4 resultados para Steroidal saponins

em AMS Tesi di Dottorato - Alm@DL - Università di Bologna


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Phenol and cresols represent a good example of primary chemical building blocks of which 2.8 million tons are currently produced in Europe each year. Currently, these primary phenolic building blocks are produced by refining processes from fossil hydrocarbons: 5% of the world-wide production comes from coal (which contains 0.2% of phenols) through the distillation of the tar residue after the production of coke, while 95% of current world production of phenol is produced by the distillation and cracking of crude oil. In nature phenolic compounds are present in terrestrial higher plants and ferns in several different chemical structures while they are essentially absent in lower organisms and in animals. Biomass (which contain 3-8% of phenols) represents a substantial source of secondary chemical building blocks presently underexploited. These phenolic derivatives are currently used in tens thousand of tons to produce high cost products such as food additives and flavours (i.e. vanillin), fine chemicals (i.e. non-steroidal anti-inflammatory drugs such as ibuprofen or flurbiprofen) and polymers (i.e. poly p-vinylphenol, a photosensitive polymer for electronic and optoelectronic applications). European agrifood waste represents a low cost abundant raw material (250 millions tons per year) which does not subtract land use and processing resources from necessary sustainable food production. The class of phenolic compounds is essentially constituted by simple phenols, phenolic acids, hydroxycinnamic acid derivatives, flavonoids and lignans. As in the case of coke production, the removal of the phenolic contents from biomass upgrades also the residual biomass. Focusing on the phenolic component of agrifood wastes, huge processing and marketing opportunities open since phenols are used as chemical intermediates for a large number of applications, ranging from pharmaceuticals, agricultural chemicals, food ingredients etc. Following this approach we developed a biorefining process to recover the phenolic fraction of wheat bran based on enzymatic commercial biocatalysts in completely water based process, and polymeric resins with the aim of substituting secondary chemical building blocks with the same compounds naturally present in biomass. We characterized several industrial enzymatic product for their ability to hydrolize the different molecular features that are present in wheat bran cell walls structures, focusing on the hydrolysis of polysaccharidic chains and phenolics cross links. This industrial biocatalysts were tested on wheat bran and the optimized process allowed to liquefy up to the 60 % of the treated matter. The enzymatic treatment was also able to solubilise up to the 30 % of the alkali extractable ferulic acid. An extraction process of the phenolic fraction of the hydrolyzed wheat bran based on an adsorbtion/desorption process on styrene-polyvinyl benzene weak cation-exchange resin Amberlite IRA 95 was developed. The efficiency of the resin was tested on different model system containing ferulic acid and the adsorption and desorption working parameters optimized for the crude enzymatic hydrolyzed wheat bran. The extraction process developed had an overall yield of the 82% and allowed to obtain concentrated extracts containing up to 3000 ppm of ferulic acid. The crude enzymatic hydrolyzed wheat bran and the concentrated extract were finally used as substrate in a bioconversion process of ferulic acid into vanillin through resting cells fermentation. The bioconversion process had a yields in vanillin of 60-70% within 5-6 hours of fermentation. Our findings are the first step on the way to demonstrating the economical feasibility for the recovery of biophenols from agrifood wastes through a whole crop approach in a sustainable biorefining process.

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CHEMICAL COMMUNICATION IN BLATTARIA: CONTRIBUTION TO THE IMPROVEMENT OF THE CONTROL TECNIQUES The management of cockroach infestations in urban environment has undergone some changes in recent years by moving to the predominant use of baits, thanks to the awareness of the risks connected with the use of spray insecticides. The effectiveness of a bait is determined by the collective performance of its components, including active and inert ingredients, the food attractant and any other attractive odour. This research has focused on the behavioral responses of Italian sinanthropic cockroaches to semiochemicals and food attractants, for the purpose of evaluating a possible practical application and of contributing to the improvement of control techniques. Behavioral and morphological studies have been carried out on Supella longipalpa (F.), a small cockroach that is spreading in Italy. Behavioral assays showed that the fourth and fifth tergites of females are significantly more attractive than other region of the body. Cuticular pores and ducts ending in glandular structures (observed with a S.E.M. = Scanning Electron Microscope) are present in large number on these tergites, suggesting that they could be involved in the production and the release of sexual pheromone. Cockroaches produce an aggregation pheromone that is excreted along with their frass and that consists of volatile and non-volatile compounds, mainly amines and steroidal glycosides. The effectiveness of faecal extracts obtained from excrements of Blattella germanica (L.), Blatta orientalis L., Periplaneta americana (L.) and S. longipalpa was evaluated, both at intraspecific and interspecific level, using a "Y" tube olfactometer. Bioassays showed that faecal extracts obtained with methanol have a good intraspecific attractiveness and, in some cases, they showed also interspecific behavioral responses. A gel was prepared, having physical characteristics that could give a good resistance to dehydration, as a potential basis for a new bait; the gel was then added faecal extracts, obtained with methanol from B. germanica and S. longipalpa frass. Arena-tests showed that the new gel containing faecal extracts is more attractive than some commercial gel formulations used as comparison: it was the only product that could attract 100% of insects placed in the arenas in 4-5 days. In conclusion, the substances involved in chemical communication of Blattaria may be able to effectively increase the attractiveness of products for monitoring and controlling cockroaches.

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Iodine is an essential microelement for human health because it is a constituent of the thyroid hormones that regulate growth and development of the organism. Iodine Deficiency Disorders (IDDs) are believed to be one of the commonest preventable human health problems in the world today, according to the World Health Organization: that diseases include endemic goiter, cretinism and fetal abnormalities, among others, and they are caused by lack of iodine in the diet, that is the main source of iodine. Since iodine intake from food is not enough respect to human needs, this can be remedied through dietary diversification, mineral supplementation, food fortification, or increasing the concentration and/or bioavailability of mineral elements in the edible portions of crops through agricultural intervention or genetic selection (biofortification). The introduction of iodized salt is a strategy widely used and accepted to eradicate iodine deficiency, because it is an inexpensive source of stable iodine. Since the intake of salt, though iodized, must still be limited according to the risk of cardiovascular disease, so the increase of iodine content in plants for the production of functional foods is representing a field of study of particular interest and a potential market. In Italy potatoes enriched with iodine are produced by a patented procedure of agronomic biofortification for the fresh market since several years, furthermore they are recently accepted and recommended by Italian Thyroid Association, as an alternative source of iodine. Researches performed during the PhD course intended to characterize this innovative vegetables products, focusing the attention on different aspects, such as chemistry, agriculture, and quality of fresh and fried potatoes. For this purpose, lipid fraction of raw material was firstly investigated, in order to assess whether the presence of iodine in plant metabolism can affect fatty acid or sterol biosynthesis, according to the hypothesis that iodine can be bounded to polyunsaturated fatty acids of cell membranes, protecting them from peroxydation; phytosterols of plant sterol are also studied because their importance in reducing serum cholesterol, especially in potato plant sterols are also involved in synthesis of glycoalkaloid, a family of steroidal toxic secondary metabolites present in plants of the Solanaceae family. To achieve this goal chromatographic analytical techniques were employed to identify and quantify fatty acids and sterols profile of common and iodine enriched row potatoes. Another aim of the project was to evaluate the effects of frying on the quality of iodine-enriched and common potatoes. Since iodine-enriched potatoes are nowadays produced only for the fresh market, preliminary trials of cultivation under controlled environment were carried out to verify if potato varieties suitable for processing were able to absorb and accumulate iodine in the tuber. In a successive phase, these varieties were grown in the field, to evaluate their potential productivity and quality at harvest and after storage. The best potato variety to be destined for processing purposes, was finally subjected to repeated frying cycles; the effects of lipid oxidation on the composition and quality of both potatoes and frying oil bath were evaluated by chromatographic and spectrophotometric analytical techniques. Special attention were paid on volatile compounds of fried potatoes.

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Il trattamento dell’osteoartrosi (OA) del cane è una sfida nella pratica clinica veterinaria. Molti trattamenti sono stati proposti, tuttavia la risposta clinica agli stessi non è sempre soddisfacente. Molti farmaci sono utilizzati per il trattamento dell’OA, tra cui farmaci anti-infiammatori non steroidei, corticosteroidi, ed inibitori della produzione dell’ossido nitrico. Lo stanozololo è un derivato sintetico del testosterone; oltre alle sue proprietà anaboliche/androgeniche , a basse dosi lo stanozololo ha un affinità per i recettori glucocorticoidi. Per questa attività antinfiammatoria e rigenerativa sui tessuti articolari danneggiati viene utilizzato nella degenerative joint desease del cavallo. Lo scopo di questo studio è stato di valutare l’efficacia clinica dello stanozololo intra-articolare a 15, 30, 45 e 60 giorni dal trattamento di gomiti con OA di cane. E’ stato eseguito uno studio cieco, multicentrico e randomizzato. Previo consenso informato, sono stati arruolati 48 cani, suddivisi in 3 gruppi e trattati con stanozololo, mavacoxib e con entrambi i farmaci. Sono state valutate zoppia, tollerabilità del trattamento, range of motion, e punteggio radiografico. Inoltre sono state stabilite e annoverate quantità e qualità del liquido sinoviale. Ai dati ottenuti sono stati applicati i test di Kruskal-Wallis, Chi-quadro e Fischer, i quali hanno dimostrato l’efficacia della terapia nei singoli gruppi e tra i diversi gruppi di studio. I risultati ottenuti hanno mostrato la riduzione di almeno un grado di zoppia e la riduzione della progressione dell’OA nei casi trattati con stanozololo. Si può quindi affermare che tale molecola per via intra-articolare può essere una valida alternativa per il trattamento dell’OA di gomito nel cane.