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Nutricional evaluation and research and characterization of peptides with inhibitory activity of angiotensin I-converting enzyme (ACE) in macroalgae of the Azores
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Abstract(s)
As macroalgas Fucus spirolis, Ulva rigida, u. compressa, Porphyra sp. E Osmundea pinnatifida são consumidas como alimento em algumas das ilhas dos Açores, enquanto que Gelidium microdon e Pterocladiella capillacea são coletadas para a produção de agar. No entanto, pouca informação está disponível sobre o seu valor como fonte natural de compostos nutricionais e funcionais.
Esta tese investigou principalmente a composição nutricional e os aspetos promotores de saúde destas macroalgas, bem como o seu potencial como fonte de frações peptídicas e/ou de péptidos purificados inibidores da ECA.
Em relação aos aspetos nutricionais das macroalgas, esta tese investigou, pela primeira vez, as proteínas, o perfil de aminoácidos, a digestibilidade das proteínas in vitro, os lípidos, o perfil de ácidos gordos (saturados, monoinsaturados, polinsaturados e a razão n6/n3 e h/H), os hidratos de carbono solúveis, a fibra alimentar, as cinzas, os minerais e a razão Na/K e Ca/ Mg, as vitaminas, a coenzima Q10 a humidade, o teor de fenólicos totais, as atividades antioxidante e inibitória da ECA in vitro e o valor energético. Os resultados sugerem que um consumo regular destas algas, quer diretamente ou através de suplementos alimentares, pode melhorar a saúde humana ou pode ter um efeito protetor sobre algumas doenças degenerativas e, consequentemente, sobre o processo de envelhecimento.
As macroalgas podem também ser utilizadas para a produção de produtos farmacêuticos com potencial valor económico. como é do conhecimento geral, a enzima conversora da angiotensina I (ECA) tomou-se um importante alvo para o controlo da pressão arterial, uma vez que catalisa a conversão de angiotensina I num potente vasoconstritor a angiotensina II. Recentemente, cada vez mais atenção tem sido dada às algas marinhas como fontes naturais de novos inibidores da ECA. Neste trabalho foram isolados e caracterizados alguns péptidos em U. rigida e os resultados revelaram, pela primeira vez, que péptidos inibidores da ECA podem ser eficientemente obtidos a partir das proteínas hidrolisadas pelas enzimas pepsina-bromelaína. Dois péptidos inibidores da ECA (IP e AFL) foram isolados e purificados com sucesso a partir deste hidrolisado. Os seus modos de inibição e estabilidade a diferentes temperaturas e os estudos in vitro do efeito das proteases gastrointestinais na atividade destes péptidos foram também caracterizados pela primeira vez. Além disso, o tripéptido AFL foi hidrolisado por peptidases da mucosa intestinal dando origem a um dipéptido FL que apresentou uma maior inibição da ECA relativamente ao seu percursor.
Esta tese também apresenta, pela primeira vez, as atividades inibitória da ECA e antioxidante in vitro por frações proteicas hidrolisadas de F. spiralis, bem como o perfil de aminoácidos e o conteúdo em fenólicos totais destas frações. Os resultados revelaram que não só os péptidos ativos, mas também os compostos fenólicos contribuem para as elevadas atividades inibitória da ECA e antioxidante das fracções proteicas hidrolisadas de F. spiralis. Avaliou-se, ainda, pela primeira vez, o efeito inibitório da ECA por extratos/frações metanólicas de F. spiralis, o respetivo conteúdo em fenólicos totais e o efeito da temperatura de armazenamento do extrato metanólico seco de F. spiralis na inibição da ECA. Os resultados sugerem que esta macroalga é muito rica em florotaninos, os polifenóis mais abundantes em algas castanhas e que têm sido referidos como sendo uma fonte potencial de compostos inibidores da ECA.
Em conclusão, as macroalgas estudadas podem ser usadas como alimentos funcionais e são uma fonte natural e potencial de frações/péptidos inibidores da ECA que podem ser utilizados para a produção de nutracêuticos e farmacêuticos para prevenir e/ou tratar a hipertensão. A sua utilização seria uma terapia natural alternativa, económica e mais segura, aos medicamentos comerciais sintéticos e atuaria como um incentivo para a conservação da biodiversidade e para a manutenção de um ambiente limpo nos Açores.
ABSTRACT: The macroalgae Fucus spiralis, Ulva rigida, U. compressa, Porphyra sp. and Osmundea pinnatifida are consumed as food in some of the Azorean Islands, whereas Gelidium microdon and Pterocladiella capillacea are collected for agar production. Little information is, however, available on their value as natural sources of nutritional and/or functional metabolites content. This thesis investigated mainly the nutritional composition and health-promoting aspects of those selected macroalgae as well as their potential as source of protein-derived ACE-inhibitory peptide fractions and/or purified peptides. Regarding the macroalgal nutritional aspects, this thesis evaluated, for the first time, the proteins, amino acid profiles, in vitro protein digestibility, lipids, fatty acid profiles (SFA, MUFA, PUFA and n6/n3 and h/H ratios), soluble carbohydrate, dietary fiber, ash, minerals and Na/K and Ca/Mg ratios, vitamins, coenzyme Q10, moisture, total phenolic content, in vitro antioxidant and ACE inhibition activities and energy values. The results suggested that a regular consumption of these macroalgae, either directly or through food supplements, may improve human health or may have a protective effect on some of the degenerative diseases and consequently on the ageing process. Macroalgae can also be used for the production of pharmaceuticals with potential economic value. It is well known that angiotensin-I converting enzyme (ACE) became a major target control for high blood pressure, since catalyzes the conversion of angiotensin I to a potent vasoconstrictor angiotensin II. Recently, increasing attention has been paid to the marine algae as natural sources of novel ACE-inhibitors. In this thesis the isolation and characterization of some peptides from U. rigida were achieved and the results revealed, for the first time, that ACE-inhibitory purified peptides could be efficiently generated from U. rigida protein hydrolyzed by the pepsin-bromelain enzymes. Two ACE-inhibitory peptides (IP and AFL) were successfully isolated and purified from this hydrolysate. Their inhibition patterns and stability at different temperatures and the in vitro study of the gastrointestinal proteases effect on the activity of these peptides were firstly characterized. Furthermore, AFL was hydrolyzed by intestinal mucosa peptidases to a dipeptide FL with a more potent ACE inhibition relatively to its precursor. This thesis also reports, for the first time, the in vitro ACE-inhibitory and antioxidant activities by F. spiralis protein hydrolysate fractions and their amino acid profiles and total phenolic content. Results suggest that not only the active peptides, but also the phenolic compounds contribute to the strong ACE-inhibitory and antioxidant activities of F. spiralis protein hydrolysate fractions. Furthermore, this is the first study reporting the ACE inhibition by methanol extract/fractions from F. spiralis, their total phenolic content and the effect of the storage temperature of F. spiralis dry powder methanol extract on ACE inhibition. Results suggest that this macroalgae is very rich in phlorotannins, the most abundant polyphenols in brown algae that have been reported to be a potential source of powerful ACE-inhibitory compounds. In conclusion, the studied Azorean macroalgae can be used for functional foods supplementation and are a natural potential source of ACE-inhibitory fractions/peptides that may be used for the production of nutraceuticals and pharmaceuticals to prevent and/or to treat hypertension. Their use would be economical, safer and a natural alternative therapy to commercial synthetic drugs, and would make an incentive for the biodiversity conservation and for the maintenance of a clean environment in the Azores.
ABSTRACT: The macroalgae Fucus spiralis, Ulva rigida, U. compressa, Porphyra sp. and Osmundea pinnatifida are consumed as food in some of the Azorean Islands, whereas Gelidium microdon and Pterocladiella capillacea are collected for agar production. Little information is, however, available on their value as natural sources of nutritional and/or functional metabolites content. This thesis investigated mainly the nutritional composition and health-promoting aspects of those selected macroalgae as well as their potential as source of protein-derived ACE-inhibitory peptide fractions and/or purified peptides. Regarding the macroalgal nutritional aspects, this thesis evaluated, for the first time, the proteins, amino acid profiles, in vitro protein digestibility, lipids, fatty acid profiles (SFA, MUFA, PUFA and n6/n3 and h/H ratios), soluble carbohydrate, dietary fiber, ash, minerals and Na/K and Ca/Mg ratios, vitamins, coenzyme Q10, moisture, total phenolic content, in vitro antioxidant and ACE inhibition activities and energy values. The results suggested that a regular consumption of these macroalgae, either directly or through food supplements, may improve human health or may have a protective effect on some of the degenerative diseases and consequently on the ageing process. Macroalgae can also be used for the production of pharmaceuticals with potential economic value. It is well known that angiotensin-I converting enzyme (ACE) became a major target control for high blood pressure, since catalyzes the conversion of angiotensin I to a potent vasoconstrictor angiotensin II. Recently, increasing attention has been paid to the marine algae as natural sources of novel ACE-inhibitors. In this thesis the isolation and characterization of some peptides from U. rigida were achieved and the results revealed, for the first time, that ACE-inhibitory purified peptides could be efficiently generated from U. rigida protein hydrolyzed by the pepsin-bromelain enzymes. Two ACE-inhibitory peptides (IP and AFL) were successfully isolated and purified from this hydrolysate. Their inhibition patterns and stability at different temperatures and the in vitro study of the gastrointestinal proteases effect on the activity of these peptides were firstly characterized. Furthermore, AFL was hydrolyzed by intestinal mucosa peptidases to a dipeptide FL with a more potent ACE inhibition relatively to its precursor. This thesis also reports, for the first time, the in vitro ACE-inhibitory and antioxidant activities by F. spiralis protein hydrolysate fractions and their amino acid profiles and total phenolic content. Results suggest that not only the active peptides, but also the phenolic compounds contribute to the strong ACE-inhibitory and antioxidant activities of F. spiralis protein hydrolysate fractions. Furthermore, this is the first study reporting the ACE inhibition by methanol extract/fractions from F. spiralis, their total phenolic content and the effect of the storage temperature of F. spiralis dry powder methanol extract on ACE inhibition. Results suggest that this macroalgae is very rich in phlorotannins, the most abundant polyphenols in brown algae that have been reported to be a potential source of powerful ACE-inhibitory compounds. In conclusion, the studied Azorean macroalgae can be used for functional foods supplementation and are a natural potential source of ACE-inhibitory fractions/peptides that may be used for the production of nutraceuticals and pharmaceuticals to prevent and/or to treat hypertension. Their use would be economical, safer and a natural alternative therapy to commercial synthetic drugs, and would make an incentive for the biodiversity conservation and for the maintenance of a clean environment in the Azores.
Description
Tese de Doutoramento, Biologia, 25 de setembro de 2017, Universidade dos Açores.
Keywords
Bioquímica Inibidores Naturais Macroalgas Marinhas Péptido Bioativo Bioactive Peptides Biochemical Composition Macroalgae Natural ACE-inhibitors Nutritional and Functional Foods
Citation
Paiva, Lisete Sousa. "Nutricional evaluation and research and characterization of peptides with inhibitory activity of angiotensin I-converting enzyme (ACE) in macroalgae of the Azores". 2017. 241 p.. (Tese de Doutoramento em Biologia). Ponta Delgada: Universidade dos Açores, 2016. [Consult. Dia Mês Ano]. Disponível em www:<http://hdl.handle.net/10400.3/4572>.