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Preparation and biological evaluation of new triterpene derivates of ursolic and oleanolic acid

Leal, Ana Sofia Mendes
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Tese de Doutorado
POR
Relevância na Pesquisa
46.61%
O cancro é uma das causas de morte mais comuns. Nos Estados Unidos, uma em cada quatro mortes é devida ao cancro. A Organização Mundial de Saúde prevê que em 2030, 30 milhões de mortes serão devidas a cancro. Estes dados remetem para a urgência na pesquisa de novas moléculas capazes de melhorar o tratamento e prevenção da doença oncológica. Os triterpenóides representam um grupo de compostos abundante e diversificado, que pode ser encontrado em plantas, frutas e vegetais. As plantas medicinais contendo triterpenóides tem constituído ao longo dos séculos uma base para a medicina tradicional no tratamento de diversas doenças. Triterpenóides como o ácido ursólico, o ácido oleanólico, a betulina, o ácido betulínico, o ácido maslínico e o ácido glicirretínico, foram isolados de extratos de plantas, demonstrando ter várias actividades biológicas, incluindo a anti-tumoral. O potencial interesse em derivados de triterpenóides extraídos de plantas com actividade anti-tumoral está bem patente no crescente número de publicações nesse domínio científico. Uma análise das publicações enquadrando os triterpenóides com actividade anti-tumoral revelou um aumento exponencial no número de artigos e patentes na referida área científica. Estes factos têm impulsionado a comunidade científica para a síntese de novos derivados triterpénicos com melhorada actividade anti-tumoral. Com o objectivo de melhorar a actividade anti-tumoral dos ácidos ursólico e oleanólico...

Modulatory effect of Byrsonima basiloba extracts on the mutagenicity of certain direct and indirect-acting mutagens in Salmonella typhimurium assays

LIRA, Walclecio de Moraes; SANTOS, Fabio Vieira dos; SANNOMIYA, Miriam; RODRIGUES, Clenilson Martins; VILEGAS, Wagner; VARANDA, Eliana Aparecida
Fonte: MARY ANN LIEBERT INC Publicador: MARY ANN LIEBERT INC
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.02%
Byrsonima basiloba A. Juss. species is a native arboreal type from the Brazilian ""cerrado"" (tropical American savanna), and the local population uses it to treat diseases, such as diarrhea and gastric ulcer. It belongs to the Malpighiaceae family, and it is commonly known as ""murici."" Considering the popular use of B. basiloba derivatives and the lack of pharmacological potential studies regarding this vegetal species, the mutagenic and antimutagenic effect of methanol (MeOH) and chloroform extracts were evaluated by the Ames test, using strains TA97a, TA98, TA100, and TA102 of Salmonella typhimurium. No mutagenic activity was observed in any of the extracts. To evaluate the antimutagenic potential, direct and indirect mutagenic agents were used: 4 nitro-o-phenylenediamine, sodium azide, mitomycin C, aflatoxin B(1), benzo[a] pyrene, and hydrogen peroxide. Both the extracts evaluated showed antimutagenic activity, but the highest value of inhibition level (89%) was obtained with the MeOH extract and strain TA100 in the presence of aflatoxin B(1). Phytochemical analysis of the extracts revealed the presence of n-alkanes, lupeol, ursolic and oleanolic acid, (+)-catechin, quercetin- 3-O-alpha-L-arabinopyranoside, gallic acid, methyl gallate...

Antileishmanial Activity of the Hydroalcoholic Extract of Miconia langsdorffii, Isolated Compounds, and Semi-Synthetic Derivatives

PEIXOTO, Juliana A.; SILVA, Marcio Luis Andrade e; CROTTI, Antonio E. M.; VENEZIANI, Rodrigo Cassio Sola; GIMENEZ, Valeria M. M.; JANUARIO, Ana H.; GROPPO, Milton; MAGALHAES, Lizandra G.; SANTOS, Fransergio F. dos; ALBUQUERQUE, Sergio; SILVA FILHO, Ademar
Fonte: MDPI AG Publicador: MDPI AG
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.46%
The in vitro activity of the crude hydroalcoholic extract of the aerial parts of Miconia langsdorffii Cogn. was evaluated against the promastigote forms of L. amazonensis, the causative agent of cutaneous leishmaniasis in humans. The bioassay-guided fractionation of this extract led to identification of the triterpenes ursolic acid and oleanolic acid as the major compounds in the fraction that displayed the highest activity. Several ursolic acid semi-synthetic derivatives were prepared, to find out whether more active compounds could be obtained. Among these ursolic acid-derived substances, the C-28 methyl ester derivative exhibited the best antileishmanial activity.; FAPESP; CNPq

Evaluation of gastroprotective activity of Plinia edulis (Vell.) Sobral (Myrtaceae) leaves in rats

ISHIKAWA, Tati; DONATINI, Raquel dos Santos; DIAZ, Ingrit Elida Collantes; YOSHIDA, Massayoshi; BACCHI, Elfriede Marianne; KATO, Edna Tomiko Myiake
Fonte: ELSEVIER IRELAND LTD Publicador: ELSEVIER IRELAND LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.22%
Plinia edulis, an arboreous species popularly known as ""cambuca"", is native to the Brazilian Atlantic Rain Forest. Despite its traditional uses, no reports are available on the safety of this utilization or on the relationship between the antiulcer activity of its extract and its phytochemical compounds. This paper reports on the investigation of the acute toxicity and gastroprotective effect of the aqueous ethanol extract of leaves of Plinia edulis on HCl/ethanol-induced ulcers. In order to correlate the secondary metabolites and the efficacy of the crude drug in traditional medicine, the extract was submitted to chromatographic fractionation after solvent partition. The extract did not show acute toxicity in mice treated with 5 g/kg p.o.. but exhibited significant antiulcer activity in rats at doses of 100, 200, and 400 mg/kg p.o., more active than the reference drug lansoprazole. The ethyl acetate fraction yielded P-amyrin, oleanolic acid, ursolic acid, and maslinic acid, which were identified based on spectrometric analyses. Since antiulcerogenic activity is not restricted to one class of compounds in plants, the triterpenoids isolated in the extract can be associated with the observed effect. (C) 2008 Elsevier Ireland Ltd. All rights reserved.; CAPES; CNPq; FAPEAM

Antimicrobial activity of the extract and isolated compounds from Baccharis dracunculifolia D. C. (Asteraceae)

SILVA FILHO, Ademar A. da; Sousa, João Paulo Barreto de; SOARES, Sandra; FURTADO, Niege A. J. C.; ANDRADE E SILVA, Marcio L.; CUNHA, Wilson R.; GREGORIO, Luis E.; NANAYAKKARA, N. R. Dhammika; BASTOS, Jairo K.
Fonte: VERLAG Z NATURFORSCH Publicador: VERLAG Z NATURFORSCH
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.05%
Baccharis dracunculifolia D. C. (Asteraceae) is the most important plant source of the Brazilian green propolis. Since propolis is known for its antimicrobial activity, the aim of this work was to evaluate the showed that the leaves extract of B. dracunculifolia (BdE) presents antifungal and antibacterial activities, especially against Candida krusei and Cryptococcus neoformans, for which the BdE showed IC50 values of 65 mu g mL(-1) and 40 mu g mL(-1), respectively In comparison to the BdE, it was observed that the green propolis extract (GPE) showed better antimicrobial activity, displaying an IC50 value of 9 mu g mL(-1) against C krusei. Also, a phytochemical study of the BdE was carried out, affording the isolation of ursolic acid (1), 2 alpha-hydroxy-ursolic acid (2), isosakuranetin (3), aromadendrin-4`-methylether (4), baccharin (5), viscidone (6), hautriwaic acid lactone (7), and the clerodane diterpene 8. This is the first time that the presence of compounds 1, 2, and 8 in B. dracunculifolia has been reported. Among the isolated compounds, 1 and 2 showed antibacterial activity against methicillin-resistant Staphylococcus aureus, displaying IC50 values of 65 mu g mL(-1) and 40 mu g mL(-1), respectively. 3 was active against C neoformans...

Trypanocidal activity and acute toxicity assessment of triterpene acids

FERREIRA, Daniele da Silva; ESPERANDIM, Viviane Rodrigues; TOLDO, Miriam Paula Alonso; SARAIVA, Juliana; CUNHA, Wilson Roberto; ALBUQUERQUE, Sergio de
Fonte: SPRINGER Publicador: SPRINGER
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.25%
The present study evaluates the in vitro and in vivo trypanocidal activity of ursolic acid and oleanolic acid against the Bolivia strain of Trypanosoma cruzi. Their acute toxicity is also assessed on the basis of median lethal dose (DL50) determination and quantification of biochemical parameters. Ursolic acid is the most active compound in vitro, furnishing IC50 of 25.5 mu M and displaying 77% of trypomastigote lysis at a concentration of 128 A mu M. In agreement with in vitro assays, the results obtained for the in vivo assay reveals that ursolic acid (at a dose of 20 mg/Kg/day) provides the most significant reduction in the number of parasites at the parasitemic peak. Results concerning the LD50 assay and the biochemical parameters evaluated in the present study demonstrate that these substances can be safely used on an experimental basis.; CAPES; CNPq; FAPESP

Biotransformation using Mucor rouxii for the production of oleanolic acid derivatives and their antimicrobial activity against oral pathogens

CAPEL, Clarissa S.; SOUZA, Ana C. D. de; CARVALHO, Tatiane C. de; SOUSA, Joao P. B. de; AMBROSIO, Sergio R.; MARTINS, Carlos H. G.; CUNHA, Wilson R.; GALAN, Rosario H.; FURTADO, Niege A. J. C.
Fonte: SPRINGER HEIDELBERG Publicador: SPRINGER HEIDELBERG
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
96.69%
The goal of this study is to produce oleanolic acid derivatives by biotransformation process using Mucor rouxii and evaluate their antimicrobial activity against oral pathogens. The microbial transformation was carried out in shake flasks at 30A degrees C for 216 h with shaking at 120 rpm. Three new derivatives, 7 beta-hydroxy-3-oxo-olean-12-en-28-oic acid, 7 beta,21 beta-dihydroxy-3-oxo-olean-12-en-28-oic acid, and 3 beta,7 beta,21 beta-trihydroxyolean-12-en-28-oic acid, and one know compound, 21 beta-hydroxy-3-oxo-olean-12-en-28-oic acid, were isolated, and the structures were elucidated on the basis of spectroscopic analyses. The antimicrobial activity of the substrate and its transformed products was evaluated against five oral pathogens. Among these compounds, the derivative 21 beta-hydroxy-3-oxo-olean-12-en-28-oic acid displayed the strongest activity against Porphyromonas gingivalis, which is a primary etiological agent of periodontal disease. In an attempt to improve the antimicrobial activity of the derivative 21 beta-hydroxy-3-oxo-olean-12-en-28-oic acid, its sodium salt was prepared, and the minimum inhibitory concentration against P. gingivalis was reduced by one-half. The biotransformation process using M. rouxii has potential to be applied to the production of oleanolic acid derivatives. Research and antimicrobial activity evaluation of new oleanolic acid derivatives may provide an important contribution to the discovery of new adjunct agents for treatment of dental diseases such as dental caries...

Antioxidative action of methanolic extract and buthanolic fraction of Vochysia tucanorum Mart. in the gastroprotection

Gomes, Renata de Camargo; Bonamin, Flavia; Darin, Denise Delabio; Seito, Leonardo Noboru; Di Stasi, Luiz Claudio; Dokkedal, Anne Ligia; Vilegas, Wagner; Monteiro Souza Brito, Alba Regina; Hiruma-Lima, Clélia Akiko
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 466-471
ENG
Relevância na Pesquisa
36.04%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Processo FAPESP: 02/105503-6; Aim of the study: Vochysia tucanorum is an important medicinal plant used in the Cerrado of Brazil against gastric disorders and this study reveals the pharmacological action of this traditional medicine use.Materials and methods: The methanolic extract (E-MeOH) and buthanolic fraction (Fr-Bu) obtained from V. tucanorum were challenged by different necrotizing agents in rodents. NO-synthase inhibitor (L-NAME) and SH blocker (NEM) were used to evaluate the participation of cytoprotective factors in E-MeOH and Fr-Bu gastroprotection. Antiulcerogenic action of V. tucanorum was evaluated in rats and mice at doses 250, 500 or 1000 mg/kg (E-MeOH) and 37.5, 75 or 150 mg/kg (Fr-Bu).Results: Both E-MeOH and Fr-Bu present elevated gastroprotective action in all in vivo experimental models, without signs of acute toxicity. The mechanisms involved in the gastroprotective action of E-MeOH and Fr-Bu are related to the antioxidant activity and protection to gastric mucosa NO levels. Phytochemical investigations of Fr-Bu identified different pentacyclic triterpenoids such as betulinic acid...

Modulatory effect of Byrsonima basiloba extracts on the mutagenicity of certain direct and indirect-acting mutagens in Salmonella typhimurium assays

Lira, Walclecio de Moraes; Dos Santos, Fabio Vieira; Sannomiya, Miriam; Rodrigues, Clenilson Martins; Vilegas, Wagner; Varanda, Eliana Aparecida
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 111-119
ENG
Relevância na Pesquisa
46.25%
Byrsonima basiloba A. Juss. species is a native arboreal type from the Brazilian cerrado (tropical American savanna), and the local population uses it to treat diseases, such as diarrhea and gastric ulcer. It belongs to the Malpighiaceae family, and it is commonly known as murici. Considering the popular use of B. basiloba derivatives and the lack of pharmacological potential studies regarding this vegetal species, the mutagenic and antimutagenic effect of methanol (MeOH) and chloroform extracts were evaluated by the Ames test, using strains TA97a, TA98, TA100, and TA102 of Salmonella typhimurium. No mutagenic activity was observed in any of the extracts. To evaluate the antimutagenic potential, direct and indirect mutagenic agents were used: 4 nitro-o-phenylenediamine, sodium azide, mitomycin C, aflatoxin B1, benzo[a]pyrene, and hydrogen peroxide. Both the extracts evaluated showed antimutagenic activity, but the highest value of inhibition level (89%) was obtained with the MeOH extract and strain TA100 in the presence of aflatoxin B1. Phytochemical analysis of the extracts revealed the presence of n-alkanes, lupeol, ursolic and oleanolic acid, (+)-catechin, quercetin-3-O-α-L-arabinopyranoside, gallic acid, methyl gallate, amentoflavone...

Secondary metabolites isolated from Richardia brasiliensis Gomes (Rubiaceae)

Pinto,Danielle S.; Tomaz,Anna Cláudia de A.; Tavares,Josean F.; Tenório-Souza,Fábio H.; Dias,Celidarque da Silva; Braz-Filho,Raimundo; da-Cunha,Emídio V. L.
Fonte: Sociedade Brasileira de Farmacognosia Publicador: Sociedade Brasileira de Farmacognosia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2008 EN
Relevância na Pesquisa
46.2%
The family Rubiaceae comprises around 637 genera and approximately 10,700 species, occurring essentially in tropical regions of Brazil. Richardia brasiliensis Gomes, known popularly as "poaia branca", is native to Brazil south region, used in folk medicine as anti-emetic and in the treatment of diabetes. This work reports the isolation and structural identification of a flavonoid glycoside, a triterpene, a coumarin and two benzoic acid derivatives, aiming at contributing to the chemotaxonomy of the genus Richardia, through a phytochemical study of Richardia brasiliensis. By means of this study the metabolites isorhamnetin-3-O-rutinoside, oleanolic acid, the coumarin scopoletin and p-hydroxy-benzoic and m-methoxy-p-hydroxy-benzoic acids were isolated and identified. All of them, but the latter, were isolated for the first time in the genus, thereby presenting relevant chemotaxonomic importance to it. The structures were identified using spectroscopic techniques such as IR, one and two-dimensional ¹H and 13C NMR besides comparison with literature data.

Evaluation of antimicrobial activity of extracts of Tibouchina candolleana (melastomataceae), isolated compounds and semi-synthetic derivatives against endodontic bacteria

Santos,Fernanda M. dos; Souza,Maria Gorete de; Crotti,Antônio E. Miller; Martins,Carlos H. G.; Ambrósio,Sérgio R.; Veneziani,Rodrigo C. S.; Silva,Márcio L. Andrade e; Cunha,Wilson R.
Fonte: Sociedade Brasileira de Microbiologia Publicador: Sociedade Brasileira de Microbiologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2012 EN
Relevância na Pesquisa
46.21%
This work describes the phytochemical study of the extracts from aerial parts of Tibouchina candolleana as well as the evaluation of the antimicrobial activity of extracts, isolated compounds, and semi-synthetic derivatives of ursolic acid against endodontic bacteria. HRGC analysis of the n-hexane extract of T. candolleana allowed identification of b-amyrin, a-amyrin, and b-sitosterol as major constituents. The triterpenes ursolic acid and oleanolic acid were isolated from the methylene chloride extract and identified. In addition, the flavonoids luteolin and genistein were isolated from the ethanol extract and identified. The antimicrobial activity was investigated via determination of the minimum inhibitory concentration (MIC) using the broth microdilution method. Amongst the isolated compounds, ursolic acid was the most effective against the selected endodontic bacteria. As for the semi-synthetic ursolic acid derivatives, only the methyl ester derivative potentiated the activity against Bacteroides fragilis.

Synthesis and biological evaluation of nitric oxide-releasing derivatives of oleanolic acid as inhibitors of HepG2 cell apoptosis

Chen, Li; Zhang, Yihua; Kong, Xiangwen; Peng, Sixun; Tian, Jide
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.45%
A total of 106 nitric oxide-releasing derivatives of oleanolic acid were synthesized and their effects on the inhibition of anti-Fas-mediated HepG2 cell apoptosis were evaluated in vitro. Several compounds inhibited anti-Fas mediated HepG2 cell apoptosis in a dose-dependent manner. Within this series of compounds, 8b is the most potent inhibitor. The development of new NO-releasing derivatives of oleanolic acid may aid in the design of NO-based medicines for the intervention of human liver inflammatory diseases.

Structure-Dependent Inhibition of Bladder and Pancreatic Cancer Cell Growth by 2-Substituted Glycyrrhetinic and Ursolic Acid Derivatives

Chadalapaka, Gayathri; Jutooru, Indira; McAlees, Alan; Stefanac, Tom; Safe, Stephen
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.25%
Derivatives of oleanolic acid, ursolic acid and glycyrrhetinic acid substituted with electron withdrawing groups at the 2-position in the A-ring which also contains a 1-en-3-one structure are potent inhibitors of cancer cell growth. In this study, we have compared the effects of several 2-substituted analogs of triterpenoid acid methyl esters derived from ursolic and glycyrrhetinic acid on proliferation of KU7 and 253JB-V bladder and Panc-1 and Panc-28 pancreatic cancer cells. The results show that the 2-cyano and 2-trifluoromethyl derivatives were the most active compounds. The glycyrrhetinic acid derivatives with the rearranged C-ring containing the 9(11)-en-12-one structure were generally more active than the corresponding 12-en-11-one isomers. However, differences in growth inhibitory IC50 values were highly variable and dependent on the 2- substitutent (CN vs. CF3) and cancer cell context.

Synthesis and Pro-Apoptotic Activity of Novel Glycyrrhetinic Acid Derivatives

Logashenko, Evgeniya B; Salomatina, Oksana V; Markov, A V; Korchagina, Dina V; Salakhutdinov, Nariman F; Tolstikov, Genrikh A; Vlassov, Valentin V; Zenkova, Marina A
Fonte: WILEY-VCH Verlag Publicador: WILEY-VCH Verlag
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
35.98%
Triterpenoids are used for medicinal purposes in many countries. Some, such as oleanolic and glycyrrhetinic acids, are known to be anti-inflammatory and anticarcinogenic. However, the biological activities of these naturally occurring molecules against their particular targets are weak, so the synthesis of new synthetic analogues with enhanced potency is needed. By combining modifications to both the A and C rings of 18βH-glycyrrhetinic acid, the novel synthetic derivative methyl 2-cyano-3,12-dioxo-18βH-olean-9(11),1(2)-dien-30-oate was obtained. This derivative displays high antiproliferative activity in cancer cells, including a cell line with a multidrug-resistance phenotype. It causes cell death by inducing the intrinsic caspase-dependent apoptotic pathway.

Efficient oxidation of oleanolic acid derivatives using magnesium bis(monoperoxyphthalate) hexahydrate (MMPP): A convenient 2-step procedure towards 12-oxo-28-carboxylic acid derivatives

Salvador, Jorge A R; Moreira, Vânia M; Pinto, Rui M A; Leal, Ana S; Paixão, José A
Fonte: Beilstein-Institut Publicador: Beilstein-Institut
Tipo: Artigo de Revista Científica
Publicado em 30/01/2012 EN
Relevância na Pesquisa
66.52%
A new, straightforward and high yielding procedure to convert oleanolic acid derivatives into the corresponding δ-hydroxy-γ-lactones, by using the convenient oxidizing agent magnesium bis(monoperoxyphthalate) hexahydrate (MMPP) in refluxing acetonitrile, is reported. In addition, a two-step procedure for the preparation of oleanolic 12-oxo-28-carboxylic acid derivatives directly from Δ12-oleananes, without the need for an intermediary work-up, and keeping the same reaction solvent in both steps, is described as applied to the synthesis of 3,12-dioxoolean-28-oic acid.

Oleanolic Acid Suppresses Migration and Invasion of Malignant Glioma Cells by Inactivating MAPK/ERK Signaling Pathway

Guo, Guocai; Yao, Weicheng; Zhang, Quanqin; Bo, Yongli
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 21/08/2013 EN
Relevância na Pesquisa
46.17%
Mitogen-activated protein kinases/Extracellular signal-regulated kinase (MAPK/ERK) pathway is essential for migration and invasion of malignant glioma. It is efficient to inhibit migration and invasion of glioma cells by targeting this pathway. Oleanolic acid (OA) has been well demonstrated to suppress survival, growth and angiogenesis of glioma cells. However, it is still unknown if OA affects the migration and invasion of glioma cells. We utilized U-87 MG glioma cell lines and primary glioma cells from patients to study the effect of OA on migration and invasion of glioma cells with multidisciplinary approaches. In this study, we found that OA significantly decreased the ability of glioma cells to migrate and invade. Epithelial-mesenchymal transition (EMT) of glioma cells was also suppressed by OA treatment. Furthermore, MAPK/ERK pathway was greatly inhibited in glioma cells under OA treatment. MAPK/ERK reactivation induced by a recombinant lentiviral vector, Lv-MEK, was able to rescue the inhibitory effect of OA on migration and invasion of glioma cells. Taken together, we provided evidences that OA was a MAPK/ERK pathway-targeting anti-tumor agent. Although the concentrations we used exceeded its physiological level, OA may be used to prevent migration and invasion of glioma cells by developing its derivatives with enhanced bioactivity.

Targeting Nrf2-Mediated Gene Transcription by Triterpenoids and Their Derivatives

Loboda, Agnieszka; Rojczyk-Golebiewska, Ewa; Bednarczyk-Cwynar, Barbara; Lucjusz, Zaprutko; Jozkowicz, Alicja; Dulak, Jozef
Fonte: The Korean Society of Applied Pharmacology Publicador: The Korean Society of Applied Pharmacology
Tipo: Artigo de Revista Científica
Publicado em /11/2012 EN
Relevância na Pesquisa
36.02%
Chemoprevention represents a strategy designed to protect cells or tissues against various carcinogens and carcinogenic metabolites derived from exogenous or endogenous sources. Recent studies indicate that plant-derived triterpenoids, like oleanolic acid, may exert cytoprotective functions via regulation of the activity of different transcription factors. The chemopreventive effects may be mediated through induction of the nuclear factor erythroid 2-related factor 2 (Nrf2) transcription factor. Activation of Nrf2 by triterpenoids induces the expression of phase 2 detoxifying and antioxidant enzymes such as NAD(P)H quinone oxidoreductase 1 (NQO1) and heme oxygenase-1 (HO-1) - proteins which can protect cells or tissues against various toxic metabolites. On the other hand, inhibition of other transcription factors, like NF-κB leads to the decrease in the pro-inflammatory gene expression. Moreover, the modulation of microRNAs activity may constitute a new mechanism responsible for valuable effects of triterpenoids. Recently, based on the structure of naturally occurring triterpenoids and with involvement of bioinformatics and computational chemistry, many synthetic analogs with improved biological properties have been obtained. Data from in vitro and in vivo experiments strongly suggest synthetic derivatives as promising candidates in the chemopreventive and chemotherapeutic strategies.

Evaluation of antimicrobial activity of extracts of Tibouchina candolleana (melastomataceae), isolated compounds and semi-synthetic derivatives against endodontic bacteria

dos Santos, Fernanda M.; de Souza, Maria Gorete; Crotti, Antônio E. Miller; Martins, Carlos H. G.; Ambrósio, Sérgio R.; Veneziani, Rodrigo C. S.; e Silva, Márcio L. Andrade; Cunha, Wilson R.
Fonte: Sociedade Brasileira de Microbiologia Publicador: Sociedade Brasileira de Microbiologia
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
36.2%
This work describes the phytochemical study of the extracts from aerial parts of Tibouchina candolleana as well as the evaluation of the antimicrobial activity of extracts, isolated compounds, and semi-synthetic derivatives of ursolic acid against endodontic bacteria. HRGC analysis of the n-hexane extract of T. candolleana allowed identification of β-amyrin, α-amyrin, and β-sitosterol as major constituents. The triterpenes ursolic acid and oleanolic acid were isolated from the methylene chloride extract and identified. In addition, the flavonoids luteolin and genistein were isolated from the ethanol extract and identified. The antimicrobial activity was investigated via determination of the minimum inhibitory concentration (MIC) using the broth microdilution method. Amongst the isolated compounds, ursolic acid was the most effective against the selected endodontic bacteria. As for the semi-synthetic ursolic acid derivatives, only the methyl ester derivative potentiated the activity against Bacteroides fragilis.

Oleanolic acid and its synthetic derivatives for the prevention and therapy of cancer: Preclinical and clinical evidence

Shanmugam, Muthu K.; Dai, Xiaoyun; Kumar, Alan Prem; Tan, Benny KH; Sethi, Gautam; Bishayee, Anupam
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.37%
Oleanolic acid (OA, 3β-hydroxyolean-12-en-28-oic acid) is a ubiquitous pentacyclic multifunctional triterpenoid, widely found in several dietary and medicinal plants. Natural and synthetic OA derivatives can modulate multiple signaling pathways including nuclear factor-κB, AKT, signal transducer and activator of transcription 3, mammalian target of rapamycin, caspases, intercellular adhesion molecule 1, vascular endothelial growth factor, and poly (ADP-ribose) polymerase in a variety of tumor cells. Importantly, synthetic derivative of OA, 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO), and its C-28 methyl ester (CDDO-Me) and C28 imidazole (CDDO-Im) have demonstrated potent antiangiogenic and antitumor activities in rodent cancer models. These agents are presently under evaluation in phase I studies in cancer patients. This review summarizes the diverse molecular targets of OA and its derivatives and also provides clear evidence on their promising potential in preclinical and clinical situations.

OLEANANE-TYPE TRITERPENES AND DERIVATIVES FROM SEED COAT OF BOLIVIAN CHENOPODIUM QUINOA GENOTYPE “SALAR”

Flores,Yonny; Díaz,Carlos; Garay,Fidel; Colque,Osmar; Sterner,Olov; Almanza,Giovanna R.
Fonte: Revista Boliviana de Química Publicador: Revista Boliviana de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2005 EN
Relevância na Pesquisa
66.61%
Bolivia is the first world exporter of quinoa (Chenopodium quinoa Willd) genotype “salar”. In its natural state quinoa has a coating of bitter-tasting (saponins), making it essentially unpalatable. Most of quinoa exported from Bolivia has been processed to remove this coating. These seed coat residues contain a high level of oleanane-type saponins. From those residues two oleanane-type triterpenes were found as the major sapogenins and their structures were identified as: oleanolic acid and deoxyphytolaccagenic acid in base of NMR means. Furthermore, two derivatives of oleanolic acid were obtained: 28-Omethyl and 3-O-acetyloleanolic acid. The importance of oleanolic acid content in this industrial residue is discussed.