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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.
11

METABÓLITOS SECUNDÁRIOS EM VERNONIA TWEEDIEANA BAKER / SECUNDARY METABOLIC OF VERNONIA TWEEDIEANA BAKER

Zanon, Ricardo Basso 07 April 2006 (has links)
The species Vernonia tweedieana Baker is an herbaceous plant widely distributed in the plains of Paraguai, Argentina and south of Brazil and popularly known as assa-peixe . This plant is used in traditional medicine as an expectorant medicament. So far, this plant was not studied on the phytochemical and biological point of view. This work is a contribution to the phytochemical study of the Asteraceae. The leaves of V. tweedieana Baker were collected in march of 2004, in Ijuí Rio Grande do Sul, Brazil, and identified by Dr. Geraldo C. Coelho (UNIJUÍ). The respective voucher specimen was deposited in the herbarium of the Federal University of Santa Maria (UFSM)-RS (code SMDB 9536). The leaves (1.900 g) were dried in an air circulating stove at 40 ºC, pulverized in mill and extracted by maceration with 65% EtOH at room temperature for seven days. The ethanolic extract was filtered and the ethanol was removed. Finally, the extract was retake in water and partitioned using organics solvents with increased polarity: CH2Cl2, AcOEt and n-BuOH. We report the isolation and identification of six constituents of the CH2Cl2 fraction: the triterpenes a-amyrin, b-amyrin and lupeol and the steroids b- sitosterol, stigmasterol and spinasterol. The flavanone eriodictyoI was isolated from the AcOEt fraction. The constituents were identified through spectral data of the infra-red, GC-MS, 1H-NMR, 13C-NMR and DEPT. No deaths and other signs of toxicity and adverse effect were observed in the evaluation of acute toxicity with doses up to 5.000 mg/kg, that is the maximum dose for acute oral toxicity test for extract of plants. Also, through DPPH method, AcOEt and n-BuOH fractions of the plant showed good antioxidant activity with IC50 22.52 and 17.44 mg/mL, respectively. / O uso de plantas medicinais sempre teve uma importância vital no cotidiano da humanidade. No entanto, apenas uma pequena parte destas já foram estudadas e tiveram suas ações farmacológicas comprovadas cientificamente. Um exemplo de planta ainda desconhecida quimicamente é Vernonia tweedieana Baker (Asteraceae), vulgarmente conhecida como assa-peixe. É uma planta característica da região Sul do Brasil que é usada popularmente para o tratamento de doenças respiratórias, principalmente pelas suas propriedades expectorantes. Este trabalho descreve o isolamento e identificação de seis constituintes químicos presentes no extrato CH2Cl2 e de um no extrato AcOEt das folhas de Vernonia Tweedieana Baker. As folhas foram coletadas em março de 2004, no município de Ijuí RS. A espécie foi localizada e identificada pelo Prof. Dr. Geraldo C. Coelho (DeBQ-UNIJUÍ). Material testemunha encontra-se depositado no Herbário do Departamento de Biologia da UFSM sob o registro n° SMDB 9536. O material vegetal seco e moído (1.900 g) foi macerado utilizando como solvente etanol:água (65:35, v/v). Após sete dias o extrato foi filtrado e concentrado sob pressão reduzida para remover o etanol. Fez-se fracionamento desse extrato bruto com solventes orgânicos de polaridades crescentes (CH2Cl2, AcOEt, n- BuOH). Da fração CH2Cl2 caracterizou-se os triterpenos a e b-amirinas e lupeol, ainda os esteróides b-sitosterol, estigmasterol e espinasterol; e da fração AcOEt o flavonóide eriodictiol. Os compostos isolados foram analisados por CG-EM-IE, IV, RMN de 1H e RMN de 13C e seus dados espectroscópicos foram comparados com os obtidos da literatura. Ainda, na avaliação da toxicidade aguda foi verificado que nenhum dos extratos apresentou toxicidade em doses até 5.000 mg/mL. Também, pelo método do DPPH, foi constatada atividade antioxidante para as frações AcOEt e n-BuOH da planta, apresentando IC50 de 22,52 e 17, 44 mg/mL, respectivamente.
12

Síntese de ésteres derivados de triterpenos e esteroides com potencial atividade biológica

Santos, Marcelo Álison Sousa dos 03 July 2015 (has links)
Submitted by Ana Hilda Fonseca (anahilda@ufba.br) on 2016-02-23T14:51:45Z No. of bitstreams: 1 Versão final 1.pdf: 11990349 bytes, checksum: 5aa2ee24e8db0a1ccd54b5641e0695b2 (MD5) / Approved for entry into archive by Ana Hilda Fonseca (anahilda@ufba.br) on 2016-05-10T16:54:19Z (GMT) No. of bitstreams: 1 Versão final 1.pdf: 11990349 bytes, checksum: 5aa2ee24e8db0a1ccd54b5641e0695b2 (MD5) / Made available in DSpace on 2016-05-10T16:54:19Z (GMT). No. of bitstreams: 1 Versão final 1.pdf: 11990349 bytes, checksum: 5aa2ee24e8db0a1ccd54b5641e0695b2 (MD5) / CAPES / A síntese de novos compostos de produtos naturais bioativos abre um amplo espectro de possibilidades estratégicas no que se refere a modular ou mesmo descobrir novas propriedades. Triterpenos e esteroides são conhecidos por suas atividades biológicas. A síntese de derivados dessas substâncias propicia a obtenção de novos compostos que podem ser mais ativos do que seus precursores. Este trabalho descreve a síntese de quarenta bromoésteres e α-aminoésteres derivados dos esteroides β-sitosterol e estigmasterol (em mistura 7:3), da substância estigmasteriol, e dos triterpenos α e β amirina (em mistura 1:1), lupeol, ácido ursólico e ácido betulínico, a maioria sendo inédita. Os derivados obtidos foram caracterizados por espectrometria de massas de alta resolução, espectroscopia na região do de infravermelho, espectroscopia de ressonância magnética nuclear de 1H e 13C. Também foram efetuadas medidas de ponto de fusão e [α]D. Os derivados serão submetidos a teste de atividade anti-HIV, atividade anti-proliferativa frente a determinadas linhagens de células tumorais e teste de atividade tripanocida. / The synthesis of new compounds from bioactivity natural products opens a large spectrum of strategic possibilities in terms of modulating or even thought find new properties. Triterpenes and steroids are known for their biological activities. The synthesis provides derivatives of these substances to obtain new compounds which may be more active than their precursors. This work describes the synthesis and forty bromoésteres α-amino esters derivatives of steroids -sitosterol and stigmasterol (7:3 in mixture) of estigmasteriol substance, of triterpenes α and β amyrin (1:1 in mixture), lupeol, ursolic acid and betulinic acid, the most being unprecedented. The derivatives were characterized by spectrometry of high resolution mass spectroscopy, infrared spectroscopy, nuclear magnetic resonance of 1H and 13 C. They were also performed melting point measurements and [α]D. The derivatives will submitted to anti-HIV activity test, anti-proliferative activity against certain cancer cell lines and trypanocide activity test.
13

Investigating the production of secondary metabolites effective in lowering blood glucose levels in Euclea Undulata Thunb. Var Myrtina (Ebenaceae)

Botha, Lynette Elizabeth 03 1900 (has links)
Euclea undulata Thunb. var myrtina is a widely distributed shrub in South Africa. The roots are used by traditional healers for the treatment of diabetes. Research indicates that roots contain epicatechin, lupeol as well α-amyrin-3O-β-(5-hydroxy) ferulic acid. It was found that α-amyrin-3O-β-(5-hydroxy) ferulic acid inhibits α-glucosidase while epicatechin lowers glucose levels in the blood. Existing literature also indicates the presence of the naphthoquinone 7-methyl-juglone in the roots, although it was not detected in all cases. Due to its cytotoxic nature, 7-methyl-juglone poses a potential threat when E. undulata is used as medicinal treatment. In order to assist the effective and safe use of this plant as a treatment for diabetes, this project aims to determine whether the presence of these metabolites is seasonal. It further aims to contribute to more sustainable harvesting methods by investigating stems and leaves in addition to the roots for the presence of these metabolites. / Environmental Sciences / M. Sc. (Environmental Science)

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