Diterpenoids

Hanson, James R.

doi:10.1039/a815093y

Cited by 21 publications

(17 citation statements)

References 204 publications

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“…These authors use this statistical result to infer that life in the Universe may be common. In a paper with results complementary to those of Lineweaver and Davis (2002), Davies (2003) hypothesizes that the rapid development of life on Earth could be due to a non-terrestrial origin, if life requires one or several improbable or "hard" steps, as discussed by Carter (1983Carter ( , 2008 and Hanson (1998). Davies (2003) suggests that life could have developed on Mars and then transported to Earth, but is likely not of extrasolar origin.…”

Section: Introductionmentioning

confidence: 94%

Effect of Metallicity on the Evolution of the Habitable Zone From the Pre-Main Sequence to the Asymptotic Giant Branch and the Search for Life

Danchi

López

2013

ApJ

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During the course of stellar evolution, the location and width of the habitable zone changes as the luminosity and radius of the star evolves. The duration of habitability for a planet located at a given distance from a star is greatly affected by the characteristics of the host star. A quantification of these effects can be used observationally in the search for life around nearby stars. The longer the duration of habitability, the more likely it is that life has evolved. The preparation of observational techniques aimed at detecting life would benefit from the scientific requirements deduced from the evolution of the habitable zone. We present a study of the evolution of the habitable zone around stars of 1.0, 1.5, and 2.0 M ⊙ for metallicities ranging from Z=0.0001 to Z=0.070. We also consider the evolution of the habitable zone from the pre-main sequence until the asymptotic giant branch is reached. We find that metallicity strongly affects the duration of the habitable zone for a planet as well as the distance from the host star where the duration is maximized. For a 1.0 M ⊙ star with near Solar metallicity, Z=0.017, the duration of the habitable zone is >10 Gyr at distances 1.2 to 2.0 AU from

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Section: Introductionmentioning

confidence: 94%

Effect of Metallicity on the Evolution of the Habitable Zone From the Pre-Main Sequence to the Asymptotic Giant Branch and the Search for Life

Danchi

López

2013

ApJ

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“…16 Os diterpenos, principais constituintes do gênero, possuem atividades biológicas, funções ecológicas e constituem protótipos na síntese de substâncias bioativas. [17][18][19][20] Dentre os diferentes tipos estruturais, os diterpenos casbanos são encontrados em apenas seis espécies da família Euphorbiaceae e merecem destaque por apresentarem atividades anticancerígena e bactericida. [21][22][23][24] Croton nepetaefolius é uma planta aromática endêmica do nordeste brasileiro conhecida popularmente como "marmeleiro sabiá", "marmeleiro cravo" ou "marmeleiro de cheiro".…”

Section: Introductionunclassified

Diterpenos casbanos e acetofenonas de Croton nepetaefolius (Euphorbiaceae)

Santos¹,

Mesquita²,

Lemos³

et al. 2008

Quím. Nova

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Recebido em 4/6/07; aceito em 6/9/07; publicado na web em 26/2/08 CASBANE DITERPENES AND ACETOPHENONES OF Croton nepetaefolius (EUPHORBIACEAE). Croton nepetaefolius is an aromatic plant native to the northeast of Brazil where it is extensively used in folk medicine as a sedative, orexigen and antispasmodic agent. The present work deals with the chromatographic analysis of the ethanolic extract of Croton nepetaefolius stalk. It allowed the isolation and characterization of two diterpenoids named 1,4-dihydroxy-2E,6E,12E-trien-5-one-casbane and 4-hydroxy-2E,6E,12E-5-one-casbane, two acetophenones named 2-hydroxy-4,6-dimethoxyacetophenone and 2-hydroxy-3,4,6-trimethoxyacetophenone and the steroids 3-O-β-D-glucopiranosylsitosterol and a mixture of β-sitosterol and stigmasterol. Structural elucidation was done on the basis of spectral data, mainly high field NMR and EIMS.Keywords: casbane diterpenoid; acetophenones; Croton nepetaefolius. INTRODUÇÃOO uso de plantas com fins terapêuticos é uma tradição milenar presente nas culturas de várias nações constituindo, ainda hoje, um recurso alternativo de grande aceitação, não somente nos centros urbanos, mas sobretudo nas pequenas comunidades rurais. Este comportamento vem chamando a atenção da comunidade científi-ca no sentido de comprovar a eficácia e promover o uso seguro desses recursos naturais.1 Vale ressaltar que as plantas são fontes naturais de uma infinidade de substâncias químicas que são biossintetizadas com várias finalidades, entre elas, protegê-las contra predadores ou atrair polinizadores.

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“…The compounds substituted at R 4 and R 5 with fluorine, and at R1 with fluorine or chlorine, are all out of the AD. All other chlorine substituted compounds in R 4 and R 5 are contained in the AD (Gv4, Gv6, Gv8, and Gv10), with predicted IC 50 values less bioactive than Casearin G. The compounds Gv1 and Gv2 were substituted with a bulkier substituent at R 5 (Dc ¼ Decanoate) resulting less bioactive than Casearin G. Gv3 substituent at R 5 with a MeO resulted to be slightly close to the experimental IC 50 value of Casearin G. Contrary to the preceding case, we have no known cytotoxic bioassay examples from literature employing fluorinated or chlorinated diterpenoids, it is reasonable to adopt the interpolated compounds for further bioassays. This in silico exercise was intended to evaluate a few possibilities in line with the objective of this work, exemplifying the use of the proposed QSAR model with new clerodane diterpenoids as anticancer agents.…”

Section: Evaluation Of New Compoundsmentioning

confidence: 99%

“…1300 tropical and subtropical species subordinated to 86 genus [1,2]. More than eight hundred isolated diterpenoids and nor-diterpenoids with the clerodane skeleton have been reported [3,4], also involving other botanical families than Flacourtiaceae. Structures of several compounds were analyzed and elucidated by NMR and X-ray spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

QSAR of Clerodane Diterpenoids with Cytotoxic and Antitumoral Activity Against V‐79 Cells

Cramer

Takahata

2009

QSAR Comb. Sci.

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This work deals with diterpenoids of the clerodane type, compounds isolated from the extracts of different plant organs from trees mainly of the Flacourtiaceae family. The aim of the present work is to study Quantitative Structure-Activity Relationship (QSAR) on Casearins isolated from the crude plant extract of the leaves of the shrub tree Casearia sylvestris Swartz, Flacourtiaceae, that show cytotoxic activities against V-79 Chinese Hamster lung cells. In total, ca. 2080 descriptors and indices were calculated for the QSAR study using various softwares. The obtained QSARs with three descriptors were developed using two independent methods, Multiple Linear Regression (MLR) and Support Vector Machine (SVM), using a small set of molecules. For external validation of the MLR QSAR we employed a training/test set that was evaluated through criteria ruled by RQK fitness functions. Both MLR and SVM QSARs were validated using the same test set, where the SVM QSAR achieved the best results. Both QSARs were applied to a data set with 113 clerodane diterpenoids never tested before against the Chinese Hamster lung fibroblast V-79 cells, and also applied to thirteen new compounds which were build in silico, adding fluorine and chlorine atoms as substituents at specific positions of the clerodane diterpenoids. Encouraging results were obtained in both cases which serve as an indicator for further studies in silico and/or bioassay of these compounds as anticancer agents.

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Diterpenoids

Cited by 21 publications

References 204 publications

Effect of Metallicity on the Evolution of the Habitable Zone From the Pre-Main Sequence to the Asymptotic Giant Branch and the Search for Life

Effect of Metallicity on the Evolution of the Habitable Zone From the Pre-Main Sequence to the Asymptotic Giant Branch and the Search for Life

Diterpenos casbanos e acetofenonas de Croton nepetaefolius (Euphorbiaceae)

QSAR of Clerodane Diterpenoids with Cytotoxic and Antitumoral Activity Against V‐79 Cells

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