtos naturais

Endophytic fungi are a rich source of new and biologically active natural products. They colonize a relatively unexplored ecological habitat and their secondary metabolism is particularly active, presumably due to metabolic interactions with their hosts. In the course of our continuing investigations for new and bioactive compounds from endophytic fungi from brazilian flora Alibertia macrophylla, Caseria sylvestris, Ocotea corymbosa, Cassia spectabilis, Piper aduncum, Cryptocaria mandioccana, Xylopia aromatica and Palicourea marcgravii were investigated. Forty two natural products were isolated and their structures were established on the basis of comprehensive spectral analysis, mainly using 1D and 2D NMR experiments. The compounds were tested in their antifungal, antioxidant, anticholinesterasic and anticancer activities.

A theoretical and experimental study to unequivocal structural assignment of tetrahydroquinoline derivatives

The tetrahydroquinoline derivatives can be easily synthesized through Povarov reaction and have several important biological activities. This work describes a comparative study for the unequivocal assignment of molecular structure of different tetrahydroquinoline derivatives, through a complete analysis of NMR 1D and 2D NMR spectra (1H, 13C, COSY, HSQC, and HMBC), and the correlation this data with theoretical calculations of energy-minimization and chemical shift (δ), employing the theory level of DFT/B3LYP with set of the cc-pVDZ basis. For these derivatives the experimental analyses and the theoretical model adopted were sufficient to obtain a good description of its structures, and these results can be used to assign the structure of various others tetrahydroquinoline derivatives. © 2013 Springer Science+Business Media New York.

Solanidane and iminosolanidane alkaloids from Solanum campaniforme

From the leaves of Solanum campaniforme (Solanaceae), eight solanidane alkaloids were isolated, four of which contain a p-hydroxyphenylethylamine unit. Their structures were established as: 22β,23β-epoxy-solanida-1,4-dien-3-one; 22α,23α-epoxy-10-epi-solanida-1,4,9-trien-3-one; 22α,23α-epoxy-solanida-4-en-3-one; 22β,23β-epoxy-solanida-4-en-3-one; (E)-N-[8′(4-hydroxyphenyl)ethyl]-22α,23α-epoxy-solanida-1,4,9-trien-3-imine; (E)-N-[8′(4-hydroxyphenyl)ethyl]-22α,23α-epoxy-solanida-1,4-dien-3-imine; (Z)-N-[8′(4-hydroxyphenyl)ethyl]-22α,23α-epoxy-solanida-1,4,9-trien-3-imine and (Z)-N-[8′(4-hydroxyphenyl)ethyl]-22α,23α-epoxy-solanida-1,4-dien-3-imine. All structures were determined using spectroscopic techniques, such as 1D and 2D NMR, and HRESIMS. The cytotoxicity and the antiophidic activities of the alkaloids were evaluated. The alkaloids did not show any cytotoxicity, but inhibited the main toxic actions of Bothrops pauloensis venom. © 2013 Elsevier Ltd. All rights reserved.

Espectroscopia de correlação bidimensional generalizada e sample-sample aplicada ao estudo da tripsina pancreática bovina

Pós-graduação em Biofísica Molecular - IBILCE

Constituintes micromoleculares de Aristolochia melastoma Manso: compostos nitrados

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo metabolômico e proteômico em Peperomia blanda (Piperaceae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação química e biológica de fungos endofíticos associados à alga marinha Padina gymnospora

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Investigação eletroquímica e aplicação de eletrodos de carbono vítreo modificados por filmes de poli-L-lisina na determinação de antioxidantes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Compostos de Pd(II) contendo ligantes piridinicos: potencialidades biologicas e aspectos estruturais

Pós-graduação em Química - IQ

Estudos químicos e biológicos de espécies do gênero Lippia (Verbenaceae) nativas no Cerrado paulista

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo fitoquímico e biológico de Aristolochia ridicula

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)