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  • 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

Transformações microbianas da lactona sesquiterpênica tagitinina C / Microbial transformation of sesquiterpene lactone tagitinin C

Rocha, Bruno Alves 22 June 2009 (has links)
A busca por moléculas de origem natural que ocupem um espaço químico diferente daquelas já existentes tornou-se uma necessidade para atender às novas demandas das indústrias farmacêuticas. A pesquisa envolvendo transformações microbianas de metabólitos secundários de origem vegetal pode ser utilizada como uma nova ferramenta na biosíntese destas novas substâncias, favorecendo a criação de bibliotecas ricas em estruturas com o emprego em diversos alvos biológicos. A tagitinina C é uma lactona sesquiterpênica isolada da Tithonia diversifolia (Asteraceae). Essa substância possui diversas atividades biológicas descritas na literatura. Contudo, há certa ressalva no uso de lactonas sesquiterpênicas para fins terapêuticos devido à elevada toxicidade apresentada por essas substâncias. A biotransformação de substâncias naturais de elevado interesse farmacológico pode ser utilizada com o intuito de diminuir seus efeitos tóxicos ou ampliar sua capacidade terapêutica. Assim, esse trabalho teve como objetivo a utilização de fungos para a biotranformação da tagitinina C. Os resultados obtidos mostraram que os fungos de solo Aspergillus terreus e Mucor rouxii possuem a capacidade de biotransformar tagitinina C. O fungo Aspergillus terreus levou a formação de um produto biotransformado através de uma reação não usual de epoxidação entres os C4-C5 e ainda metoxilação do C1, formando então 1-metóxi-3-hidróxi-3,10-4,5-diepóxi-8-isobutiroilóxi-germacra-11(13)-en-6,12-olido. Os resultados obtidos nesse trabalho demostram que é possível a utilização de fungos na biotransformação da tagitinina C, levando a alterações na molécula que podem influenciar no seu potencial tóxico ou terapêutico. / The search for molecules of natural origin that place a chemical space which is different from the already existing has become that a need in process of discovery new chemical entities with pharmacological interest that support the demand of the pharmaceutical industries. Research involving microbial transformations the secondary metabolites from plants can be used as an alternative for the biosynthesis of such new compounds, thus facilitating the creation of libraries which are rich in structures to be screened against diverse biological targets. Tagitin C is a sesquiterpene lactone isolated from Tithonia diversifolia (Asteraceae) that displays several biological activities already described in the literature. Howeever, due to several reports describing toxic effects of sesquiterpenes lactones, there is a concern in its oral use. Thus, the biotransformation of pharmacologically interesting substances can be carried out with the aim to decrease their toxic effects or amplify their therapeutic properties. Therefore, this work aimed at using of fungi to perform biotransformations of tagitin C. The results showed that the soil fungi Aspergillus terreus and Mucor rouxii have the ability to carry out biological transformations of tagitinin C. The fungus A. terreus led to the formation of a different product through an unusual reaction of epoxidation between C4-C5 and metoxilation of C1 of tagitinin C, the derivative 1-methoxy-3-hydroxy-3,10-4,5-diepoxy-8-isobutiroyloxygermacr- 11 (13)-en-6 ,12-olide. The results of this work show that it is possible to use soil fungi in the biotransformation of tagitinin C, leading to changes in the chemical structure that may influence its toxic or therapeutic potential.
2

Identification of glutathione S-transferase inhibiting natural products from Matricaria chamomilla and biotransformation studies on oxymatrine and harmine

Iverson, Chad 10 September 2010 (has links)
This thesis describes the results obtained from the phytochemical analysis of Matricaria chamomilla, and the microbial transformation of oxymatrine (85) and harmine (87), as summarized below. 1. Chemical investigation of the crude methanolic extract of Matricaria chamomilla resulted in the isolation of a new natural product, matriisobenzofuran (72), along with four known compounds: apigenin (73), apigenin-7-O-β-glucopyranoside (74), scopoletin (75), and fraxidin (76). The structures of compounds 72-76 were elucidated with the aid of extensive NMR and mass spectroscopic studies. All of the aforementioned compounds showed moderate to good inhibitory activities against glutathione S-transferase, an enzyme which has been implicated in the resistance of cancer cells to chemotherapeutic agents. These compounds were also evaluated for antioxidant activity and displayed moderate to good free radical scavenging activity. Additionally, compounds 72-76 were screened for anti-leishmanial activity. Compounds 75 and 76 were significantly active in this assay, while the remaining compounds were weakly active. In the antibacterial and antifungal assays, compounds 72-76 were not active. 2. The second part of this thesis deals with the biotransformation studies on oxymatrine (85) and harmine (87). Oxymatrine (85) was metabolized to the deoxy analogue, matrine (84) by Penicillum chrysogeneum (ATCC 9480), Cunninghamella bainieri (ATCC 9244), Cunninghamella blakesleena (ATCC 9245 and 8688A), Curvularia lunata (ATCC 12017), and Fusarium sp. In the time-based analysis of this transformation, the metabolism of oxymatrine (85) could be detected after 48 hours of incubation. Additionally, incubation of harmine (87) with Mucor plumbeus (ATCC 4740) resulted in the isolation of harmine-N-oxide (94). The biotransformed products (84 and 94) were identified using IR, UV, NMR, and mass spectroscopic techniques. Compound 94 was evaluated for its ability to inhibit the enzyme acetylcholinestrase, whose overexpression has been linked to Alzheimer’s disease, and was found to possess weaker activity than harmine (87).
3

Identification of glutathione S-transferase inhibiting natural products from Matricaria chamomilla and biotransformation studies on oxymatrine and harmine

Iverson, Chad 10 September 2010 (has links)
This thesis describes the results obtained from the phytochemical analysis of Matricaria chamomilla, and the microbial transformation of oxymatrine (85) and harmine (87), as summarized below. 1. Chemical investigation of the crude methanolic extract of Matricaria chamomilla resulted in the isolation of a new natural product, matriisobenzofuran (72), along with four known compounds: apigenin (73), apigenin-7-O-β-glucopyranoside (74), scopoletin (75), and fraxidin (76). The structures of compounds 72-76 were elucidated with the aid of extensive NMR and mass spectroscopic studies. All of the aforementioned compounds showed moderate to good inhibitory activities against glutathione S-transferase, an enzyme which has been implicated in the resistance of cancer cells to chemotherapeutic agents. These compounds were also evaluated for antioxidant activity and displayed moderate to good free radical scavenging activity. Additionally, compounds 72-76 were screened for anti-leishmanial activity. Compounds 75 and 76 were significantly active in this assay, while the remaining compounds were weakly active. In the antibacterial and antifungal assays, compounds 72-76 were not active. 2. The second part of this thesis deals with the biotransformation studies on oxymatrine (85) and harmine (87). Oxymatrine (85) was metabolized to the deoxy analogue, matrine (84) by Penicillum chrysogeneum (ATCC 9480), Cunninghamella bainieri (ATCC 9244), Cunninghamella blakesleena (ATCC 9245 and 8688A), Curvularia lunata (ATCC 12017), and Fusarium sp. In the time-based analysis of this transformation, the metabolism of oxymatrine (85) could be detected after 48 hours of incubation. Additionally, incubation of harmine (87) with Mucor plumbeus (ATCC 4740) resulted in the isolation of harmine-N-oxide (94). The biotransformed products (84 and 94) were identified using IR, UV, NMR, and mass spectroscopic techniques. Compound 94 was evaluated for its ability to inhibit the enzyme acetylcholinestrase, whose overexpression has been linked to Alzheimer’s disease, and was found to possess weaker activity than harmine (87).
4

Transformações microbianas da lactona sesquiterpênica tagitinina C / Microbial transformation of sesquiterpene lactone tagitinin C

Bruno Alves Rocha 22 June 2009 (has links)
A busca por moléculas de origem natural que ocupem um espaço químico diferente daquelas já existentes tornou-se uma necessidade para atender às novas demandas das indústrias farmacêuticas. A pesquisa envolvendo transformações microbianas de metabólitos secundários de origem vegetal pode ser utilizada como uma nova ferramenta na biosíntese destas novas substâncias, favorecendo a criação de bibliotecas ricas em estruturas com o emprego em diversos alvos biológicos. A tagitinina C é uma lactona sesquiterpênica isolada da Tithonia diversifolia (Asteraceae). Essa substância possui diversas atividades biológicas descritas na literatura. Contudo, há certa ressalva no uso de lactonas sesquiterpênicas para fins terapêuticos devido à elevada toxicidade apresentada por essas substâncias. A biotransformação de substâncias naturais de elevado interesse farmacológico pode ser utilizada com o intuito de diminuir seus efeitos tóxicos ou ampliar sua capacidade terapêutica. Assim, esse trabalho teve como objetivo a utilização de fungos para a biotranformação da tagitinina C. Os resultados obtidos mostraram que os fungos de solo Aspergillus terreus e Mucor rouxii possuem a capacidade de biotransformar tagitinina C. O fungo Aspergillus terreus levou a formação de um produto biotransformado através de uma reação não usual de epoxidação entres os C4-C5 e ainda metoxilação do C1, formando então 1-metóxi-3-hidróxi-3,10-4,5-diepóxi-8-isobutiroilóxi-germacra-11(13)-en-6,12-olido. Os resultados obtidos nesse trabalho demostram que é possível a utilização de fungos na biotransformação da tagitinina C, levando a alterações na molécula que podem influenciar no seu potencial tóxico ou terapêutico. / The search for molecules of natural origin that place a chemical space which is different from the already existing has become that a need in process of discovery new chemical entities with pharmacological interest that support the demand of the pharmaceutical industries. Research involving microbial transformations the secondary metabolites from plants can be used as an alternative for the biosynthesis of such new compounds, thus facilitating the creation of libraries which are rich in structures to be screened against diverse biological targets. Tagitin C is a sesquiterpene lactone isolated from Tithonia diversifolia (Asteraceae) that displays several biological activities already described in the literature. Howeever, due to several reports describing toxic effects of sesquiterpenes lactones, there is a concern in its oral use. Thus, the biotransformation of pharmacologically interesting substances can be carried out with the aim to decrease their toxic effects or amplify their therapeutic properties. Therefore, this work aimed at using of fungi to perform biotransformations of tagitin C. The results showed that the soil fungi Aspergillus terreus and Mucor rouxii have the ability to carry out biological transformations of tagitinin C. The fungus A. terreus led to the formation of a different product through an unusual reaction of epoxidation between C4-C5 and metoxilation of C1 of tagitinin C, the derivative 1-methoxy-3-hydroxy-3,10-4,5-diepoxy-8-isobutiroyloxygermacr- 11 (13)-en-6 ,12-olide. The results of this work show that it is possible to use soil fungi in the biotransformation of tagitinin C, leading to changes in the chemical structure that may influence its toxic or therapeutic potential.
5

Biotransformação da B-lapachona utilizando culturas microbianas: uma alternativa para estudos de metabolismo in vitro / Biotransformation of B-lapachone using microbial cultures: an alternative to in vitro metabolism studies

Paludo, Camila Raquel 05 March 2013 (has links)
A B-lapachona é uma orto-naftoquinona consagrada por suas atividades farmacológicas, principalmente pela antitumoral, porém não há descrição de estudos de biotransformação microbiana da ?-lapachona. Tais estudos podem propiciar a obtenção de novos derivados dessa naftoquinona, além de fornecerem informações importantes sobre seu metabolismo. Muitos trabalhos descrevem que micro-organismos podem catalisar reações mimetizando enzimas humanas. Para o desenvolvimento dessa pesquisa, a ?-lapachona foi obtida por semissíntese a partir do lapachol. Nos processos de biotransformação foram utilizados os fungos filamentosos Mucor rouxii, Cunninghamella elegans, Cunninghamella echinulata, Penicillium crustosum e Papulaspora immersa e as bactérias gastrointestinais Escherichia coli, cultivada em aerobiose e anaerobiose, Lactobacillus acidophilus, Bifidobacterium sp. e cultura mista composta por Lactobacillus acidophilus, Bifidobacterium sp. e Streptococcus salivarius subesp. thermophilus. Com o intuito de estabelecer uma comparação entre o metabolismo microbiano da ?-lapachona com o do seu isômero ?-lapachona, estudos de biotransformação utilizando o fungo M. rouxii foram também conduzidos com a ?-lapachona. Sete derivados de biotransformação da ?-lapachona com o fungo M. rouxii foram identificados, sendo um inédito, cinco já descritos na literatura em um trabalho de metabolismo dessa naftoquinona utilizando sangue de mamíferos e humanos e uma espirobenzolactona relatada em um trabalho de síntese. Outros dois derivados inéditos da ?-lapachona, os quais são regioisômeros conjugados com glicose, foram produzidos após formação de hidroquinona no processo coduzido com o fungo C. elegans. O fungo P. immersa forneceu duas lactonas isoméricas também obtidas com a biotransformação com o fungo M. rouxii. Houve resultados positivos, com detecção de possíveis produtos de biotransformação da ?-lapachona por CLAE-DAD, com as bactérias E. coli em aerobiose e Bifidobacterium sp. No entanto, esses processos apresentaram um baixo rendimento, sendo possível a identificação de apenas um derivado com a E. coli, que também foi obtido com a biotransformação com o fungo M. rouxii. Um derivado glicosilado da ?-lapachona foi produzido após 24 horas de incubação no processo desenvolvido com o fungo M. rouxii, sendo posteriormente convertido em hidroxilapachol, que por sua vez originou a ?-lapachona novamente e também a ?-lapachona, a qual foi metabolizada também. O derivado glicosilado majoritário, obtido da biotransformação com a ?-lapachona com o fungo C. elegans, foi submetido à avaliação da atividade citotóxica frente à linhagem de câncer de mama humano SKBR-3 apresentando IC50 igual a 312,5 ?M, sendo o IC50 da ?-lapachona frente à mesma linhagem igual a 5,6 ?M. O derivado majoritário não apresentou citotoxidade frente à linhagem de fibroblastos normais humanos GM07492-A, enquanto a ?-lapachona foi altamente citotóxica (IC50 igual a 7,25 ?M). Esse mesmo derivado inédito foi também produzido em pequena quantidade no processo desenvolvido com o fungo C. echinulata. Na metabolização microbiana da ?-lapachona ocorreram tanto reações de fase I como de fase II, havendo mimetização do metabolismo de mamíferos, inclusive de humanos, como relatado em trabalhos da literatura. / B-lapachone is considered an important ortho-naphthoquinone by their pharmacological activities, mainly antitumor, but there is no description of microbial biotransformation studies of ?-lapachone. These researches may furnish new derivatives and significant information on its metabolism. Many studies describe that microorganisms can catalyze reactions mimicking human enzymes. ?-lapachone was obtained by semisynthetic procedure from lapachol. Biotransformation processes were carried out using the filamentous fungi Mucor rouxii, Cunninghamella elegans, Cunninghamella echinulata, Penicillium crustosum and Papulaspora immersa and the gastrointestinal bacteria Escherichia coli grown aerobically and anaerobically, Lactobacillus acidophilus, Bifidobacterium sp. and mixed culture with Lactobacillus acidophilus, Bifidobacterium sp. and Streptococcus salivarius subsp. thermophilus. In order to establish a comparison between ?-lapachone microbial transformation and those of its isomer ?-lapachone, biotransformation studies of ?-lapachone were also carried out using M. rouxii. Seven derivatives of ?-lapachone were produced in the process performed by M. rouxii, including one unpublished, five already described in a study of metabolism by mammalian and human blood and one spirobenzolactone reported in a syntetic study. Other two unpublished derivatives of ?-lapachone, which are regioisomers conjugated with glucose, were produced after formation of hydroquinone in the process carried out by C. elegans. P. immersa provided two isomeric lactones also obtained by biotransformation with M. rouxii. Possible biotransformation products were detected by using HPLC-DAD in the processes carried out by the bacteria E. coli under aerobic condition and Bifidobacterium sp. However, these processes exhibited a low yield, and it was possible to identify only one derivative produced by E. coli, which was also obtained in the process performed by M. rouxii. A glycosylated derivative of ?-lapachone was produced by biotransformation with M. rouxii after 24 hours of incubation and subsequently was converted in hydroxylapachol, which in turn gave rise to ?-lapachone again and also to ?-lapachone, which was also metabolized. The major derivative produced in the process carried out by C. elegans was submitted to cytotoxic activity evaluation using human breast cancer cell line SKBR3 showing IC50 312.5 ?M, being the ?-lapachone IC50 5.6 ?M against the same cell line. The major derivative did not show cytotoxicity to normal human fibroblast GM07492-A cell line, while ?-lapachone was highly cytotoxic (IC50 7.25 ?M). The same major derivative was also produced in smaller yield in the process performed by C. echinulata. In the ?-lapachone microbial transformation studies occurred phase I and phase II reactions, mimicking the metabolism of mammals, including humans, as reported in literature.
6

Biotransformação da B-lapachona utilizando culturas microbianas: uma alternativa para estudos de metabolismo in vitro / Biotransformation of B-lapachone using microbial cultures: an alternative to in vitro metabolism studies

Camila Raquel Paludo 05 March 2013 (has links)
A B-lapachona é uma orto-naftoquinona consagrada por suas atividades farmacológicas, principalmente pela antitumoral, porém não há descrição de estudos de biotransformação microbiana da ?-lapachona. Tais estudos podem propiciar a obtenção de novos derivados dessa naftoquinona, além de fornecerem informações importantes sobre seu metabolismo. Muitos trabalhos descrevem que micro-organismos podem catalisar reações mimetizando enzimas humanas. Para o desenvolvimento dessa pesquisa, a ?-lapachona foi obtida por semissíntese a partir do lapachol. Nos processos de biotransformação foram utilizados os fungos filamentosos Mucor rouxii, Cunninghamella elegans, Cunninghamella echinulata, Penicillium crustosum e Papulaspora immersa e as bactérias gastrointestinais Escherichia coli, cultivada em aerobiose e anaerobiose, Lactobacillus acidophilus, Bifidobacterium sp. e cultura mista composta por Lactobacillus acidophilus, Bifidobacterium sp. e Streptococcus salivarius subesp. thermophilus. Com o intuito de estabelecer uma comparação entre o metabolismo microbiano da ?-lapachona com o do seu isômero ?-lapachona, estudos de biotransformação utilizando o fungo M. rouxii foram também conduzidos com a ?-lapachona. Sete derivados de biotransformação da ?-lapachona com o fungo M. rouxii foram identificados, sendo um inédito, cinco já descritos na literatura em um trabalho de metabolismo dessa naftoquinona utilizando sangue de mamíferos e humanos e uma espirobenzolactona relatada em um trabalho de síntese. Outros dois derivados inéditos da ?-lapachona, os quais são regioisômeros conjugados com glicose, foram produzidos após formação de hidroquinona no processo coduzido com o fungo C. elegans. O fungo P. immersa forneceu duas lactonas isoméricas também obtidas com a biotransformação com o fungo M. rouxii. Houve resultados positivos, com detecção de possíveis produtos de biotransformação da ?-lapachona por CLAE-DAD, com as bactérias E. coli em aerobiose e Bifidobacterium sp. No entanto, esses processos apresentaram um baixo rendimento, sendo possível a identificação de apenas um derivado com a E. coli, que também foi obtido com a biotransformação com o fungo M. rouxii. Um derivado glicosilado da ?-lapachona foi produzido após 24 horas de incubação no processo desenvolvido com o fungo M. rouxii, sendo posteriormente convertido em hidroxilapachol, que por sua vez originou a ?-lapachona novamente e também a ?-lapachona, a qual foi metabolizada também. O derivado glicosilado majoritário, obtido da biotransformação com a ?-lapachona com o fungo C. elegans, foi submetido à avaliação da atividade citotóxica frente à linhagem de câncer de mama humano SKBR-3 apresentando IC50 igual a 312,5 ?M, sendo o IC50 da ?-lapachona frente à mesma linhagem igual a 5,6 ?M. O derivado majoritário não apresentou citotoxidade frente à linhagem de fibroblastos normais humanos GM07492-A, enquanto a ?-lapachona foi altamente citotóxica (IC50 igual a 7,25 ?M). Esse mesmo derivado inédito foi também produzido em pequena quantidade no processo desenvolvido com o fungo C. echinulata. Na metabolização microbiana da ?-lapachona ocorreram tanto reações de fase I como de fase II, havendo mimetização do metabolismo de mamíferos, inclusive de humanos, como relatado em trabalhos da literatura. / B-lapachone is considered an important ortho-naphthoquinone by their pharmacological activities, mainly antitumor, but there is no description of microbial biotransformation studies of ?-lapachone. These researches may furnish new derivatives and significant information on its metabolism. Many studies describe that microorganisms can catalyze reactions mimicking human enzymes. ?-lapachone was obtained by semisynthetic procedure from lapachol. Biotransformation processes were carried out using the filamentous fungi Mucor rouxii, Cunninghamella elegans, Cunninghamella echinulata, Penicillium crustosum and Papulaspora immersa and the gastrointestinal bacteria Escherichia coli grown aerobically and anaerobically, Lactobacillus acidophilus, Bifidobacterium sp. and mixed culture with Lactobacillus acidophilus, Bifidobacterium sp. and Streptococcus salivarius subsp. thermophilus. In order to establish a comparison between ?-lapachone microbial transformation and those of its isomer ?-lapachone, biotransformation studies of ?-lapachone were also carried out using M. rouxii. Seven derivatives of ?-lapachone were produced in the process performed by M. rouxii, including one unpublished, five already described in a study of metabolism by mammalian and human blood and one spirobenzolactone reported in a syntetic study. Other two unpublished derivatives of ?-lapachone, which are regioisomers conjugated with glucose, were produced after formation of hydroquinone in the process carried out by C. elegans. P. immersa provided two isomeric lactones also obtained by biotransformation with M. rouxii. Possible biotransformation products were detected by using HPLC-DAD in the processes carried out by the bacteria E. coli under aerobic condition and Bifidobacterium sp. However, these processes exhibited a low yield, and it was possible to identify only one derivative produced by E. coli, which was also obtained in the process performed by M. rouxii. A glycosylated derivative of ?-lapachone was produced by biotransformation with M. rouxii after 24 hours of incubation and subsequently was converted in hydroxylapachol, which in turn gave rise to ?-lapachone again and also to ?-lapachone, which was also metabolized. The major derivative produced in the process carried out by C. elegans was submitted to cytotoxic activity evaluation using human breast cancer cell line SKBR3 showing IC50 312.5 ?M, being the ?-lapachone IC50 5.6 ?M against the same cell line. The major derivative did not show cytotoxicity to normal human fibroblast GM07492-A cell line, while ?-lapachone was highly cytotoxic (IC50 7.25 ?M). The same major derivative was also produced in smaller yield in the process performed by C. echinulata. In the ?-lapachone microbial transformation studies occurred phase I and phase II reactions, mimicking the metabolism of mammals, including humans, as reported in literature.

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