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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

Iskorišćenje sporednog proizvoda uve (Arctostaphylos uva ursi L.) u cilju dobijanja novih biljnih ekstrakata savremenim tehnikama ekstrakcije / Utilization of uva (Arctostaphylos uva ursi L.) by product in order to obtain new herbal extracts by modern extraction techniques

Naffati Abdulhakim 01 February 2019 (has links)
<p style="text-align: justify;">U okviru ove doktorske disertacije ispitana je mogućnost ekstrakcije bioaktivnih jedinjenja iz biljne pra&scaron;ine A. uva-ursi, koja nastaje kao sporedni proizvod u fabrici filter čaja. Za ekstrakciju bioaktivnih jedinjenja primenjene su različite tehnike ekstrakcije (klasična ekstrakcija, ultrazvučna ekstrakcija i ekstrakcija subkritičnom vodom), kao i različiti ekstragensi: voda na sobnoj temperaturi, 30-70% etanol i subkritična voda. Sadržaj bioaktivnih jedinjenja u ekstraktima ispitan je primenom odgovarajućih spektrofotometrijskih metoda i HPLC metode. U ekstrakciji biljne pra&scaron;ine A. uva-ursi detaljno je matematički analiziran uticaj procesnih parametara na ekstrakciju subkritičnom vodom bioaktivnih jedinjenja iz materijala ovog tipa i u tom smislu je posmatran uticaj temperature, vremena i dodatka kiseline, a takođe su određeni uslovi pri kojima je, primenom ove tehnike, moguće ostvariti maksimalnu ekstrakciju bioaktivnih jedinjenja od značaja. Pored toga prikazana je i mogućnost primene spray drying tehnike za su&scaron;enje tečnih i proizvodnju suvih ekstrakta A. uva-ursi u formi praha. Na kraju, na osnovu koncentracije bioaktivnih jedinjenja i njihovog delovanja, dat je predlog nekoliko novih preparata na bazi ekstrakata A. uva-ursi, u tečnoj i čvrstoj formi.</p> / <p>This dissertation investigated the possibility to extract bioactive compounds from A. uva-ursi herbal dust, which occurs as a by-product at the filter-tea<br />factory. Various extraction techniques (classical extraction, ultrasound assisted extraction and subcritical water extraction), were applied for the extraction of bioactive compounds, as well as different solvents: water at room temperature, 30-70% ethanol and subcritical water. The content of bioactive compounds in the extracts was investigated using appropriate spectrophotometric methods and the HPLC method. In the extraction of A. uva-ursi herbal dust a detailed mathematical analysis of the influence of process parameters on subcritical water extraction of bioactive compounds from this type of material was conducted. In this regard the influence of temperature, time and acid addition was observed and the conditions under which it is possible to achieve maximum extraction of significant bioactive compounds, by applying this technique, were determined. In addition, the possibility of applying the spray drying technique for drying the liquid and producing dry A. uva-ursi extracts in the form of powder is also presented. Eventually, based on the concentration of the bioactive compounds and their activity, a proposal for a several new preparations in liquid and solid form, based on A. uva-ursi extracts is given.</p>
12

Brassica oleracea var. capitata: EXTRAÇÃO, CARACTERIZAÇÃO QUÍMICA E ATIVIDADE BIOLÓGICA DE METABÓLITOS SECUNDÁRIOS / Brassica oleracea var. capitata: EXTRACTION, CHEMICAL CHARACTERIZATION AND BIOLOGICAL ACTIVITY OF SECONDARY METABOLITES

Prá, Valéria Dal 22 July 2013 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The main objective of this work was to evaluate the antioxidant and antibacterial activities of extracts of Brassica oleracea var. capitata, obtained by supercritical CO2 and ultrasound-assisted extractions, as well as to carry out the characterization of these extracts using gas chromatography coupled with mass detector. For supercritical CO2, five extractions were performed to investigate the influence of pressure (10-25 MPa) and temperature (20-60°C) on the extraction yield, chemical composition and antioxidant activity towards peroxyl, superoxide and hydroxyl radicals. The highest extraction yield was 0.47% at 60 °C and 25 MPa. In the characterization of the extracts was possible to identify compounds like sulforaphane and iberin nitrile. All extracts showed antioxidant activity for the three radicals, although the highest activity for all radicals was obtained using the extract obtained at 60 °C and 25 MPa (run 2). For the ultrasound-assisted extraction were evaluated the effects of solvent concentration and temperature. The extracts obtained in the optimized extraction condition, were subjected to different hydrolysis conditions before use in biological assays. It was evaluated the antioxidant activity against DPPH, superoxide and peroxyl radicals, besides the antibacterial activity against S. aureus and E. coli. Both crude and hydrolyzed extracts were characterized by gas chromatography coupled with mass detector. The best condition for extraction was 30 ° C and 60% (w /v) of ethanol. All extracts showed antioxidant activity towards DPPH, superoxide and peroxyl radicals, but the use of hydrolyzed extracts improved considerably the antioxidant activities. Antibacterial activity was detected only in extracts hydrolysates Brassica oleracea var. capitata. The main contributions of this work were that the use of supercritical CO2 extraction to obtain bioactive compounds from Brassica oleracea var. capitata showed a promising alternative to conventional methods of extraction, since it allowed the extraction of compounds of interest in science and industry. Besides, in this work was demonstrated that the hydrolysis of extracts can increase the antioxidant activity of plant extracts. / O objetivo principal deste trabalho foi avaliar a atividade antioxidante e antibacteriana de extratos de Brassica oleracea var. capitata, obtidos a partir de extração supercrítica e extração por ultrassom, além de caracterizá-los por cromatografia gasosa acoplada à detector de massas. Para os compostos bioativos apolares de Brassica oleracea var. capitata, utilizou-se extração com CO2 supercrítico e avaliou-se o potencial antioxidante dos extratos. Foram realizadas cinco extrações para investigar a influência da pressão (10 - 25 MPa) e temperatura (20 - 60°C) no rendimento da extração, na composição química e na atividade antioxidante frente os radicais peroxila, superóxido e hidroxila. Obteve-se o maior rendimento de extração 0,47% a 60 °C e 25 MPa. Na caracterização dos extratos foi possível a identificação de compostos como sulforafano e iberin nitrila. Todos os extratos apresentaram atividade antioxidante para os três radicais, porém a maior atividade para todos os radicais foi o extrato obtido a 60°C e 25 MPa. Para os compostos bioativos polares, otimizou-se a extração assistida por ultrassom. Os extratos obtidos nas melhores condições de extração foram submetidos a diferentes condições de hidrólise, antes da sua utilização nos ensaios biológicos. Avaliou-se a atividade antioxidante, frente ao radical DPPH, superóxido e peroxila, além da atividade antibacteriana, frente a S.aureus e E.coli. Tanto os extratos brutos quanto os hidrolisados, foram caracterizados por cromatografia gasosa acoplada à detector de massas. A melhor condição de extração foi a 30ºC e 60% (m/v) de etanol. Todos os extratos apresentaram atividade antioxidante frente aos radicais DPPH, superóxido e peroxila, mas o uso de extratos hidrolisados melhorou consideravelmente a atividade antioxidante. Em relação à atividade antibacteriana, apenas uma amostra, que foi submetida à condição de hidrólise alcalina apresentou ação frente a E.coli. Uma das principais contribuições deste trabalho foi que a utilização de extração com CO2 supercrítico, para obtenção de compostos bioativos de Brassica oleracea var. capitata, mostrou ser uma alternativa promissora em relação aos métodos convencionais de extração, pois permitiu a extração de compostos com interesse científico e industrial. Além disso, foi demonstrado que a hidrólise dos extratos pode aumentar consideravelmente a atividade antioxidante de extratos vegetais em relação aos extratos brutos.
13

Estudo dos processos de extração do óleo de candeia (Eremanthus erythropappus) com fluidos pressurizados e solvente assistido por ultrassom / Study of candeia (Eremanthus erythropappus ) oil extraction with pressurized fluids and ultrasound-assisted solvente

Santos, Kátia Andressa 02 March 2018 (has links)
Submitted by Marilene Donadel (marilene.donadel@unioeste.br) on 2018-04-27T00:49:59Z No. of bitstreams: 1 Katia_A_Santos_2018.pdf: 1940481 bytes, checksum: dd10357b3e5c25bdf7e64bb4148af513 (MD5) / Made available in DSpace on 2018-04-27T00:49:59Z (GMT). No. of bitstreams: 1 Katia_A_Santos_2018.pdf: 1940481 bytes, checksum: dd10357b3e5c25bdf7e64bb4148af513 (MD5) Previous issue date: 2018-03-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Candeia (Eremanthus erythropappus) is a native species of the Brazilian Atlantic forest from which an essential oil with high concentration of sesquiterpene α-bisabolol is extracted. α-Bisabolol is an active principle of important application in the cosmetic and pharmaceutical industries due to its anti-inflammatory, antispasmodic, sedative, antiallergic, anti-irritant, cicatrizant and vermifugal properties. Steam distillation is the most common method used to obtain this oil, with requires long periods of time extraction besides the degradation of thermosensitive compounds. Within this context, the aim of this study was to evaluate the quality of the candeia wood oils obtained by non-conventional methods of extraction (supercritical technology by using carbon dioxide and cosolvents, pressurized liquid and ultrasound-assisted extraction), in terms of oil yield, bisabolol content and antioxidant activity. In addition, the oil re-extraction from the industrial residue was also evaluated. The extractions were carried out with CO2 at temperatures of 40, 55 and 70 oC and pressures of 160, 200 and 240 bar, with a solvent mass flow rate of 1.96 x 10−3 kg min−1 and 120 min of total extraction. The highest extraction yield obtained was 1.42 wt% for the candeia wood and 0.41 wt% for the residue, both at 70 oC and 240 bar, and this condition was selected to perform the extractions using cosolvents. Ethanol and ethyl acetate were added to supercritical CO2 at concentrations of 1, 3 and 5 % (v/v), obtaining up to 2.35 wt% of yield. The Soxhlet (360 min) and pressurized liquid (40, 55 and 70 oC; 100 bar and 20 min) extractions showed the affinity of the candeia compounds for polar solvents and the positive effect of the temperature on the yield, which varied from 0.53 to 7.23 wt%. A Box-Benhken design was employed to evaluate the effect of the variables temperature (40, 50 and 60 oC), n-hexane volume to wood mass (10, 15 and 20 mL g-1) and nominal power (150, 300 and 450 W) on the yield of ultrasound-assisted extractions, obtaining in 7 minutes of extraction, up to 83% of the yield obtained in the conventional technique in Soxhlet (1.57 wt%), with a solvent volume 2.5 times smaller. The major compounds identified in the candeia oil were the sesquiterpenes α-bisabolol, eremanthin and costunolide, and the α-bisabolol content in the oil is favored by the lowest CO2 density, with 74.45 % being obtained for the candeia wood and 50.62 % for the residue, in both cases in oil extracted at 70 oC and 160 bar. The addition of ethanol and ethyl acetate cosolvents to CO2 increased the α-bisabolol yield by 41 %. Also, the cosolvents increased the amount of total phenolic content in the oil, and consequently, its antioxidant capacity. The oil fractionation by column chromatography was efficient for α-bisabolol isolation. However, unlike the candeia wood oil, this compound was not effective in inhibiting the Staphylococcus aureus growth. In relation to the supercritical extractions, the Sovová mathematical model presented a good adjustment to the experimental data for all the conditions used. / A candeia (Eremanthus erythropappus) é uma árvore nativa da Mata Atlântica da qual se extrai um óleo essencial com elevada concentração do sesquiterpeno α-bisabolol, princípio ativo de grande aplicação nas indústrias de cosméticos e farmacêutica devido às suas propriedades anti-inflamatória, antiespasmódica, sedativa, antialérgica, anti-irritante, cicatrizante e vermífuga. A obtenção deste óleo em escala industrial é realizada pelo processo de destilação por arraste a vapor, com elevado tempo de extração, além da degradação de compostos termossensíveis. Neste contexto, o presente trabalho tem como objetivo avaliar a qualidade dos óleos da madeira de candeia, obtidos por métodos não convencionais de extração (tecnologia supercrítica com dióxido de carbono e cossolventes, líquidos pressurizados e solvente assistido por ultrassom), em termos de rendimento, teor de α-bisabolol e atividade antioxidante. Ainda, avaliar a re-extração do óleo do resíduo industrial. As extrações foram realizadas com CO2 nas temperaturas de 40, 55 e 70 oC e pressões de 160, 200 e 240 bar, com vazão mássica de solvente de 1,96 x 10-3 kg min-1 e tempo total de 120 minutos. O maior rendimento obtido para o óleo da candeia nas extrações supercríticas foi de 1,42 % e de 0,41 % para o resíduo, ambos em 70 oC e 240 bar, condição selecionada para os experimentos com cossolventes. Os solventes etanol e acetato de etila foram utilizados nas concentrações de 1, 3 e 5 % (v/v) junto ao CO2, proporcionando rendimentos de até 2,35 %. As extrações Soxhlet (360 min) e com líquidos pressurizados (40, 55 e 70 oC; 100 bar e 20 min) evidenciaram a afinidade dos compostos por solventes polares e o efeito positivo da temperatura sobre o rendimento, de 0,53 a 7,23 %. Um planejamento Box-Behnken foi empregado para avaliar efeitos da temperatura (40, 50 e 60 oC), razão volume de n-hexano/massa de madeira (10, 15 e 20 mL g-1) e potência ultrassônica nominal do equipamento (150, 300 e 450 W) sobre rendimento em óleo, obtendo-se, em 7 minutos de extração, até 83 % do rendimento obtido na técnica convencional em Soxhlet (1,57 %), com volume de solvente 2,5 vezes menor. Os compostos majoritários identificados no óleo da candeia foram os sesquiterpenos α-bisabolol, eremantina e costunolida, e o conteúdo do α-bisabolol no óleo foi favorecido pela menor densidade do CO2 supercrítico, sendo de até 74,5 % para a madeira de candeia e 50,6 % para o resíduo, ambos extraídos na condição de 70 oC e 160 bar. A adição dos cossolventes etanol e acetato de etila ao CO2 elevou o rendimento de α-bisabolol em até 41 %. Também aumentaram a quantidade de fenólicos totais no óleo e, consequentemente, sua capacidade antioxidante. O fracionamento do óleo por cromatografia em coluna foi eficiente para o isolamento do α-bisabolol. No entanto, diferentemente do óleo da madeira de candeia, este composto não foi efetivo na inibição do crescimento de Staphylococcus aureus. Em relação às cinéticas das extrações supercríticas, o modelo matemático de Sovová se ajustou aos dados experimentais em todas as condições utilizadas.
14

Caractérisation des fruits et de la pulpe de six accessions de Mammea americana : Aptitude à la transformation des fruits et caractérisation des composés phénoliques de la pulpe / Pulp and fruits characterization of six Mammea americana accessions. : Suitability for food processing and characterization of the phenolic compounds of the pulp

Péroumal, Armelle 10 January 2014 (has links)
Dans cette étude, nous nous sommes intéressés aux propriétés physiques et chimiques de six accessions de Mammea americana afin de pouvoir identifier les accessions les plus prometteuses pour la vente en frais ou la transformation. Nous avons également cherché à évaluer l’activité antioxydante de la pulpe, identifier et quantifier ses composés phénoliques et optimiser leur extraction à l’aide de la technique assistée par ultrasons.Nos résultats montrent que les accessions étudiées présentent des caractéristiques physiques, physico-chimiques et fonctionnelles significativement différentes. Pavé 11, Lézarde et Ti Jacques sont intéressants pour la vente en frais, en raison de leurs fruits sucrés avec une teneur élevée en caroténoïdes et composés phénoliques totaux. Sonson, Pavé 11 et Lézarde présentent une adaptabilité à la transformation. La composition polyphénolique de la pulpe déterminée par HPLC-DAD et UPLC-MS, a mis en évidence la présence d’acides phénoliques, de tanins condensés, de flavonols et flavanols dans nos échantillons. D’autre part, les tests d’activité antioxydante (DPPH et ORAC) révèlent que Ti jacques est l’extrait le plus actif. Un plan d’expérimentation a été mis en œuvre afin d’optimiser l’extraction des polyphénols à l’aide d’une technique d’extraction assistée par ultrasons. Les résultats montrent que l’extrait obtenu est riche en polyphénols et contient les mêmes teneurs en acides phénoliques et flavonols comparé à celui obtenu par la méthode conventionnelle. De plus, l’extrait obtenu à l’aide d’un solvant « vert » possède de bonnes propriétés organoleptiques. / Our work focuses on the physical and chemical properties of six mamey apple cultivars in order to select elite cultivars suitable for food processing or as table fruit. The antioxidant activity of the fruit pulp, the identification and quantification of the polyphenols responsible for it, and ultrasound assisted extraction method were also investigated.According to our results, the postharvest routes for every cultivar could be different. Pavé 11, Lézarde and Ti Jacques were found to be good for consumption, giving sweeter fruits with high total phenolic and carotenoid contents. Sonson, pavé 11 and Lézarde had suitable characteristics for the manufacturing of mamey products. The polyphenolic composition of the pulp determined by HPLC-DAD and UPLC-MS showed the presence of phenolic acids, condensed tannins, flavonols and flavanols. The results of the antioxidant test (DPPH and ORAC) point out that the most antioxidant cultivar was Ti Jacques. The design and optimization of the ultrasound assisted extraction method has done for polyphenols extraction. The results showed that the polyphenols rich extract contains the same content of phenolic acids and flavonols in comparison to the conventional method. Additionally, the dry extract obtained with a “green” solvent, had good organoleptic properties.
15

Mise au point des espèces du genre Stephania au Cambodge : études systématique, phytochimique et pharmacologique / Update on the species of the genus Stephania in Cambodia : systematic, phytochemical and pharmacological studies

Dary, Chhavarath 18 July 2016 (has links)
L’objectif de la thèse est une mise au point des espèces de Stephania répertoriées au Cambodge par l’étude systématique, phytochimique et pharmacologique. Du point de vue systématique, les travaux ont permis de répertorier sept espèces et deux variétés de Stephania au Cambodge : S. cambodica, S. japonica var. discolor et var. timoriensis, S. oblata, S. pierrei, S. rotunda (espèce-type), S. suberosa, et S. venosa. La clef de détermination établie lors de ce travail de thèse permet d’identifier ces espèces. D’après les résultats phylogénétiques, seul S. pierrei est monophylétique, ce qui représente moins de 10% des espèces de Stephania. L’étude chimique de cinq espèces a été réalisée par des méthodes chromatographiques (CLHP, UCLHP) et des méthodes spectroscopiques. Différents alcaloïdes ont été proposés comme marqueurs : la palmatine, la roémérine et la tétrahydropalmatine pour S. cambodica et S. rotunda, la cépharanthine, la tétrahydropalmatine et la xylopinine pour S. suberosa, la cépharanthine pour S. pierrei, la crébanine, et la tétrahydropalmatine pour S. venosa. Neuf alcaloïdes ont été isolés à partir du tubercule de S. cambodica, dont un nouveau composé dénommé «angkorwatine ». Une méthode d’éco-extraction des alcaloïdes assistée par ultrasons a été mise au point et optimisée par un plan d’expérience pour cette espèce. Une méthode analytique par UCLHP a été développée et validée pour le contrôle qualité de S. cambodica. Les résultats montrent que les extraits hydroéthanoliques obtenus par macération à partir du tubercule de S. suberosa, S. venosa et S. rotunda présentent une activité anti-inflammatoire importante (in vitro) avec un ratio anti-inflammatoire élevé. / The thesis aims to provide update on species of the genus Stephania recorded in Cambodia by systematic, phytochemical and pharmacological studies.The systematic study allowed to list seven species and two varieties of Stephania in Cambodia: S. cambodica, S. japonica var. discolor and var. timoriensis, S. oblata, S. pierrei, S. rotunda (type species), S. suberosa and S. venosa. The presence of S. japonica var. timoriensis and S. oblata is reported for the first time in Cambodia. According to the phylogenetic results, only S. pierrei is monophyletic, which represents less than 10% of species in the genus Stephania. Chemical studies on the tubers of five species were carried out using chromatographic methods (HPLC, UHPLC) and spectroscopic methods. Different isolated alkaloids have been proposed as markers: palmatine, roemerine and tetrahydropalmatine for S. cambodica and S. rotunda, cepharanthine, tetrahydropalmatine, and xylopinine for S. suberosa, cepharanthine for S. pierrei, crebanine, and tetrahydropalmatine for S. venosa. Nine alkaloids belonging to five classes were isolated from the tuber of S. cambodica and a new compound namely "angkorwatine" was described. Ultrasound assisted extraction of alkaloids was developed and optimized by Design of Experiment for this species. This innovative extraction is a good alternative to conventional methods. An analytical UHPLC method was developed and validated for the quality control of S. cambodica. Results show that hydroethanolic extracts obtained by maceration of S. suberosa, S. rotunda and S. venosa exhibit significant anti-inflammatory activity with high anti-inflammatory ratio (selectivity index).
16

Savremene metode ekstrakcije očajnice (Marrubium vulgare L.) i sušenje odabranih ekstrakata, hemijski sastav i biološke aktivnosti / Contemporary methods of extraction of white horehound (Marrubium vulgare L.) and drying of selected extracts, chemical composition and biological activities

Gavarić Aleksandra 11 December 2020 (has links)
<p>U okviru ove disertacije ispitane su mogućnosti primene savremenih metoda za dobijanje tečnih ekstrakata (ultrazvučna ekstrakcija, mikrotalasna ekstrakcija i ekstrakcija subkritičnom vodom) i lipofilnih ekstrakata (ekstrakcija superkritičnim ugljendioksidom) bogatih polifenolima iz nadzemnog dela očajnice (Marrubium vulgare L.). Tečni ekstrakti su optimizovani primenom eksperimentalnog dizajna i metode odzivne povr&scaron;ine, i podvrgnuti su spray drying tehnici su&scaron;enja. Tečni i suvi ekstrakti su detaljno ispitani po pitanju hemijskog sastava i biolo&scaron;ke aktivnosti, antimikrobne i in vitro antihiperglikemijske aktivnosti.<br />Za svaku od navedenih ekstrakcionih tehnika ispitan je uticaj glavnih parametara: ultrazvučna ekstrakcija (temperatura, vreme ekstrakcije i snaga ultrazvuka), mikrotalasna ekstrakcija (koncentracija etanola, vreme ekstrakcije i snaga mikrotalasa) i ekstrakcija subkritičnom vodom (temperatura, vreme ekstrakcije i koncentracija HCl u ekstragensu). Kod tečnih ekstrakata dobijenih ultrazvučnom i mikrotalasnom ekstrakcijom na optimizovanim uslovima utvrđeno je prisustvo hlorogenske kiseline i kvercetina koji nisu detektovani u maceratima. Ispitana je antimikrobna aktivnost oba ekstrakta i utvrđeno da je B. cereus najosetljiviji bakterijski soj, dok je u slučaju kvasaca S. cerevisiae posebno osetljiv na oba ekstrakta. Pored ove aktivnosti ispitana je i in vitro antihiperglikemijska aktivnost oba ekstrakta prema &alpha;-amilazi i &alpha;-glukozidazi, pri čemu ultrazvučni ekstrakt pokazuje veću antihiperglikemijsku aktivnost (50,63% inhibira &alpha;-amilazu i 48,67% inhibira &alpha;-glukozidazu) &scaron;to se potencijalno može objasniti prisustvom hlorogenske kiseline (33,11 &mu;g/mL) i kvercetina (34,88 &mu;g/mL). U subkritičnom ekstraktu, dobijenom na optimalnim uslovima, detektovano je jedino prisustvo hidroksi metilfurfurala usled čega ovaj ekstrakt nije podvrgnut ispitivanju antimikrobne i antihiperglikemijske aktivnosti.<br />U cilju ekstrakcije lipofilnih komponenata M. vulgare primenjene su destilacija etarskog ulja (0,05%), Soxhlet ekstrakcija (3,23%) i ekstrakcija superkritičnim ugljendioksidom na pritiscima 100, 200 i 300 bar i temperaturama 40, 50 i 60 &deg;C. Najdominantnija komponenta u svim dobijenim superkritičnim ekstraktima je hemotaksonomski marker marubiin koji nije identifikovan u Soxhlet ekstraktu.<br />Tečni ekstrakti dobijeni ultrazvučnom i mikrotalasnom ekstrakcijom na optimizovanim uslovima i macerat su osu&scaron;eni spray drying tehnikom (uz dodatak 10 i 50% maltodekstrina) u cilju dobijanja stabilnije forme suvog ekstrakta. Suvim ekstraktima su određene najznačajnije fizičke osobine i hemijski sastav kao i antimikrobna i antihiperglikemijska aktivnost kako bi se procenila mogućnost njihove inkorporacije u funkcionalnu hranu, dijetetske suplemente ili u formulaciji različitih gotovih proizvoda koji se primenjuju preventivno ili radi pobolj&scaron;anja zdravlja ljudi.</p> / <p>Within the scope of this dissertation, the possibilities of applying modern methods for obtaining liquid (ultrasonic extraction, microwave extraction and subcritical water extraction) and lipophilic extracts (extraction with supercritical carbon dioxide) rich in polyphenols from the aboveground part of white horehound (Marrubium vulgare L.) were examined. Liquid extracts were optimized using an experimental design and response surface method, and subjected to spray drying. Liquid and dry extracts have been extensively examined for their chemical composition and biological activity, antimicrobial and in vitro antihyperglycaemic activities.<br />For each of these extraction techniques, the influence of the main parameters was examined: ultrasonic extraction (temperature, extraction time and ultrasound power), microwave extraction (ethanol concentration, extraction time and microwave power) and subcritical water extraction (temperature, extraction time and HCl concentration in the extractant). Liquid extracts obtained by ultrasonic and microwave extraction under optimized conditions revealed the presence of chlorogenic acid and quercetin, which were not detected in macerates. The antimicrobial activity of both extracts was examined and B. cereus was found to be the most sensitive bacterial strain, whereas in the case of yeast S. cerevisiae was particularly sensitive to both extracts. In addition to this activity, the in vitro antihyperglycaemic activities of both extracts against &alpha;-amylase and &alpha;-glucosidase were investigated, with ultrasound extract showing higher antihyperglycemic activity (50.63% inhibited &alpha;-amylase and 48.67% inhibited &alpha;-glucosidase) which could potentially be explained by the presence of chlorogenic acid (33.11 &mu;g/mL) and quercetin (34.88 &mu;g/mL). In the subcritical extract, obtained under optimal conditions, only the presence of hydroxy methylfurfural was detected, and this extract was not subjected to antimicrobial and antihyperglycemic activity.<br />For the extraction of lipophilic components of M. vulgare, distillation of essential oil (0.05%), Soxhlet extraction (3.23%) and extraction with supercritical carbon dioxide at pressures of 100, 200 and 300 bar and at temperatures of 40, 50 and 60 &deg; C were applied. The most dominant component in all the supercritical extracts obtained is the chemotaxonomic marker marubiin, which was not identified in the Soxhlet extract.<br />The liquid extracts obtained by the ultrasound and microwave extraction under optimized conditions and the macerate were spray dried (with the addition of 10 and 50% maltodextrin) to obtain a more stable form of the dry extract. Dry extracts underwent determination of the most important physical properties and chemical composition as well as antimicrobial and antihyperglycemic activities to evaluate their incorporation into functional foods, dietary supplements or in the formulation of various finished dosage forms that are administered preventively or to improve human health.</p>

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