Actividad antibiofilm de un extracto antibacteriano de schinus fasciculatus y sus componentes

Las bacterias fitopatógenas poseen la capacidad de adherirse y colonizar los tejidos vegetales mediante biofilms. La formación de estas películas bacterianas puede verse afectadas por la presencia de bactericidas en concentraciones sub-letales, algo que sucede comúnmente cuando la aplicación de estos compuestos no es homogénea sobre la superficie de la planta. En este contexto, la actividad antibiofilm de un compuesto antibacteriano podría contribuir al control de enfermedades vegetales que producen grandes pérdidas en los cultivos. En este trabajo se evaluó la capacidad de inhibición de biofilm de un extracto con actividad antimicrobiana de Schinus fasciculatus y sus componentes en concentraciones sub-letales. El extracto foliar fAcet de Schinus fasciculatus y sus componentes, los flavonoides agatisflavona, quercetina, kaempferol se ensayaron en Concentraciones sub-letales previamente establecidas (125-1,9 μg/mL) para determinar su capacidad de inhibir la formación de biofilm de 5 cepas fitopatógenas, Pseudomonas syringae pv tomato Pseudomonas corrugata, Xanthomonas campestris pv vesicatoria, Erwinia carotovora var carotovora y Agrobacterium tumefaciens, mediante el ensayo de cristal violeta en microplaca descripto por O?Toole. Los resultados fueron analizados estadísticamente utilizando los test de Shapiro-Wilk, ANOVA y Kruskal-Wallis del software STATISTICA, version 7. La inhibición de biofilm fue dependiente de la cepa bacteriana, y en menor medida del compuesto ensayado, siendo E. carotovora var. carotovora y A. tumefaciens las más susceptibles, con inhibiciones de entre un 40-80%, mientras que P. corrugata y X. campestres pv vesicatoria fueron las menos susceptibles con una inhibición máxima de un 39%. El extracto y los flavonoides inhibieron en un 40 a 80% la formación de biofilm de las especies bacterianas ensayadas, por lo que en concentraciones sub-letales estos compuestos serían capaces de atenuar la patogenicidad de las bacterias fitopatógenas investigadas.Fil: Terán Baptista, Zareath Pamela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; ArgentinaFil: Aredes Fernández, Pedro Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; ArgentinaFil: Mandova, T.. Universidad Paris Descartes; FranciaFil: Kritsanida, M.. Universidad Paris Descartes; FranciaFil: Grougnet, R.. Universidad Paris Descartes; FranciaFil: Sampietro, Diego Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; ArgentinaIV Reunión Conjunta de Sociedades de Biología de la República Argentina: nuevas evidencias y cambios de paradigmas en Ciencias BiológicasMendozaArgentinaSociedad de Biología de CórdobaSociedad de Biología de CuyoAsociación de Biología de Tucumá

Antimutagenic properties of a polyphenol-enriched extract derived from sesame-seed perisperm

A polyphenolic mixture derived from sesame-seed perisperm (SSP) strongly reduced the mutagenicity of hydrogen peroxide (H2O2), sodium azide (NaN3), and benzo[a]pyrene (BaP) in strains TA100 and/or TA98 of Salmonella typhimurium. It exhibited desmutagenic activity against H2O2, BaP in TA98 and/or TA100 and biomutagenic activity (apparently by affecting the DNA-repair system) against NaN3 in strain TA100. According to in vitro experiments the polyphenolic mixture inhibited the activity of the CYP1A1 (EROD) enzyme responsible for the activation of BaP in the Ames' test, as well as that of the cytosolic enzyme GST. A cytosolic fraction from liver of male Wistar rats treated with either 20% SSP in the food, or 3 mg or 6 mg of polyphenolic mixture/20 g food/day for a time period of 8 weeks reduced the mutagenic potential of BaP in strains TA100 and TA98, with the cytosolic fraction from rats treated with SSP causing the strongest reduction. Furthermore, a microsomal fraction from the 20% SSP-treated rats inhibited the mutagenicity of BaP in strains TA100 (26.3%) and TA98 (23%). In contrast, a microsomal fraction from rats treated with 3 mg of polyphenolic mixture stimulated the mutagenicity of BaP in TA100 but reduced it in TA98, while for the microsomal fraction from rats treated with 6 mg of polyphenolic mixture, these effects on TA100 and TA98 were reversed. © 2007 Elsevier B.V. All rights reserved

Sesamolinol glucoside, disaminyl ether, and other lignans from sesame seeds

The application of a procedure based on XAD-4 adsorption resin permitted the obtainment of an enriched polyphenolic extract from Sesamum indicum seeds. Chemical analysis of the obtained extract led to the identification of 12 lignans. Among them, 2 lignans, (+)-sesamolinol-4′-O-β-d-glucoside and disaminyl ether, are reported for the first time as natural compounds. Their structure has been determined by spectroscopic methods, mainly by the application of one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) techniques [heteronuclear multiple-quantum coherence (HMQC), heteronuclear multiple-bond correlation (HMBC), and nuclear Overhauser effect spectrometry (NOESY)] and mass spectroscopy. The isolated compounds were evaluated for their antimutagenic activity. Among the tested lignans, the most active lignan was found to be sesamolin, followed by sesamolinol and samin, against H2O2. Additionally, some of the tested lignans showed desmutagenic activity against benzo[a]pyrene (BaP). © 2011 American Chemical Society

New lignans from the perisperm of Sesamum indicum

A procedure, based on XAD-4 adsorption resin, which permits the obtainment of enriched polyphenolic extracts from Sesamum indicum perisperm (coat) has been developed. Chemical analysis of the obtained extracts led to the identification of 16 lignans. Among them, two new lignans, (+)-saminol and (+)-episesaminone-9-O-β-D-sophoroside, have been isolated. Additionally, the relative stereochemistry of (-)-sesamolactol, previously reported as todolactol A epimer, has been unequivocally defined using X-ray crystallography. The structures of all new compounds were determined by spectroscopic methods, mainly by the concerted application of 1D and 2D NMR techniques (HMQC, HMBC, and NOESY) and mass spectroscopy. © 2006 American Chemical Society

Dammarane triterpenes from Gardenia aubryi vieill.

Three new dammarane triterpenoids, gardaubryones A-C (1-3), were isolated from the gum collected on the aerial parts of Gardenia aubryi Vieill., together with the known compounds hydroxydammarenone II (4), ocotillone (5), cabraleone, and hollongdione. The structures of the novel compounds were established on the basis of mass spectrometry, NMR experiments, and chemical-correlation reactions. Copyright © 2011 Verlag Helvetica Chimica Acta AG, Zürich, Switzerland

Koniamborine, the first pyrano[3,2-b]indole alkaloid and other secondary metabolites from Boronella koniambiensis

Two new alkaloids, (-)-cis-1,2-dihydroxy-1,2-dihydromedicosmine (3) and koniamborine (4), have been isolated from Boronella koniambiensis aerial parts. Their structures have been established from NMR and mass data. Koniamborine is a novel type of alkaloid, which derives from the pyrano[3,2-6]indole basic skeleton, described for the first time from nature. 6-Methoxy-1-methylisatin, also present in the plant material, can be considered biogenetically as a degradation product of the fused pyrone ring of 4. © 2005 American Chemical Society and American Society of Pharmacognosy

Pyrrolizidine alkaloids in medicinal tea of ageratum conyzoides

It is now widely-recognized that the view that herbal remedies have no adverse effects and/or toxicity is incorrect; some traditionally-used plants can present toxicity. The well-established popular use of Ageratum conyzoides has led to its inclusion in a category of medicinal crude drugs created by the Brazilian Health Surveillance Agency. Ageratum belongs to the Eupatorieae tribe, Asteraceae, and is described as containing toxic pyrrolizidine alkaloids. Aqueous extracts of Ageratum conyzoides L. harvested in Brazil (commercial, flowering and non-fowering samples) were prepared according to the prescribed method and analyzed by HPLC-HRMS. The pyrrolizidine alkaloids lycopsamine, dihydrolycopsamine, and acetyl-lycopsamine and their N-oxides, were detected in the analyzed extracts, lycopsamine and its N-oxide being known hepatotoxins and tumorigens. Together with the pyrrolizidine alkaloids identifed by HPLC-HRMS, thirteen phenolic compounds were identified, notably, methoxylated favonoids and chromenes. Toxicological studies on A. conyzoides are necessary, as is monitoring of its clinical use. To date, there are no established safety guidelines on pyrrolizidine alkaloids-containing plants, and their use in Brazil

Two new peltogynoids from acacia nilotica delile with kinase inhibitory activity

Two new peltogynoids, acanilol A (1) and acanilol B (2), were isolated from the stem bark of Acacia nilotica (L.) Delile, together with the known triterpene lupenone. The structures of the new compounds were established on the basis of their spectral data, mainly UV, NMR, and mass spectrometry. The new compounds were tested as kinase inhibitors against CDK1, GSK3, CK1, and DYRK1A, and acanilol B was identified as a DYRK1A inhibitor, with an IC50 of 19μM. © Georg Thieme Verlag KG Stuttgart · New York