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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

Otimização do processo de extração do óleo essencial de priprioca (Cyperus articulatus L.) por arraste com vapor

CORUMBÁ, Lorena Gomes 29 May 2009 (has links)
Submitted by Edisangela Bastos (edisangela@ufpa.br) on 2014-01-16T17:54:01Z No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_OtimizacaoProcessoExtracao.pdf: 1728893 bytes, checksum: 262b730869c7327a928b377968bf568b (MD5) / Approved for entry into archive by Ana Rosa Silva(arosa@ufpa.br) on 2014-01-23T14:04:12Z (GMT) No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_OtimizacaoProcessoExtracao.pdf: 1728893 bytes, checksum: 262b730869c7327a928b377968bf568b (MD5) / Made available in DSpace on 2014-01-23T14:04:12Z (GMT). No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_OtimizacaoProcessoExtracao.pdf: 1728893 bytes, checksum: 262b730869c7327a928b377968bf568b (MD5) Previous issue date: 2009 / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / Analisa-se experimentalmente o processo de extração do óleo essencial de rizomas de priprioca (Cyperus articulatus L.) por arraste com vapor d’água saturado, em um protótipo em escala de bancada. Por meio de experimentos estatisticamente planejados, estimam-se as condições ótimas o processo de modo a maximizar as variáveis de resposta rendimento em óleo e teor de mustacona, componente majoritário do óleo essencial de priprioca, em função de variáveis operacionais de entrada do processo. As variáveis independentes e respectivos níveis são: carga de rizomas de priprioca, em gramas (64, 200, 400, 600, 736); granulometria dos rizomas, em milímetros (0,61; 1,015; 1,6; 2,19; 2,58) e tempo de extração, em minutos (40, 60, 90, 120, 140). Utilizando um planejamento composto central, com auxílio do aplicativo Statistica® 7.0, são propostos modelos matemáticos para as respostas em função das variáveis independentes isoladas e de suas combinações. Constata-se que o rendimento em óleo essencial e os teores de mustacona podem ser estimados adequadamente por modelos polinomiais de segunda ordem. São obtidos simultaneamente maiores rendimentos em óleo e teores de mustacona, quando a carga de rizomas varia de 105 a 400 gramas para tempos de extração compreendidos entre 105 e 140 minutos. / It is analyzed the process of extraction of the essential oil of priprioca (Cyperus articulatus L.) rhizomes experimentally with water steam, in a prototype in bench scale. Through design of experiments and response surfaces methodology, they are considered the optimal conditions to maximize the response variables yield and mustakone concentration, majority component of the essential oil of priprioca, in function of operational entrance variables of the process. The independent variables and respective levels are: load or mass of priprioca rhizomes, in grams (64, 200, 400, 600, 736); granulometry of the rhizomes, in millimeters (0,61; 1,015; 1,6; 2,19; 2,58) and extraction time, in minutes (44, 60, 90, 120, 140). Using a central composite design, with aid of the application StatisticaR 7.0, mathematical models are proposed for the responses in function of the isolated independent variables and of their combinations. It is verified that the yield in essential oil and the mustakone tenors can be fitted appropriately for second order polynomials models. They are obtained larger yield simultaneously in oil and mustakone tenors, when the load of rhizomes varies from 105 to 400 grams for extraction times between 105 and 140 minutes.
2

Investigation of Nigerian Ethno-medicinal Plants as Potential Sources of Cytotoxic and Anti-plasmodial Compounds. Biological activity of Vitellaria paradoxa, Cyperus articulatus, Securidaca longepedunculata and semi-synthetic halogenated analogues of cryptolepine isolated from Cryptolepis sanguinolenta

Abacha, Yabalu Z. January 2020 (has links)
Natural products are acknowledged sources of novel compounds for use in the treatment of diseases such as cancer, malaria, and human African trypanosomiasis. However, health burdens of such diseases still remain high, with drug resistance leading to failure of current medication. Therefore, there is a need for new treatments, and this project considers the potential of Nigerian ethno-medicinal plants and their products. Firstly, the aims were to isolate cytotoxic compounds through bio-guided evaluation and fractionation from 3 medicinal plants; Vitellaria paradoxa, Cyperus articulatus and Securidaca longepedunculata used traditionally in the treatment of cancer in North-East Nigeria. Extracts from S. longepedunculata were the most active when assessed in a panel of cancer cell lines, with IC50 values below 10 µg/ml, whilst fractions isolated from V. paradoxa and C. articulatus were moderately cytotoxic and able to overcome drug resistance mechanisms in drug resistant cell lines. In the second part of the thesis, novel cryptolepine analogues were semi-synthesized using environmentally friendly methods and evaluated for cytotoxic, anti-plasmodial and anti-trypanosomal activity. The compounds were found to be highly cytotoxic in cancer cell lines with the ability to overcome drug resistant mechanisms, with sub-µM IC50 values, and were also active against drug resistant strains of Plasmodium parasites in addition to Trypanosoma brucei, with IC50 values below 500 nM, and 300 pM respectively. / Schlumberger Faculty for the Future Foundation

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