DBQ - Departamento de Bioquímica

URI Permanente desta comunidadehttps://repositorio.ufrn.br/handle/1/6

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Antioxidant sulfated polysaccharide from edible red seaweed Gracilaria birdiae is an inhibitor of calcium oxalate crystal formation
(MDPI, 2020-04-28) Oliveira, Leticia Castelo Branco Peroba; Queiroz, Moacir Fernandes; Fidelis, Gabriel Pereira; Melo, Karoline Rachel Teodosio; Câmara, Rafael Barros Gomes da; Alves, Monique Gabriela das Chagas Faustino; Costa, Leandro Silva; Teixeira, Dárlio Inácio Alves; Melo-Silveira, Raniere Fagundes; Rocha, Hugo Alexandre de Oliveira
The genus Gracilaria synthesizes sulfated polysaccharides (SPs). Many of these SPs, including those synthesized by the edible seaweed Gracilaria birdiae, have not yet been adequately investigated for their use as potential pharmaceutical compounds. Previous studies have demonstrated the immunomodulatory effects of sulfated galactans from G. birdiae. In this study, a galactan (GB) was extracted from G. birdiae and evaluated by cell proliferation and antioxidant tests. GB showed no radical hydroxyl (OH) and superoxide (O2−) scavenging ability. However, GB was able to donate electrons in two further different assays and presented iron- and copper-chelating activity. Urolithiasis affects approximately 10% of the world’s population and is strongly associated with calcium oxalate (CaOx) crystals. No efficient compound is currently available for the treatment of this disease. GB appeared to interact with and stabilize calcium oxalate dihydrate crystals, leading to the modification of their morphology, size, and surface charge. These crystals then acquired the same characteristics as those found in healthy individuals. In addition, GB showed no cytotoxic effect against human kidney cells (HEK-293). Taken together, our current findings highlight the potential application of GB as an antiurolithic agent
A fucan of a brown seaweed and its antitumoral property on HT-29 and immunomodulatory activity in murine RAW 264.7 macrophage cell line
(Springer, 2017-02-19) Pinheiro, Thuane de Sousa; Santos, Marilia da S. Nascimento; Castro, Luiza Sheyla E. P. Will; Paiva, Almino Afonso de O.; Alves, Luciana G.; Cruz, Ana Katarina M.; Nobre, Leonardo Thiago Duarte Barreto; Alves, Monique Gabriela das Chagas Faustino; Leite, Edda Lisboa
Polysaccharides from algae are also proper candidates with therapeutic properties and immunomodulatory and antitumor effects. The brown seaweed Lobophora variegata synthesizes different groups of anionic polysaccharides with several biological properties. Sulfated polysaccharides were obtained by delipidation of seaweed, proteolysis, and fractionation with different volumes of acetone. A fraction of sulfated polysaccharides, fucans or fucoidans, was extracted with 0.8 v acetone and named L. variegata (LV). This fucan was assessed in the inflammatory process in rats, antitumor action on human colon adenocarcinoma (HT-29 cells), apoptosis, and its effect on the cell cycle. LV fraction, a galactofucan, exhibited a high ratio of total sugar/sulfate (1.5) and a very low level of proteins. This polysaccharide showed an antiinflammatory effect on two models of inflammation induced by croton oil and oxazolone in rats. LV was analyzed in cellular proliferation of HT-29. We also demonstrated the cytotoxic action against this cell line and induction in the apoptosis and decreased the cell cycle in phases S and G2/M and the accumulation of cells in the G1 phase. Our studies with LV showed a marked immunomodulatory action without and with lipopolysaccharide (LPS) on RAW 264.7 cells. Comparative studies of two fucans, LV and FV (Fucus vesiculosus), with different structures were assessed on viability in macrophages, RAW 264.7 cells. Both showed cytotoxicity in these cells. We observed high levels of nitric oxide (NO) production, interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) when treated at 0.25, 0.5, and 1.0 mg mL−1 of LV. Data also suggest that LV has potential antitumor effects on HT-29 and antiinflammatory and immunomodulatory effects on RAW 264.7 cells

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