59 resultados para Clerodane diterpenes


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The Natural Rubber Latex (NRL) from Hevea brasiliensis has shown promise in biomedical applications due to its low cost, easy handling, mechanical properties and biocompatibility, being used for bone regeneration and wound healing due to its natural stimulus to angiogenesis. The aim of this work was to incorporate Casearia sylvestris Sw. extract in NRL biomembranes and study its release behavior. The complex membrane-extract has as object of study a new approach of using C. sylvestris extract in the treatment of wounds, for possessing antiseptic activity, anti-inflammatory and analgesic properties. The C. sylvestris species (Salicaceae), popularly known as "guaçatonga", presents great distribution and is used in folk medicine as antiulcer, wound healing, anti-snake venom, properties which have been proven and related to clerodane diterpenes (casearins A-X). The release rate of C. sylvestris compounds from extract-membrane complex was monitored and analyzed using the method of optical spectroscopy (UV-VIS). The release varied with temperature ranging from 14 to 33 days, releasing more than 90%, with an interesting and promising biomedical application, such as wound healing and burns.

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The insecticidal activity of hexane extracts from the roots and leaves of Aristolochia malmeana was evaluated against Anticarsia gemmatalis larvae by topical application. Extract from the roots was the most active and caused 50% mortality in larvae at 308.4 mu g/mu L. From this extract, a clerodane diterpene, (-)-kolavenic acid, and three lignans, (-)-kusunokinin, (-)-hinokinin, and (8S,8'R,9S)cubebin, were isolated by chromatography and partition procedures and then evaluated for their insecticidal activities either individually or in pairs. (-)-Kusunokinin showed higher activity against A. gemmatalis (LD10 = 9.3, LD50 = 230.1 mu g/mu L) than the crude extract, and its activity was dosedependent, whereas the other constituents did not exhibit any significant activity. Together with (-)kusunokinin and (-)-hinokinin, (-)-copalic acid, (-)-2-oxokolavenic acid, (-)-ent-6-beta-hydroxy-copalic acid, (8R,8'R,9R)- and (8R,8'R,9S)-cubebins, (-)-fargesin, and (-)-phillygenin were isolated from the hexane extract of the leaves. The compounds were identified on the basis of spectroscopic analysis.

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Chemical investigation of the leaves of Guarea trichilioides afforded six diterpenoids, including four labdane and two clerodane derivatives. The following four are new: 3-oxolabd-8(17),12Z,14-triene, 3α-hydroxylabd-8(17),12Z,14-triene, 3β-hydroxylabd-8(17),12Z,14-triene and(-)-2-oxo-13-hydroxy,3,14-clerodandiene. Copyright © 1996 Elsevier Science Ltd. All rights reserved.

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Studies have shown that Casearia sylvestris compounds protect DNA from damage both in vitro and in vivo. Complementarily, the aim of the present study was to assess the chemopreventive effect of casearin B (CASB) against DNA damage using the Ames test, the comet assay and the DCFDA antioxidant assay. The genotoxicity was assessed by the comet assay in HepG2 cells. CASB was genotoxic at concentrations higher than 0.30μM when incubated with the FPG (formamidopyrimidine-DNA glycosylase) enzyme. For the antigenotoxicity comet assay, CASB protected the DNA from damage caused by H2O2 in the HepG2 cell line in concentrations above 0.04μM with post-treatment, and above 0.08μM with pre-treatment. CASB was not mutagenic (Ames test) in TA 98 and TA 102. In the antimutagenicity assays, the compound was a strong inhibitor against aflatoxin B1 (AFB) in TA 98 (>88.8%), whereas it was moderate (42.7-59.4%) inhibitor against mytomicin C (MMC) in TA 102. Additionally, in the antioxidant assay using DCFDA, CASB reduced reactive oxygen species (ROS) generated by H2O2. In conclusion, CASB was genotoxic to HepG2 cells at high concentrations; was protective of DNA at low concentrations, as shown by the Ames test and comet assay; and was also antioxidant. © 2012 Elsevier Ltd.

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Phytochemical examination of Aristolochia cymbifera, A. esperanzae and A. galeata led to the isolation of furofuran and dibenzylbutyrolactone type lignans, as well as of clerodane and ent-labdane type diterpenes. Structural assignments for two new ent-labdans are presented and discussed. © 1988.

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This paper provides a general survey of the occurrence of diterpenes in the Asteraceae. Data on 4351 botanical occurrences were obtained from the literature. These were grouped by skeleton for each genus. Then, the genera were grouped by subtribes, which, in turn, were gathered in tribes, followed by subfamilies. In spite of the low number of species containing diterpenes, it was possible to describe some structural features of these compounds, i.e. The skeletal types in various taxa and the positions in some skeletons that are always oxidized or never undergo oxidation in some genera. Thus, it was verified that: in the subfamily Cichorioideae, only a few of the studied species possess diterpenes, wherein kaurane is the most frequent diterpene skeleton. In the Asteroideae, the presence of diterpenes is much greater than that in the Cichorioideae and Carduoideae. At tribal taxonomic level, for example, the Astereae produce labdanes and clerodanes; Heliantheae and Eupatorieae produce kauranes and labdanes, respectively; and Calenduleae produce pimaranes. Some taxonomic implications are presented. (c) 2005 the Linnean Society of London.

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Ryanodane diterpenes, named 14-O-methyl-ryanodanol and ryanodanol, were isolated from ripe fruit of Erythroxylum passerinum. Compound 2 was also found in the leaves of this species, while 1 was obtained from the leaves of E. nummularia. Compound 1 showed insecticidal activity against Aedes aegypti larvae. (c) 2007 Elsevier Ltd. All rights reserved.