• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 25
  • 8
  • 5
  • 4
  • 3
  • 3
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 55
  • 24
  • 11
  • 10
  • 8
  • 6
  • 6
  • 6
  • 6
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 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.
31

Development and Investigation of Electrocyclization Reactions Leading Towards Indene and Thiatriazole Formation and their Functionalization

Rosocha, Yaroslav Gregory S. 19 January 2012 (has links)
No description available.
32

Development Of New Synthetic Methodologies For The Synthesis Of Unusual Isocoumarin And Indole Derivatives:the Chemistry Of Homophthalic Acid

Ozcan, Sevil 01 January 2007 (has links) (PDF)
Many heterocyclic compounds containing nitrogen, oxygen and sulfur show wide range of physiological activities and their synthesis has always been attracted the interest of chemists. The aim of this research is to develop new synthetic methodologies leading to the synthesis of new derivatives of isocoumarines, indoles, isoquinolines, benzodiazepinones and quinazolines, which have been found to show important biological activities. Starting from homophthalic acid and bishomophthalic acid the corresponding acyl azides were proposed to be synthesized, which then would be used for the synthesis of various heterocycles. The proposed diazide from homophthalic was not formed due to the tendency of the ortho-positioned acid to undergo cyclization. Instead, new unusual benzochromen and isocoumarin derivatives have been synthesized in a single step, for which reasonable mechanisms have been proposed. The half ester produced from homophthalic acid was an important key compound for the synthesis of new highly substituted indole derivatives, which are expected to be biologically active. The diisocyanate derived from was synthesized directly from ortho-bromo xylene was treated with alcohols and hydrazine to produce seven membered rings. Instead of the intramolecular cyclization reaction, they underwent polymerization to form new polymers. Furthermore, new synthetic method for the synthesis of pyrazoles has been developed.
33

AVALIAÇÃO DOS EFEITOS FARMACOLÓGICO E TOXICOLÓGICO DE 4- ORGANOCALCOGENO-ISOQUINOLINAS / EVALUATION OF PHARMACOLOGYC AND TOXICOLOGYC EFFECTS OF 4-ORGANOCHALCOGEN-ISOQUINOLINES

Sampaio, Tuane Bazanella 12 March 2014 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Monoamine oxidase (MAO) is a target enzyme in the treatment of several pathologies, being that new molecules which inhibit of a selective, potent and reversible manner their isoforms and without adverse effects are searched. In this way, the first manuscript of this dissertation evaluated the in vitro inhibitory potential of the 4-organochalcogen-isoquinolines on cerebral MAO-A and B activities, elucidating their kinetics profile and the interaction compound x enzyme. The results demonstrated that all compounds were selective inhibitors of MAO-B, being compound 3-phenyl-4-(selenophenyl) isoquinoline the most potent. The kinetics profile revealed a mixed and reversible inhibition of enzyme, consistent to the results of molecular docking. It is known that both organic selenium compounds and isoquinolines are linked to pro-oxidants situations, thus, it was investigated the in vitro effect of 4-organoseleno-isoquinolines on cerebral activities of the enzymes δ- aminolevulinate dehydratase (δ-ALA-D) e Na+, K+-ATPase, which have easily oxidized cysteine residues. Data demonstrated that compounds substituted with chloro, fluoro and trifluoromethyl in the aromatic ring bonded to the selenium atom of compound 3-phenyl-4-(selenophenyl) isoquinoline inhibited both sulfhydryl enzymes, which was not observed in the compound substituted with methyl and in a nonsubstituted compound. Furthermore, since the inhibition of enzymes δ-ALA-D and Na+, K+-ATPase was restored by dithiothreitol it is possible to propose the oxidation of cysteine residues by compounds. The selective and reversible inhibition of MAO-B and the low toxicological potential demonstrated by compound 3-phenyl-4- (selenophenyl) isoquinoline become this compound a candidate for more studies, which aim this enzyme as a therapeutic target. / A monoamina oxidase (MAO) é uma enzima alvo no tratamento de diversas patologias, sendo que novas moléculas que a inibam de maneira seletiva, potente, reversível, e ausente de efeitos adversos suas isoformas são procuradas. Neste sentido, o primeiro manuscrito desta dissertação avaliou o potencial inibitório dos 4- organocalcogeno-isoquinolinas na atividade cerebral da MAO-A e B in vitro, elucidando seus perfis cinéticos e a interação composto e enzima. Os resultados demonstram que todos os compostos apresentam inibição seletiva da MAO-B, sendo o composto 3-fenil-4-(selenofenil) isoquinolina o mais potente. O perfil cinético revelou inibição do tipo mista e reversível da enzima, coerente aos resultados do docking molecular. Sabe-se que tanto compostos orgânicos de selênio quanto isoquinolinas relacionam-se a situações pró-oxidantes, deste modo, investigou-se o efeito in vitro dos 4-organoseleno-isoquinolinas na atividade cerebral das enzimas δ- aminolevulinato dehidratase (δ-ALA-D) e Na+, K+-ATPase, as quais possuem resíduos de cisteína facilmente oxidáveis. Os dados demonstram que os compostos substituídos com cloro, flúor e trifluormetil no anel aromático ligado ao átomo de Se do composto 3-fenil-4-(selenofenil) isoquinolina inibem ambas as enzimas sulfidrílicas, o que não foi observado com o composto substituído com metil e com o composto não substituído. Além disso, visto que a inibição das enzimas δ-ALA-D e Na+, K+-ATPase foi revertida por ditiotreitol é possível propor o envolvimento da oxidação dos resíduos de cisteína pelos compostos. Devido à inibição seletiva e reversível da MAO-B e ao baixo potencial toxicológico demonstrado, o composto 3- fenil-4-(selenofenil) isoquinolina torna-se um candidato a mais estudos que possuam esta enzima como alvo terapêutico.
34

Part A: Rhodium-catalyzed Synthesis of Heterocycles / Part B: Mechanistic Studies on Tethering Organocatalysis Applied to Cope-type Alkene Hydroamination

Guimond, Nicolas January 2012 (has links)
The last decade has been marked by a large increase of demand for green chemistry processes. Consequently, chemists have focused their efforts on the development of more direct routes toward different classes of targets. In that regard catalysis has played a crucial role at enabling key bond formations that were otherwise inaccessible or very energy and resources consuming. The central theme of this body of work concerns the formation of C–N bonds, either through transition metal catalysis or organocatalysis. These structural units being highly recurrent in biologically active molecules, the establishment of more efficient routes for their construction is indispensable. The first part of this thesis describes a new method for the synthesis of isoquinolines from the oxidative coupling/annulation of alkynes with N-tert-butyl benzaldimines via Rh(III) catalysis (Chapter 2). Preliminary mechanistic investigations of this system pointed to the involvement of Rh(III) in the C–H bond cleavage step as well as in the C–N bond reductive elimination that provides the desired heterocycle. Following this oxidative process, a Rh(III)-catalyzed redox-neutral approach to isoquinolones from the reaction of benzhydroxamic acids with alkynes is presented (Chapter 3). The discovery that an N–O bond contained in the substrate can act as an internal oxidant was found to be very enabling. Indeed, it allowed for milder reaction conditions, broader scope (terminal alkyne and alkene compatible) and low catalyst loadings (0.5 mol%). Mechanistic investigations on this system were also conducted to identify the nature of the C–N bond formation/N–O bond cleavage as well as the rate-determining step. The second part of this work presents mechanistic investigations performed on a recently developed intermolecular hydroamination reaction catalyzed through tethering organocatalysis (Chapter 4). This transformation operates via the reversible covalent attachment of two reactants, a hydroxylamine and an allylamine, to an aldehyde catalyst by the formation of a mixed aminal. This allows a difficult intermolecular Cope-type hydroamination to be performed intramolecularly. The main kinetic parameters associated with this reaction were determined and they allowed the generation of a more accurate catalytic cycle for this transformation. Attempts at developing new families of organocatalysts are also discussed.
35

Caenorhabditis elegans as a whole organism screening system for isoquinoline alkaloid bioactivities / 個体の線虫を用いたイソキノリンアルカロイド生理活性スクリーニングシステムに関する研究

Chow, Yit Lai 24 March 2014 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(生命科学) / 甲第18421号 / 生博第301号 / 新制||生||40(附属図書館) / 31279 / 京都大学大学院生命科学研究科統合生命科学専攻 / (主査)教授 佐藤 文彦, 教授 永尾 雅哉, 教授 福澤 秀哉 / 学位規則第4条第1項該当 / Doctor of Philosophy in Life Sciences / Kyoto University / DFAM
36

Regioselectivity of palladium-catalyzed sonogashira cross-coupling of 2-aryl-4-chloro-3-iodoquinoline- derivatives with terminal alkynes

Makelane, Hlamulo Reply 06 1900 (has links)
Please note that the structures do not display correctly in the pdf document. Therefore the original manuscript in MSWord has also been uploaded. Please contact us email if you cannot view these files. / Sonogashira cross-coupling of 2-aryl-4-chloro-3-iodoquinoline derivatives with stoichiometric amount of terminal alkynes in the presence of bis(triphenylphosphine)palladium(II)chloride and copper iodide in triethylamine afforded the 3-(alkynyl)-2-aryl-4-chloroquinoline, exclusively. On the other hand, the 2-aryl-4-chloro-3-iodoquinolines with excess (2.5 equiv.) of terminal alkynes in the presence of PdCl2(PPh3)2-CuI catalyst mixture and NEt3 in dioxane-water (3:1 v/v) afforded the 2-aryl-3,4-bis(alkynyl)quinoline derivatives in a one-step operation. Further transformation of the 2-aryl-3-(alkynyl)-4-chloroquinoline via Suzuki cross-coupling reaction with boronic acid derivatives in the presence of tetrakis(triphenylphosphine)palladium and tricyclohexylphosphine as a ligand in dioxane-water (3:1 v/v) afforded the 2,4-diaryl-3-(alkynyl)quinolines in moderate to high yields. The 2-aryl-3-(alkynyl)-4-chloroquinolines were also transformed to the corresponding 2-aryl-4-(methylamino)-3-(alkynyl)quinoline derivatives using methylamine in ethanol under reflux. / Chemistry / M.Sc.
37

Aspectos químicos e atividade antiprotozoária in vitro de Annona coriacea Mart. (Annonaceae) / Chemical aspects and activity antiprotozoal in vitro of Annona coriacea Mart.

Siqueira, Carlos Alberto Theodoro 17 June 2010 (has links)
Estudos anteriores dos alcalóides totais (AT) de Annona coriacea Mart. (Annonaceae) revelaram atividade antiprotozoária promissora. No presente trabalho, realizou-se o fracionamento biomonitorado dos AT de folha e selecionaram-se duas frações ativas (100% morte), frente às formas promastigotas de Leishmania (L.) chagasi in vitro, para a caracterização dos alcalóides, por CG-EM. Os AT bioativos de caule (100% morte) foram analisados sem fracionamento prévio. Em paralelo, efetuou-se amostragem de três exemplares de A. coriacea, analisados em conjunto, para o acompanhamento da variação do rendimento em AT e da atividade leishmanicida, por 12 meses. Nas frações bioativas de folha, foram caracterizados: estefarina (proaporfínico) e nornuciferina (noraporfínico) e nos AT de caule: pronuciferina (proaporfínico), asimilobina (noraporfínico) e boldina (aporfínico). A presença de boldina foi confirmada pela análise CG-EM do padrão, nas mesmas condições dos AT. Os resultados mostraram-se inéditos para a espécie e a ocorrência de pronuciferina e boldina constituiu o primeiro relato, no gênero Annona. Os dados referentes ao rendimento em AT (folha e caule) e à atividade antipromastigota in vitro indicaram comportamento, praticamente, constante dos parâmetros ao longo do ano. O óleo volátil de folha foi analisado, por CG-EM, tendo-se identificado 60 compostos, em mistura complexa de sesquiterpenos (76,7%) e monoterpenos (23,3%). O constituinte majoritário foi o sesquiterpeno biciclogermacreno (39,8%). O óleo volátil foi avaliado in vitro e apresentou atividade frente às formas promastigotas de quatro espécies de Leishmania e nas formas tripomastigotas de T. cruzi. A determinação e obtenção dos compostos bioativos motiva a continuidade da pesquisa. / Previous studies of total alkaloids (TA) from Annona coriacea Mart. (Annonaceae) have revealed potential antiprotozoal activity. In this study a bioguided fractionation of leaves TA was conducted and two fractions were active in vitro against Leishmania (L.) chagasi promastigotes (100% death) and selected in order to identify the alkaloid constituents, by GC-MS analysis. Stem bioactive TA (100% death) were also analyzed, without previous fractionation. Parallel to that, a sample of three combined specimens of A. coriacea (leaves and stem) was evaluated for the annual variation of TA production and the leishmanicide activity. Stefarine (proaporphine) and nornuciferine (noraporphine) were identified in the bioactive fractions of leaves while pronuciferine (proaporphine), asimilobine (noraporphine) and boldine (aporphine) were identified in stem TA. Boldine was confirmed by the GC-MS evaluation of the standard, under the same conditions of the TA. It was the first report of those alkaloids in this species and for pronuciferine and boldine occurrence in Annona genus. The TA yields (leaves and stem) and the in vitro antipromastigote activity remained almost unaltered throughout the year. The volatile oil of leaves was also analyzed by GC-MS. Sixty compounds were indentified in a complex mixture of sesquiterpenes (76.7%) and monoterpenes (23.3%). Byciclogermacrene was its major component (39.8%). The volatile oil was evaluated in vitro and was active against four species of Leishmania promastigotes and also against T. cruzi tripomastigotes. The identification of the bioactive constituents and their isolation are promising for further studies.
38

Avaliação da atividade antibacteriana e citotóxica dos alcalóides isoquinolínicos de Annona hypoglauca Mart / Antibacterial and cytotoxic evaluation of isoquinoline alkaloids from Annona hypoglauca Mart

Maria Valeria Nani Rinaldi 03 October 2007 (has links)
Annona hypoglauca Mart. foi coletada em área inundada da Floresta Amazônica, próximo à Manaus (Brasil). Os alcalóides foram obtidos do extrato bruto do caule por partição ácido-base, e a partir do resíduo dessa extração foi realizada a partição com solventes de diferentes polaridades, originando as frações livres de alcalóides. A partir da análise de CG-EM dos alcalóides totais foi possível caracterizar sete alcalóides aporfínicos (actinodafinina, anonaina, glaucina, isoboldina, isodomesticina, nornuciferina e roemerina) e possivelmente duas protoberberinas (esculerina e caseadina). Os alcalóides totais foram fracionados em coluna cromatográfica e posteriormente purificados em placa cromatográfica preparativa permitindo o isolamento de dois alcalóides aporfínicos: actinodafinina e isoboldina. As estruturas desses produtos naturais foram definidos com base em espectros de dados, incluindo 1H RMN, 13C RMN, 13C DEPT e CG-EM. Pela primeira vez a ocorrência da actinodafinina esta sendo reportada em uma espécies de Annona. O extrato bruto, as frações livres de alcalóides, os alcalóides totais e suas frações foram submetidos a avaliação da atividade antibacteriana por microdiluição e atividade citotóxica in vitro frente a células de tumores humanos. Para todos os extratos testados, somente os alcalóides totais e suas frações apresentaram atividade frente a bactérias Gram +. No ensaio de citotoxicidade com linhagens de células de tumores, o extrato bruto foi capaz de inibir o crescimento de todas as linhagens celulares testadas, apresentando efeito letal para a linhagem de Câncer de Cólon (KM-12), enquanto as frações livres de alcalóides demonstraram baixa atividade. Por outro lado, as frações livres de alcalóides apresentaram atividade mais pronunciada para a linhagem de Câncer de Pulmão (NCIH-460) do que os alcalóides. Assim, a atividade citotóxica encontrada no extrato bruto é decorrente do sinergismo ou complementação entre os componentes das frações alcaloídicas e não alcaloídicas, isto é, nenhuma das frações isoladamente é responsável pela atividade observada no extrato bruto. / Annona hypoglauca Mart. was collected in the flooded areas of the Amazonian Forest near Manaus (Brazil). The alkaloids were obtained from the stems crude extract by acid-base partitioning and the remaining alkaloid-free extract was partitioned with organic solvents of different polarity. The GC/MS analysis of the total alkaloids allowed the identification of seven aporphine alkaloids (actinophanine, anonaine, glaucine, isoboldine, isodomesticine, nornuciferine and roemerine) and possibly two proberberine alkaloids (scoulerine and caseadine). The total alkaloids were fractionated by column chromatography and further purified by preparative thin-layer chromatography allowing the isolation of two aporphine alkaloids: actinodaphnine and isoboldine. The structures of these natural products were defined based on their spectral data, including 1H NMR, 13C NMR, 13C DEPT and CG/MS. This is the first report for the occurrence of actinodaphnine in Annona species. The crude extract, alkaloid-free organic extracts, total alkaloids and its fractions were tested for their antibacterial activity by the microdilution broth assay and cytotoxic activity against in vitro tissue culture cells of human. From all the extracts assayed, only the total alkaloids and their fractions showed a relevant antibacterial activity against Gram positive organisms. In the cytotoxicity assay with human tumor cell lines, the crude extract was able to inhibit the growth of all cell lines tested, with a lethal effect for the colon cancer (KM-12) cell line. The evaluation of this activity with the total alkaloid and alkaloid-free fractions indicated selectivity for the different cellular lines. The alkaloid fraction presented high growth inhibition for the colon cancer cell line (KM-12), while the alkaloid-free fractions displayed lower activity. On the other hand, the alkaloid free fractions showed a higher activity for the lung cancer cell line (NCIH-460) than the total alkaloids. Thus, the cytotoxic activity found in the crude extract is the result of the synergism or complementary activity among the components of the alkaloid and alkaloid-free fractions, e.g, none of the fractions separately is responsible for the activity observed in the crude extract.
39

Aspectos químicos e atividade antiprotozoária in vitro de Annona coriacea Mart. (Annonaceae) / Chemical aspects and activity antiprotozoal in vitro of Annona coriacea Mart.

Carlos Alberto Theodoro Siqueira 17 June 2010 (has links)
Estudos anteriores dos alcalóides totais (AT) de Annona coriacea Mart. (Annonaceae) revelaram atividade antiprotozoária promissora. No presente trabalho, realizou-se o fracionamento biomonitorado dos AT de folha e selecionaram-se duas frações ativas (100% morte), frente às formas promastigotas de Leishmania (L.) chagasi in vitro, para a caracterização dos alcalóides, por CG-EM. Os AT bioativos de caule (100% morte) foram analisados sem fracionamento prévio. Em paralelo, efetuou-se amostragem de três exemplares de A. coriacea, analisados em conjunto, para o acompanhamento da variação do rendimento em AT e da atividade leishmanicida, por 12 meses. Nas frações bioativas de folha, foram caracterizados: estefarina (proaporfínico) e nornuciferina (noraporfínico) e nos AT de caule: pronuciferina (proaporfínico), asimilobina (noraporfínico) e boldina (aporfínico). A presença de boldina foi confirmada pela análise CG-EM do padrão, nas mesmas condições dos AT. Os resultados mostraram-se inéditos para a espécie e a ocorrência de pronuciferina e boldina constituiu o primeiro relato, no gênero Annona. Os dados referentes ao rendimento em AT (folha e caule) e à atividade antipromastigota in vitro indicaram comportamento, praticamente, constante dos parâmetros ao longo do ano. O óleo volátil de folha foi analisado, por CG-EM, tendo-se identificado 60 compostos, em mistura complexa de sesquiterpenos (76,7%) e monoterpenos (23,3%). O constituinte majoritário foi o sesquiterpeno biciclogermacreno (39,8%). O óleo volátil foi avaliado in vitro e apresentou atividade frente às formas promastigotas de quatro espécies de Leishmania e nas formas tripomastigotas de T. cruzi. A determinação e obtenção dos compostos bioativos motiva a continuidade da pesquisa. / Previous studies of total alkaloids (TA) from Annona coriacea Mart. (Annonaceae) have revealed potential antiprotozoal activity. In this study a bioguided fractionation of leaves TA was conducted and two fractions were active in vitro against Leishmania (L.) chagasi promastigotes (100% death) and selected in order to identify the alkaloid constituents, by GC-MS analysis. Stem bioactive TA (100% death) were also analyzed, without previous fractionation. Parallel to that, a sample of three combined specimens of A. coriacea (leaves and stem) was evaluated for the annual variation of TA production and the leishmanicide activity. Stefarine (proaporphine) and nornuciferine (noraporphine) were identified in the bioactive fractions of leaves while pronuciferine (proaporphine), asimilobine (noraporphine) and boldine (aporphine) were identified in stem TA. Boldine was confirmed by the GC-MS evaluation of the standard, under the same conditions of the TA. It was the first report of those alkaloids in this species and for pronuciferine and boldine occurrence in Annona genus. The TA yields (leaves and stem) and the in vitro antipromastigote activity remained almost unaltered throughout the year. The volatile oil of leaves was also analyzed by GC-MS. Sixty compounds were indentified in a complex mixture of sesquiterpenes (76.7%) and monoterpenes (23.3%). Byciclogermacrene was its major component (39.8%). The volatile oil was evaluated in vitro and was active against four species of Leishmania promastigotes and also against T. cruzi tripomastigotes. The identification of the bioactive constituents and their isolation are promising for further studies.
40

Avaliação da atividade antibacteriana e citotóxica dos alcalóides isoquinolínicos de Annona hypoglauca Mart / Antibacterial and cytotoxic evaluation of isoquinoline alkaloids from Annona hypoglauca Mart

Rinaldi, Maria Valeria Nani 03 October 2007 (has links)
Annona hypoglauca Mart. foi coletada em área inundada da Floresta Amazônica, próximo à Manaus (Brasil). Os alcalóides foram obtidos do extrato bruto do caule por partição ácido-base, e a partir do resíduo dessa extração foi realizada a partição com solventes de diferentes polaridades, originando as frações livres de alcalóides. A partir da análise de CG-EM dos alcalóides totais foi possível caracterizar sete alcalóides aporfínicos (actinodafinina, anonaina, glaucina, isoboldina, isodomesticina, nornuciferina e roemerina) e possivelmente duas protoberberinas (esculerina e caseadina). Os alcalóides totais foram fracionados em coluna cromatográfica e posteriormente purificados em placa cromatográfica preparativa permitindo o isolamento de dois alcalóides aporfínicos: actinodafinina e isoboldina. As estruturas desses produtos naturais foram definidos com base em espectros de dados, incluindo 1H RMN, 13C RMN, 13C DEPT e CG-EM. Pela primeira vez a ocorrência da actinodafinina esta sendo reportada em uma espécies de Annona. O extrato bruto, as frações livres de alcalóides, os alcalóides totais e suas frações foram submetidos a avaliação da atividade antibacteriana por microdiluição e atividade citotóxica in vitro frente a células de tumores humanos. Para todos os extratos testados, somente os alcalóides totais e suas frações apresentaram atividade frente a bactérias Gram +. No ensaio de citotoxicidade com linhagens de células de tumores, o extrato bruto foi capaz de inibir o crescimento de todas as linhagens celulares testadas, apresentando efeito letal para a linhagem de Câncer de Cólon (KM-12), enquanto as frações livres de alcalóides demonstraram baixa atividade. Por outro lado, as frações livres de alcalóides apresentaram atividade mais pronunciada para a linhagem de Câncer de Pulmão (NCIH-460) do que os alcalóides. Assim, a atividade citotóxica encontrada no extrato bruto é decorrente do sinergismo ou complementação entre os componentes das frações alcaloídicas e não alcaloídicas, isto é, nenhuma das frações isoladamente é responsável pela atividade observada no extrato bruto. / Annona hypoglauca Mart. was collected in the flooded areas of the Amazonian Forest near Manaus (Brazil). The alkaloids were obtained from the stems crude extract by acid-base partitioning and the remaining alkaloid-free extract was partitioned with organic solvents of different polarity. The GC/MS analysis of the total alkaloids allowed the identification of seven aporphine alkaloids (actinophanine, anonaine, glaucine, isoboldine, isodomesticine, nornuciferine and roemerine) and possibly two proberberine alkaloids (scoulerine and caseadine). The total alkaloids were fractionated by column chromatography and further purified by preparative thin-layer chromatography allowing the isolation of two aporphine alkaloids: actinodaphnine and isoboldine. The structures of these natural products were defined based on their spectral data, including 1H NMR, 13C NMR, 13C DEPT and CG/MS. This is the first report for the occurrence of actinodaphnine in Annona species. The crude extract, alkaloid-free organic extracts, total alkaloids and its fractions were tested for their antibacterial activity by the microdilution broth assay and cytotoxic activity against in vitro tissue culture cells of human. From all the extracts assayed, only the total alkaloids and their fractions showed a relevant antibacterial activity against Gram positive organisms. In the cytotoxicity assay with human tumor cell lines, the crude extract was able to inhibit the growth of all cell lines tested, with a lethal effect for the colon cancer (KM-12) cell line. The evaluation of this activity with the total alkaloid and alkaloid-free fractions indicated selectivity for the different cellular lines. The alkaloid fraction presented high growth inhibition for the colon cancer cell line (KM-12), while the alkaloid-free fractions displayed lower activity. On the other hand, the alkaloid free fractions showed a higher activity for the lung cancer cell line (NCIH-460) than the total alkaloids. Thus, the cytotoxic activity found in the crude extract is the result of the synergism or complementary activity among the components of the alkaloid and alkaloid-free fractions, e.g, none of the fractions separately is responsible for the activity observed in the crude extract.

Page generated in 0.079 seconds