Um método rápido utilizando cromatografia liquida (LC) foi desenvolvido para determinação simultânea de 7 pesticidas piretróides (bifentrina, cipermetrina, fenpropatrina, fenvalerato, permetrina, lambda-cialotrina, e deltametrina). Os resíduos são extraídos com acetona e a partição realizada de acordo com o método multi-resíduos DFG-S19, substituindo diclorometano por acetato de etila/ciclohexano (1+1) e purificação usando cromatografia de permeação a gel com uma coluna Biobeads SX3 e acetato de etila/ciclohexano (1+1) como eluente. A separação por LC é realizada com uma coluna LiChrospher 100 RP-18 e acetonitrila/água (8+2) como fase móvel. Os pesticidas são detectados em 212nm. As recuperações dos 7 pesticidas piretróides em amostras de feijão fortificadas em 0,010; 0,100; e 1,000 mg/kg ficaram entre 71-105%. A diferença particular deste método é o limite de quantificação, os quais ficaram entre 0,004-0,011 mg/kg, abaixo de muitos outros métodos de LC descritos na literatura. A cromatografia a gás (GC) com detector de captura de elétrons é mais sensível que a LC, mas o método com LC facilita a identificação dos picos. A GC apresenta muitos picos enquanto a LC apresenta apenas um para a maioria dos piretróides. A análise com LC é uma boa alternativa para a determinação de resíduos de piretróides em feijão. Durante o ano de 2005, um total de 48 amostras de feijão comercializadas na cidade de São Paulo, foram analisadas. Nenhum resíduo de pesticida piretróide foi detectado nas amostras. / A rapid liquid chromatographic (LC) method has been developed for simultaneous determination of 7 pyrethroid insecticides (bifenthrin, cypermethrin, fenpropathrin, fenvalerate, permethrin, lambda-cyhalothrin and deltamethrin) in beans. Residues are extracted from beans with acetone and the partition realized according to the multi-residue method DFG-S19, replacing dichloromethane by ethyl acetate/cyclohexane (1+1) and cleaned up using gel-permeation with a Biobeads SX3 column and ethyl acetate/cyclohexane (1+1) as eluant. LC separation is performed on a LiChrospher 100 RP-18 column with acetonitrile/water (8+2) as mobile phase. The pesticides are detected at 212 nm. Recoveries of 7 pyrethroid insecticides from beans fortified at 0.010; 0.100; 1.000 mg/kg levels were 71-105 %. The particular differential of this method is the quantification limits, which were between 0.004-0.011 mg/kg, lower than most of the limits reported for LC methods described in the literature. The gas chromatographic (GC) with electron capture detection is more sensitive than LC, but the LC method facilitates the identification of the peaks. Analysis of pyrethroids by GC shows several peaks, but LC shows only one for most pyrethroids. The analysis by LC was a good alternative for determination pyrethroid residues in beans. During 2005 year, a total of 48 bean samples commercialized in Sao Paulo City were analyzed. No residues of pyrethroids pesticides were detected in the samples.

PDI ("potato cathepsin D inhibitor ") and NID ("novel inhibitor of cathepsin D ") from potato (Solanum tuberosum) belong to the protein family of Kunitz inhibitors (I3 family, Merops database). These 20 kDa isoinhibitors with the typical β-trefoil architecture inhibit aspartic and serine peptidases. In this thesis, the constructs for recombinant expression of PDI and NID in the yeast Pichia pastoris system were prepared and high-producing colonies were selected. Both proteins were identified in the cultivation media by mass spectrometry and N-terminal sequencing. A purification protocol for PDI with three chromatographic steps was designed. Analogous functional properties were demonstrated for the purified recombinant PDI and the native PDI isolated from a natural source. Analysis of the inhibitory specificity showed that PDI is a potent inhibitor of selected aspartic peptidases from the A1 family and serine peptidases from the S1 family, including a relevant enzyme of insect origin. This finding supports the hypothesis that Kunitz inhibitors are involved in plant defense against herbivorous insects. The inhibitors prepared within the project will be used for analysis of the reactive centers against target peptidases by protein crystallography. (In Czech) Key words: proteolytic enzymes, activity...

Moderne analytische Verfahren ermöglichen eine höchst effiziente Auftrennung und eine selektive Detektion von Zielanalyten. Dies ist vor allem in der Medizin von Bedeutung, da eine frühzeitige Diagnose von Krankheiten in den meisten Fällen zu einer wesentlich erfolgreicheren Behandlung beiträgt. In unserer heutigen Industriegesellschaft werden daher hochsensitive und effiziente Analysemethoden stärker benötigt als je zuvor. Diverse Umweltgifte oder gesundheitliche Schadstoffe gelangen vermehrt in Grundwasser und Umwelt. Eine Analyse ist aufgrund der oft nur geringen Konzentrationen und der Komplexität diverser Proben häufig mit großen Schwierigkeiten verbunden. Obwohl die Sensitivität und Effizienz zur Bestimmung von Krankheitsmarkern (Biomarker) und Schadstoffen immer weiter zunimmt, stoßen selbst höchstsensitive Analysemethoden an ihre Grenzen. Gerade bei kleinsten Konzentrationen an Zielanalyten oder bei komplexen Gemischen ist eine direkte Detektion ohne weitere Vorbehandlung, wie Aufkonzentrierungen oder Markierungen, äußerst schwierig oder nicht möglich. Eine Optimierung dieser Methoden, deren Automatisierung sowie sensitivere Detektorsysteme werden benötigt. Darüber hinaus ist die Entwicklung von neuartigen, selektiveren mobilen und stationären Phasen ein hochinteressantes und umfangreich untersuchtes Forschungsgebiet. Die Verwendung von hochselektiven Additiven, wie Cyclodextrinen, Kronenethern, Mizellen und andere chirale Selektoren in der Hochleistungsflüssigkeitschromatographie (HPLC), Kapillarelektrophorese (CE)[1,2] oder in der Dünnschicht-Chromatographie (TLC)[3] wurde bereits umfangreich untersucht und etabliert. Hochfunktionalisierte Polymere als äußerst spezifische Selektoren mit hoher Selektivität stellen vielversprechende Materialien dar, die ebenfalls eine Optimierung in der HPLC und CE erzielen.[4-9] Der Einsatz von Polymeren in molekular geprägten Matrizen (molecular imprinted polymers, MIP) oder in monolithischen Trennsäulen wird bereits äußerst erfolgreich in der TLC, HPLC und CE genutzt.[7-11] Eine solch hochselektive Säulenmodifizierung bietet eine sehr gute Performance und hervorragende Trennleistungen. Ein Nachteil dieser hochselektiven Modifizierung ist jedoch die Spezialisierung nur auf das jeweilige Problem. Eine universelle Verwendung für komplexe Gemische und eine Fülle von Analyten ist limitiert. Ein sehr vielversprechender Aspekt ist der Einsatz von Polymeren als chirale Selektoren in der stationären wie auch in der mobilen Phase. Die große Anzahl an kommerziell erhältlichen Trennsäulen mit einer Polymermodifizierung und das ständig umfangreichere Angebot solcher Säulen[12] verdeutlichen diesen Trend und zeigen, dass die Nutzung von polymeren Architekturen für eine weitere Optimierung diverse Möglichkeiten bietet. Hochverzweigte Polymere stellen unter den Polymeren vielversprechende Materialien dar, die aufgrund ihrer Vorteile zu einer effektiven Optimierung beitragen können.[12] Die hohe Anzahl an terminalen Gruppen ermöglichen es, gut zugängliche anwendungsorientierte Modifizierungen durchzuführen, um gewünschte Eigenschaften zu generieren. Durch die hohe Variabilität der Polymere selbst und der diversen Modifizierungsmöglichkeiten zeigen maßgeschneiderte Polymere ein enormes Potential und die Möglichkeit hochselektive Wechselwirkungen mit Zielanalyten zu etablieren. Die Modifizierung mit einer Schale um den polymeren Kern ermöglicht weitere Optimierungen für den Einsatz von Kern-Schale-Architekturen. Beispiele hierfür sind unter anderem die Vermittlung höherer Löslichkeit durch eine Modifizierung des hydrophilen/hydrophoben polymeren Kerns zur Etablierung einer äußeren Schale. Ebenso können durch die Modifizierung gezielte Eigenschaften generiert werden, die eine spezifische Interaktion mit Oberflächen oder Wirkstoffen ermöglichen. Die Zielsetzung dieser Arbeit ist die Synthese und die Untersuchung von Kern-Schale-Architekturen als chromatographische Selektoren. Als polymerer Kern wird hochverzweigtes Poly(ethylenimin) (PEI) verwendet, das mit einer Oligosaccharidschale modifiziert wird. Das PEI wird mit den Kerngrößen 5 und 25 kDa verwendet, wodurch eine Untersuchung des Kerneinflusses möglich ist. Weiterhin wird die Dichte der Oligosaccharidschale eingestellt. Dafür wird eine dichte, moderate bis offene und eine sehr offene Oligosaccharidschale um den polymeren Kern generiert. Infolge dessen kann der Einfluss der Schalendichte auf die Interaktion mit Beispielanalyten evaluiert werden. Für die Oligosaccharidschale (OS) werden darüber hinaus drei verschiedene Oligosaccharide (Maltose, Lactose und Maltotriose) verwendet, um den Einfluss der Art der Schale zu prüfen. Durch diese Variationen können 15 unterschiedliche PEI-OS Kern-Schale-Architekturen synthetisiert und untersucht werden. Weiterhin soll der hydrophobe Anteil der Kern-Schale-Architekturen durch die Anbindung von unpolaren Seitenketten an einen PEI-Kern erhöht werden. Auf diese Art und Weise können nicht-kovalente Wechselwirkungen mit lipophilen Systemen untersucht werden. Um polymere Kern-Schale-Architekturen möglichst effizient in der TLC, HPLC und CE einsetzen zu können, ist es essentiell, ihre Eigenschaften und die Art und Weise der Wechselwirkungen zu kennen, die sie mit möglichen Gastmolekülen eingehen. Durch die Untersuchung dieser Wechselwirkungen können Informationen über deren Interaktionen und eine mögliche Manipulation bzw. Optimierung dieser erhalten werden. Ein zielgerichteter und effektiver Einsatz mit diesen Kern-Schale Architekturen kann so vorbereitet werden. [1] T. J. Ward, K. D. Ward, Anal. Chem. 2012, 84, 626-35. [2] W. J. Cheong, S. H. Yang, F. Ali, J. Sep. Sci. 2013, 36, 609-28. [3] M. D. Bubba, L. Checchini, L. Lepri, Anal. Bioanal. Chem. 2013, 405, 533-554. [4] M. Hanson, K. K. Unger, Trends Anal. Chem. 1992, 11, 368-373. [5] J. Kirkland, J. Chromatogr. A 2004, 1060, 9-21. [6] F. Gasparrini, D. Misiti, R. Rompietti, C. Villani, J. Chromatogr. A 2005, 1064, 25-38. [7] A. Martin-Esteban, Trends Anal. Chem. 2013, 45, 169-181. [8] I. Nischang, J. Chromatogr. A 2013, 1287, 39-58. [9] R. D. Arrua, M. Talebi, T. J. Causon, E. F. Hilder, Anal. Chim. Acta 2012, 738, 1-12. [10] P. Jandera, J. Chromatogr. A 2013, 1313, 37-53. [11] F. Svec, J. Sep. Sci. 2004, 27, 1419-1430. [12] M. Tang, J. Zhang, S. Zhuang, W. Liu, Trends Anal. Chem. 2012, 39, 180-194.

The present thesis work is dedicated to the implementation of novel electrochemical methods for the assay of drug compounds such as paracetamol and ascorbic acid and biologically relevant biothiols such as cysteine and glutathione. Particular attention has been paid to the development and application of amperometric detectors allowing for a readily surface renewing and for highly selective and sensitive assays.<p>Coupling of a screen printed electrochemical detector with a monolithic chromatographic column was performed for high-throughput analysis along with selectivity, sensitivity and good precision. The modification of a glassy carbon electrode with a perm-selective membrane was investigated in order to provide an electrochemical sensor for on-site analysis. Acetaminophen was investigated as a model drug compound because of its extensive use in drug “pain killer” medication.<p>Along with the aims of this thesis, a silver polycrystalline electrode was investigated as a sensitive and class selective electrode for the assay of small thiol-based molecules. The silver electrode was implemented for the first time as an amperometric detector coupled to liquid chromatography for the assay of thiols. Application to the study of thiol species present in white wines was realized in order to illustrate the potential of the silver working electrode as amperometric detector. / Doctorat en Sciences biomédicales et pharmaceutiques / info:eu-repo/semantics/nonPublished

<p>Steroidna jedinjenja spadaju u grupu supstanci sa &scaron;irokim spektrom biolo&scaron;kog delovanja i predstavljaju dobru polaznu osnovu za sintezu mnogih derivata sa željenim biolo&scaron;kim potencijalom. Organskim sintezama se do&scaron;lo do velikog broja steroidnih derivata, od kojih su neki pokazali značajnu biolo&scaron;ku aktivnost, kao &scaron;to je citotoksičnost prema različitim ćelijskim linijama kancera. Karakterizacija novosintetisanih jedinjenja može se izvesti eksperimentalnim i računarskim (in silico) metodama. U ovoj doktorskoj disertaciji predstavljeno je eksperimentalno određivanje lipofilnosti 17&alpha;-pikolil i 17(E)-pikoliniliden androstanskih derivata primenom visokopritisne tečne hromatografije na obrnutim fazama, a potom hemometrijska analiza hromatografskog pona&scaron;anja (hromatografske lipofilnosti) QSRR pristupom. Hemijska struktura analiziranih derivata opisana je numerički, pomoću izračunatih molekulskih deskriptora. U drugom delu doktorske disertacija predstavljena je QSAR analiza citotoksične aktivnosti 17&alpha;-pikolil i 17(E)-pikoliniliden androstanskih derivata prema ćelijama androgen-receptor negativnog kancera prostate (AR-neg. PC-3). Odabir najkvalitetnijih QSRR i QSAR modela obavljen je na osnovu izračunatih statističkih parametara, a njihovo rangiranje izvedeno je primenom metode sume razlika rangova (SRD). Pored regresionih QSRR i QSAR hemometrijskih metoda, primenjene su i klaster analiza i analiza glavnih komponenata sa ciljem utvrđivanja sličnosti ili razlika između analiziranih derivata na<br />osnovu izračunatih molekulskih deskriptora.</p> / <p>Steroidal compounds belong to the group of substances with wide spectrum of biological activity and represent the basic material for synthesis of many derivatives<br />with preferred biological potential. A grate number of steroidal derivatives have been<br />obtained through organic syntheses, many of which have demonstrated significant<br />biological activity, such as cytotoxicity toward various cancer cell lines. Characterization of newly synthesized compounds can be achieved experimentally<br />and by computational approach (in silico). This doctoral dissertation describes<br />experimental determination of lipophilicity of 17&alpha;-picolyl and 17(E)-picolinylidene<br />androstane derivatives applying reversed-phase high pressure liquid chromatography followed by quantitative structure-retention relationship (QSRR)<br />chemometric analysis of chromatographic behaviour (chromatographic lipophilicity).<br />Chemical structure of the analyzed derivatives was described numerically by in silico<br />molecular descriptors. The second part of this dissertation describes quantitative<br />structure-activity relationship (QSAR) analysis of cytotoxic activity of 17&alpha;-picolyl and<br />17(E)-picolinylidene androstane derivatives toward androgen-receptor negative<br />prostate cancer cell line (AR-neg. PC-3). Selection of the best QSRR and QSAR<br />models was carried out based on their statistical parameters, and their ranking was<br />done by sum of ranking differences (SRD) method. Besides the regression QSRR and QSAR chemometric methods, cluster analysis and principal components analysis were conducted in order to reveal possible similarities and dissimilarities among the studied derivatives on the basis of calculated molecular descriptors.</p>

No description available.

No / Shallow oval bowls used on the Baltic coast in the Mesolithic have been suggested as oil lamps, burning animal fat. Here researchers confirm the use of four coastal examples as lamps burning blubber-the fat of marine animals, while an inland example burned fat from terrestrial mammals or freshwater aquatics-perhaps eels. The authors use a combination of lipid biomarker and bulk and single-compound carbon isotope analysis to indicate the origin of the residues in these vessels.

Plantas medicinais são utilizadas tradicionalmente pela população para a prevenção e tratamento da úlcera gástrica. A úlcera gástrica é uma patologia heterogênea de etiologia multifatorial. É uma doença que acomete pessoas em todo mundo tendo como consequência a elaboração de fármacos com a finalidade de amenizar os sintomas e possibilitar a cura. Entretanto, o tratamento prolongado com os recursos terapêuticos disponíveis pode ocasionar vários efeitos colaterais. Extrato de folhas de Kalanchoe pinnata (Lam.) Pers. (Crassulaceae) é utilizado pela população para o tratamento de problemas gástricos. Esta espécie está incluída na Relação Nacional de Plantas com Interesse ao SUS (RENISUS). Com a finalidade de investigar a atividade antiúlcera foram ensaiados dois modelos de lesões gástricas em animais. No modelo de indução por etanol acidificado, o extrato bruto de K. pinnata apresentou diminuição das lesões gástricas em 74% na dose de 200 mg/kg (p<0.05) e de 98% (p<0.01) na dose de 400 mg/kg. A fração acetato de etila, quando experimentada nas doses de 100 mg/kg, 200 mg/kg e 400 mg/kg, exibiu significante redução nas lesões gástricas (p<0.001), em 77%, 95% e 96%, respectivamente. O ensaio com a fração aquosa também mostrou gastroproteção visualizada pela diminuição das úlceras gástricas em 69% e 91% nas doses de 200 mg/kg (p<0.05) e 400 mg/kg (p<0.01), respectivamente. Em modelo de indução por ácido acético não houve diferença estatística na redução da lesão gástrica nas doses (100 mg/kg, 200 mg/kg e 400 mg/kg) analisadas de extrato bruto de K. pinnata, após 7 dias de tratamento. No entanto, foi observado uma tendência na redução da lesão gástrica nas doses de 200 mg/kg e 400 mg/kg. Células polimorfonucleares, células mononucleares, fibroblastos e matriz extracelular foram quantificadas pela técnica de estimativa de volume celular, para verificação do processo de cicatrização. Foi constatado que nas doses de 200 mg/kg e 400 mg/kg ocorreu uma redução da fração de volume ocupada por leucócitos polimorfonucleares, favorecendo a promoção do reparo da mucosa gástrica. Paralelamente aos estudos farmacológicos, foi efetuada a padronização do extrato e frações, a obtenção do perfil cromatográfico por Cromatografia em Camada Delgada (CCD) do extrato bruto e frações (clorofórmica, acetato de etila e aquosa) e também por Cromatografia Líquida de Alta Eficiência (CLAE) das frações acetato de etila e aquosa. O cromatograma resultante da fração acetato de etila evidenciou dois picos de maior intensidade e o perfil cromatográfico da fração aquosa apresentou um composto majoritário. Os compostos majoritários foram isolados e caracterizados como pertencentes à classe dos flavonoides. Quercitrina foi isolada da fração acetato de etila e quercetina 3-O-&#945;-L-arabinopiranosil (1&#8594;2) &#945;- L-ramnopiranosídeo foi isolada em ambas as frações. Os resultados da quantificação de flavonoides, da quantificação de substâncias fenólicas e da atividade antioxidante estão em consonância com os resultados biológicos apresentados, sugerindo uma possível relação dos flavonoides presentes no extrato com a atividade gastroprotetora e com a facilitação da cicatrização de úlceras gástricas. / Traditionally medicinal plants have been used to prevent and to treat gastric ulcer. Gastric ulcer is a heterogeneous disease of mutifactorial etiology. This illness affects a considerable number of people in the world. The clinical importance about this pathology resulted in the development of pharmaceutical products. However, these pharmaceutical products are not completely effective and produce many adverse effects. Extract of leaves of Kalanchoe pinnata (Lam.) Pers. (Crassulaceae) is often used for treating gastric ulcer by the population. K. pinnata is included in RENISUS. So, two distinct ulcer models in rats were performed. For this were realized two distinct ulcer models in rats. In acidified ethanol model, the crude extract from leaves of K. pinnata showed a protection of about 74% (p<0.05) at the dose of 200 mg/kg and 98% (p<0.01) at the dose of 400 mg/kg. Significant inhibition (p<0.001) of gastric ulcer by 77%, 95% and 96% was observed in pretreatment with ethyl acetate fraction at all the doses (100 mg/kg, 200 mg/kg and 400 mg/kg), respectively. The aqueous fraction reduced gastric lesions about 69% (p<0.05) and 91% (p<0.01) at the doses of 200 mg/kg and 400 mg/kg (p<0.01), respectively. In acid acetic model a statistic difference in reduction of gastric ulcer for all doses of the crude extract, after 7 days of treatment, wasn\'t observed. Nevertheless, the tendency about healing ulcer was verified for doses of 200 mg/kg and 400 mg/kg. Polymorphonuclear cells, mononuclear cells, fibroblasts and extracellular matrix were quantified by the technique of volume estimation to detect healing effects on gastric ulcer. These doses of 200 mg/kg and 400 mg/kg reduced the volume fraction occupied by polymorphonuclear cells. This fact contributes to healing of gastric ulcer. In parallel with the pharmacological studies, the standardization of the extract and fractions was made. The chemical analysis was performed through TLC (thin layer chromatography) and HPLC (high-performance liquid chromatography). The HPLC assay showed the presence of two major components in ethyl acetate fraction and one major presence of a component in aqueous fraction. These compounds were isolated and identified as flavonoids. Quercitrin was isolated from ethyl acetate fraction and quercetin 3-O-&#945;-L-arabinopyranosyl (1&#8594;2) &#945;-L-rhamnopyranoside was identified in the both fractions. The results of flavonoid quantification, phenolic quantification and antioxidant activity are probably correlated with the pharmacologic activity presented. These results suggest that the flavonoids present in the extract can promote gastroprotection and facilitate the healing of gastric ulcer.

Chromatography and extraction techniques, and also chemiluminescence have been utilized to develop new rapid and informative tools in the evaluation of long-term properties and environmental effects of polymeric materials. Methods were developed for classification of materials and for early and rapid degradation detection. Degradable polyethylene films were classified on the basis of their incorporated prooxidant systems using chromatographic fingerprinting of carboxylic acids, the dominating type of degradation product. The fingerprints were also shown to be useful for prediction of the degradation states and evaluation of the degradation mechanisms. Classification and prediction models were obtained by Multivariate Data Analysis, where the diacids were grouped according to both their type of prooxidant system and their state of degradation. The use of total luminescence intensity (TLI) measurements was also investigated as a means of classifying films and for the early detection of degradation. Comparisons were carried out with common techniques, e.g. FTIR and DSC, after both thermal and UV oxidation. TLI gave an earlier detection of degradation and was more sensitive than carbonyl index and crystallinity measurements to relative differences in degradation between the materials. It furthermore offered complementary information regarding changes in activation energies during the course of the degradation. The results were compared with the chromatographic fingerprints. A new way to evaluate the low temperature long-term stabilisation efficiency of antioxidants was investigated. A prooxidant was used to obtain catalytic oxidation, instead of using thermal acceleration, to evaluate the stabilisation efficiency of antioxidants at low temperatures but still during reasonably short aging times. Comparisons were made between polypropylene films stabilised with primary antioxidants (Irganox 1076, Irganox 1010 and α-tocopherol) with and without the prooxidant manganese stearate at different temperatures. The relative efficiencies of the antioxidants obtained under prooxidant acceleration test correlated better than thermal acceleration test with the results of a long-term low temperature test. Additives in plastic packaging materials may affect the environment after migration from the packaging to e.g. their contents, especially if they consist of organic aqueous solutions or oils. The use of Solid-Phase Microextraction (SPME) for the specific task of extraction from an organic aqueous solution such as a simulated food or pharmaceutical solution consisting of 10 vol-% ethanol in water was investigated. Methods were developed and evaluated for extraction both with direct sampling and with headspace sampling. If the extraction method and temperature were selected to suit the concentration levels of the analytes, it was possible to quantify several degradation products simultaneously. Comparisons made with Solid Phase Extraction showed the advantage of SPME for this purpose. / QC 20100929

Plantas medicinais são utilizadas tradicionalmente pela população para a prevenção e tratamento da úlcera gástrica. A úlcera gástrica é uma patologia heterogênea de etiologia multifatorial. É uma doença que acomete pessoas em todo mundo tendo como consequência a elaboração de fármacos com a finalidade de amenizar os sintomas e possibilitar a cura. Entretanto, o tratamento prolongado com os recursos terapêuticos disponíveis pode ocasionar vários efeitos colaterais. Extrato de folhas de Kalanchoe pinnata (Lam.) Pers. (Crassulaceae) é utilizado pela população para o tratamento de problemas gástricos. Esta espécie está incluída na Relação Nacional de Plantas com Interesse ao SUS (RENISUS). Com a finalidade de investigar a atividade antiúlcera foram ensaiados dois modelos de lesões gástricas em animais. No modelo de indução por etanol acidificado, o extrato bruto de K. pinnata apresentou diminuição das lesões gástricas em 74% na dose de 200 mg/kg (p<0.05) e de 98% (p<0.01) na dose de 400 mg/kg. A fração acetato de etila, quando experimentada nas doses de 100 mg/kg, 200 mg/kg e 400 mg/kg, exibiu significante redução nas lesões gástricas (p<0.001), em 77%, 95% e 96%, respectivamente. O ensaio com a fração aquosa também mostrou gastroproteção visualizada pela diminuição das úlceras gástricas em 69% e 91% nas doses de 200 mg/kg (p<0.05) e 400 mg/kg (p<0.01), respectivamente. Em modelo de indução por ácido acético não houve diferença estatística na redução da lesão gástrica nas doses (100 mg/kg, 200 mg/kg e 400 mg/kg) analisadas de extrato bruto de K. pinnata, após 7 dias de tratamento. No entanto, foi observado uma tendência na redução da lesão gástrica nas doses de 200 mg/kg e 400 mg/kg. Células polimorfonucleares, células mononucleares, fibroblastos e matriz extracelular foram quantificadas pela técnica de estimativa de volume celular, para verificação do processo de cicatrização. Foi constatado que nas doses de 200 mg/kg e 400 mg/kg ocorreu uma redução da fração de volume ocupada por leucócitos polimorfonucleares, favorecendo a promoção do reparo da mucosa gástrica. Paralelamente aos estudos farmacológicos, foi efetuada a padronização do extrato e frações, a obtenção do perfil cromatográfico por Cromatografia em Camada Delgada (CCD) do extrato bruto e frações (clorofórmica, acetato de etila e aquosa) e também por Cromatografia Líquida de Alta Eficiência (CLAE) das frações acetato de etila e aquosa. O cromatograma resultante da fração acetato de etila evidenciou dois picos de maior intensidade e o perfil cromatográfico da fração aquosa apresentou um composto majoritário. Os compostos majoritários foram isolados e caracterizados como pertencentes à classe dos flavonoides. Quercitrina foi isolada da fração acetato de etila e quercetina 3-O-&#945;-L-arabinopiranosil (1&#8594;2) &#945;- L-ramnopiranosídeo foi isolada em ambas as frações. Os resultados da quantificação de flavonoides, da quantificação de substâncias fenólicas e da atividade antioxidante estão em consonância com os resultados biológicos apresentados, sugerindo uma possível relação dos flavonoides presentes no extrato com a atividade gastroprotetora e com a facilitação da cicatrização de úlceras gástricas. / Traditionally medicinal plants have been used to prevent and to treat gastric ulcer. Gastric ulcer is a heterogeneous disease of mutifactorial etiology. This illness affects a considerable number of people in the world. The clinical importance about this pathology resulted in the development of pharmaceutical products. However, these pharmaceutical products are not completely effective and produce many adverse effects. Extract of leaves of Kalanchoe pinnata (Lam.) Pers. (Crassulaceae) is often used for treating gastric ulcer by the population. K. pinnata is included in RENISUS. So, two distinct ulcer models in rats were performed. For this were realized two distinct ulcer models in rats. In acidified ethanol model, the crude extract from leaves of K. pinnata showed a protection of about 74% (p<0.05) at the dose of 200 mg/kg and 98% (p<0.01) at the dose of 400 mg/kg. Significant inhibition (p<0.001) of gastric ulcer by 77%, 95% and 96% was observed in pretreatment with ethyl acetate fraction at all the doses (100 mg/kg, 200 mg/kg and 400 mg/kg), respectively. The aqueous fraction reduced gastric lesions about 69% (p<0.05) and 91% (p<0.01) at the doses of 200 mg/kg and 400 mg/kg (p<0.01), respectively. In acid acetic model a statistic difference in reduction of gastric ulcer for all doses of the crude extract, after 7 days of treatment, wasn\'t observed. Nevertheless, the tendency about healing ulcer was verified for doses of 200 mg/kg and 400 mg/kg. Polymorphonuclear cells, mononuclear cells, fibroblasts and extracellular matrix were quantified by the technique of volume estimation to detect healing effects on gastric ulcer. These doses of 200 mg/kg and 400 mg/kg reduced the volume fraction occupied by polymorphonuclear cells. This fact contributes to healing of gastric ulcer. In parallel with the pharmacological studies, the standardization of the extract and fractions was made. The chemical analysis was performed through TLC (thin layer chromatography) and HPLC (high-performance liquid chromatography). The HPLC assay showed the presence of two major components in ethyl acetate fraction and one major presence of a component in aqueous fraction. These compounds were isolated and identified as flavonoids. Quercitrin was isolated from ethyl acetate fraction and quercetin 3-O-&#945;-L-arabinopyranosyl (1&#8594;2) &#945;-L-rhamnopyranoside was identified in the both fractions. The results of flavonoid quantification, phenolic quantification and antioxidant activity are probably correlated with the pharmacologic activity presented. These results suggest that the flavonoids present in the extract can promote gastroprotection and facilitate the healing of gastric ulcer.