Antiproliferative activity of fucan nanogel

Sulfated fucans comprise families of polydisperse natural polysaccharides based on sulfated l-fucose. Our aim was to investigate whether fucan nanogel induces cell-specific responses. To that end, a non toxic fucan extracted from Spatoglossum schröederi was chemically modified by grafting hexadecylamine to the polymer hydrophilic backbone. The resulting modified material (SNFuc) formed nanosized particles. The degree of substitution with hydrophobic chains was close to 100%, as estimated by elemental analysis. SNFfuc in aqueous media had a mean diameter of 123 nm and zeta potential of −38.3 ± 0.74 mV, as measured by dynamic light scattering. Nanoparticles conserved their size for up to 70 days. SNFuc cytotoxicity was determined using the MTT assay after culturing different cell lines for 24 h. Tumor-cell (HepG2, 786, H-S5) proliferation was inhibited by 2.0%–43.7% at nanogel concentrations of 0.05–0.5 mg/mL and rabbit aorta endothelial cells (RAEC) non-tumor cell line proliferation displayed inhibition of 8.0%–22.0%. On the other hand, nanogel improved Chinese hamster ovary (CHO) and monocyte macrophage cell (RAW) non-tumor cell line proliferation in the same concentration range. The antiproliferative effect against tumor cells was also confirmed using the BrdU test. Flow cytometric analysis revealed that the fucan nanogel inhibited 786 cell proliferation through caspase and caspase-independent mechanisms. In addition, SNFuc blocks 786 cell passages in the S and G2-M phases of the cell cycle.The present study was supported by CAPES, MCT, FAPERN/CNPq and CNPq, Brazil, as well as FCT, Portugal. N Dantas-Santos, J Almeida-Lima, AAJ Vidal, HAO Rocha are grateful to the CNPq and CAPES for their fellowship support. This research was submitted to the Graduate Program in Health Sciences at the Federal University of Rio Grande do Norte as part of the D.Sc. thesis of ND-S

CARACTERIZAÇÃO E ATIVIDADE ANTICOAGULANTE DE POLISSACARÍDEOS SULFATADOS EXTRAÍDOS DA ALGA MARROM Dictyopteris justii

O aumento da incidência de doenças cardiovasculares e os efeitos adversos do seu medicamento anticoagulante principal (Heparina) estimulam a busca de novos compostos anticoagulantes. No presente estudo, cinco frações ricas em polissacarídeos sulfatadas denominadas de F0,3V; F0,4v; F0,5V; F1,2v, e F1,9v foram obtidas a partir da alga Dictyopteris justii através da digestão proteolítica, seguido de fracionamento com acetona. A presença de polissacarídeos sulfatados foi confirmada por análise eletroforética. Além disso, esta análise mostrou também que D. justii sintetiza três tipos de polissacarídeos sulfatados (duas heterofucanas e uma glucana), que são distribuídos ao longo das frações. Um resultado importante foi a atividade aPTT da fração F0, 4v, que foi semelhante ao da Heparina. F0 4v, é composta principalmente de uma hetofucana chamada de população A. Esta é, portanto, um agente promissor para a sua possível utilização em terapia anticoagulant

Heterofucan from Sargassum filipendula Induces Apoptosis in HeLa Cells

Fucan is a term used to denominate a family of sulfated polysaccharides rich in sulfated l-fucose. Heterofucan SF-1.5v was extracted from the brown seaweed Sargassum filipendula by proteolytic digestion followed by sequential acetone precipitation. This fucan showed antiproliferative activity on Hela cells and induced apoptosis. However, SF-1.5v was not able to activate caspases. Moreover, SF-1.5v induced glycogen synthase kinase (GSK) activation, but this protein is not involved in the heterofucan SF-1.5v induced apoptosis mechanism. In addition, ERK, p38, p53, pAKT and NFκB were not affected by the presence of SF-1.5v. We determined that SF-1.5v induces apoptosis in HeLa mainly by mitochondrial release of apoptosis-inducing factor (AIF) into cytosol. In addition, SF-1.5v decreases the expression of anti-apoptotic protein Bcl-2 and increased expression of apoptogenic protein Bax. These results are significant in that they provide a mechanistic framework for further exploring the use of SF-1.5v as a novel chemotherapeutics against human cervical cancer

Antioxidant and Antiproliferative Activities of Heterofucans from the Seaweed Sargassum filipendula

Fucan is a term used to denominate a type of polysaccharide which contains substantial percentages of l-fucose and sulfate ester groups. We obtained five heterofucans from Sargassum filipendula by proteolytic digestion followed by sequential acetone precipitation. These heterofucans are composed mainly of fucose, glucose, glucuronic acid, galactose and sulfate. These fucans did not show anticoagulant activity in PT and aPTT tests. Their antioxidant activity was evaluated using the follow tests; total antioxidant capacity, scavenging hydroxyl and superoxide radicals, reducing power and ferrous ion [Fe(II)] chelating. All heterofucans displayed considerable activity, especially SF-1.0v which showed the most significant antioxidant potential with 90.7 ascorbic acid equivalents in a total antioxidant capacity test and similar activity when compared with vitamin C in a reducing power assay. The fucan antiproliferative activity was performed with HeLa, PC3 and HepG2 cells using MTT test. In all tested conditions the heterofucans exhibited a dose-dependent effect. The strongest inhibition was observed in HeLa cells, where SF-1.0 and SF-1.5 exhibited considerable activity with an IC50 value of 15.69 and 13.83 μM, respectively. These results clearly indicate the beneficial effect of S. filipendula polysaccharides as antiproliferative and antioxidant. Further purification steps and additional studies on structural features as well as in vivo experiments are needed to test the viability of their use as therapeutic agents

Influência de meios de cultura e suplementações hormonais sobre a indução e desenvolvimento de calos <i>in</i> <i>vitro</i> em variedades de <i>Gossypium</i> <i>hirsutum</i> L.

Objetivou-se, com este trabalho, averiguar o efeito de dois meios de cultura, Murashige e Skoog (1962) e Nitch (1974), na indução de calos embriogênicos e seu desenvolvimento (peso); sob influência dos reguladores de crescimento 2,4-D (ácido 2,4-diclorofenoxiacético) e 2IP (2-isopenteniladenina) em três variedades distintas de algodão

Evaluation of seawater salinity effect on proximate composition of the green seaweed Caulerpa cupressoides var. flabellata

Macroalgas marinhas são consumidas em grande quantidade em países asiáticos. Contudo, o seu consumo em países ocidentais, como o Brasil, ainda é muito baixo por várias razões. Uma delas é a falta de informações sobre a composição centesimal das macroalgas brasileiras. Este dado é importante para o uso de um alimento em várias atividades relacionadas com as áreas de nutrição humana e ciências dos alimentos. Neste trabalho, objetivou-se analisar a composição química, através do método de composição centesimal, da macroalga verde Caulerpa cupressoides var. flabellata, coletada em duas diferentes praias do litoral do Rio Grande do Norte (Camapum e Búzios). Os dados mostraram que a salinidade da água dessas duas praias é bem distinta: em Búzios é de 33,7 ppm; em Camapum, 40,5 ppm. Apesar disso, a composição centesimal da C. cupressoides não variou com a salinidade. Ainda, foi possível observar uma baixa quantidade de lipídios e uma alta quantidade de proteínas em C. cupressoides, nesse caso, maior até do que aquela encontrada em outras algas comestíveis. Os dados apontam que C. cupressoides poderia ser uma fonte alternativa de baixo custo de proteínas, tanto para uso em nutrição animal, como humana.Seaweeds as a staple diet has been used in Asian countries for thousands of years. However, in countries like Brazil, consumption of seaweeds as food is still very small due to many reasons. One is the lack of data on Brazilian seaweed’s proximate food composition. This data are very important to any activity related to food science and human nutrition area. The objective of this work was to analyze the chemical composition of the green seaweed Caulerpa cupressoides var. flabellata, collected in two different beaches of the coast of Rio Grande do Norte (Camapum and Búzios). The data showed that the salinity of the water on these two beaches is quite different: The water salinity of Camapum was around 40.5 ppm whereas in Buzios beach was 33.7 ppm. Despite this, the proximate composition of C. cupressoides did not change with increased salinity. Moreover, interestingly, it has low amount of lipids and high amount of proteins, greater even than other edible seaweeds, which indicates that C. cupresoides could be used as protein source for human and animal diet

Interferência da salinidade do mar na composição centesimal da macroalga Caulerpa cupressoides var. flabellata

Seaweeds as a staple diet has been used in Asian countries for thousands of years. However, in countries like Brazil, consumption of seaweeds as food is still very small due to many reasons. One is the lack of data on Brazilian seaweed’s proximate food composition. This data are very important to any activity related to food science and human nutrition area. The objective of this work was to analyze the chemical composition of the green seaweed Caulerpa cupressoides var. flabellata, collected in two different beaches of the coast of Rio Grande do Norte (Camapum and Búzios). The data showed that the salinity of the water on these two beaches is quite different: The water salinity of Camapum was around 40.5 ppm whereas in Buzios beach was 33.7 ppm. Despite this, the proximate composition of C. cupressoides did not change with increased salinity. Moreover, interestingly, it has low amount of lipids and high amount of proteins, greater even than other edible seaweeds, which indicates that C. cupresoides could be used as protein source for human and animal diet.Macroalgas marinhas são consumidas em grande quantidade em países asiáticos. Contudo, o seu consumo em países ocidentais, como o Brasil, ainda é muito baixo por várias razões. Uma delas é a falta de informações sobre a composição centesimal das macroalgas brasileiras. Este dado é importante para o uso de um alimento em várias atividades relacionadas com as áreas de nutrição humana e ciências dos alimentos. Neste trabalho, objetivou-se analisar a composição química, através do método de composição centesimal, da macroalga verde Caulerpa cupressoides var. flabellata, coletada em duas diferentes praias do litoral do Rio Grande do Norte (Camapum e Búzios). Os dados mostraram que a salinidade da água dessas duas praias é bem distinta: em Búzios é de 33,7 ppm; em Camapum, 40,5 ppm. Apesar disso, a composição centesimal da C. cupressoides não variou com a salinidade. Ainda, foi possível observar uma baixa quantidade de lipídios e uma alta quantidade de proteínas em C. cupressoides, nesse caso, maior até do que aquela encontrada em outras algas comestíveis. Os dados apontam que C. cupressoides poderia ser uma fonte alternativa de baixo custo de proteínas, tanto para uso em nutrição animal, como humana

Methanolic Extracts from Brown Seaweeds Dictyota cilliolata and Dictyota menstrualis Induce Apoptosis in Human Cervical Adenocarcinoma HeLa Cells

Carcinoma of the uterine cervix is the second most common female tumor worldwide, surpassed only by breast cancer. Natural products from seaweeds evidencing apoptotic activity have attracted a great deal of attention as new leads for alternative and complementary preventive or therapeutic anticancer agents. Here, methanol extracts from 13 species of tropical seaweeds (Rhodophytas, Phaeophyta and Chlorophyta) collected from the Northeast of Brazil were assessed as apoptosis-inducing agents on human cervical adenocarcinoma (HeLa). All extracts showed different levels of cytotoxicity against HeLa cells; the most potent were obtained from the brown alga Dictyota cilliolata (MEDC) and Dictyota menstrualis (MEDM). In addition, MEDC and MEDM also inhibits SiHa (cervix carcinoma) cell proliferation. Studies with these two extracts using flow cytometry and fluorescence microscopy showed that HeLa cells exposed to MEDM and MEDC exhibit morphological and biochemical changes that characterize apoptosis as shown by loss of cell viability, chromatin condensation, phosphatidylserine externalization, and sub-G1 cell cycle phase accumulation, also MEDC induces cell cycle arrest in cell cycle phase S. Moreover, the activation of caspases 3 and 9 by these extracts suggests a mitochondria-dependent apoptosis route. However, other routes cannot be ruled out. Together, these results point out the methanol extracts of the brown algae D. mentrualis and D. cilliolata as potential sources of molecules with antitumor activity

Antioxidant, antiproliferative, and immunostimulatory effects of cell wall α-d-mannan fractions from Kluyveromyces marxianus

This study evaluated the antioxidant, antiproliferative, and immunostimulatory properties of cell wall α-d-mannan fractions from yeast Kluyveromyces marxianus CCT7735. Filter centrifugation was used to obtain four fractions (KMM-1, KMM-2, KMM-3, and KMM-4) with molecular weight ranging from 7.6 to 75.1 kDa. KMM-1 and KMM-2 comprised D-mannose with traces of D-glucose, whereas other fractions contained only D-mannose. Total sugar found in samples ranged from 85.9% to 96.1%, while protein and phenolic contents were 1.21% and 0.41%, respectively. Although only KMM-1 was able to scavenge superoxide radicals, all fractions presented total antioxidant capacity as well as reducing power, hydroxyl-radical scavenging, and copper- and iron-chelating activities. No fraction was cytotoxic to HeLa cells. However, all samples inhibited the proliferation of the tumor cell Hep-G2 and presented minor cytotoxicity against normal 3T3 cells. All fractions showed mitogenic activity in macrophages and all, except KMM-4, induced nitric oxide production in macrophages, suggestive of their immunostimulatory effects

Evaluation of Sulfated Polysaccharides from the Brown Seaweed Dictyopteris Justii as Antioxidant Agents and as Inhibitors of the Formation of Calcium Oxalate Crystals

Oxalate crystals and other types of crystals are the cause of urolithiasis, and these are related to oxidative stress. The search for new compounds with antioxidant qualities and inhibitors of these crystal formations is therefore necessary. In this study, we extracted four sulfated polysaccharides, a fucoglucoxyloglucuronan (DJ-0.3v), a heterofucan (DJ-0.4v), and two glucans (DJ-0.5v and DJ-1.2v), from the marine alga Dictyopteris justii. The presence of sulfated polysaccharides was confirmed by chemical analysis and FT-IR. All the sulfated polysaccharides presented antioxidant activity under different conditions in some of the in vitro tests and inhibited the formation of calcium oxalate crystals. Fucan DJ-0.4v was the polysaccharide that showed the best antioxidant activity and was one of the best inhibitors of the crystallization of calcium oxalate. Glucan DJ-0.5v was the second most potent inhibitor of the formation of oxalate crystals, as it stabilized dehydrated oxalate crystals (less aggressive form), preventing them from transforming into monohydrate crystals (more aggressive form). The obtained data lead us to propose that these sulfated polysaccharides are promising agents for use in the treatment of urolithiasis