Márcia Barbosa de Sousa

α-, β-caroteno e α-tocoferol em algas marinhas in natura

The aim of this work was to evaluate the potential of 32 marine macro algae species, members of Chlorophyta, Rhodophyta and Phaeophyta, as sources of a-carotene, b-carotene and a-tocopherol. Both b-carotene and a-carotene were found in all species of green macroalgae analyzed. The maximum content of a-carotene was detected in algae belonging to Caulerpa genus and the minimum in Codium decorticatum. The amount of b-carotene found was minimum in Caulerpa mexicana and maximum in Ulva fasciata. Among the Rhodophyta species, eleven contain a-carotene, the maximum content was found in Botryocladia occidentalis. b-Carotene was found in all red macroalgae analyzed presenting the lowest and highest values in Gracilaria caudata and Bryothamnion triquetrum, respectively. Species of Phaeophyta contained b-carotene but no a-carotene. The lowest value for b-carotene was found in Dictyopteris delicatula and the highest in Padina gymnospora. In Chlorophyta, the amount of a-tocopherol was maximum in Codium decorticatum and minimum in Caulerpa prolifera. In Rhodophyta, twelve species contained a-tocopherol, the highest value was found in Enantiocladia duperreyi. a-Tocopherol was detected in all Phaeophyta species analyzed. The highest and lowest values were found in Lobophora varigata and Dictyota dichotoma, respectively.

Antioxidant potential and cytotoxic activity of two red seaweed species, Amansia multifida and Meristiella echinocarpa, from the coast of Northeastern Brazil

Natural antioxidants found in marine macroalgae are bioactive compounds known to play an important role in the prevention of diseases associated with aging cells protecting them against the oxidative damage. The purpose of this study was to evaluate the antioxidant and cytotoxic activity of ethanolic extracts of two species of red seaweeds, Amansia multifida and Meristiella echinocarpa. In vitro antioxidant activity was determined by DPPH radical scavenging assay, ferric-reducing antioxidant power (FRAP) assay, ferrous ion chelating (FIC) assay, β-carotene bleaching (BCB) assay and total phenolic content (TPC) quantification. Cytotoxicity was evaluated with the brine shrimp Artemia sp. lethality test. The TPC values observed in the present study indicated that both species A. multifida and M. echinocarpa are rich in phenolic compounds, reaching values of 45.40 and 28.46 mg gallic acid equivalent (GAE) g-1 of ethanolic extract, respectively. DPPH radical scavenging and ferrous ion chelating showed values of 60% and 17%, respectively. Both seaweed extracts inhibited β-carotene oxidation by approximately 40%. None of the algal extracts were potentially cytotoxic. The results have showed that extracts of both species of marine red algae exhibit antioxidant potential and low toxicity. They are sources of natural antioxidant compounds.

Seasonal changes of α-tocopherol in green marine algae (Caulerpa genus).

Marine algae are a promising source of beneficial compounds for human use. Among these, pro-vitamin A carotenoids and vitamins B, C, and E stand out. The objective of this study was to investigate seasonal variation of α-tocopherol levels in 5 species of green marine algae of the Caulerpa genus. This research was carried out with both fresh and dry specimens; and, in addition, differences arising as a result of the drying process were examined. Analyses were carried out by high-performance liquid chromatography (HPLC) using an isocratic system and a reversed-phase C-18 column. The distribution of α-tocopherol throughout the year in Caulerpa genus was variable. All samples of both fresh and dried algae contained α-tocopherol, except for the dried C. racemosa from March 2006. The drying process was responsible for losses of α-tocopherol ranging from 21% to 93%.

Aminas biogênicas em macroalgas marinhas do Estado do Ceará, Brasil

Muitas aminas sao comumente encontradas em alimentos de origem vegetal e animal, porem apenas um pequeno numero e de interesse por produzirem reacoes adversas se ingeridas e absorvidas no organismo humano. Dentre elas, a histamina e a tiramina podem desencadear sintomas de intoxicacao. As algas marinhas sao amplamente consumidas pelos povos orientais, e, no Ocidente, seu consumo encontra-se em expansao. O Brasil nao tem esta tradicao, mas a diversidade de especies encontradas no litoral brasileiro as torna potencialmente uteis como alimento humano. Para promove-las com essa finalidade, sao necessarios estudos quimicos e bioquimicos. No presente trabalho, treze especies de macroalgas marinhas coletadas na praia do Pacheco, no municipio de Caucaia - CE, foram preliminarmente analisadas quanto a presenca de histamina e tiramina por cromatografia liquida de alta eficiencia. A identificacao destas aminas biogenicas foi feita com base nos tempos de retencao dos padroes comerciais de dicloridrato de histamina e cloridrato de tiramina, comparados com aqueles correspondentes aos mesmos compostos nos extratos algais. Nenhuma das treze especies estudadas neste trabalho apresentou histamina e/ou tiramina em quantidades capazes de provocar sintomas de intoxicacao atraves do seu consumo.

Teores de β-caroteno em suplementos e biomassa de Spirulina

A cianobacteria Spirulina tem sido utilizada ha seculos, tendo em vista suas propriedades nutricionais e medicinais. Neste trabalho, objetivou-se analisar os teores de β-caroteno tanto em suplementos alimentares a base de Spirulina comercializados em estabelecimentos de produtos naturais no mercado varejista, quanto em S. platensis cultivada em laboratorio. Alguns pigmentos carotenoides possuem atividade de vitamina A e, dentre eles, o β-caroteno e o que apresenta maior atividade biologica. A extracao de β-caroteno foi feita com metanol:agua (90:10 v/v), seguida de saponificacao e particao em n-hexano. As analises cromatograficas foram realizadas em coluna Waters Spherisorb S5 ODS 2 (4,6 x 250 mm), usando metanol:tetrahidrofurano (90:10, v/v) bombeado a 2 mL min-1, com registro dos cromatogramas em 450 nm. Os suplementos alimentares a base de Spirulina apresentaram baixos teores de β-caroteno. A maior concentracao foi encontrada em S. platensis cultivada a 24o C com fotoperiodo de 16 h claro e 8 h escuro. Considerando sua atividade provitaminica, os teores de retinol equivalente (RE) nas microalgas analisadas no presente trabalho foram calculados a partir do β-caroteno para classifica-las como fonte excelente ou fonte util de vitamina A.