This study analyzes the action of sulfated polysaccharides, fucans, from algae Lobophora variegata on zymosan-induced arthritis in rats. Groups of fucans, obtained after acetone fractionation (0.3-2.0 volumes), were denominated F0.3, F0.5, F0.8, F1, F1.5, and F2. The results that F1 contained a high yield in relation to other fractionated fucans. Chemical and structure analysis of F1 was performed by nuclear magnetic resonance (NMR) and infrared (IR) spectroscopies. The in vitro antioxidant activities of the fraction F1 were also observed. Thus, 2 mg/mL of F1 inhibited the phosphomolybdate in the total antioxidant activity assay. The EC(50) values were 0.3 mg/mL and 0.12 mg/mL for superoxide and hydroxyl radicals, respectively. Fucan F1 (25, 50, and 75 mg/kg by body weight), diclofenac sodium (10 mg/kg), and L-NAME (25 mg/kg) were administered intraperitoneally (i.p.) in rats, according to body weight of different groups of animals (n=6). After 6 h, analyses of cell influx and nitrite levels were conducted. Then after 96 h, analysis of edema and concentration of serum TNF-α was carried out along with histopathological analysis. F1 at 25, 50, and 75 mg/kg i.p. by body weight reduced cell influx in 52.1-96.7% and nitric oxide level in 27.2-39% compared with the control group. The reduction of edema and serum TNF-α was observed at 50 mg/kg i.p. (p<0.001). These results suggest that this heterofucan from the brown algae L. variegata has potential anti-inflammatory activity in acute zymosan-induced arthritis in rats and that antioxidant activity promotes modulation in the cellular redox state.

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 G 2 /M and the accumulation of cells in the G 1 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.