Fucanas extraídas da alga Dictyota menstrualis com atividade antioxidante, antiproliferativa e anticoagulante

Abstract

Fucans consist in a group of sulphated polysaccharides found in the mucilaginous matrix of brown algae constituted by sulfated fucose and a varied percentage of other monosaccharides. Faced with the great demand for new medicines, fucanas are outstanding due to their pharmacological potential, whose repertoire of properties includes anticoagulant, antioxidant, anti-inflammatory, antiproliferative, antinociceptive, hepato and neuroprotective activities. The fraction FDM1,0 rich in fucanas was fractionated. Fucan FDM1,0 of the algae Dictyota menstrualis obtained in a previous study was chosen because it had the best yield to be purified. FDM1.0 was fractionated by molecular mass resulting in 7 subfractions (F1 to F7) which were chemically characterized. The highest dry weight obtained was F1 with yield of 61.34%, because of that F1 was chosen to be evaluated about your pharmacological properties. FDM1.0 and F1 were compared for their effect in antioxidant activity, anticoagulant, antiproliferation and cell death assays. FDM1.0 and F1 presented 48.6 and 51.8% of total sugars, 2.3 and 6.1% of sulfate and low protein contamination, respectively. Infrared analysis of FDM1.0 and F1 showed characteristic polysaccharide signals. Both FDM1.0 and F1 presented high inhibition superoxide radicals (76 and 61%) and DPPH radicals (74 and 68%). No chelation activity was observed for iron and copper ions. F1 presented the same effect as low molecular weight commercial heparin in the aPTT assay, at the concentration of 66.7 μg / mL, while FDM1.0 at the concentration of 83.3 μg / mL. In the PT assay, none of the fractions presented anticoagulant activity, indicating that the mechanism of action of FDM1,0 and F1 is directed towards the intrinsic pathway of coagulation. In the MTT assay (3- [4,5-dimethylthiazol-2-yl] -2,5- diphenyltetrazolium bromide), 100μg of FDM1.0 inhibited B16-F10 (murine malignant melanoma) by 77%. FDM1.0 and F1 inhibited 92 and 100%, respectively, 786-O (human renal cell adenocarcinoma) cells under the 100 μg mass, when treated for 24 h. In the 786-O cell death assay using anexin-V and propidium iodide (PI), under the same concentration, no fraction caused cell death. These results suggest that the FDM1.0 and F1 fractions present high inhibition of reduction of MTT to formazan in 786-O cells, elevated antioxidant activity, especially inhibiting superoxide radicals, making them the potential antioxidants to be explored. The high anticoagulant activity observed on the intrinsic coagulation pathway suggests that sulphated polysaccharides of D. menstrualis may be a source of possible anticoagulant agents and the high inhibition of 786-O cells in the MTT assay should be further investigated to verify their potential inhibition activity on the cancer cell line.