Facile Preparation of Bioactive <i>seco</i>-Guaianolides and Guaianolides from <i>Artemisia gorgonum</i> and Evaluation of Their Phytotoxicity

Commercially available santonin was used to synthesize seven sesquiterpene lactones using a facile strategy that involved a high-yielding photochemical reaction. Three natural products from <i>Artemisia gorgonum</i> were synthesized in good yields, and in the case of two compounds, absolute configurations were determined from X-ray quality crystals. The structures previously reported for these compounds were revised. Sesquiterpene lactones were tested using the etiolated wheat coleoptile bioassay, and the most active compounds were assayed in standard target species. <i>seco</i>-Guaianolide (<b>4</b>) showed higher phytotoxic activities than the known herbicide Logran. This high activity could be due to the presence of a cyclopentenedione ring. These results suggest that compound <b>4</b> should be involved in defense of <i>A</i>. <i>gorgorum</i>, displaying a wide range of activities that allow proposing them as new leads for development of a natural herbicide model with a <i>seco</i>-guaianolide skeleton

Facile Preparation of Bioactive <i>seco</i>-Guaianolides and Guaianolides from <i>Artemisia gorgonum</i> and Evaluation of Their Phytotoxicity

Commercially available santonin was used to synthesize seven sesquiterpene lactones using a facile strategy that involved a high-yielding photochemical reaction. Three natural products from <i>Artemisia gorgonum</i> were synthesized in good yields, and in the case of two compounds, absolute configurations were determined from X-ray quality crystals. The structures previously reported for these compounds were revised. Sesquiterpene lactones were tested using the etiolated wheat coleoptile bioassay, and the most active compounds were assayed in standard target species. <i>seco</i>-Guaianolide (<b>4</b>) showed higher phytotoxic activities than the known herbicide Logran. This high activity could be due to the presence of a cyclopentenedione ring. These results suggest that compound <b>4</b> should be involved in defense of <i>A</i>. <i>gorgorum</i>, displaying a wide range of activities that allow proposing them as new leads for development of a natural herbicide model with a <i>seco</i>-guaianolide skeleton

Facile Preparation of Bioactive <i>seco</i>-Guaianolides and Guaianolides from <i>Artemisia gorgonum</i> and Evaluation of Their Phytotoxicity

Commercially available santonin was used to synthesize seven sesquiterpene lactones using a facile strategy that involved a high-yielding photochemical reaction. Three natural products from <i>Artemisia gorgonum</i> were synthesized in good yields, and in the case of two compounds, absolute configurations were determined from X-ray quality crystals. The structures previously reported for these compounds were revised. Sesquiterpene lactones were tested using the etiolated wheat coleoptile bioassay, and the most active compounds were assayed in standard target species. <i>seco</i>-Guaianolide (<b>4</b>) showed higher phytotoxic activities than the known herbicide Logran. This high activity could be due to the presence of a cyclopentenedione ring. These results suggest that compound <b>4</b> should be involved in defense of <i>A</i>. <i>gorgorum</i>, displaying a wide range of activities that allow proposing them as new leads for development of a natural herbicide model with a <i>seco</i>-guaianolide skeleton

Bioprospection of Phytotoxic Plant-Derived Eudesmanolides and Guaianolides for the Control of Amaranthus viridis, Echinochloa crus-galli, and Lolium perenne Weeds

The phytotoxicities of a selection of eudesmanolides and guaianolides, including natural products and new derivatives obtained by semisynthesis from plant-isolated sesquiterpene lactones, were evaluated in bioassays against three weeds of concern in agriculture (Amaranthus viridis L., Echinochloa crus-galli L., and Lolium perenne L.). Both eudesmanolides and guaianolides were active against the root and shoot growth of all the species, with the eudesmanolides generally showing improved activities. The IC50 values obtained for the herbicide employed as positive control (on root and shoot growth, respectively, A. viridis: 27.8 and 85.7 μM; E. crus-galli: 167.5 and 288.2 μM; L. perenne: 99.1 and 571.4 μM) were improved in most of the cases. Structure–activity relationships were discussed, finding that hydroxylation of the A-ring and C-13 as well as the position, number, and orientation of the hydroxyl groups and the presence of an unsaturated carbonyl group can significantly influence the level of phytotoxicity. γ-Cyclocostunolide was the most active compound in the series, followed by others such as dehydrozaluzanin C and α-cyclocostunolide (outstanding their IC50 values on A. viridis)natural products that can therefore be suggested as models for herbicide development if further research indicates effectiveness on a larger scale and environmental safety in ecotoxicological assessments

Phytotoxins from <i>Tithonia diversifolia</i>

<i>Tithonia diversifolia</i> (Mexican sunflower) is a dominant plant of the Asteraceae family, which suggests it produces allelochemicals that interfere with the development of surrounding plants. The study described herein was conducted to identify the compounds that have phytotoxic activity in <i>T. diversifolia</i> extracts. Ethyl acetate extracts of the leaves, stems, and roots showed significant inhibition of wheat coleoptile growth, and the leaf extract had similar inhibitory effects to a commercial herbicide. Fourteen compounds, 12 of which were sesquiterpene lactones, have been isolated. Two sesquiterpene lactones are reported for the first time and were isolated as an inseparable mixture of 8β-<i>O</i>-(2-methylbutyroyl)­tirotundin (<b>4</b>) and 8β-<i>O</i>-(isovaleroyl)­tirotundin (<b>5</b>). Their structures were determined by spectroscopic analysis, including NMR techniques and mass spectrometry. The sesquiterpene lactones 1β-methoxydiversifolin (<b>6</b>), tagitinin A (<b>7</b>), and tagitinin C (<b>8</b>) were the major products identified. These compounds were active on etiolated wheat coleoptiles, seed germination, and the growth of STS and weeds. The phytotoxic activity shown by these sesquiterpene lactones indicates that they are the compounds responsible for the activity exhibited by the initial extracts

Identificación de los factores epigenéticos en el cáncer papilar de tiroides y su correlación clínica

La punción aspiración con aguja fina (PAAF) de nódulos tiroideos ha ganado una amplia aceptación como un valioso método para distinguir nódulos neoplásicos o susceptibles de malignidad y la identificación de los pacientes que pueden ser candidatos para cirugía como factor independiente de otras características clínicas. La clasificación etiopatogénica de las lesiones tiroideas (benignas y malignas) con especial énfasis al etiquetado del carácter neoplásico o benigno de las lesiones nodulares, adenomatosas o multifocales del tiroides que producen bocio, así como el descubrimiento de las bases moleculares de las mismas podrá ayudar a mejorar las indicaciones de los distintos tipos de cirugía en cada paciente. En este proyecto se ha seleccionado una variedad de genes relacionados con la patología tiroidea. Empleando marcadores intragénicos en estos genes y el análisis multilocus se pretende identificar patrones genéticos específicos de cada patología en estudio. La consecución, aún parcial, en la identificación de patrones predictivos, aplicables al diagnostico diferencial de la patología tiroidea, podría revolucionar el manejo clínico de los pacientes mediante la racionalización y priorización de tratamientos más o menos agresivos

Phytotoxicity Study on <i>Bidens sulphurea</i> Sch. Bip. as a Preliminary Approach for Weed Control

Farmers of the Franca region in Brazil observed that <i>Bidens sulphurea</i> was able to eliminate the <i>Panicum maximum</i> weed, which infected coffee plantations, without affecting the crop. In an effort to determine if the inhibitory effects observed were due to the presence of phytotoxic compounds from leaves and roots, a biodirected isolation and spectroscopic characterization has been carried out. The leaf dichloromethane and root acetone extracts were the most active, and the former appeared to be more phytotoxic to the target species, including four weeds. A total of 26 compounds were isolated from leaves and roots, and four of them are described here for the first time. The major compounds in the leaf extract are the sesquiterpene lactones costunolide, reynosin, and santamarine, and these showed marked inhibition. <i>Amaranthus viridis</i> and <i>Panicum maximum</i> were the most sensitive species of the weeds tested. These three phytotoxic lactones were also evaluated on <i>A. viridis</i> and <i>P. maximum</i> under hydroponic conditions. <i>A. viridis</i> was the most affected species with the three lactones, and santamarine was the most phytotoxic compound on both. This is the first time that the phytotoxicity of sesquiterpene lactones has been evaluated on hydroponic culture. The work described here is a preliminary approach for the use of <i>B. sulphurea</i> for weed control in agriculture, both as a cover crop and by use of its components as natural herbicide leads