3 resultados para Pests of plants

em Instituto Politécnico de Bragança


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Natural resources like plants are currently used all over developed and under developed countries of the world as traditional home remedies and are promising agents for drug discovery as they play crucial role in traditional medicine. The use of plants for medicinal purpose usually varies from country to country and region to region because their use depends on the history, culture, philosophy and personal attitudes of the users (Ahmad et al., 2015). The use of plants and plant products as drugs predates the written human history (Hayta et al., 2014). Plants are a very important resource for traditional drugs and around 80% of the population of the planet use plants for the treatment of many diseases and traditional herbal medicine accounts for 30-50% of the total medicinal consumption in China. In North America, Europe and other well-developed regions over 50% of the population have used traditional preparations at least once (Dos Santos Reinaldo et al., 2015). Medicinal plants have been used over years for multiple purposes, and have increasingly attract the interest of researchers in order to evaluate their contribution to health maintenance and disease’s prevention (Murray, 2004). Recently between 50,000 and 70,000 species of plants are known and are being used in the development of modern drugs. Plants were the main therapeutic agents used by humans from the 19th century, and their role in medicine is always topical (Hayta et al., 2014). The studies of medicinal plants are rapidly increasing due to the search for new active molecules, and to improve the production of plants or bioactive molecules for the pharmaceutical industries (Rates, 2001). Several studies have been reported, but numerous active compounds directly responsible for the observed bioactive properties remain unknown, while in other cases the mechanism of action is not fully understood. According to the WHO 25% of all modern medicines including both western and traditional medicine have been extracted from plants, while 75% of new drugs against infective diseases that have arrived between 1981 and 2002 originated from natural sources, it was reported that the world market for herbal medicines stood at over US $60 billion per year and is growing steadily (Bedoya et al., 2009). Traditional medicine has an important economic impact in the 21st century as it is used worldwide, taking advantage on the low cost, accessibility, flexibility and diversity of medicinal plants (Balunas & Kinghorn, 2005).

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Angiogenesis is a biological process through which there is the formation of new blood vessels from preexisting ones [I]. However, in pathological cases, the abnormal growth of new blood vessels promotes the development of various diseases including cancer [2) through the production of atypically large amounts of angiogenesis factors, e.g. the vascular endothelial growth factor (VEGF) [3]. The plant secondary metabolites have been the subject of several studies to evaluate their benefits to human health. In particular, the phenolic compounds have high potential for use in the food industry, including the development of functional foods. Among these, apigenin has been associated with chemopreventive effects related to cancer [4]. In fact, chemoprevention is a present-day concept and contemplates the use of medicines, biological compounds or nutrients as an intervention strategy of cancer prevention. In this work, an Arenaria montana L hydroethanolic extract was prepared and after characterization by HPLC-DAD-ESI/MS showed to be rich in apigenin derivatives. Furthermore, it exhibited ability to inhibit the phosphorylation of VEGFR-2 (vascular endothelium growth factor receptor) through an enzymatic assay. However, for the major protection of bioactive compounds, the extract was microencapsulated by an atomization/coagulation technique with alginate as the matrix material. Posteriorly, the hydroethanolic extract, in free and microencapsulated forms, was incorporated in yogurts in order to develop a novel chemopreventer food in relation to the angiogenesis process. The functionalized yogurts with A. montana extracts (free and microencapsulated) showed a nutritional value similar to the used control (yogurt without extract); however, the samples enriched with extracts revealed added-value regarding the VEGFR-2 phosphorylation inhibition ability. This effect was more effectively preserved over time in the samples functionalized with the protected extract. Overall, this work contributes to the valorization of plants rich in flavonoids, exploring its antiangiogenic potential with VEGFR-2 as target. Moreover, the atomization/coagulation technique allowed the production of viable microspheres enriched with the plant extract. The microspheres were effectively incorporated into yogurts, protecting the extract thus envisaging the development of novel functional foods with chemopreventive effects.

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Foeniculum vulgare Mill. (fennel) and Matricaria recutita L. (chamomile) are two examples of plants with reported antioxidant and antimicrobial properties, which can be related with their composition in phenolic compounds [1,2]. Furthermore, according to previous results of our research group, the direct incorporation of the aqueous extracts showed capacity to maintain the nutritional properties of the cottage cheeses, up to 7 days of storage, while improving the antioxidant potential. However, after 14 days, a decrease in the antioxidant properties was observed [1,2], which can be related with factors such as light, moisture, temperature and pH, that can cause bioactive compounds degradation. Therefore, the aim of the present study was to prepare microcapsules with the aqueous extracts of fennel and chamomile for incorporation in cottage cheese samples, in order to protect the bioactive molecules present in the extracts, such as phenolic compounds, and prevent the decrease of the antioxidant activity observed after the 14 days period. The microspheres were prepared using an atomization/coagulation technique. Sodium alginate was used as the matrix material to produce the microspheres that were characterized through optical microscopy (OM), during and after atomization, for inspecting morphology. The encapsulation efficiency (EE) was determined by HPLC-DAD by an indirect method by analysing the coagulation solution. FTIR was also used to attest the presence of the extract inside of the alginate matrix. These microencapsulated extracts were incorporated in cottage cheese samples that were further characterized in terms of nutritional properties and antioxidant potential right after incorporation, and after 7 and 14 days of storage at 4•c. The EE was estimated as -100% and the FTIR analysis confirmed the presence of the extracts inside the microspheres. The results showed that the incorporation of the microencapsulated extracts did not cause changes in the nutritional value of cottage cheeses (through a comparison with control samples without extracts). The predominant fatty acids were palmitic (C16:0) and oleic (CI8:0) acids. The order of abundance of fatty acids was as follows: saturated fatty acids (SF A)> monounsaturatcd fatty acids (MUF A)> polyunsaturated fatty acids (PUF A). Regarding free sugars, lactose was the only sugar identified and quantified in all samples. Regarding the antioxidant activity, the samples functionalized with the microencapsulated extracts showed a higher preservation of this property even after the 7th day of storage. Overall, the incorporation of the protected plant extracts in dairy foods can be a strategy to provide health benefits to consumers.