• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 5
  • Tagged with
  • 5
  • 5
  • 5
  • 5
  • 3
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

ContribuiÃÃo ao Conhecimento QuÃmico - FarmacolÃgico de Plantas do Nordeste do Brasil: Luffa operculata Cogn / Chemical-biological contribution to our knowledge of plants of northeast Brazil: Luffa operculata Cogn.

Cleia Rocha de Sousa Feitosa 20 December 2011 (has links)
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Luffa operculata (Cucurbitaceae) is a plant widely distributed in Northeastern Brazil, where is known as âcabacinhaâ. An aqueous solution from the fruit of âcabacinhaâ has been popularly used for the treatment of sinusitis as a bitter stomachic and purgative remedy. The broad spectrum of pharmacological effects reported in the literature and the abundance of this plant in rural Northeastern Brazil justified this study. The plant was subjected to phytochemical study with the objective of isolation and characterization of their secondary metabolites. The Cucurbitaceae are characteristically rich in cucurbitacins, which are oxidative modified triterpenes that together with their glycosides counterparts are considered the agents responsible for the potent toxicity observed in extracts of the fruit of Luffa operculata. Through various chromatographic steps the elements were purified and isolated. The ethanol extract of the fruit of Luffa operculata yielded the isolation of six triterpenoids (cucurbitacin D, isocucurbitacin D, 3-epi-isocucurbitacin D, cucurbitacin I, cucurbitacin B and arvenin I). The ethanol extract of the stems yielded two quinones (emodine and chrisophanol), as well as a mixture of aliphatic esters (hexadecanoic acid, ethyl ester and octadecanoic acid, ethyl ester) and one rare triterpene friedolenane type (bryonolic acid). Furthermore, a mixture of steroids [(22E, 24S)-ethyl-5α-cholest-7,22-dien-3β-ol and (22E,24R)-ethyl-5α-cholest-7,22,25-trien-3β-ol]; ceramides (1,3,4-trihydroxy-2-[2Â-hydroxydocosanoylamino]-19-tetracasadecene and 1,3,4-tryhydroxy-2-[2Â-hydroxyhenicosanoylamino]-19-tetracasadecene) were isolated from the ethanol extract of the fruit bark. Meanwhile, a mixture of steroids was isolated from the hexane extract of the leaves [(22E, 24S)-ethyl-5α-cholest-7,22-dien-3β-ol and (22E,24R)-ethyl-5α-cholest-7,22,25-trien-3β-ol), while the hexane extract of the stems yielded one steroid (spinasterol) and a mixture of ceramides [(N-(2-isopropoxy-ethyl)eicosamide, N-(2-isopropoxy-ethyl)nonadecanamide, N-(2-isopropoxy-ethyl)octadacanamide, N-(2-isopropoxy-ethyl)heptadacanamide, N-(2-isopropoxy-ethyl)hexadecanamide]. In order to provide training activities in the laboratory and to collect structural proof of the extracts, several derivatives were prepared by classical reactions such as oxidation, esterification, hydrolysis and methanolysis. In addition, crude extracts and a few of the isolated natural products were assessed for biological activities. Some of the compounds found were described for the first time from Luffa opeculata, while the ceramides isolated from the extract are new to the literature. The 1H and 13C NMR, IV and MS spectra and a comparison with previous spectral data allowed the research team to fully understand the chemical structure of all compounds. / Luffa operculata(Cucurbitaceae) is a plant widely distributed in Northeastern Brazil, where is known as âcabacinhaâ. An aqueous solution from the fruit of âcabacinhaâ has been popularly used for the treatment of sinusitis as a bitter stomachic and purgative remedy. The broad spectrum of pharmacological effects reported in the literature and the abundance of this plant in rural Northeastern Brazil justified this study. The plant was subjected to phytochemical study with the objective of isolation and characterization of their secondary metabolites. The Cucurbitaceae are characteristically rich in cucurbitacins, which are oxidative modified triterpenes that together with their glycosides counterparts are considered the agents responsible for the potent toxicity observed in extracts of the fruit of Luffa operculata. Through various chromatographic steps the elements were purified and isolated. The ethanol extract of the fruit of Luffa operculata yielded the isolation of six triterpenoids (cucurbitacin D, isocucurbitacin D, 3-epi-isocucurbitacin D, cucurbitacin I, cucurbitacin B and arvenin I). The ethanol extract of the stems yielded two quinones (emodine and chrisophanol), as well as a mixture of aliphatic esters (hexadecanoic acid, ethyl ester and octadecanoic acid, ethyl ester) and one rare triterpene friedolenane type (bryonolic acid). Furthermore, a mixture of steroids [(22 E , 24S) - ethyl - 5 α - cholest - 7,22 - dien - 3 β - ol and (22 E ,24R) - ethyl - 5 α - cholest - 7,22,25 - trien - 3 β - ol]; ceramides (1,3,4-trihydroxy-2- [2 ́ - hydroxydocosanoylamino] - 19 - tetracasadecene and 1,3,4-tryhydroxy - 2 - [2 ́ - hydroxyhenicosanoylamino] - 19 - tetracasadecene) were isolated from the etha nol extract of the fruit bark. Meanwhile, a mixture of steroids was isolated from the hexane extract of the leaves [(22 E , 24S) - ethyl - 5 α - cholest - 7,22 - dien - 3 β - ol and (22 E ,24R) - ethyl - 5 α - cholest - 7,22,25 - trien - 3 β - ol), while the hexane extract of the stems yield ed one steroid (spinasterol) and a mixture of ceramides [(N-(2-isopropoxy-ethyl)eicosamide, N - (2 - isopropoxy - ethyl)nonadecanamide, N - (2 - isopropoxy - ethyl)octadacanamide, N-(2-isopropoxy - ethyl)heptadacanamide, N-(2-isopropoxy-ethyl)hexadecanamide]. In order to provide training activities in the laboratory and to collect structural proof of the extracts, several derivatives were prepared by classical reactions such as oxidation, esterification, hydrolysis and methanolysis. In addition, crude extracts and a few of the isolated natural products were assessed for biological activities. Some of the compounds found were described for the first time from Luffa opeculata, while the ceramides isolated from the extract are new to the literature. The1H and 13C NMR, IV an d MS spectra and a comparison with previous spectral data allowed the research team to fully understand the chemical structure of all compounds.
2

Galactana sulfatada da alga vermelha Acanthophora muscoides: potencial anticoagulante e antitrombÃtico / Sulfated galactan from the red alga Acanthophora Muscoid: potential antithrombotic and anticoagulant

Bruno Pedrosa Fontes 23 March 2012 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Anticoagulantes atualmente disponÃveis apresentam limitaÃÃes significativas, o que demonstra a necessidade de agentes alternativos. Os polissacarÃdeos sulfatados de algas marinhas com atividade anticoagulante e/ou antitrombÃtica abrem novas perspectivas no tratamento de distÃrbios tromboembÃlicos. No presente estudo, analisamos a atividade anticoagulante e antitrombÃtica da galactana sulfatada alga marinha vermelha Acanthophora muscoides (AmII). A atividade anticoagulante foi analisada atravÃs dos ensaios de TTPa, TTPa ex vivo e do tempo de recalcificaÃÃo. AlÃm disso, as proteases (IIa ou Xa) e inibidores da coagulaÃÃo (AT ou HCII) foram utilizados para melhor avaliar a atividade anticoagulante. Modelos experimentais de trombose venosa e arterial foram utilizados para investigar o potencial antitrombÃtico da galactana sulfatada. O teste de ativaÃÃo do fator XII tambÃm foi realizado. A investigaÃÃo da interaÃÃo AmII-antitrombina foi realizada atravÃs da medida de emissÃo de fluorescÃncia. AlÃm disso, AmII foi utilizada em ensaios de agregaÃÃo plaquetÃria induzida por ADP ou por colÃgeno. A galactana sulfatada de A. muscoides apresentou baixo potencial anticoagulante no TTPa, TTPa ex vivo e no tempo de recalcificaÃÃo quando comparada à heparina. A galactana sulfatada, somente em altas concentraÃÃes, apresentou um aumento na inibiÃÃo da trombina mediada por AT ou HCII. Em contraste, quando o fator Xa foi utilizado como a protease alvo, a galactana apresentou efeito anticoagulante semelhante à heparina. AlÃm disso, a galactana sulfatada mostrou-se um antitrombÃtico potente em doses baixas (atà 0,5 mg/kg de peso corporal), em modelo trombose venosa, no entanto em doses elevadas, seu efeito antitrombÃtico foi reduzido. Na avaliaÃÃo da trombose arterial, a galactana sulfatada apresentou efeito antitrombÃtico semelhante à heparina em todas as doses testadas. Em contraste com a heparina, a galactana sulfatada ativou fator XII e nÃo apresentou tendÃncia hemorrÃgica. AlÃm disso, AmII nÃo apresentou nenhum efeito sobre a agregaÃÃo plaquetÃria e, em associaÃÃo com antitrombina, nÃo alterou a emissÃo de fluorescÃncia, indicando que esta interaÃÃo pode ocorrer por um mecanismo diferente da interaÃÃo heparina-antitrombina. A galactana sulfatada da alga A. muscoides apresentou baixo potencial anticoagulante e elevado potencial antitrombÃtico. Esses resultados sugerem que esta galactana abre novas perspectivas para um possÃvel desenvolvimento de novos fÃrmacos antitrombÃticos. / Currently available anticoagulants have significant limitations, which demonstrate the necessity of alternative agents. Sulfated polysaccharides from marine algae with anticoagulant and/or antithrombotic activities open new perspectives in the treatment of thromboembolic disorders. In the present study, we analyzed the anticoagulant and the antithrombotic activities of a sulfated galactan from the marine red alga Acanthophora muscoides (AmII). The anticoagulant activity was analyzed using the aPTT, the aPTT ex vivo and the recalcification time assays. In addition, specific proteases (IIa or Xa) and coagulation inhibitors (AT or HCII) were used to further investigate the anticoagulant activity. Experimental models of venous and arterial thrombosis were used to investigate the antithrombotic potential of the sulfated galactan. The factor XII activation assay was also performed. The AmII-antithrombin interaction was analyzed by measures of fluorescence emissions. Furthermore, AmII was used in ADP or collagen-induced platelet aggregation assays. The sulfated galactan from A. muscoides presented a lower anticoagulant activity on aPTT, the aPTT ex vivo and the recalcification time assays when compared with heparin. The sulfated galactan only enhanced the thrombin inhibition mediated by AT or HCII at high concentrations. In contrast, when factor Xa was used as the target protease, the sulfated galactan from A. muscoides presented a potent anticoagulant effect, similar to heparin. In addition, the sulfated galactan was shown to be a very potent antithrombotic agent in low doses (up to 0.5 mg/kg body weight), on venous thrombosis model, but these effects were reduced in higher doses. In the arterial experimental thrombosis, the sulfated galactan had antithrombotic effect similar to heparin at all doses tested. In contrast with heparin, the sulfated galactan activated factor XII, but the sulfated galactan did not present hemorrhagic effect in rats. In addition, AmII had no effect on platelet aggregation, and AmII together with antithrombin did not alter the fluorescence emission, indicating that this interaction might occur by a different mechanism than heparin-antithrombin interaction. The sulfated galactan from alga Acanthophora muscoides presented low anticoagulant potential and potent antithrombotic effect. These results suggest that this sulfated galactan opens new perspectives for a possible development of new antithrombotic drugs.
3

Estudo FitoquÃmico e BiolÃgico de Hymenaea courbaril L. / Phytochemical and Biological Study of Hymenaea courbaril L.

Josà ClÃudio Dias Aguiar 30 April 2009 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / O estudo fitoquÃmico de Hymenaea courbaril L., conhecida popularmente como âjatobÃâ, foi realizado com as cascas dos frutos desta espÃcie, a qual tem aplicaÃÃes em processos inflamatÃrios e em distÃrbios intestinais. Das cascas dos frutos maduros, foi extraÃdo o Ãleo essencial, do qual 76,17% dos constituintes foram identificados, sendo -copaeno, o majoritÃrio. A composiÃÃo deste Ãleo foi comparada com a do Ãleo essencial obtido a partir dos frutos verdes, do qual 93,34% dos constituintes foram identificados, sendo germacreno-D, o majoritÃrio. Em ambos os Ãleos, foi verificada a presenÃa somente de sesquiterpenos. O estudo dos constituites fixos possibilitou o isolamento dos diterpenos ent-labdÃnicos, Ãcido zanzibÃrico e Ãcido isoÃzico, e do sesquiterpeno caryolano-1,9-diol, sendo, a Ãltima substÃncia, inÃdita no gÃnero Hymenaea. O estudo biolÃgico revelou bons agentes larvicidas sobre Aedes aegypti, para os Ãleos essenciais de frutos maduros e verdes, com valores de CL50 iguais a 14,85 Â 0,44 ppm e 28,44 Â 0,27 ppm, respectivamente. TambÃm, foi verificada uma satisfatÃria atividade antioxidante sobre o radical livre DPPH, com o extrato em metanol, com valor de CI50 igual a 0,04 mg/mL. O extrato em acetato de etila apresentou uma considerÃvel atividade alelopÃtica sobre Lactuca sativa L., com inibiÃÃo do crescimento de hipocÃtilos em 44,68%, na concentraÃÃo 0,4 mg/mL, e com inibiÃÃo do crescimento de radÃculas em 31,47%, na concentraÃÃo 0,8 mg/mL. / The phytochemical study of Hymenaea courbaril L., named âjatobÃâ, was executed by fruit`s bark of this vegetal, that is applied in inflammatory and intestinal diseases. Essential oil was extracted from mature fruit and 76,17% of the constituents were identified. The major constituent was -copaene. The composition of this oil was compared with the composition of the oil obtained on immature fruit, whose 93,34% of the constituents were identified. The major constituent of immature fruit was germacrene-D. Sesquiterpenes were present into both oils. The study of the fixe constituents permitted to isolate two ent-labdanic diterpenes, zanzibaric acid and isoozic acid, and the sesquiterpene caryolane-1,9-diol, that was a inedited substance in Hymenaea species. The biological study revealed that essential oils of mature fruit and immature fruit were satisfactory larvicidal agentes about Aedes aegypti and their LC50 14,85 Â 0,44 ppm and 28,44 Â 0,27 ppm, respective. A satisfactory antioxidant activity about DPPH free radicals was verified for extract in methanol whose IC50 0,04 mg/mL. The extract in ethyl acetate showed notable allelopathic effect on Lactuca sativa L., and hypocotyls growth was reduced in 44,68% (in concentration 0,4 mg/mL) and radicules growth was reduced in 31,47% (in concentration 0,8 mg/mL).
4

CaracterizaÃÃo estrutural e biolÃgica das lectinas de sementes de Parkia biglobosa (Jacq.) Benth e Vatairea guianensis Aublet. / Characterization of structural and biological lectins seed Parkia biglobosa (Jacq.) Benth and Vatairea guianensis Aublet.

Helton Colares da Silva 21 June 2013 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Lectinas sÃo proteÃnas que contÃm pelo menos um domÃnio nÃo catalÃtico que se liga reversivelmente a mono ou oligossacarÃdeos especÃficos. Por serem capazes de âdecifrar os glicocÃdigosâ codificados na estrutura dos glicoconjugados, as lectinas sÃo molÃculas que possuem um grande potencial biotecnolÃgico e despertam um grande interesse cientÃfico. As Lectinas de Leguminosas representam o grupo mais bem estudado, contudo a maioria dos estudos de lectinas de leguminosas tem envolvido membros da subfamÃlia Papilionoideae, enquanto que investigaÃÃes de lectinas de outras duas subfamÃlias, Caesalpinoideae e Mimosoideae, sÃo escassas. Mesmo dentro da subfamÃlia Papilionoideae, a grande maioria dos estudos com lectinas se concentram em membros da tribo Phaseoleae, prinicpalmente das subtribos Diocleinae e Vicieae, enquanto que as outras tribos desta subfamÃlia ainda sÃo pouco exploradas. Neste contexto, o presente trabalho descreve a caracterizaÃÃo estrutural e biolÃgica das de duas novas lectinas purificadas de sementes de Parkia biglobosa (SubfamÃlia Mimosoideae, tribo Parkiae) e Vatairea guianensis Aublet (SubfamÃlia Papilionoideae, tribo Dalbergieae). Sementes de P. biglobosa possuem uma lectina (PBL) especÃfica para manose/glicose que foi eficientemente purificada por cromatografia de afinidade em gel de Sephadex G-100. PBL à composta por uma cadeia polipeptÃdica Ãnica, nÃo glicosilada e composta por trÃs domÃnios relacionados a jacalina organizados em sequÃncia. A lectina exibe atividade antiinflamatÃria que està associada à inibiÃÃo da migraÃÃo de leucÃcitos e uma atividade antiniciceptiva que pode estar associada à inibiÃÃo da dor inflamatÃria. PBL foi cristalizada e os dados produzidos nos experimentos de difraÃÃo do cristal por raios X possibilitarÃo a futura resoluÃÃo da estrutura tridimensional desta proteÃna. Com relaÃÃo a lectina especÃfica para N-acetil-D-galactosamina/D-galactose presente nas sementes de V. guianensis (VGL) foi evidenciado que esta exibe similaridade de estrutura primÃria com outras lectinas isoladas de espÃcies de plantas taxonomicamente relacionadas, tais como lectinas isoladas da tribo Sophoreae e a lectina VML, com a qual VGL compartilha o mesmo processamento pÃs- traducional. AlÃm disso, ficou evidente que VGL exibe um efeito vasorrelaxante in vitro em aortas de ratos, sendo que este efeito à dependente da presenÃa de endotÃlio, envolve a participaÃÃo do Ãxido nÃtrico e à mediado pelo sÃtio de ligaÃÃo a carboidratos da lectina. / Lectins are defined as structurally heterogeneous proteins of non-immune origin, possessing at least one non-catalytic domain by which they reversibly bind to specific mono- or oligosaccharides. By deciphering the codes present in the glycan structure, lectins are attracting increasing interest in biotechnology. The most studied group of carbohydrate-binding proteins consists of lectins purified from species of the Leguminosae family. Among the studies of the lectins from Leguminosae. many are focused on members of the Papilionoideae subfamily, while investigations of lectins of the other two subfamilies, Caesalpinioideae and Mimosoideae, are scarce. Even within the subfamily Papilionoideae, the vast majority of studies focus on lectins from Phaseoleae and Vicieae tribes, while the other tribes of this subfamily are still poorly explored. In this context, this work describes the structural and biological characterization of two new lectins purified from seeds of Parkia biglobosa (Mimosoideae subfamily, tribe Parkiae) and Vatairea guianensis Aublet (subfamily Papilionoideae, tribe Dalbergieae). P. biglobosa seeds (subfamily Mimosoidae) possess mannose/glucose-specific lectin (PBL) that was purified by affinity chromatography on a Sephadex G-100 column. PBL is composed by a single nonglycosylated polypeptide chain of three tandemly arranged jacalin-related domains and showed important antinociceptive activity associated to the inhibition of inflammatory process. PBL was crystallized and the data produced in the X-ray diffraction experiments will enable the future resolution three-dimensional structure of this protein. With respect to the N-acetyl-D-galactosamine/D-galactose specific lectin present in the V. guianensis seeds (VGL) was demonstrated that this protein presents high similarity in primary structure to other lectins from evolutionarily related plants, such as VML and lectins belonging to the Sophoreae tribe. VGL exhibits vasorelaxant activity in contracted rat aortas, an effect that is strictly dependent on the endothelium and involves NO and the lectin domain.
5

Study Chemical and Biological Margaritopsis carrascoana Wright (Rubiaceae) / Estudo QuÃmico e BiolÃgico de Margaritopsis carrascoana Wright (Rubiaceae).

Raimundo Regivaldo Gomes do Nascimento 16 December 2014 (has links)
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Margaritopsis carrascoana is a small shrub belonging to the Rubiaceae family and endemic from northeastern of Brazil flora growing in the sandy soils of the region of Ibiapaba and Araripe plateaus â Cearà state. The absence of reports of phytochemical studies related to this species, combined with occurrence of bioactive alkaloids in the genus, motivated us to perform chemical study. The plant specimen was collected in Araripe plateu, in MoreilÃndia-PE county. The phytochemical investigation of the ethanolic extract from the stems yielded the alkaloids calycosidine, hodgkinsine, N-8â-formyl-calycosidine and N-8â-methyl-N-1â-desmethylisocalycosidine, besides neolignan dihydrodehydrodiconiferyl alcohol 4-O-β-D-glucopyranoside, the flavonol luteolin 7-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl, the triterpenes lupeol and ursolic acid, and the mixture of β-sitosterol and stigmasterol steroids, as aglycones and glycosylated. From the ethanolic extract of the leaves were isolated the flavonoid luteolin 7-O-[β-D-apiofuranosyl-(1→6)]-β-D-glucopyranoside, chrysoeriol 7-O-[β-D-apiofuranosyl-(1→6)]-β-D-glucopyranoside, luteolin 7-O-{β-D-apiofuranosyl-(1→6)-[β-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranosyl} and luteolin 7-O-{α-L-rhamnopyranosyl-(1→6)-[β-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranosyl}. The alkaloids N-8"-formyl-calycosidine, N-8â-methyl-N-1â-desmethylisocalycosidine, luteolin 7-O-{β-D-apiofuranosyl-(1→6)-[β-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranosyl} and luteolin 7-O-{α-L-rhamnopyranosyl-(1→6)-[β-L-rhamnopyranosyl-(1→2)]-β-D-glucopyra-nosyl}, are being reported for the first time in the literature, and the other secondary metabolites are unprecedented in the genus Margaritopsis. The secondary metabolites were isolated using classical chromatography techniques; including adsorption chromatography on silica gel, exclusion chromatography on Sephadex LH-20, reverse phase chromatography (C-18), and high performance liquid chromatography (HPLC). For structural characterization were used infrared spectroscopy, mass spectrometry and nuclear magnetic resonance techniques including uni (1H NMR and 13C NMR and DEPT 135) and two-dimensional experiments (HMBC, HSQC, COSY and NOESY), and comparison with the literature data. In addition, the flavonoids flavonol luteolin 7-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl, luteolin 7-O-[β-D-apiofuranosyl-(1→6)]-β-D-glucopyranoside, luteolin 7-O-{β-D-apiofuranosyl-(1→6)-[β-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranosyl} and luteolin 7-O-{α-L-rhamnopyranosyl-(1→6)-[β-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranosyl, sho-wed antioxidant activity greater than the BHT and quercetin standards, while ethanol extracts of stems and leaves showed inhibitory activity on the acetylcholinesterase enzyme. On the other hand, hodgkinsine showed potent cytotoxic activity against ovary, glioblastoma and colon cancer cells lines. The ethanol extract of the leaves and its alkaloidal fraction were submitted to nociception test and yielded good results. The ethanolic extract of the leaves was subjected to gastric antiulcer activity test, leading to a significant reduction in gastric lesions induced by ethanol in mice. / Margaritopsis carrascoana à um pequeno arbusto pertencente à famÃlia Rubiaceae e endÃmico da flora do Nordeste brasileiro, que cresce em solos arenosos do planalto da Ibiapaba e serra do Araripe - CearÃ. A ausÃncia de relatos acerca de estudos fitoquÃmicos relacionados à espÃcie, aliada a ocorrÃncia de alcalÃides bioativos no gÃnero, nos motivou ao seu estudo quÃmico. Desta forma, o espÃcimen vegetal foi coletado na chapada do Araripe, municÃpio de MoreilÃndia-PE. A investigaÃÃo fitoquÃmica do extrato etanÃlico dos talos resultou no isolamento dos alcalÃides calicosidina, hodgkinsina, N-8â-formilcalicosidina e N-8â-metil-N-1â-desmetilisocalicosidina, da neolignana Ãlcool 4-O-β-D-glicopiranosil-di-hidro-desidrodiconiferÃlico, do flavonÃide 7-O-[α-L-ramnopiranosil-(1→2)-β-D-glicopiranosil luteolina, dos triterpenos lupeol e o Ãcido ursÃlico, e da mistura de esterÃides β-sitosterol e estigmasterol, como agliconas e nas formas glicosiladas. A partir do estudo do extrato etanÃlico das folhas foram isolados os flavonÃides 7-O-[β-D-glicopiranosil-(1→6)-β-D-apiofuranosil] luteolina, 7-O-[β-D-glicopiranosil-(1→6)-β-D-apiofuranosil] crisoeriol, 7-O-{β-D-apiofuranosil-(1→6)-[α-L-ramnopiranosil-(1→2)-β-D-glicopiranosil} luteolina e 7-O-{α-L-ramnopiranosil - (1→6) - [α-L-ramnopiranosil-(1→2)-β-D-glicopiranosil} luteolina. Os alcalÃides N-8â-formilcalicosidina e N-8â-metil-N-1â-desmetilisocalicosidina, e os flavonÃides 7-O-{β-D-apiofuranosil-(1→6)-[α-L-ramnopiranosil-(1→2)-β-D-glicopiranosil} luteolina e 7-O-{α-L-ramnopiranosil-(1→6)-[α-L-ramnopiranosil-(1→2)-β-D-glicopiranosil} luteolina, estÃo sendo relatados pela primeira vez na literatura, enquanto todas as demais substÃncias possuem carÃter inÃdito no gÃnero Margaritopsis. O isolamento dos metabÃlitos secundÃrios foi conduzido atravÃs de tÃcnicas cromatogrÃficas clÃssicas, incluindo cromatografia de adsorÃÃo em gel de sÃlica, cromatografia por exclusÃo molecular em Sephadex LH-20, cromatografia de fase reversa (C-18) e cromatografia lÃquida de alta eficiÃncia (CLAE). Para a caracterizaÃÃo estrutural foram utilizadas tÃcnicas espectroscÃpicas utilizando infravermelho, espectrometria de massas e ressonÃncia magnÃtica nuclear, incluindo tÃcnicas uni (RMN 1H e RMN 13C e DEPT 135) e bidimensionais (HMBC, HSQC, COSY e NOESY), alÃm de comparaÃÃo com dados descritos na literatura. Em adiÃÃo, os flavonÃides 7-O-[α-L-ramnopiranosil-(1→2)-β-D-glicopiranosil luteolina, 7-O-[β-D-glicopiranosil-(1→6)-β-D-apiofuranosil] luteolina, 7-O-{β-D-apiofuranosil-(1→6)-[α-L-ramnopiranosil-(1→2)-β-D-glicopiranosil} luteolina e 7-O-{α-L-ramnopiranosil-(1→6) - [α-L-ramnopiranosil-(1→2)-β-D-glicopiranosil} luteolina apresentaram atividade antioxidante maior que os padrÃes BHT e quercetina, enquanto os extratos etanÃlicos dos talos e folhas apresentaram atividade inibidora da enzima acetilcolinesterase. Por outro lado, o alcaloide hodgkinsina apresentou potencial citotÃxico frente Ãs cÃlulas de ovÃrio, glioblastoma e colon. No teste de nocicepÃÃo, realizado com o extrato etanÃlico das folhas e a fraÃÃo alcalÃidica, foram observados resultados positivos para ambas as fraÃÃes. O extrato etanÃlico das folhas foi submetido a teste de atividade antiÃlcera gÃstrica, levando a uma reduÃÃo significativa da Ãrea de lesÃo gÃstrica induzida pelo etanol em camundongos.

Page generated in 0.0726 seconds