Interacção de fármacos com lipossomas: áreas de aplicação

Os lipossomas têm a capacidade de simular muitas das propriedades das membranas celulares, constituindo ferramentas valiosas para o estudo das consequências da interacção fármaco-lípido a nível das propriedades físico-químicas e estruturais, quer da membrana quer do fármaco e respectivos efeitos no mecanismo de acção deste. Por outro lado, devido à singular morfologia e capacidade de intervir em fenómenos de transporte na bicamada fosfolipídica, o uso de lipossomas como transportadores de fármacos tem sido largamente estudado. Liposomes are able to simulate many of the properties of cell membranes, providing valuable tools for the study of drug-lipid interaction consequences. Such consequences can be changes on whether the membrane’s or the drug’s physical-chemical and structural properties, and its effects on the action mechanism of the latter. Furthermore, due to natural morphology and ability to intervene in the transport phenomena in phospholipic bilayer, the use of liposomes as carriers of drugs has been widely studied

Development of innovative nanotechnology-based drug delivery systems for cancer therapy

Controlled drug delivery systems are not a new subject in the biomedical field. The continuously increasing need for the improvement of health care services has been the driving force for both search and development of such systems. Among these, micro- and nano-sized vehicles (e.g. nanocapsules, liposomes and mixed micelles) have received special attention over the last decade; they have been used for the delivery and vectorization of many pharmacologically active molecules, as is the case of anti-neoplastic drugs.Os sistemas de libertação controlada de fármacos não são uma temática recente na área das ciências biomédicas: a crescente exigência no sector dos cuidados de saúde despoletou o desenvolvimento desta área científica. De entre os vários tipos de sistemas propostos, as micro- e nano-estruturas (i.e., nanocápsulas, lipossomas e micelas mistas) têm recebido especial atenção por parte dos investigadores ao longo da última década, tendo sido desenvolvidos sistemas de libertação e vectorização de muitas moléculas farmacologicamente activas, nomeadamente de fármacos anti-neoplásicos.info:eu-repo/semantics/publishedVersio

Proteins and peptides: non-invasive delivery

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Trace minerals in human health: iron, zinc, copper, manganese and fluorine

Trace elements exist in the environment in small amounts but play an essential part in sustaining various physiological and metabolic processes occurring within living tissues, as enzymes structure and function, bone and blood maintenance, immune responses or transmission of nerve impulses. They must be obtained from diet, being a varied and balanced diet important for obtaining a series of elements necessary for our body. The total amount of a mineral in a food that is dependent on digestion, its release from the food matrix and the absorption rate by the intestinal cells. If minerals are not supplied in adequate quantities, signs and symptoms of trace elements deficiencies appear. Beyond the nutritional aspects, trace elements have applications in the pharmaceutical industry, integrating pharmacologically active compounds. Usually, in the form of metal complexes, these metal-based drugs are used as anticancer therapeutics, antiinflammatories, antidiabetic drugs or antimicrobial agents. This evolving field is developing metal complexes with remarkable actions, and new metal-based drugs are emerging every year. This article aims to review the main effects of trace elements in human health, namely iron, zinc, copper, manganese and fluorine, focusing on the physiopathology and consequences of lack or excess of these elements. Also, it offers an overview of research information published in recent years concerning the use of these metals in compounds that show promising pharmacological activities.info:eu-repo/semantics/publishedVersio

Esteroisómeros na terapêutica com bloqueadores beta-adrenérgicos

A maioria dos fármacos comercializados atualmente são estereoisómeros, podendo estes apresentarse na forma de enantiómeros ou diastereómeros. Desde que a talidomida causou inúmeros casos de malformações fetais, as indústrias química e farmacêutica aperceberam-se da importância do estudo da quiralidade dos fármacos e das suas propriedades estereoquímicas. A análise da correlação entre a quiralidade e as propriedades toxicológicas e farmacológicas dos compostos levou, não só à eliminação de efeitos adversos, como também a benefícios terapêuticos. Tem surgido uma tendência para a comercialização de novos fármacos sob a forma de enantiómeros puros, pois apresentam vantagens em relação às misturas racémicas. A escolha entre um enantiómero ou uma mistura racémica depende das vantagens terapêuticas, dos efeitos adversos e dos custos de desenvolvimento. Este trabalho evidência as diferenças a nível da atividade biológica e dos parâmetros farmacocinéticos entre os racematos e os estereoisómeros dos bloqueadores β-adrenérgicos. À semelhança do que acontece com outros fármacos, na sua maioria, os bloqueadores β são prescritos como racematos.Contudo, em humanos, os seus S-enantiómeros são muito mais eficazes que os seus antípodas, por exemplo, no tratamento de patologias cardíacas, podendo a purificação e administração do eutómero traduzir-se em benefício clínico para o doente.info:eu-repo/semantics/publishedVersio

Valorization of watermelon fruit (Citrullus lanatus) byproducts: phytochemical and biofunctional properties with emphasis on recent trends and advances

Watermelon (Citrullus lanatus) a fruit crop, is an herbaceous creeping plant belonging to the family Cucurbitaceae. It is a tropical plant, mainly propagated by seeds and thrives best in warm areas. While the fruit pulp is consumed, seeds are often discarded. The continuously growing global market for the main tropical fruits is currently estimated at 85 million tons, of which approximately half is lost or wasted throughout the whole processing chain. Developing novel processes for the conversion of these byproducts into value‐added products could provide a viable way to manage this waste problem, aiming at the same time to create a sustainable economic growth within a bio‐economy perspective. Given the ever‐increasing concern about sustainability, complete valorization through a bio‐refinery approach, that is, zero waste concepts is therefore most important. This paper aims to report the status on the valorization of tropical fruit byproducts, more specifically in watermelon seeds and their content in bioactive compounds, such as phenolic acids, flavonoids, carotenoids, alkaloids. Moreover, the bioactivity of the different types of phytochemicals and their possible application as a resource for different sectors (food, pharmaceutical, and environmental sciences) is discussed. Consequently, this review presents the concepts of tropical fruit byproducts recovery, and the potential applications of the isolated fractions.info:eu-repo/semantics/publishedVersio

Usos populares de plantas medicinais da flora transmontana

Neste trabalho é apresentado um estudo sobre o uso tradicional das plantas medicinais de dois concelhos da região de Trás-os-Montes. Durante o estudo, foram obtidos resultados relativos às plantas com maior uso medicinal e suas aplicações terapêuticas bem como as partes da planta mais usadas de 88 espécies pertencentes a 47 famílias de plantas indígenas. As propriedades terapêuticas mais referenciadas são os efeitos diurético, antiasténico e como vulnerário. Partindo de um relatório etnofarmacológico de várias plantas serão, posteriormente, seleccionadas aquelas que, tendo larga aplicação na medicina tradicional, não tenham sido estudadas do ponto de vista bioquímico e de actividade terapêutica. In this work a study of folk use of the medicinal plants of two councils bellowing to Trás-os-Montes region is presented. During the study, data for 88 species were obtained belonging to 47 families of vascular plants. The most report therapeutic properties are as diuretic, as anti-asthenia and as vulnerary. From an ethnopharmacological report done, will be subsequently selected those plants that, having, not only, a wide range of usage in traditional medicine but also, have not yet been studied in biochemical or therapeutic activity terms

Noninvasive methods to determine the critical micelle concentration of some bile acid salts

In this work the critical micelle concentrations (cmc) of four bile salts, sodium cholate, sodium glycocholate, sodium deoxycholate, and sodium glycodeoxycholate, are determined and presented. Three independent noninvasive methodologies (potentiometry, derivative spectrophotometry, and light scattering) were used for cmc determination, at 25 degrees C with ionic strength adjusted to 0.10 M with NaCl. Spectrophotometric and potentiometric studies of some bile salts were also executed at various ionic strength values, thus allowing the influence of the ionic strength on the cmc value of the bile salt to be assessed. A critical comparison of the cmc values obtained with data collected from the literature is presented. Furthermore, this work makes an evaluation of the conceptual bases of different methodologies commonly used for cmc determination, since variations in the results obtained can be related mainly to different intrinsic features of the methods used (such as sensitivity or the need to include tracers or probes) or to the operational cmc definition applied. The undoubted definition of the experimental bile salt concentration that corresponds to cmc (operational cmc) is essential since in the case of these amphiphiles the formation of micelles is not as abrupt as in the case of ordinary association colloids. The biphasic nature of their aggregation leads to a "round-shaped" variation of the experimental parameters under analysis, which makes difficult the evaluation of the cmc values and can be responsible for the different results obtained.info:eu-repo/semantics/publishedVersio

Antispasmodic activity of aqueous extracts from Mentha x piperita native from Trás-os-Montes region (Portugal)

The wild mint Mentha x piperita (Mentha rotundifolia Huds.), has been used by the local people in a northern region of Portugal to prepare infusions for treating digestive pain and spasms, as an appetite stimulant and for treating headache and migraine. This suggests that these aqueous extracts have analgesic; antispasmodic and stomachic properties. In the present study the antioxidant potential of aqueous extracts of Mentha x piperita is investigated since natural antioxidants can scavenge the reactive oxygen species, ROS, and thus might attenuate inflammation pathways. The antispasmodic activity was also checked. The antioxidant potential of the extract was evaluated by the DPPH• method, by the quantification of the total phenolic compounds and by characterization of the main phenolic compounds. The antispasmodic effects were investigated by performing pharmacological assays using the distal ileum of guinea pigs. The aqueous extract exhibits antioxidant properties that may be due to its phenolic content. The main phenolic compounds were quinic, caffeic, rosmarinic and chlorogenic acids. The antispasmodic affects are observed after electrical stimulation of segments of distal ileum of guinea pigs and may be attributed, at least, to a alfa-1 blockage.info:eu-repo/semantics/publishedVersio