Thesis (Ph. D.)--University of Michigan.

Dissertation (Ph.D.)--University of Michigan

<p>To examine cyclooxygenase-2 (COX-2) inhibitory effects of natural compounds and structurally related compounds, a radiochemical assay for measuring inhibition of COX-2 and COX-1 catalysed prostaglandin biosynthesis was optimised. That process resulted in the development of a reliable assay for finding COX-2 inhibitors in plants, and for investigating plant constituents pertaining to the inhibition of COX-2 and COX-1. </p><p>By means of bioassay-guided isolation of the plant Plantago major L., several inhibitors of COX-2 were found: ursolic, oleanolic, a-linolenic and linoleic acid. Subsequently, structural derivatives of these triterpenoids and fatty acids were investigated. The polyunsaturated and the thioether containing fatty acids were the most potent COX-2 and COX-1 inhibitors, with a-linolenic and all-(Z)-5-thia-8,11,14,17-eicosatetraenoic acid expressing selectivity toward COX-2. </p><p>For rapid evaluation of plant constituents, a COX-2 assay using scintillation proximity assay-technology was used to evaluate 49 ubiquitous plant metabolites of different biosynthetic origin for inhibition of COX-2. Eugenol, cinnamaldehyde, and pyrogallol expressed inhibition. Later, in an attempt to find COX-2 inhibitors in plants, but without prior purification, several approaches to the surface plasmon resonance technique were examined, with the measurement of prostaglandin E2 being most successful.</p><p>In mouse macrophage cells, two fatty acids were analysed for effects on COX-2 and iNOS, mRNA, protein, prostaglandin E2, and nitrite levels. 5-Thia-8,11,14,17-eicosatetraenoic acid decreased COX-2 protein expression.</p><p>This thesis contributes to our growing knowledge of methods for measuring COX-2 inhibition, and also knowledge of COX-2 inhibitory effects of commonly occurring compounds in plants, herbal drugs and functional food. Thus the experimental results can facilitate future searches for new COX-2 inhibitors of natural origin.</p>

<p>In inflammatory events, the cyclooxygenase-2 enzyme (COX-2) catalyses prostaglandin biosynthesis. This is a process, which could possibly be affected by natural compounds including those abundant in food. Two systems have been established to enable investigations of the effects of natural compounds on COX-2. The first method developed was an in vitro method suitable for measuring inhibition of COX-2 catalysed prostaglandin E₂ biosynthesis, based on scintillation proximity assay technology. The second system established, comprises a cell model, suitable for studying the effects of compounds on COX-2 and inducible nitric oxide synthase (iNOS) at different cellular levels, including the effects on mRNA, protein, prostaglandin E₂ and nitrite levels.</p><p>The plants, <i>Plantago major</i> L. and <i>Urtica dioica</i> L., were subjected to bioassay-guided isolation and fatty acids, e.g. α-linolenic acid and linoleic acid, were isolated as COX-2 inhibitory principles. The effects of structurally related fatty acids were also studied and the most potent COX-2 inhibitors were eicosapentaenoic acid and its synthetic derivative all-(<i>Z</i>) -5-thia-8,11,14,17-eicosatetraenoic acid. The latter was also found to decrease COX-2 protein levels assessed by the cell model. The inhibitory effects on COX-2 catalysed prostaglandin biosynthesis of 49 plant metabolites with different biosynthetic origin were studied. The phenolic compounds, eugenol, pyrogallol, but also cinnamaldehyde, were found to inhibit COX-2.</p><p>Recently, COX-2 has attracted attention because of its involvement in cancer. The compounds in our diet are suggested to play an important role in the aetiology of colon cancer. To investigate the influence of diet on COX-2 in relation to colon cancer cells, a number of human faecal water samples were assessed for their effects on COX-2 enzymatic activity and protein synthesis. Of the faecal waters tested, two samples exhibited a weak inhibitory effect on COX-2 enzymatic activity, and one sample decreased COX-2 protein levels in a colon cancer cell line. The chemical content of faecal water was analysed and a variety of phenolic compounds were identified, including flavonoids and phenolic acids. Hitherto, a number of the identified compounds in faecal water have been assessed for the effects on COX-2, but none of the tested compounds were found to be responsible for the observed effects of faecal water on COX-2. Moreover, the cytotoxic effects of natural COX-2 inhibitors, traditional non-steroidal anti-inflammatory drugs, and the selective COX-2 inhibitor rofecoxib were evaluated using a human cancer cell line panel. Of the compounds tested, curcumin was found to be most potent.</p><p>This thesis contributes to increase the general knowledge of the effects on COX-2 of commonly occurring plant constituents, including fatty acids and phenolic compounds. As natural parts of our diet, these compounds, abundant in fruits and vegetables, may affect different targets in our bodies, including COX-2.</p>

To examine cyclooxygenase-2 (COX-2) inhibitory effects of natural compounds and structurally related compounds, a radiochemical assay for measuring inhibition of COX-2 and COX-1 catalysed prostaglandin biosynthesis was optimised. That process resulted in the development of a reliable assay for finding COX-2 inhibitors in plants, and for investigating plant constituents pertaining to the inhibition of COX-2 and COX-1. By means of bioassay-guided isolation of the plant Plantago major L., several inhibitors of COX-2 were found: ursolic, oleanolic, a-linolenic and linoleic acid. Subsequently, structural derivatives of these triterpenoids and fatty acids were investigated. The polyunsaturated and the thioether containing fatty acids were the most potent COX-2 and COX-1 inhibitors, with a-linolenic and all-(Z)-5-thia-8,11,14,17-eicosatetraenoic acid expressing selectivity toward COX-2. For rapid evaluation of plant constituents, a COX-2 assay using scintillation proximity assay-technology was used to evaluate 49 ubiquitous plant metabolites of different biosynthetic origin for inhibition of COX-2. Eugenol, cinnamaldehyde, and pyrogallol expressed inhibition. Later, in an attempt to find COX-2 inhibitors in plants, but without prior purification, several approaches to the surface plasmon resonance technique were examined, with the measurement of prostaglandin E2 being most successful. In mouse macrophage cells, two fatty acids were analysed for effects on COX-2 and iNOS, mRNA, protein, prostaglandin E2, and nitrite levels. 5-Thia-8,11,14,17-eicosatetraenoic acid decreased COX-2 protein expression. This thesis contributes to our growing knowledge of methods for measuring COX-2 inhibition, and also knowledge of COX-2 inhibitory effects of commonly occurring compounds in plants, herbal drugs and functional food. Thus the experimental results can facilitate future searches for new COX-2 inhibitors of natural origin.

In inflammatory events, the cyclooxygenase-2 enzyme (COX-2) catalyses prostaglandin biosynthesis. This is a process, which could possibly be affected by natural compounds including those abundant in food. Two systems have been established to enable investigations of the effects of natural compounds on COX-2. The first method developed was an in vitro method suitable for measuring inhibition of COX-2 catalysed prostaglandin E2 biosynthesis, based on scintillation proximity assay technology. The second system established, comprises a cell model, suitable for studying the effects of compounds on COX-2 and inducible nitric oxide synthase (iNOS) at different cellular levels, including the effects on mRNA, protein, prostaglandin E2 and nitrite levels. The plants, Plantago major L. and Urtica dioica L., were subjected to bioassay-guided isolation and fatty acids, e.g. α-linolenic acid and linoleic acid, were isolated as COX-2 inhibitory principles. The effects of structurally related fatty acids were also studied and the most potent COX-2 inhibitors were eicosapentaenoic acid and its synthetic derivative all-(Z) -5-thia-8,11,14,17-eicosatetraenoic acid. The latter was also found to decrease COX-2 protein levels assessed by the cell model. The inhibitory effects on COX-2 catalysed prostaglandin biosynthesis of 49 plant metabolites with different biosynthetic origin were studied. The phenolic compounds, eugenol, pyrogallol, but also cinnamaldehyde, were found to inhibit COX-2. Recently, COX-2 has attracted attention because of its involvement in cancer. The compounds in our diet are suggested to play an important role in the aetiology of colon cancer. To investigate the influence of diet on COX-2 in relation to colon cancer cells, a number of human faecal water samples were assessed for their effects on COX-2 enzymatic activity and protein synthesis. Of the faecal waters tested, two samples exhibited a weak inhibitory effect on COX-2 enzymatic activity, and one sample decreased COX-2 protein levels in a colon cancer cell line. The chemical content of faecal water was analysed and a variety of phenolic compounds were identified, including flavonoids and phenolic acids. Hitherto, a number of the identified compounds in faecal water have been assessed for the effects on COX-2, but none of the tested compounds were found to be responsible for the observed effects of faecal water on COX-2. Moreover, the cytotoxic effects of natural COX-2 inhibitors, traditional non-steroidal anti-inflammatory drugs, and the selective COX-2 inhibitor rofecoxib were evaluated using a human cancer cell line panel. Of the compounds tested, curcumin was found to be most potent. This thesis contributes to increase the general knowledge of the effects on COX-2 of commonly occurring plant constituents, including fatty acids and phenolic compounds. As natural parts of our diet, these compounds, abundant in fruits and vegetables, may affect different targets in our bodies, including COX-2.

No description available.

O objetivo deste trabalho foi estudar a atividade antioxidante de um extrato padronizado da raiz de Pothomorphe umbellata L. Miq, incorporado em diadermina (creme óleo em água - O/A), sobre a pele de camundongos Hairless e avaliar esta atividade antioxidante em comparação à atividade antioxidante do &#945;-tocoferol, incorporado na mesma base. A peroxidação lipídica foi avaliada como medida de TBARS e de quimiluminescência. Animais tratados com o extrato de Pothomorphe umbellata demonstraram um decréscimo significativo nos parâmetros de peroxidação lipídica, em concentrações de até 0,1% p/p de 4-nerolidilcatecol (o que equivale a uma concentração de 4% p/p de extrato) incorporado na diadermina. Em nosso modelo o decréscimo significativo destes indicadores, nos animais tratados com &#945;-tocoferol, só foi observado em concentrações superiores a 5%. Os resultados indicam uma potente atividade antioxidante do extrato da raiz de Pothomorphe umbellata, sugerindo sua aplicação em formulações cosméticas. / Antioxidants may play a significant role in ameliorating or preventing oxidative damage to skin. In this work antioxidant activity of P. umbellata root extract, with known concentration of 4-nerolidylcathecol, incorporated to a hydrophilic ointment in different concentrations, was evaluated on skin of Hairless mice. This antioxidant activity was compared with that of different concentrations of &#945;-tocopherol (Sigma) incorporated in the same vehicle. Lipid peroxidation of skin homogenates was evaluated as thiobarbituric acid reactants (TBARS) and chemiluminescense (CL). Animals treated with P. umbellata root extract showed a decrease up to 90% in the lipid peroxidation parameters, for concentrations higher than 0.1%. Our model demonstrated a significant decrease in TBARS an CL only for higher concentrations of &#945;-tocopherol (5 and 10% w/w). The results indicate a potent antioxidant activity of the Pothomorphe umbellata root extract, suggesting its application in cosmetic formulations.

Não consta resumo na publicação. / Chamaecrista nictans subsp.patellaria var. ramosa Irwin & Barneby (Cassia Patellaria Dc), popularly know as \"peninha\", \"mata-pasto\", \"falsa-sensitiva\" e \"falsa-dormideira\", is Brazilian plant of the family Leguminosae. It is considered a garden and plantation weed, but in folk medicine is used for kidney problems and renal calculi. In order to identify their plant as a drug the morfology, histology, phytochemical screening, caracterization of fluid extract and plant powder were studied. In phytochemical screening the presence of flavonoid, saponins, steroids, tanins and coumarins was detected. A pharmacological assay was also carried out to test effect of chronic treatment with fluid extract in the experimental urolithiases in rats, through the development of calculi by surgical insertion of a foreign body their bladder. In rats, the results showed that chronic treatment with the same dosage of that used in folk medicine had no influence on the stones formed.

O objetivo deste trabalho foi estudar a atividade antioxidante de um extrato padronizado da raiz de Pothomorphe umbellata L. Miq, incorporado em diadermina (creme óleo em água - O/A), sobre a pele de camundongos Hairless e avaliar esta atividade antioxidante em comparação à atividade antioxidante do &#945;-tocoferol, incorporado na mesma base. A peroxidação lipídica foi avaliada como medida de TBARS e de quimiluminescência. Animais tratados com o extrato de Pothomorphe umbellata demonstraram um decréscimo significativo nos parâmetros de peroxidação lipídica, em concentrações de até 0,1% p/p de 4-nerolidilcatecol (o que equivale a uma concentração de 4% p/p de extrato) incorporado na diadermina. Em nosso modelo o decréscimo significativo destes indicadores, nos animais tratados com &#945;-tocoferol, só foi observado em concentrações superiores a 5%. Os resultados indicam uma potente atividade antioxidante do extrato da raiz de Pothomorphe umbellata, sugerindo sua aplicação em formulações cosméticas. / Antioxidants may play a significant role in ameliorating or preventing oxidative damage to skin. In this work antioxidant activity of P. umbellata root extract, with known concentration of 4-nerolidylcathecol, incorporated to a hydrophilic ointment in different concentrations, was evaluated on skin of Hairless mice. This antioxidant activity was compared with that of different concentrations of &#945;-tocopherol (Sigma) incorporated in the same vehicle. Lipid peroxidation of skin homogenates was evaluated as thiobarbituric acid reactants (TBARS) and chemiluminescense (CL). Animals treated with P. umbellata root extract showed a decrease up to 90% in the lipid peroxidation parameters, for concentrations higher than 0.1%. Our model demonstrated a significant decrease in TBARS an CL only for higher concentrations of &#945;-tocopherol (5 and 10% w/w). The results indicate a potent antioxidant activity of the Pothomorphe umbellata root extract, suggesting its application in cosmetic formulations.