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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

Computer-aided detection systems for HPLC : Development, assessment and application of digital techniques for peak purity validation in HPLC utilising photodiode array detection

Marr, J. G. D. January 1988 (has links)
No description available.
2

Dobilų (Trifolium L.) genties augalų izoflavonų kiekybinės sudėties tyrimas / Quantitative research of isoflavones composition in Clover (Trifolium L.) genus

Kurantavičius, Vytautas 21 June 2010 (has links)
Tyrimo objektas ir metodai: dobilų genties augalų lapų, stiebų, žiedų žaliavų tyrimas. Izoflavonai nustatyti ESC metodu. Darbo tikslas: Atlikti izoflavonų genisteino, formononetino ir daidzeino analizę dobilų genties augaluose, taikant ESC metodą. Darbo uždaviniai: atlikti literatūros analizę, apibendrinant dobilų (Trifolium L) genties augalų biologines savybes, izoflavonų taikymą gydymo tikslais ir nustatymo metodus. Parinkti ekstrakcijos sąlygas, įvertinant pasirinkto ekstrakcijos tirpiklio, jo poliškumo ir ekstrakcijos laiko įtaką. Optimizuoti ESC metodą dobilų žaliavos tyrimui ir pagrįsti metodo tinkamumą izoflavonų kiekio nustatymui. Atlikti įvairių dobilų rūšių lapų, žiedų, stiebų ir šaknų mėginių analizę optimizuotu ESC metodu ir nustatyti izoflavonų kiekius juose. Įvertinti izoflavonų kiekio įvairavimą skirtingose dobilų rūšyse. Nustatyti izoflavonų kiekybinės sudėties pasiskirstymą augalų dalyse. Palyginti T. pratense izoflavonų kiekių skirtumus augalo dalyse. Palyginti izoflavonų kiekybinės sudėties skirtumus T. pratense kultivuojamų ir laukinės populiacijos augalų žaliavose. Išvados: atlikus mokslinės literatūros šaltinių analizę, apibendrintos dobilų genties augalų biologinės savybės, izoflavonų taikymas gydymo tikslais ir flavonoidų bei izoflavonoidų nustatymo metodai. Įvertintas tirpiklio poliškumas ir taikomos ekstrakcijos trukmės įtaka izoflavonų kiekiui. Optimizuotas ESC metodas kiekybinei izoflavonų analizei dobilų (Trifolium L.) genties augalų žaliavoms... [toliau žr. visą tekstą] / Object and methods: phytochemical analysis of different parts (leaves, blossoms, roots) of clover genus plants. Aim: to perform analysis of isoflavons genistein, formononetin and daidzein in clover genus plants by HPLC method. Objective: to perform analysis of scientific literature and evaluate characteristics of clover genus (Trifolium L.) plants and their usage for medical purpose, and analysis methods of active components. Select the conditions of extraction considering influence of solvent, its polarity and time of extraction. Optimize HPLC method for raw material analysis of clover genus and justify its suitability for quantitative analysis of isoflavons. Perform analysis of isoflavons in different parts of various clover genus plants by optimized HPLC method. Evaluate quantity difference between isoflavons in various genus of clover. Evaluate quantity difference between isoflavons in different parts of plants. Compare quantities of isoflavons in different parts of T. pratense pants. Compare quantity difference between isoflavons in raw materials of cultivated and naturally grown T. pretense plants. Results: performed scientific literature analysis justified characteristics and therapeutic effects of clover genus (Trifolium L.) plants, evaluated analysis methods of flavonoids and isoflavonoids. Also was evaluated influence of polarity of solvent and time of extraction to quantity of isoflavons. Quantitative HPLC analysis method for isoflavons in raw materials of clover... [to full text]
3

Analysis of Selenium Toxicity on Reduced Thiol Content

Kulkarni, Samatha January 2010 (has links)
No description available.
4

Augalinio vaistinio preparato kiekybinio stabilumo pagrindimas efektyviosios skysčių chromatografijos metodu / Justification of quantitative stability of herbal medicinal product by HPLC method

Kaduševičiūtė, Giedrė 21 June 2010 (has links)
Tyrimo objektas ir metodai: eksperimentinės augalinio vaistinio preparato Silymarinum – Aconitum 140 mg kietos kapsulės, kurių veiklioji medžiaga yra silimarinas. Kiekybinė jų sudėtis nustatyta ESC metodu. Darbo tikslas: pagrįsti augalinio vaistinio preparato kiekybinį stabilumą validuotu ESC metodu. Darbo uždaviniai: atlikti mokslinės literatūros šaltinių analizę įvertinant pasirinkto vaistinio augalinio preparato savybes bei aktyvių junginių nustatymo metodikas. Optimizuoti ir validuoti ESC metodiką kiekybiniam pasirinkto vaistinio augalinio preparato įvertinimui. Validuotu metodu atlikti eksperimentinių augalinio vaistinio preparato serijų stabilumo kiekybinę analizę. Apdoroti ir įvertinti augalinio vaistinio preparato stabilumo duomenis, remiantis mokslinių gairių nurodytais kriterijais ir gautais rezultatais pagrįsti preparato stabilumą. Išvados: atlikta mokslinės literatūros šaltinių analizė, pagrindžianti gydomąsias augalinio vaistinio preparato Silymarinum – Aconitum 140 mg kietomis kapsulėmis savybes, aktyvių junginių nustatymo metodikas bei taikomus metodo optimizavimo ir validacijos kriterijus. Optimizuotas ESC metodas eksperimentinio augalinio vaistinio preparato Silymarinum – Aconitum 140 mg kietomis kapsulėmis kiekybinei analizei. Validacijos eksperimentų metu pagrįstas metodikos glaudumas ir tiesiškumas. Atlikta kiekybinė eksperimentinio augalinio vaistinio preparato Silymarinum – Aconitum 140 mg kietomis kapsulėmis mėginių analizė. Preparato mėginiuose... [toliau žr. visą tekstą] / Object and methods: experimental herbal medicinal product Silymarinum – Aconitum 140 mg in hard capsules, as the main active component is silimarin. Assay analysis has been performed by HPLC method. Aim: to justify herbal medicinal product quantitative stability by validated HPLC method. Objective: to perform analysis of scientific literature and evaluate characteristics of chosen herbal medicinal product, and analysis methods of active components. Optimize and validate HPLC method for quantitative evaluation of chosen herbal medicinal product. Perform stability indicating quantitative analysis of experimental herbal medicinal product. Evaluate stability data of herbal medicinal product and justify its stability with reference to scientific guidelines and gained results. Results: performed scientific literature analysis justified therapeutic effect of herbal medicinal product Silymarinum – Aconitum 140 mg in hard capsules, evaluated analysis methods of active components and applicable criteria for method optimization and validation. HPLC method for quantitative analysis of experimental herbal medicinal product Silymarinum – Aconitum 140 mh in hard capsules was optimized. Precision and linearity of method was justified during experiments of validation. Assay analysis of herbal medicinal product Silymarinum – Aconitum 140 mg in hard capsules clarified, that amount of total silymarin varies from 136,966 mg to 146,573 mg. Stability testing clarified that herbal medicinal... [to full text]
5

Flavonoidų nustatymas efektyviosios skysčių chromatografijos metodu, kanadinės rykštenės (L. Solidago canadensis) ekstraktuose / High-performance liquid chromatography analysis of the flavonoids in extracts from Canadian goldenrod (Solidago canadensis)

Sendrauskaitė, Kristina 30 June 2014 (has links)
Tyrimo objektas – kanadinės rykštenės lapų bei žiedų ekstraktai. Tyrimo metu kokybiniam ir kiekybiniam flavonoidų nustatymui naudojamas efektyviosios skysčių chromatografijos metodas. Darbo tikslas – nustatyti flavonoidų kokybinę ir kiekybinę sudėtį kanadinės rykštenės (Solidago canadensis L.) augalinėje žaliavoje naudojant ESC metodą. Atlikta mokslinių literatūros šaltinių analizė, pagrindžianti kanadinės rykštenės (Solidago canadensis L.) gydomąsias savybes, flavonoidų išskyrimo bei nustatymo metodikas , taip pat taikomo metodo optimizavimo ir validacijos kriterijus. Optimizuotas ECS metodas flavonoidų vertinimui, naudojant turimą laboratorinę įrangą. Pasirinkta 150×4,6 mm, 3 µm YMC kolonėlė, kurios temperatūra 25°C. Injekcijos tūris – 10µl. Kiekybiniam nustatymui pasirinktas gradavimo grafiko metodas, taikant tiesines kalibracines kreives. Validacijos eksperimentų metu buvo pagrįstas metodikos pakartojamumas, tiesiškumas, aptikimo ir nustatymo ribos. Validuota metodika pritaikyta kanadinės rykštenės (Solidago canadensis L.) ekstrakto tyrimui, nustatyta, kad kanadinės rykštenės lapų ekstrakte flavonoidų vidutiniškai yra 23,0 mg/g, iš jų vidutiniškai rutino nustatyta 18,99 mg/g, izokvercitrino – 0,44 mg/g, hiperozido 0,19 mg/g, kvercitrino 3,38 mg/g. Kanadinės rykštenės žiedų ekstraktuose flavonoidų nustatyta vidutiniškai 23,27 mg/g, iš jų rutino nustatyta 19,70 mg/g, izokvercitrino – 0,68 mg/g, hiperozido – 0,47 mg/g, o kvercitrino – 2,42 mg/g. / The object of the research – extracts of Canadian goldenrod leaves and flowers. The high performance liquid chromatography method was used for the quantitative determination of flavonoids in the research. The aim of work was to determine the qualitative and quantitative composition of flavonoids in the plant raw material of Canadian goldenrod (Solidago canadensis L.) using HPLC method. Analysis of scientific literature was performed to support the medicinal properties of the Canadian goldenrod (Solidago canadensis L.), methods for extraction and detection of flavonoids, as well as the validation criteria of the applied optimization method. The HPLC method for determining the quantity of flavonoids was optimized using the available laboratory equipment. YMC column of 150×4.6 mm, 3 µl, was chosen with a temperature of 25°C. The injection volume – 10 µl. The graph calibration method was selected for using linear calibration curves. Validation experiments justified the method repeatability, linearity and the limits. The validated methodology was applied for the research of Canadian goldenrod (Solidago canadensis L.) extract, and it was determined that the leaf extract of Canadian goldenrod contains an average of 23.0 mg/g flavonoids, of which, the average amount of rutin found was 18.99 mg/g, isoquercitrin – 0.44 mg/g, hyperoside 0.19 mg/g, quercitrin 3.38 mg/g. The average flavonoid content in the flower extract of Canada goldenrod was 23.27 mg/g, of them rutin 19.70 mg/g... [to full text]
6

Φυτοχημική ανάλυση εκχυλίσματος πόας υπερικού

Μαργιάννη, Ευαγγελία 10 May 2012 (has links)
Το Hypericum perforatum (Υπερικό το διάτρητο) είναι ένα από τα πιο παλιά φαρμακευτικά φυτά που χρησιμοποιούταν στη λαϊκή θεραπευτική πολλών διαφορετικών πολιτισμών, ως επουλωτικό, αντιφλεγμονώδες και αντικαταθλιπτικό. Αλκοολικά εκχυλίσματα αυτού συνιστούν σκευάσματα που κυκλοφορούν ως συμπληρώματα ή φάρμακα για διαταραχές της ήπιας και μέτριας κατάθλιψης. Φλαβονοειδή, φαινολικά οξέα, ναφθοδιανθρόνες και φλωρογλουκινόλες είναι οι κύριες ομάδες συστατικών που βρίσκονται σε μεγάλη περιεκτικότητα στα φυτικά εκχυλίσματα. Στην παρούσα μελέτη πραγματοποιήθηκε ανάπτυξη αναλυτικής μεθόδου για τον προσδιορισμό και την ποσοτικοποίηση κύριων βιοδραστικών συστατικών του Hypericum perforatum με τη χρήση υγρής χρωματογραφίας υψηλής απόδοσης με ανιχνευτή συστοιχίας φωτοδιόδων (Ηigh Performance Liquid Chromatography - Diode Array Detector, HPLC-DAD). Μετά από πιλοτικά πειράματα σε στήλη ανάστροφης φάσης Luna C-18, ο διαχωρισμός των συστατικών του μεθανολικού εκχυλίσματος έγινε με χρήση συστήματος βαθμιδωτής έκλουσης με τρεις διαλύτες: ρυθμιστικό διάλυμα 10 mM οξικού αμμωνίου, pH=4,5/ ακετονιτρίλιο/ μεθανόλη και ροή 1.0 mL/min. Η μέθοδος πιστοποιήθηκε με πρότυπα χλωρογενικού οξέος, ρουτίνης, υπεροζίτη, κερσετίνης, ισοκερσετίνης και υπερικίνης και τα ποιοτικά χαρακτηριστικά της μεθόδου είναι εντός των αποδεκτών ορίων που θεσπίζει ο ΕΜΕΑ. Η αναπτυχθείσα μέθοδος μπορεί να εφαρμοσθεί για τον ποιοτικό και ποσοτικό έλεγχο εκχυλισμάτων Hypericum, όπως και για τον χαρακτηρισμό της σύστασης διαφόρων taxa Hypericum τα οποία δεν έχουν μελετηθεί. Πρόσφατη μελέτη αναφέρθηκε στις νευροπροστατευτικές ιδιότητες του εκχυλίσματος σε διαβητικά πειραματόζωα και αυτό αποτέλεσε το έναυσμα διερεύνησης της επίδρασης αυτού στη μη ενζυμική γλυκοζυλίωση των πρωτεϊνών, που συμβαίνει σε συνθήκες υπεργλυκαιμίας στους ασθενείς με σακχαρώδη διαβήτη. Η πλεονάζουσα γλυκόζη αντιδρά μη ενζυμικά με πλήθος πρωτεϊνικών μορίων, επηρεάζοντας τη δομή και τη λειτουργία αυτών. Σε συνθήκες εμμένουσας υπεργλυκαιμίας και διάρκειας εβδομάδων η αντίδραση αυτή έχει ως αποτέλεσμα το σχηματισμό φθοριζουσών τελικών προϊόντων, μη-αναστρέψιμων (Advanced Glycation End-products, AGEs), τα οποία συνεισφέρουν στην ανάπτυξη των αγγειακών διαβητικών επιπλοκών. Ο έλεγχος της έντασης φθορισμού έγινε μετά από επώαση τριών ημερών αλβουμίνης βόειου ορού (10 mg/mL) και ριβόζης (0,5 M) σε όγκο 350 μL, παρουσία ή απουσία του φυτικού εκχυλίσματος και των συστατικών αυτού. Τα αποτελέσματα έδειξαν σημαντική ανασταλτική δράση του εκχυλίσματος (100 μg/mL) (70%) και των μεμονωμένων συστατικών του (100 μΜ), κύρια δε των φλαβονοειδών. Τα αποτελέσματα αυτά συνεισφέρουν στην επιστημονική αναζήτηση μη τοξικών αναστολέων σχηματισμού AGEs για την αντιμετώπιση των αγγειακών επιπλοκών του διαβήτη. Λέξεις-κλειδιά: Hypericum perforatum, HPLC ανάλυση, Τελικά προϊόντα προχωρημένης γλυκοζυλίωσης (AGEs) / Hypericum perforatum (Saint John’s wort) has been used since antiquity in folk medicine as a wound-healing, anti-inflammatory and antidepressant drug. Alcoholic extracts of this plant are the constituents of drug preparations or supplements that are used for mild to moderate depression. Flavonoids, phenolic acids, napthodianthrones and phloroglucinols are the main constituents of high content in herbal extracts. In the present study, a High Performance Liquid Chromatography (HPLC) analytical method was developed for the quality and quantity control of bioactive components of Hypericum perforatum methanolic extracts. After a great variety of elution gradients on a C-18 Luna column, the natural products were completely separated by a linear gradient of 10mM ammonium acetate (pH=4,5) -acetonitrile-methanol in one run within 60 min and flow 1.0 mL/min. The chromatographic method was validated using commercially available standards of chlorogenic acid, rutin, hyperoside, quercetin, isoquercitrin and hypericin and the quality values were within the acceptable limits of EMEA. The developed method can be applied towards the quality and quantity control of hypericum extracts and the characterization of the composition of Hypericum taxa, which have not been studied. A recent study mentioned the neuroprotective capacity of the extract in diabetic rats and that was the beginning of a research about its effect in non-enzymatic glycosylation of proteins that occurs in diabetic patients, in hyperglycaemia conditions. The redundant glycose react non-enzymatically with a number of proteins, affecting their structure and function. Under sustained hyperglycaemia conditions and in natural aging, further glycation of proteins causes the generation of AGEs (Advanced Glycation End-products).AGEs may fluoresce under ultraviolet light and contribute to the development of diabetic vascular complications. The measurement of fluorescence intensity was realized after a 3-days incubation of bovine serum albumin (10 mg/mL) with ribose (0,5 M) in the presence or absence of herbal extract and its constituents. The final volume of reaction was 350 μL. The results showed significant inhibitory effect of the extract (100 μg/mL) (70%) and its components (100 μΜ), mainly that of flavonoids. The present results contribute to scientific research of non-toxic inhibitors of AGEs formation in order to get faced the diabetic vascular complications.
7

Physicochemical Characterization and Isoflavone Profiling of Sourdough Soy Bread

Yezbick, Gabrielle 30 August 2012 (has links)
No description available.
8

Monitoração toxinológica do pescado comercializado nos municípios de São Sebastião e Caraguatatuba, SP / Toxinological monitoring of fisheries comercialized in São Sebastião and Caraguatatuba cities, São Paulo state

Stranghetti, Bruno Garcia 10 September 2007 (has links)
As toxinas do envenenamento paralisante por moluscos (Paralytic Shellfish Poisoning – PSP) são compostos naturais bioativos conhecidos devido ao consumo acidental de frutos do mar contaminados. Estas moléculas, das quais a mais potente é a saxitoxina (STX), são uma classe de alcalóides neurotóxicos que possuem diferentes análogos e diferentes toxicidades, e são produzidas por algumas cianobactérias e algumas espécies de dinoflagelados do gênero Alexandrium, Gymnodinium e Pyrodinium. As toxinas paralisantes são neurotoxinas solúveis em água que agem sobre células nervosas e musculares através do bloqueio dos canais de sódio dependentes de voltagem, desta maneira, impedindo a condução do sinal no neurônio o que leva a uma paralisia muscular. Em casos graves, pode ocorrer morte por insuficiência respiratória. O envenenamento diarréico por moluscos (Diarrhetic Shelfish Poisoning – DSP) é caracterizado por problemas gastrointestinais com sintomas como diarréia, náusea, vômito, dor de cabeça, calafrios e dores abdominais. DSP é conseqüência do consumo de mariscos contaminados que ingeriram dinoflagelados do gênero Dynophysis e Prorocentrun através de sua alimentação por filtração da água. Contaminação de frutos do mar por toxinas PSP ou DSP coloca-se como sério problema para a indústria pesqueira e para a saúde pública. Neste estudo, estabeleceu-se um programa de monitoração para mexilhões (Perna perna) e para peixes (Sardinella brasiliensis, Anchoviella lepidentostole e Brevoortia aurea) coletados em peixarias e entrepostos de pesca no municípios de Caraguatatuba e São Sebastião, São Paulo. Os extratos para PSP foram preparados de duas maneiras: de acordo com a AOAC (Association of Official Analytical Chemists), através do aquecimento por 5 min de uma mistura de 100 g de tecidos homogeneizados com ácido acético 0,1 N; ou a partir da concentração de extratos etanólicos de músculo + pele dos peixes. Os bioensaios com camundongos para PSP consistem na injeção intraperitonial de 1 mL do extrato ácido em cada um dos três camundongos (~ 20 g). O animal é observado quanto aos sintomas clássicos de PSP e o tempo de morte é anotado e então a toxicidade é determinada (em mouse units, MU) pela tabela de Sommer. Para as toxinas causadoras de DSP, os extratos foram preparados pela extração com acetona do homogeneizado das glândulas digestivas, e a determinação da presença destas toxinas é feita através da injeção intraperitonial em camundongos. Nos bioensaios com os extratos preparados segundo o método da AOAC, não houve casos positivos. Para o bioensaio realizado com extratos etanólicos obtiveram-se resultados positivos para 77,8% dos extratos testados. A média de MU de todas as amostras, neste caso, foi de 0,147 MU/g. Nos bioensaios para DSP, três amostras resultaram em sinais que evidenciam a presença destas toxinas, pois os camundongos injetados apresentaram quadro diarréico. Os extratos etanólicos, com positividade para as toxinas de PSP, foram fracionados usando-se colunas Sep-Pak C18. A primeira eluição, com ácido acético 0,1 M, foi analisada usando-se o método de préderivatização e cromatografia líquida de alta eficiência com detecção de fluorescência. As analises em CLAE indicaram a presença de compostos semelhantes às toxinas paralisantes de PSP, confirmando os bioensaios. Portanto, pela primeira vez no Brasil demonstrou-se que as espécies S. brasiliensis, A. lepidentostole e B. aurea são portadoras de toxinas paralisantes, semelhantes às PSP, em pequenas concentrações e que um programa de monitoração é necessário em nosso país para verificação da presença dessas toxinas em organismos que são usados como alimento pela população. / The Paralytic Shellfish Poisoning (PSP) toxins are well-known natural bioactive compounds due to their accidental consumption in contaminated seafood. These molecules, of which the most potent representative is saxitoxin (STX), are a class of neurotoxic alkaloids, having different isoforms and varied toxicities, that are produced by some cyanobacteria and some species of dinoflagellates from the genus Alexandrium, Gymnodinium and Pyrodinium. PSP toxins are water-soluble neurotoxins that act on nerve and muscle cells by blocking sodium channels voltage-dependent, thus preventing the conductance of neuron signal leading to muscular paralysis. In severe cases, death may result due to respiratory failure. Diarrhetic Shellfish Poisoning (DSP) is a gastrointestinal illness with symptoms such as diarrhea, nausea, vomiting, headache, chills and moderate to severe abdominal pain. DSP is usually a consequence of consuming contaminated shellfish that have ingested dinoflagellates of the genera Dinophysis and Prorocentrun through their filter feeding activities. Contamination of seafood by PSP and DSP toxins has posed serious problems to the fisheries industry as well to public health. In this study, was stabilized a monitoring program to shellfish (Perna perna) and finfish (Sardinella brasiliensis, Anchoviella lepidentostole and Brevoortia aurea) collected in fish markets in Caraguatatuba and São Sebastião cities, São Paulo state. The extracts for PSP were prepared by two ways: according to AOAC (Association of Official Analytical Chemists), through the heating for 5 min of blend of 100 g of well mixed sample with 0.1 N HCl; or through of the concentration of ethanolic extracts from finfish’s muscle + skin. The PSP mouse bioassay for PSP toxins involves intraperitonial injection (i.p.) of 1 mL of the acid extract into each of three mice (~ 20 g). The mice were observed for classical PSP symptoms and the time to mouse death was recorded and the toxicity was determinate (in mouse units, MU) from the Sommer’s table. To DSP toxins, the extracts was prepared trough the extraction of digestive glands with acetone, and i.p injection in mice was used to determine the presence of theses toxins. In the mouse bioassay for the extracts prepared by AOAC method no positive results was obtained. For the mouse bioassay with ehtanolic extracts was obtained positive results to 77.8 % of the tested extracts. The media of MU of all samples, in this case, was 0,147 MU/g. To the mouse bioassay for the DSP toxins, three samples gives evidence of presence of the diarrhetic toxins, because the mice showed signal like diarrhea. The ethanolic extracts, that was positive to the PSP toxins, was fractionated by a Sep-Pak C18 cartridge. The first elution, with 0.1 M acetic acid, was analyzed by using prechromatographic oxidation and liquid chromatography with fluorescence detection. The HPLC analysis indicated the presence of the PSP toxins, confirming the bioassays. Therefore, in the first time in Brazil was demonstrated that the species S. brasiliensis, A. lepidentostole and B. aurea are carriers of toxins like PSP in little concentrations and that a monitoring program is necessary in our country to verify the presence of these toxins in organisms that are used as food by the population.
9

Monitoração toxinológica do pescado comercializado nos municípios de São Sebastião e Caraguatatuba, SP / Toxinological monitoring of fisheries comercialized in São Sebastião and Caraguatatuba cities, São Paulo state

Bruno Garcia Stranghetti 10 September 2007 (has links)
As toxinas do envenenamento paralisante por moluscos (Paralytic Shellfish Poisoning – PSP) são compostos naturais bioativos conhecidos devido ao consumo acidental de frutos do mar contaminados. Estas moléculas, das quais a mais potente é a saxitoxina (STX), são uma classe de alcalóides neurotóxicos que possuem diferentes análogos e diferentes toxicidades, e são produzidas por algumas cianobactérias e algumas espécies de dinoflagelados do gênero Alexandrium, Gymnodinium e Pyrodinium. As toxinas paralisantes são neurotoxinas solúveis em água que agem sobre células nervosas e musculares através do bloqueio dos canais de sódio dependentes de voltagem, desta maneira, impedindo a condução do sinal no neurônio o que leva a uma paralisia muscular. Em casos graves, pode ocorrer morte por insuficiência respiratória. O envenenamento diarréico por moluscos (Diarrhetic Shelfish Poisoning – DSP) é caracterizado por problemas gastrointestinais com sintomas como diarréia, náusea, vômito, dor de cabeça, calafrios e dores abdominais. DSP é conseqüência do consumo de mariscos contaminados que ingeriram dinoflagelados do gênero Dynophysis e Prorocentrun através de sua alimentação por filtração da água. Contaminação de frutos do mar por toxinas PSP ou DSP coloca-se como sério problema para a indústria pesqueira e para a saúde pública. Neste estudo, estabeleceu-se um programa de monitoração para mexilhões (Perna perna) e para peixes (Sardinella brasiliensis, Anchoviella lepidentostole e Brevoortia aurea) coletados em peixarias e entrepostos de pesca no municípios de Caraguatatuba e São Sebastião, São Paulo. Os extratos para PSP foram preparados de duas maneiras: de acordo com a AOAC (Association of Official Analytical Chemists), através do aquecimento por 5 min de uma mistura de 100 g de tecidos homogeneizados com ácido acético 0,1 N; ou a partir da concentração de extratos etanólicos de músculo + pele dos peixes. Os bioensaios com camundongos para PSP consistem na injeção intraperitonial de 1 mL do extrato ácido em cada um dos três camundongos (~ 20 g). O animal é observado quanto aos sintomas clássicos de PSP e o tempo de morte é anotado e então a toxicidade é determinada (em mouse units, MU) pela tabela de Sommer. Para as toxinas causadoras de DSP, os extratos foram preparados pela extração com acetona do homogeneizado das glândulas digestivas, e a determinação da presença destas toxinas é feita através da injeção intraperitonial em camundongos. Nos bioensaios com os extratos preparados segundo o método da AOAC, não houve casos positivos. Para o bioensaio realizado com extratos etanólicos obtiveram-se resultados positivos para 77,8% dos extratos testados. A média de MU de todas as amostras, neste caso, foi de 0,147 MU/g. Nos bioensaios para DSP, três amostras resultaram em sinais que evidenciam a presença destas toxinas, pois os camundongos injetados apresentaram quadro diarréico. Os extratos etanólicos, com positividade para as toxinas de PSP, foram fracionados usando-se colunas Sep-Pak C18. A primeira eluição, com ácido acético 0,1 M, foi analisada usando-se o método de préderivatização e cromatografia líquida de alta eficiência com detecção de fluorescência. As analises em CLAE indicaram a presença de compostos semelhantes às toxinas paralisantes de PSP, confirmando os bioensaios. Portanto, pela primeira vez no Brasil demonstrou-se que as espécies S. brasiliensis, A. lepidentostole e B. aurea são portadoras de toxinas paralisantes, semelhantes às PSP, em pequenas concentrações e que um programa de monitoração é necessário em nosso país para verificação da presença dessas toxinas em organismos que são usados como alimento pela população. / The Paralytic Shellfish Poisoning (PSP) toxins are well-known natural bioactive compounds due to their accidental consumption in contaminated seafood. These molecules, of which the most potent representative is saxitoxin (STX), are a class of neurotoxic alkaloids, having different isoforms and varied toxicities, that are produced by some cyanobacteria and some species of dinoflagellates from the genus Alexandrium, Gymnodinium and Pyrodinium. PSP toxins are water-soluble neurotoxins that act on nerve and muscle cells by blocking sodium channels voltage-dependent, thus preventing the conductance of neuron signal leading to muscular paralysis. In severe cases, death may result due to respiratory failure. Diarrhetic Shellfish Poisoning (DSP) is a gastrointestinal illness with symptoms such as diarrhea, nausea, vomiting, headache, chills and moderate to severe abdominal pain. DSP is usually a consequence of consuming contaminated shellfish that have ingested dinoflagellates of the genera Dinophysis and Prorocentrun through their filter feeding activities. Contamination of seafood by PSP and DSP toxins has posed serious problems to the fisheries industry as well to public health. In this study, was stabilized a monitoring program to shellfish (Perna perna) and finfish (Sardinella brasiliensis, Anchoviella lepidentostole and Brevoortia aurea) collected in fish markets in Caraguatatuba and São Sebastião cities, São Paulo state. The extracts for PSP were prepared by two ways: according to AOAC (Association of Official Analytical Chemists), through the heating for 5 min of blend of 100 g of well mixed sample with 0.1 N HCl; or through of the concentration of ethanolic extracts from finfish’s muscle + skin. The PSP mouse bioassay for PSP toxins involves intraperitonial injection (i.p.) of 1 mL of the acid extract into each of three mice (~ 20 g). The mice were observed for classical PSP symptoms and the time to mouse death was recorded and the toxicity was determinate (in mouse units, MU) from the Sommer’s table. To DSP toxins, the extracts was prepared trough the extraction of digestive glands with acetone, and i.p injection in mice was used to determine the presence of theses toxins. In the mouse bioassay for the extracts prepared by AOAC method no positive results was obtained. For the mouse bioassay with ehtanolic extracts was obtained positive results to 77.8 % of the tested extracts. The media of MU of all samples, in this case, was 0,147 MU/g. To the mouse bioassay for the DSP toxins, three samples gives evidence of presence of the diarrhetic toxins, because the mice showed signal like diarrhea. The ethanolic extracts, that was positive to the PSP toxins, was fractionated by a Sep-Pak C18 cartridge. The first elution, with 0.1 M acetic acid, was analyzed by using prechromatographic oxidation and liquid chromatography with fluorescence detection. The HPLC analysis indicated the presence of the PSP toxins, confirming the bioassays. Therefore, in the first time in Brazil was demonstrated that the species S. brasiliensis, A. lepidentostole and B. aurea are carriers of toxins like PSP in little concentrations and that a monitoring program is necessary in our country to verify the presence of these toxins in organisms that are used as food by the population.
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Molécules bioactives issues de la biodiversité cambodgienne : Vernonia cinerea Less. et Vernonia elliptica DC. / Bioactive molecules from the cambodian biodiversity : Vernonia cinerea Less. and Vernonia elliptica DC.

Khay, Mom 23 February 2015 (has links)
Nos travaux de doctorat s’inscrivent dans la démarche de la valorisation de la biodiversité végétale cambodgienne. Les objectifs portaient sur les travaux phytochimique et pharmacologique de deux plantes cambodgiennes : Vernonia cinerea et Vernonia elliptica. Une méthode de dosage par CLHP du composé 8α-tigloyloxyhirsutinolide 13-O-acetate (H1) appartenant à la classe des lactones sesquiterpènes de V. cinerea a été mise au point et validée dans le but de déterminer la teneur de ce composé. La teneur en H1 varie entre 0,08 % à 0,17 % pour les échantillons étudiés provenant de 4 régions du Cambodge. L’évaluation de l’activité antiproliférative in vitro des extraits de V. cinerea, et du composé H1 a été réalisée vis-à-vis de deux lignées cellulaires cancéreuses humaines HT29 et HepG2. Le composé H1 présente une CI50 similaire à celle du contrôle positif 5FU, 4,3 ± 0,2 versus 5,4 ± 0,9 µM vis-à-vis de la lignée HepG2. Les résultats intéressants obtenus sur V. cinerea nous ont incités à travailler sur d’autres espèces du genre Vernonia qui poussent au Cambodge, Vernonia elliptica. L’étude phytochimique menée sur cette plante a permis d’isoler un lignane [(+)-Syringaresinol] et deux lactones sesquiterpènes [(+)-8,13-diacetyl-piptocarphol et Glaucolide B]. Ces composés sont décrits dans cette plante pour la première fois. L’étude in vitro de l’activité antiproliférative des extraits de V. elliptica montre que l’extrait dichlorométhane obtenu à partir de l’extrait aqueux est très actif. / Our PhD work is in the process of valorization of the Cambodian plant biodiversity. The objectives focused on phytochemical and pharmacological studies of two Cambodian plants of the Vernonia genus: Vernonia cinerea and Vernonia elliptica.An analytical HPLC method was developed and validated to quantify the major compound 8α-tigloyloxyhirsutinolide 13-O-acetate (H1) of Vernonia cinerea. We found that the compound H1 content ranges from 0.08% to 0.17% in samples collected from cambodian regions. We thus evaluated the anti-proliferative activity in vitro of extracts of V. cinerea and H1 compound against two human cancer cell lines HT29 and HepG2. For HepG2 cell line, the compound H1 has a similar IC50 to the positive control 5FU, 4.3 ± 0.2 versus 5.4 ± 0.9 µM. The interesting results on V. cinerea encouraged us to study other species of Vernonia genus growing in Cambodia, Vernonia elliptica. The phytochemical study conducted on this plant led to isolate a lignan [(+)-syringaresinol] and two sesquiterpene lactones [(+)-8,13-diacetyl-piptocarphol and Glaucolide B]. These compounds were described in this plant for the first time. The in vitro study of the anti-proliferative activity of the extracts of V. elliptica shows that the dichloromethane extract obtained from aqueous extract is very active.

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