No description available.

農林水産研究情報センターで作成したPDFファイルを使用している。

Stuttgart, Univ., Diss., 2002.

Universiẗat, Diss., 2002--Stuttgart.

Cecropia obtusa é popularmente utilizada na Amazônia para vários fins medicinais, e possui atividade antioxidante comprovada por diferentes metodologias. Neste trabalho objetivou-se caracterizar o extrato; avaliar o potencial fotoquimioprotetor; separar os constituintes por CLAE; identificar os constituintes majoritários e desenvolver formulações tópicas. O conteúdo de polifenóis e flavonoides totais foi de 371,5 mg EGA/g e 66,68 mg EQ/g, respectivamente, e os IC50 para os radicais DPPHo, O2 o- e 1O2 foram, respectivamente1,83, 0,34 e 0,55 ?g/mL, respectivamente. Para o radical OHo, 125 ?g/mL de extrato foi capaz de inibir a formação do radical em 35,48%. O extrato demonstrou fotoestabilidade e capacidade de absorver a radiação UVB e UVA-II. O FPS calculado pela metodologia de Mansur e estimado pelo experimento de fotoproteção em cultura de células foi de 16. O método analítico cromatográfico apresentou boa resolução e separação, sendo linear para o intervalo de 5 a 125 ?g/mL e apresentando coeficientes de variação que variaram de 3,12% a 4,51%. Através da espectrometria de massas foi possível sugerir a presença do ácido clorogênico e três flavonas-C-heterosídicas (duas luteolinas-C-heterosídicas e uma apigenina-C-heterosídicas). Em cultura de células HaCaT submetidas à radiação UVA, o extrato diminuiu a produção de espécies reativas do oxigênio, protegeu contra o processo de peroxidação lipídica e contra a depleção da glutationa reduzida induzidos pela radiação, além de proteger contra a diminuição da atividade das enzimas catalase e superóxido dismutase. Em cultura de fibroblastos humanos submetidos à radiação UVA/UVB, o tratamento com o extrato forneceu maior proteção do que o ácido clorogênico contra o aumento da proteína carbonilada. O extrato foi capaz de retornar o conteúdo de ácido hialurônico ao nível basal enquanto o tratamento com ácido clorogênico foi capaz de aumentar acima do nível basal. Em relação ao conteúdo de colágeno, tanto o extrato quanto o ácido clorogênico foram capazes de retornar os valores ao nível basal da célula. O extrato também foi capaz de diminuir a atividade da enzima metaloproteinase enquanto o ácido clorogênico não exibiu efeito. Em relação às formulações desenvolvidas, as mudanças mais significativas nos parâmetros de estabilidade avaliados foram para as formulações incubadas a 40?C: o decréscimo da atividade antioxidante em aproximadamente 40% entre 0 e 2 meses, a diminuição do pH abaixo do limite de estabilidade do agente de viscosidade e, para a reologia, o aumento da área de histerese entre 4 e 6 meses. A formulação com oleato de isodecila dobrou a quantidade de extrato penetrada na pele em 12 e 6 horas, em comparação com as outras duas formulações, além de ter mantido a atividade de absorção da radiação. O extrato apresentou atividade fotoquimioprotetora e a formulação promoveu a penetração do extrato e manteve a atividade de absorção da radiação, sugerindo a incorporação do extrato de C. obtusa em formulações contendo filtros, visando aumentar o espectro de absorção e promover um efeito atenuador do estresse oxidativo na pele. / Cecropia obtusa is commonly used in Amazon with different medicinal purposes and the antioxidant activity of this specie has been proved by different methodologies. The aim of this work was: to characterize the purified extract of C. obtusa; to evaluate the photochemoprotective effect in cell culture; develop an HPLC methodology to separate the extract\'s compounds; suggest the identification of the major compounds, and develop a stable formulation that would be able to penetrate on the skin to exert the antioxidant effect, besides absorbing the radiation. The contents of total polyphenols and flavonoids were 371.5 mg GAE/g and 66.68 mg QE/g, respectively, and the IC50 for the radicals DPPHo, O2 o- and 1O2 were respectively 1.83, 0.34 and 0.55 ?g/mL. For the OHo radical, 125 ?g/mL of extract was able to inhibit the radical formation by 35.48%. The extract was photo stable and exhibited the ability to absorb UVB and UVA-II radiation. The SPF calculated by the Mansur methodology and confirmed by the photoprotection experiment in cell culture was 16. The HPLC method exhibited good resolution and separation, being linear from 5 to 125 ?g/mL and presenting coefficients of variation ranging from 3.12% to 4.51%. By employing mass spectrometry, it was possible to suggest the presence of chlorogenic acid and three C-heterosidic flavones (two Cheterosidic luteolins and one C-heterosidic apigenin). In HaCaT culture exposed to UVA radiation, the extract decreased the production of reactive oxygen species, protected against the lipid peroxidation process and against the depletion of the reduced glutathione. In addition, extract also protected against the decrease in the activity of the enzymes catalase and superoxide dismutase. In human fibroblasts exposed to UVA/UVB radiation, the treatment with the extract provided higher protection than chlorogenic acid against the increase in the production of carbonyl protein. The extract was able to return the content of hyaluronic acid to the basal level while the treatment with chlorogenic acid was able to increase above the basal level. Regarding the collagen content, both the extract and the chlorogenic acid were able to return the values to the basal level of the cell. The extract was also able to decrease metalloproteinase activity, while chlorogenic acid had no effect. Regarding the developed formulations, the most significant changes in the stability parameters were for the formulations incubated at 40°C: the decrease in the antioxidant activity, which was, approximately, 40% between 0 and 2 months, and the increase of hysteresis area and decrease of the pH below the limit for the viscosity agent, between 4 and 6 months. The formulation with isodecyl oleate doubled the amount of extract penetrated into the skin in 12 and 6 hours compared with the other two formulations. The extract exhibited photochemoprotective effect, and the formulation penetrated on the skin, besides absorbing the UV radiation, which suggests the incorporation of C. obtusa extract in formulations containing filters, aiming to increase the absorption spectrum and to attenuate the oxidative stress in the skin.

Grindžiant sąsajas tarp ežero ir paežerės ekosistemų ir remiantis tuo, kad medžių lapų paklotės irimo produktai yra alochtoninės ištirpusios organinės anglies (IOA) šaltinis, buvo tiriamas paprastojo buko (Fagus sylvatica L.) ir paprastojo ąžuolo (Querqus robur L.) lapų vandeninių ekstraktų poveikis žvaigždėtojo maurašakio (Nitellopsis obtusa (Desv.) J. Groves) ląstelei fermentiniu, plazmalemos ir ląstelės gyvybingumo lygmeniu. Koncentracinėmis ir laiko priklausomybėmis parodyta, kad ekstraktai, tarp jų ir gauti per 30 dienų savaiminio lapų irimo, sukelia oksidacinio streso fermentų aktyvumo ir ląstelės membranos potencialo pakitimus bei ląstelių žūtį – taip preziumuojamas priežastinis ryšys tarp ankstyvųjų reakcijų ir letalumo. Santykinai jautresnės reakcijos vyko fermentiniame lygmenyje, negrįžtamiems ląstelės membranos ramybės potencialo pokyčiams ir mirtingumui aptikti reikia didesnių nei aptinkamų gamtiniuose vandens telkiniuose IOA koncentracijų arba ilgesnės poveikio trukmės. Tai leidžia manyti, kad paklotės lapai yra svarbus aplinkos veiksnys, turintis įtakos vandens augalijos rūšinei įvairovei gėlavandenėse ekosistemose. / Aqueous extracts of common beech (Fagus sylvatica L.) and European oak (Quercus robur L.) leaves from leaf litter were used as allochthonous source of dissolved organic carbon (DOC) to investigate cell response of starry stonewort (Nitellopsis obtusa (Desv.) J. Groves) at enzymatic, cell membrane and whole cell levels. Dose and time dependent exposure experiments with leaf litter extracts including 30 day leaf litter degradation ones, were carried out to show activity modulations of oxidative stress enzymes, cell resting potential (RP) and survivorship. Charophytes manifested a certain level of antioxidative resilience depending on the DOC source. Relatively more sensitive reactions were detected at enzymatic level, however, to identify irreversible cell RP changes and lethality, higher than those of natural aquatic bodies DOC concentrations or prolonged exposure were needed. Changes in activities of oxidative stress enzymes and cell membrane potential invoked by extracts predicted cell mortality, which allowed us to presume causality between more sensitive initial reactions and lethality. By linking lake and lake shore ecosystems it was concluded that beech and oak leaf litter has the potential to adversely affect algae and, thus, might eventually be important environmental factor impacting aquatic vegetation species diversity in freshwater ecosystems.

Aqueous extracts of common beech (Fagus sylvatica L.) and European oak (Quercus robur L.) leaves from leaf litter were used as allochthonous source of dissolved organic carbon (DOC) to investigate cell response of starry stonewort (Nitellopsis obtusa (Desv.) J. Groves) at enzymatic, cell membrane and whole cell levels. Dose and time dependent exposure experiments with leaf litter extracts including 30 day leaf litter degradation ones, were carried out to show activity modulations of oxidative stress enzymes, cell resting potential (RP) and survivorship. Charophytes manifested a certain level of antioxidative resilience depending on the DOC source. Relatively more sensitive reactions were detected at enzymatic level, however, to identify irreversible cell RP changes and lethality, higher than those of natural aquatic bodies DOC concentrations or prolonged exposure were needed. Changes in activities of oxidative stress enzymes and cell membrane potential invoked by extracts predicted cell mortality, which allowed us to presume causality between more sensitive initial reactions and lethality. By linking lake and lake shore ecosystems it was concluded that beech and oak leaf litter has the potential to adversely affect algae and, thus, might eventually be important environmental factor impacting aquatic vegetation species diversity in freshwater ecosystems. / Grindžiant sąsajas tarp ežero ir paežerės ekosistemų ir remiantis tuo, kad medžių lapų paklotės irimo produktai yra alochtoninės ištirpusios organinės anglies (IOA) šaltinis, buvo tiriamas paprastojo buko (Fagus sylvatica L.) ir paprastojo ąžuolo (Querqus robur L.) lapų vandeninių ekstraktų poveikis žvaigždėtojo maurašakio (Nitellopsis obtusa (Desv.) J. Groves) ląstelei fermentiniu, plazmalemos ir ląstelės gyvybingumo lygmeniu. Koncentracinėmis ir laiko priklausomybėmis parodyta, kad ekstraktai, tarp jų ir gauti per 30 dienų savaiminio lapų irimo, sukelia oksidacinio streso fermentų aktyvumo ir ląstelės membranos potencialo pakitimus bei ląstelių žūtį – taip preziumuojamas priežastinis ryšys tarp ankstyvųjų reakcijų ir letalumo. Santykinai jautresnės reakcijos vyko fermentiniame lygmenyje, negrįžtamiems ląstelės membranos ramybės potencialo pokyčiams ir mirtingumui aptikti reikia didesnių nei aptinkamų gamtiniuose vandens telkiniuose IOA koncentracijų arba ilgesnės poveikio trukmės. Tai leidžia manyti, kad paklotės lapai yra svarbus aplinkos veiksnys, turintis įtakos vandens augalijos rūšinei įvairovei gėlavandenėse ekosistemose.

農林水産研究情報センターで作成したPDFファイルを使用している。

農林水産研究情報センターで作成したPDFファイルを使用している。

農林水産研究情報センターで作成したPDFファイルを使用している。