Searching for biocompounds in algae and seagrasses with potential use in thetreatment of Alzheimer’s disease

• Autor(a) principal: Silvestre, Águeda Laura dos Santos
• Data de Publicação: 2017
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.1/10712
• topic: Alzheimer; Actividade quelante; Acetilcolinesterase; Butirilcolinesterase; Recursos naturais marinhos; Neuroproteção

The number of older people at risk of developing dementia is growing rapidly worldwide, and Alzheimer’s disease (AD) represents the most common cause of dementia in the elderly. The principal characteristics of AD include the presence of amyloid plaques, neurofibrillary tangles, brain atrophy in specific brain areas and loss of the neurotransmitter acetylcholine (ACh), which is hydrolysed by the cholinesterases (ChE) acetylcholinesterase (AChE) and secondly by butyrilcholinesterase (BChE). Pharmacological treatments currently used to alleviate AD symptoms include ChE inhibitors, but they exhibit bioavailability problems and side effects like hepatotoxicity and gastrointestinal disorders. Thus, there is a high interest in finding better ChE inhibitors from natural sources. Due to the high oxygen consumption and lipid content, the central nervous system (CNS) is more sensitive to oxidative stress compared to other parts of our body. Thus, special interest has been assigned in nutritional antioxidants and metal chelation therapy as viable neuroprotective approaches for neurodegenerative disorders. Marine organisms are recognized as rich sources of novel biologically active compounds. However, its application in the treatment of neurological disorders is still scarcely explored. In this context, the main goal of this study was to evaluate the AChE and BChE inhibitory activity of methanol extracts made from different species of macro- and microalgae, seagrasses and halophytes, as well as evaluate their chelating activity on iron (Fe2+) and copper (Cu2+) ions. The most active species against both enzymes were the brown macroalgae Cystoseira compressa, C. nodicaulis and C. tamariscifolia and the halophytes Carpobrotus edulis and Frankenia laevis. The chelating activity was higher for Cu2+ than for Fe2+ in the majority of the species tested, being the most active the red macroalgae Plocamium cartilageneum. These species are thus promising candidates for more detailed in vitro and in vivo studies aiming their use as sources of innovative products with neuroprotective aplications.