Composição química, atividades inibidora da acetilcolinesterase e antifúngica de Pera glabrata (Schott) Baill. (Euphorbiaceae)

Pera glabrata (Schott) Baill. was selected for this study after showing a preliminary positive result in a screening of Atlantic Forest plant species in the search for acetylcholinesterase inhibitors and antifungal compounds. The bioassays were conducted with crude ethanol extract of the leaves using direct bioautography method for acetylcholinesterase and antifungal activities. This extract was partitioned with hexane, chloroform and ethyl acetate solvents. The active chloroform fraction was submitted to silica gel chromatography column affording 12 groups. Caffeine, an alkaloid, which showed detection limits of 0.1 and 1.0 µg for anticholinesterasic and antifungal activities, respectively, was isolated from group nine. After microplate analyses, only groups four, nine, 10, 11 and 12 showed acetylcholinesterase inhibitory activity of 40% or higher. The group 12 was purified by preparative layer chromatography affording four sub-fractions. Two sub-fractions from this group were analyzed by gas chromatography-mass spectrometry and gas chromatography-flame ionization detector. The first sub-fraction showed anticholinesterasic activity and contained two major compounds: 9-hydroxy-4-megastigmen-3-one (84%) and caffeine (6%). The second sub-fraction presented five major compounds identified as 9-hydroxy-4-megastigmen-3-one, isololiolide, (-) loliolide, palmitic acid and lupeol and did not show activity.Pera glabrata (Schott) Baill. foi selecionada para este estudo a partir de uma triagem de espécies vegetais da Mata Atlântica na busca de substâncias com atividades anticolinesterásica e antifúngica. A técnica da bioautografia direta foi utilizada para a detecção das atividades anticolinesterásica e antifúngica. O extrato etanólico bruto obtido das folhas foi particionado com hexano, clorofórmio e acetato de etila. A fração clorofórmica ativa foi fracionada por cromatografia em coluna de sílica gel fornecendo 12 grupos. Do grupo nove foi isolado o alcalóide cafeína com limites de detecção de 0,1 e 1,0 µg para as atividades anticolinesterásica e antifúngica, respectivamente. Após bioensaio em microplaca, somente os grupos quatro, nove, 10, 11 e 12 apresentaram inibição da acetilcolinesterase maior ou igual a 40%. O grupo 12 foi purificado por cromatografia em camada delgada preparativa de sílica gel fornecendo quatro sub-frações. Duas sub-frações deste grupo foram analisadas por cromatografia a gás-espectrometria de massas e cromatografia a gás com detector de ionização de chama. A primeira sub-fração contém dois compostos majoritários: 9-hidroxi-4-megastigmen-3-ona (78%) e cafeína (6%), e apresentou atividade anticolinesterásica. A segunda sub-fração contém cinco compostos principais identificados como 9-hidroxi-4-megastigmen-3-ona, isololiolida, (-) loliolida, ácido palmítico e lupeol e não apresentou atividade.FapespCNPq - PibicCapes - Prodo

Composição dos óleos essenciais de variedades de coloração de frutos de Eugenia brasiliensis Lam.

A espécie Eugenia brasiliensis Lam. apresenta a coloração dos frutos variável, sendo reconhecidas três variedades. Entretanto, a definição de variedades não é fácil para espécies de Myrtaceae e também não é amplamente aceita. Duas variedades de Eugenia brasiliensis, baseado na cor dos frutos (roxos e amarelos), tiveram a composição de seus óleos essenciais analisadas com a finalidade de obter indícios de variedade botânica para esta espécie. Embora, os componentes principais nos óleos das folhas fossem os mesmos monoterpenos para ambas as variedades, alfa-pineno, beta-pineno e 1,8-cineol, a variedade com frutos roxos acumulou maior quantidade de sesquiterpenos oxigenados (33,9%) do que aquela com frutos amarelos (3,8%). As diferenças principais ocorreram nos frutos roxos que apresentaram como componente principal o óxido de cariofileno (22,2%) e o alfa-cadinol (10,4%), não detectados no óleo das folhas, e o óleo dos frutos amarelos apresentou uma composição similar àquela observada para as folhas. Estas variedades de coloração dos frutos de E. brasilensis podem ser considerados como dois quimiotipos distintos, uma vez que na variedade com frutos roxos a rota biossintética para sesquiterpenos encontra-se mais operante do que naquela com frutos amarelos, onde são acumulados principalmente os monoterpenos.Eugenia brasiliensis Lam. is a variable species concerning fruit colour, with three recognized varieties. However, the definition of varieties is not easy for Myrtaceae species and not widely accepted. Two fruit colour varieties (purple and yellow) of E. brasiliensis had their essential oil composition analysed in order to give support to the existence of varieties for this species. Although, the major components in the leaf oil are the same monoterpenes for both varieties, alpha-pinene, beta-pinene and 1,8-cineol, the purple fruit variety accumulates more oxygenated sesquiterpenes (33.9%) than the one with yellow fruits (3.8%). The major differences occurred in purple fruits that present as major components caryophyllene oxide (22.2%) and alpha-cadinol (10.4%), not found in the leaf oil, and the yellow fruit oil presented a similar composition as observed for the leaves. These fruit colour varieties of E. brasilensis can be considered as two distinct chemotypes, since the sesquiterpene pathway is more operant in the purple variety than in the yellow one, in which monoterpenes are mainly accumulated

Chemical Composition, Antimicrobial and Antioxidant Activities of Eugenia Dysenterica DC Essential Oil

Eugenia dysenterica DC is a native species from the Cerrado biome and can be found in several states of Brazil. This study evaluated the chemical composition, antimicrobial and antioxidant activities from the essential oils of a population collected in São Paulo state. Essential oils were obtained by conventional means, and their compositions were analyzed by GC-MS. Screening assays for antimicrobial activity were carried out by the microdilution method and the antioxidant potential was assessed by the DPPH scavenging method. The GC-MS analysis indicated that 52.63% of the essential oil is composed by oxygenated sesquiterpenes and the major compound is (-)-elema-1,3,11(13)-trien-12-ol (24.86%). The antimicrobial assay indicated MIC 42.1 µg/mL for S. aureus and MIC > 10000 µg/mL for the other tested microorganisms, Gram negative bacteria and fungi. The oil showed an IC50 of 5.4±0.632 mg/mL for in the DPPH assay. The essential oil had a different chemical composition from previous studies. The essential oil did not present a potent antioxidant activity. However, it can be considered a promising antimicrobial agent against S. aureus

Saponinas triterpênicas de Tocoyena brasiliensis Mart. (Rubiaceae)

The present communication reports the isolation and identification of four triterpenoid saponins from the chloroform extract of the leaves of Tocoyena brasiliensis: 3-O-β-D-quinovopyranosyl quinovic acid, 3-O-β-D- quinovopyranosyl cincholic acid, 3-O-β-D-glucopyranosyl quinovic acid and the 28-O-β-D-glucopyranosyl ester derivative of quinovic acid as binary mixtures, respectively. From the ethanol extract a flavonoid identified as ramnazin-3-O-rutinoside was obtained. The structures of these compounds were assigned by data analysis of ID and 2D NMR spectrometry and comparison with data recorded in the literature for these compounds

Targeted Isolation of Indolopyridoquinazoline Alkaloids from Conchocarpus fontanesianus Based on Molecular Networks

A dichloromethane-soluble fraction of the stem bark of Conchocarpus fontanesianus showed antifungal activity against Candida albicans in a bioautography assay. Off-line high-pressure liquid chromatography activity-based profiling of this extract enabled a precise localization of the compounds responsible for the antifungal activity that were isolated and identified as the known compounds flindersine (17) and 8-methoxyflindersine (18). As well as the identification of the bioactive principles, the ultra-high-pressure liquid chromatography-high-resolution mass spectrometry metabolite profiling of the dichloromethane stem bark fraction allowed the detection of more than 1000 components. Some of these could be assigned putatively to secondary metabolites previously isolated from the family Rutaceae. Generation of a molecular network based on MS(2) spectra indicated the presence of indolopyridoquinazoline alkaloids and related scaffolds. Efficient targeted isolation of these compounds was performed by geometric transfer of the analytical high-pressure liquid chromatography profiling conditions to preparative medium-pressure liquid chromatography. This yielded six new indolopyridoquinazoline alkaloids (5, 16, 19-22) that were assigned structurally. The medium-pressure liquid chromatography separations afforded additionally 16 other compounds. This work has demonstrated the usefulness of molecular networks to target the isolation of new natural products and the value of this approach for dereplication. A detailed analysis of the constituents of the stem bark of C. fontanesianus was conducted

Composição dos óleos essenciais de variedades de coloração de frutos de Eugenia brasiliensis Lam

A espécie Eugenia brasiliensis Lam. apresenta a coloração dos frutos variável, sendo reconhecidas três variedades. Entretanto, a definição de variedades não é fácil para espécies de Myrtaceae e também não é amplamente aceita. Duas variedades de Eugenia brasiliensis, baseado na cor dos frutos (roxos e amarelos), tiveram a composição de seus óleos essenciais analisadas com a finalidade de obter indícios de variedade botânica para esta espécie. Embora, os componentes principais nos óleos das folhas fossem os mesmos monoterpenos para ambas as variedades, α-pineno, β-pineno e 1,8-cineol, a variedade com frutos roxos acumulou maior quantidade de sesquiterpenos oxigenados (33,9%) do que aquela com frutos amarelos (3,8%). As diferenças principais ocorreram nos frutos roxos que apresentaram como componente principal o óxido de cariofileno (22,2%) e o α-cadinol (10,4%), não detectados no óleo das folhas, e o óleo dos frutos amarelos apresentou uma composição similar àquela observada para as folhas. Estas variedades de coloração dos frutos de E. brasilensis podem ser considerados como dois quimiotipos distintos, uma vez que na variedade com frutos roxos a rota biossintética para sesquiterpenos encontra-se mais operante do que naquela com frutos amarelos, onde são acumulados principalmente os monoterpenos.Eugenia brasiliensis Lam. is a variable species concerning fruit colour, with three recognized varieties. However, the definition of varieties is not easy for Myrtaceae species and not widely accepted. Two fruit colour varieties (purple and yellow) of E. brasiliensis had their essential oil composition analysed in order to give support to the existence of varieties for this species. Although, the major components in the leaf oil are the same monoterpenes for both varieties, α-pinene, β-pinene and 1,8-cineol, the purple fruit variety accumulates more oxygenated sesquiterpenes (33.9%) than the one with yellow fruits (3.8%). The major differences occurred in purple fruits that present as major components caryophyllene oxide (22.2%) and α-cadinol (10.4%), not found in the leaf oil, and the yellow fruit oil presented a similar composition as observed for the leaves. These fruit colour varieties of E. brasilensis can be considered as two distinct chemotypes, since the sesquiterpene pathway is more operant in the purple variety than in the yellow one, in which monoterpenes are mainly accumulated