Daniel Barroso de Alencar

In vivo anti-inflammatory effect of a sulfated polysaccharide isolated from the marine brown algae Lobophora variegata.

Context: Lobophora variegata J.V. Lamouroux (Dictyotaceae) is a brown marine alga widely encountered in the Brazilian sea coast that presents high content of fucans. Anti-inflammatory effects of fucans are reported mostly in models in vitro, but little is known about its effects in vivo. Objective: To investigate vascular and cellular effects of a sulfated polysaccharide from the brown marine algae L. variegata (SP-Lv) in acute inflammatory models. Materials and methods: SP-Lv was isolated by DEAE-cellulose and analyzed by agarose gel electrophoresis and evaluated for its inhibitory effect on paw edema, vascular permeability, leukocyte migration and peritoneal nitrite content induced by zymosan in Wistar rats. Anticoagulant activities and possible systemic toxicity were also evaluated. Results: SP-Lv inhibited the paw edema (120 min: 1.42 ± 0.11 vs. 0.95 ± 0.05 mL), plasma exudation (21.53 ± 0.62 vs. 11.96 ± 0.68 μg/g), nitrite content (4.42 ± 0.33 vs. 2.86 ± 0.003 μM) and leukocyte migration (5.15 ± 1.21 vs. 1.99 ± 0.16 cells/103 mL) induced by zymosan. SP-Lv and l-NAME reduced the paw edema (60–120 min) elicited by l-arginine. However, at 180 min SP-Lv effect was more accentuated and sustained until 240 min, while that of l-NAME was abolished. Similarly to indomethacin, SP-Lv inhibited the entire edema time-course induced by phospholipase A2, except for the time of 60 min. Discussion and conclusion: The anti-edematogenic effect of SP-Lv seems to occur via inhibition of nitric oxide synthase and cyclooxygenase activities. These results suggest a potential applicability of polysaccharides from alga origin in acute inflammatory conditions.

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%.

Antioxidant, hemolytic, antimicrobial, and cytotoxic activities of the tropical Atlantic marine zoanthid Palythoa caribaeorum

Marine invertebrates are capable of synthesizing bioactive compounds, which may be beneficial to human health. The aim of this study was to evaluate the antioxidant, hemolytic, antimicrobial and cytotoxic activities of crude extract (70% EtOH), and dichloromethane (DCM), ethyl acetate (EtOAc), and aqueous (Aq) fractions of the marine zoanthid Palythoa caribaeorum. The phenolic compound contents of the crude extract, DCM, EtOAc and Aq fractions were 12.33, 18.17, 10.53, and 3.18 mg GAE per gram, respectively. DPPH radical scavenging activity showed slight variation. IC50 of crude extract, DCM, EtOAc and Aq fractions were 11.13, 11.25, 11.74, and 11.28 µg mL(-1), respectively. Among the sample, ferrous ion chelating was the highest in crude extract (IC50 302.90 µg mL(-1)), followed by EtOAc, Aq, and DCM fractions with 457.77, 547.91, and 641.82 µg mL(-1), respectively. Ferric-reducing antioxidant power showed optical density at about 0.5. The samples tested exhibited low hemolytic activity under 10% up to a concentration of 50 μg mL(-1). No antimicrobial activity was observed against any of the tested bacterial strains. For the cytotoxic activity, LC50 of DCM, crude extract, EtOAc, and Aq were 52.10, 83.06, 86.34, and 117.45 μg mL(-1), showing high toxicity.

Antibacterial and antioxidant activities of Derriobtusone A isolated from Lonchocarpus obtusus

This study evaluated the effect of derriobtusone A, a flavonoid isolated from Lonchocarpus obtusus, on two important pathogenic bacteria, Staphylococcus aureus and Escherichia coli, as well as its antioxidant activity and toxicity. Planktonic growth assays were performed, and the inhibition of biofilm formation was evaluated. In addition, antioxidant activity was assessed by DPPH radical scavenging assay, ferrous ion chelating assay, ferric-reducing antioxidant power assay, and β-carotene bleaching assay. Toxicity was evaluated by the brine shrimp lethality test. Results showed that derriobtusone A completely inhibited the planktonic growth of S. aureus at 250 and 500 μg/mL; however, it did not have the same activity on E. coli. Derriobtusone A reduced the biomass and colony-forming unit (cfu) of S. aureus biofilm at concentrations of 250 and 500 μg/mL. In various concentrations, it reduced the biofilm biomass of E. coli, and, in all concentrations, it weakly reduced the cfu. Derriobtusone A showed highly efficient antioxidant ability in scavenging DPPH radical and inhibiting β-carotene oxidation. The compound showed no lethality to Artemia sp. nauplii. In conclusion, derriobtusone A may be an effective molecule against S. aureus and its biofilm, as well as a potential antioxidant compound with no toxicity.

Structural basis of ConM binding with resveratrol, an anti-inflammatory and antioxidant polyphenol.

Resveratrol can also inhibit the activation of proinflammatory mediators and cytokines at the early gene expression stage. It is well known that lectins are sugar-binding proteins that act as both pro- and anti-inflammatory molecules. Thus, the objective of this work was to verify the binding of a polyphenol compound with a lectin of Canavalia maritima (ConM) based on their ability to inhibit pro-inflammatory processes. To accomplish this, ConM was purified and crystallized, and resveratrol was soaked at 5mM for 2h of incubation. The crystal belongs to the monoclinic space group C2, the final refinement resulted in an Rfactor of 16.0% and an Rfree of 25.5%. Resveratrol binds in the rigid β-sheet through H-bonds and hydrophobic interaction with amino acids that compose the fifth and sixth β-strands of the rigid β-sheet of ConM. The ConM and resveratrol inhibited DPPH oxidation, showing synergic activity with the most effective ratio of 2:3 and carbohydrate binding site is not directly related to antioxidant activity. It is the interaction between ConM and resveratrol that indicates the synergism of these two molecules in acting as free radicals scavengers and in reducing the inflammatory process through the inhibition of many pro-inflammatory events.

Chemical composition of volatile compounds in two red seaweeds, Pterocladiella capillacea and Osmundaria obtusiloba, using static headspace gas chromatography mass spectrometry

Volatile organic compounds (VOCs) from the red seaweeds Pterocladiella capillacea and Osmundaria obtusiloba were obtained by static headspace extraction and then analyzed qualitatively by gas chromatography mass spectrometry (GC-MS) and quantitatively by gas chromatography (GC) equipped with a flame ionization detector (FID). In total, 31 constituents were identified in the two species of algae. In P. capillacea, among the 21 constituents (100%), the major ones were hexanal (50.4%), 2-pentylfuran (9.2%), and heptadecene (8.8%). In O. obtusiloba, of the 21 constituents (100%), the most representatives were heptadecene (57.3%), hexanal (20.5%), and 1-pentadecene (2.6%). This is the first report on the identification and quantification of VOCs in the Rhodophyta, P. capillacea and O. obtusiloba.

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.