Bioprospección y diversidad química

17 páginas, 13 tablas y 73 esquemas de compuestos orgánicosUna de las herramientas necesarias para la conservación y el aprovechamiento sostenible de la biodiversidad botánica es el conocimiento de su valor añadido. El contenido en productos naturales bioactivos de las plantas se conoce desde la antigüedad por su valor medicinal y plaguicida. Sin embargo, aún existe un gran desconocimiento de la diversidad química del planeta, agravado por la presión humana sobre la biodiversidad y la consecuente desaparición de especies. Aquí vamos a presentar una pequeña muestra de diversidad química, su valor añadido y posibles soluciones a su aprovechamiento sostenible.Centro de Ciencias Medioambientales- CSIC MadridInstituto de Productos Naturales y Agrobiología - CSIC La Laguna-TenerifeUDI-Fitopatología Fac de Biología - La Laguna-TenerifePeer reviewe

Persea indica as a natural source of the insecticide Ryanodol

Since Persea indica is a natural source of the insecticidal diterpene ryanodol, 20 mature naturally growing trees from two locations were surveyed fo their content in this compound, as well as for nitrogen, water and total phenolies. The foliar ryanodol content of the water and total phenolies. The foliar ryanodol content of the tree did not show seasonal variations and did not correlate with the nitrogen, water of phenolic content. This diterpene did vary however, among the individual trees and was found to accumulutate in the stems. The results are discussed in the light of the prospects for using this plants as a sourcem¡ of natural pesticide.We gratefully acknowledge A. Fernández, Director of Garajonay National Park (ICONA) for his constant support. We also thank M. J. Contreras and the Park Rangers for their assistance in plant collection, S. Carlin for editing the english language and P. Ewscoubas for his constructive comments.Peer reviewe

Genotoxicity of the insecticide rotenone in cultured human lymphocytes

7 páginas y 6 tablas estadísticasWe have investigated the genotoxic activity of rotenone on three genetic endpoints, sister-chromatid exchanges (SCE), chromosome aberrations (CA)and micronuclei (MN) in human lymphocyte cultures in the presence and absence of a metabolic activation system (S9 mix). Our results indicate that rotenone increases the frequency of binucleated micronucle- ated (BNMN)cells and causes a delay in the cell cycle but does not increase the frequency of CA and SCE at the concentrations used. The presence of S9 mix reduces the genotoxic activity of rotenone.This work was supported by a grant from the DGICYT-Spain (PB 94/0020/B).Peer reviewe

Development of a new bioluminescent mutagenicity assay based on the Ames test

5 páginasy 5 figurasA newly developed rapid mutagenicíty assay based on the adenosine triphosphate (ATP)-bioluminescence techníque and the Ames test is described. Salmonella typhimurium strains TA98 and TA100 were exposed in an appropriate liquid medium to the direct mutagens 4-nitroquinoline-N-oxide and methyl methanesulphonate, respectively, and to the indirect mutagen 2-aminoanthracene. Both euxotrophic and prototrophic growth were monitored throughout the incubation period as variations in the intracellular ATP levels by means of the luciferin-luciferase assay. Ater 9-12 h of incubation a dose-response increase in the levels of ATP was readily detected. In order to demonstrate that this increase was due to the growth of revertant bacteria, aliquots from each culture were plated un minimal agar plates. A very good correlation berween the changes in ATP Ievels and the appearance of revertant colonies on the plates was found . Given the rapidity of this method as compared with conventional mutagenicity assays, ít has potential for industrial and environmental applications.Other potential applications are also díscussed.Peer reviewe

3-0-Acetyl-narcissidine, a Bioactive Alkaloid from Hippeastrum puniceum Lam. (Anaryllidaceae)

5 pages, figures, and tables statistics.In the context of the study on plant defensive compounds we have isolated the main alkaloid from Hippeastrum puniceum (Amaryllidaceae), 3-0-acetyl-narcissidine. and its biological activities tested against two divergent insect species and severalplant species, was isolated from to bioactive alkaloidal fraction of H. puniceum. Its chemical structure was established by spectroscopic analysis. The biological activity test showed that is an antifeedant against the polyphagous insect. Spodoptera littoralis but not against the olyphage Lepinotarsa decemlineata. Furthermore. the root growth of Amaranthus hypochondriacus. Rottboellia cochinchinensis. Panicum maximum and Solanum Icypersicum was significantly affected by These results a plant protective role for H. puniceum alkaloids.Peer reviewe

A new method for microwave assisted ethanolic extraction of Mentha rotundifolia bioactive terpenoids

A new microwave-assisted extraction (MAE) method using ethanol as solvent has been optimized by means of a Box-Behnken experimental design for the enhanced extraction of bioactive terpenoids from Mentha rotundifolia leaves; 100°C, 5 min, 1.125 g dry sample: 10 mL solvent and a single extraction cycle were selected as optimal conditions. Improved performance of MAE method in terms of extraction yield and/or reproducibility over conventional solid-liquid extraction and ultrasound assisted extraction was also previously assessed. A comprehensive characterization of MAE extracts was carried out by GC-MS. A total of 46 compounds, mostly terpenoids, were identified; piperitenone oxide and piperitenone were the major compounds determined. Several neophytadiene isomers were also detected for the first time in MAE extracts. Different procedures (solid-phase extraction and activated charcoal (AC) treatment) were also evaluated for clean-up of MAE extracts, with AC providing the highest enrichment in bioactive terpenoids. Finally, the MAE method here developed is shown as a green, fast, efficient and reproducible liquid extraction methodology to obtain M. rotundifolia bioactive extracts for further application, among others, as food preservatives.This work has been funded by Fundación Ramón Areces (project CIVP17A2843) and by Ministerio de Economía, Industria y Competitividad (MINEICO) of Spain (project AGL2016- 80475-R). The authors also thank financial support from the Comunidad Autónoma of Madrid and European funding from FEDER program (project S2013/ABI-3028, AVANSECAL). A.C.S. thanks MINECO for a Ramón y Cajal contract.Peer Reviewe

Insecticidal and Mutagenic evaluation of two annonaceous acetogenins

3 páginas, 1 figura y 2 tablas estadísticasAnnonaceous acetogenins represent a new class of bioactive compounds whose primary mode of action is the inhibition of NADH−ubiquinone oxidoreductase. Given the potential pesticidal use of such a class of compounds, we have further evaluated the antifeedant and insecticidal effects of squamocin and annonacin, two annonaceous acetogenins, on Spodoptera littoralis, Leptinotarsa decemlineata, and Myzus persicae. Additionally, to partially assess their environmental risk, we have also tested their mutagenicity in Salmonella typhimurium strains TA98, TA100, and TA102 in the presence and absence of a metabolic activation system. Among the test compounds, annonacin showed antifeedant effects on L. decemlineata, while squamocin was toxic to L. decemlineata and M. persicae. Neither acetogenin was mutagenic, although both were toxic in the absence of a metabolic activation system. We compared these results with those obtained with rotenone, a well-known respiratory inhibitor that was highly toxic to L. decemlineata and M. persicae and showed no mutagenicity/toxicity in the S. typhimurium strains tested up to a concentration of 1000 μg per plate.Grant DGICYT- Spain (PB) 94/OO20/BPeer reviewe

Optimization of fungicidal and acaricidal metabolite production by endophytic fungus Aspergillus sp. SPH2

Abstract The endophytic fungus Aspergillus sp. SPH2 was isolated from the stems of the endemic plant Bethencourtia palmensis and its extracts were found to have strong fungicidal effects against Botrytis cinerea and ixodicidal effects against Hyalomma lusitanicum at different fermentation times. In this study, the fungus was grown using three different culture media and two methodologies, Microparticulate Enhancement Cultivation (MPEC) and Semi-Solid-State Fermentation (Semi-SSF), to increase the production of secondary metabolites during submerged fermentation. The addition of an inert support to the culture medium (Semi-SSF) resulted in a significant increase in the extract production. However, when talcum powder was added to different culture media, unexpected results were observed, with a decrease in the production of the biocompounds of interest. Metabolomic analyses showed that the production of aspergillic, neoaspergillic, and neohydroxyaspergillic acids peaked in the first few days of fermentation, with notable differences observed among the methodologies and culture media. Mellein production was particularly affected by the addition of an inert support to the culture medium. These results highlight the importance of surface properties and morphology of spores and mycelia during fermentation by this fungal species. Graphical Abstrac