Total synthesis of lamellarin D and analogs library

Larnellarins are a group of marine natural products isolated from the prosobranch mollusc Lamellaria sp., the ascidian Didemnum sp., and the sponge Dendrilla Cactos. Several of them exhibit interesting biological activities. Natural as well as synthetic lamellarins should be excellent candidates for the development of new drugs due to their unique skeletal structure and their important biological activities especially as antitumor agents. Lamelarin O has been recently characterized as a topoisomerase 1-targeted anti tumor agent. A variety of synthetic approaches have been developed for this family of alkaloids. Herein we describe a new route to the synthesis of Lamellarin D, from a methyl 2-pyrrolecarboxylate. Transformation of the starting material into the scaffold, a substituted 5,6-dihydropyrrolo (2,l ­a)isoquinoline (5,6-DHPl), was afforded by N-alkylation followed by intramolecular Heck cyclization. From this scaffold the synthetic strategy is based on two sequential regioselective bromination!Suzuki cross-coupling reactions which permitted the introduction of differently substituted aryl groups on positions 1 and 2 followed by oxidation, deprotection, and lactonization.

Synthetic approaches towards the Lycopodium alkaloids

The Lycopodium alkaloids are a structurally diverse group of natural products isolated from Lycopodium with important biological effects for the potential treatment of cancer and severe neurodegenerative diseases. To date, full biological studies have been hampered by lack of material from natural sources. Total synthesis represents a possible solution to meet this demand as well as the most effective way to design new compounds to determine structural activity relationships and obtain more potent compounds. The aim of this chapter is to summarise the work carried out in this field so far by presenting an overview of the synthetic strategies used to access each of the four key Lycopodium alkaloid types. Particular emphasis has been placed on methods that rapidly construct each nucleus utilizing tandem reactions.

Synthetic approaches towards the Lycopodium alkaloids

The Lycopodium alkaloids are a structurally diverse group of natural products isolated from Lycopodium with important biological effects for the potential treatment of cancer and severe neurodegenerative diseases. To date, full biological studies have been hampered by lack of material from natural sources. Total synthesis represents a possible solution to meet this demand as well as the most effective way to design new compounds to determine structural activity relationships and obtain more potent compounds. The aim of this chapter is to summarise the work carried out in this field so far by presenting an overview of the synthetic strategies used to access each of the four key Lycopodium alkaloid types. Particular emphasis has been placed on methods that rapidly construct each nucleus utilizing tandem reactions.

Larock Reaction in the synthesis of heterocyclic compounds

The indole ring is one of the most common features in natural products and small molecules with important bioactivity. Larock reported a new methodology for the synthesis of the indole ring system based on the palladium-catalyzed heteroannulation of 2-iodoaniline and substituted alkyne moieties. This procedure was subsequently extended to the preparation of other nitrogen- and oxygen- containing heterocycles. This is the process of choice for the synthesis of a large number of heterocyclic derivatives, as it provides outstanding regioselectivity and good to excellent yields.

Larock Reaction in the synthesis of heterocyclic compounds

The indole ring is one of the most common features in natural products and small molecules with important bioactivity. Larock reported a new methodology for the synthesis of the indole ring system based on the palladium-catalyzed heteroannulation of 2-iodoaniline and substituted alkyne moieties. This procedure was subsequently extended to the preparation of other nitrogen- and oxygen- containing heterocycles. This is the process of choice for the synthesis of a large number of heterocyclic derivatives, as it provides outstanding regioselectivity and good to excellent yields.

Effect of high pressure processing on the microbiology of skin-vacuum packaged sliced meat products: cooked pork ham, dry cured pork ham and marinated beef loin

High hydrostatic pressure is being increasingly investigated in food processing. It causes microbial inactivation and therefore extends the shelf life and enhances the safety of food products. Yeasts, molds, and vegetative cells of bacteria can be inactivated by pressures in the range of 200 to 700 MPa. Microorganisms are more or less sensitive to pressure depending on several factors such as type, strain and the phase or state of the cells. In general, Gram-positive organisms are usually more resistant than Gram-negative. High pressure processing modifies the permeability of the cell membrane, the ion exchange and causes changes in morphology and biochemical reactions, protein denaturations and inhibition of genetic mechanisms. High pressure has been used successfully to extend the shelf life of high-acid foods such as refrigerated fruit juices, jellies and jams. There is now an increasing interest in the use of this technology to extend the shelf life of low-acid foods such as different types of meat products.

Estudi preliminar per la creació d'una nova categoria d'impacte ambiental dins el marc de l'ACV: la dimensió natural del paisatge

L’Anàlisi de Cicle de Vida (ACV) és una eina emprada per gestionar els impactes ambientals i els recursos usats al llarg del cicle de vida d’un bé o servei. Existeixen reptes de futur en el desenvolupament de l’ACV, tals com la introducció de noves categories d’impacte ambiental, que permetin una anàlisi més específica dels impactes sobre determinats elements del medi, com ara el paisatge. En el present estudi s’analitza la dimensió natural del paisatge per tal de proposar la creació d’un índex de paisatge. Així doncs, s’han revisat les noves propostes de categories d’impacte en ACV que inclouen directament o indirecta el paisatge i s’ha analitzat una mostra de 33 estudis d’indicadors de paisatge. Aquesta cerca deriva en l’elecció de 6 indicadors: els usos del sòl, la diversitat paisatgística, la fragmentació, la connectivitat, la riquesa d’espècies i la densitat de carreteres. En la determinació dels seus respectius mètodes de càlcul s’ha detectat la importància de l’ús dels SIG, l’elecció d’una base de dades d’usos del sòl comuna (CORINE) i les interrelacions que existeixen entre indicadors. La proposta de l’índex hauria de poder ésser un punt de partida per a futurs estudis en aquest àmbit i derivar en una nova categoria d’impacte de paisatge, donat que caldrà estudiar alguns elements, com la interrelació entre indicadors.

Qualitat microbiològica dels productes vegetals frescos mínimament processats i desenvolupament de tecnologies de bioconservació mitjançant bacteris de l'àcid làctic

Food safety today is conditiones by the implementation of new Tecnologies for food preservation based on mild treatments and mínimum process, Novel foods, severe restrictions in the toxicològic profile of chemical preservatives, And the drastic limitation /prohibition of antibiotics, and as a consequence, by the New emergint pathogens or by the increase of classical food-borne pathogens. Biopreservatives appear within this context with strong expectations, because thei are safe microorganisms of ten isolated from foods, chemical compounds of natural origin -antimicrobial peptides and proteins, botanical extracts, enzymes- and sintetic compounds based on natural structures, but less toxic and more eficients, like the amtimicrobial peptides. Among the microbial biopreservatives, lactic acid bacteria have shown great possibilities in the preservation of cured meat products, ready to eat fresh fruit and vegetables, as well as to decrease microbial spoilage in food by products before processing for valorization. Our laboratory has performed an extense survey of the microbiological quality of fresh fruit and vegetables, and of ready-to-eat products, and have detect low levels, but significant of Salmonella sp., E. coli and Listeria spp., including L.monocytogenes, in retail markets and Supermarkets of Catalonia. Due to this reason, we started a project consisting of Developing application of lactic acid bacteria (LAB) obtained from these products, as biopreservatives. LAB were abundant in ready-to-eat fresh fruits and vegetables, specially in germinated seeds. From these products we obtained strains of Leuconostoc, Lactobacillus and Weissella, producing bacteriocins and with a Significant activity of control of L.monocytogenes in fresh apple and cut salad. Ather strains were efective in the inhibition of fungal rot during postharvest caused by Penicillium expansum

Measurement of total estrone content in foods. Application to dairy products.

Estrone is a powerful growth-inducing hormone that is present in milk, mainly in the form of fatty acid esters, at concentrations that promote growth in experimental animals. We present here a method useful for the measurement of this natural hormone in foods and applied it to several common dairy products. Samples were frozen, finely powdered, and lyophilized then extracted with trichloromethane/methanol; the dry extract was saponified with potassium hydroxide. The free estrone evolved was extracted with ethyl acetate and was used for the estimation of total estrone content through radioimmunoassay. Application of the method to dairy products showed high relative levels of total estrone (essentially acyl-estrone) in milk, in the range of 1 ¿M, which were halved in skimmed milk. Free estrone levels were much lower, in the nanomolar range. A large proportion of estrone esters was present in all other dairy products, fairly correlated with their fat content. The amount of estrone carried by milk is well within the range, where its intake may exert a physiological response in the sucklings for which it is provided. These growth-inducing and energy expenditure-lowering effects may affect humans ingesting significant amounts of dairy products.

Contribution of microbial and invertebrate communities to leaf litter colonization in a Mediterranean stream

Leaf litter inputs and retention play an important role in ecosystem functioning in forested streams. We examined colonization of leaves by microbes (bacteria, fungi, and protozoa) and fauna in Fuirosos, an intermittent forested Mediterranean stream. Black poplar (Populus nigra) and plane (Platanus acerifolia) leaf packs were placed in the stream for 4 mo. We measured the biomasses and calculated the densities of bacteria, fungi, protozoa, meiofauna, and macroinvertebrates to determine their dynamics and potential interactions throughout the colonization process. Colonization was strongly correlated with hydrological variability (defined mainly by water temperature and discharge). The 1st week of colonization was characterized by hydrological stability and warm water temperatures, and allocation of C from microbial to invertebrate compartments on the leaf packs was rapid. Clumps of fine particulate organic matter (FPOM) were retained by the leaf packs, and enhanced rapid colonization by microfauna and meiofaunal collector-gatherers (ostracods and copepods). After 2 wk, an autumnal flood caused a 20-fold increase in water flow. Higher discharge and lower water temperature caused FPOM-related fauna to drift away from the packs and modified the subsequent colonization sequence. Fungi showed the highest biomass, with similar values to those recorded at the beginning of the experiment. After 70 d of postflood colonization, fungi decreased to nearly 40% of the total C in the leaf packs, whereas invertebrates became more abundant and accounted for 60% of the C. Natural flood occurrence in Mediterranean streams could be a key factor in the colonization and processing of organic matter.