The Protective Role of Sulfated Polysaccharides from Green Seaweed Udotea flabellum in Cells Exposed to Oxidative Damage

Abstract

Seaweed is a rich source of bioactive sulfated polysaccharides. We obtained six sulfated polysaccharide-rich fractions (UF-0.3, UF-0.5, UF-0.6, UF-0.7, UF-1.0, and UF-2.0) from the green seaweed Udotea flabellum (UF) by proteolytic digestion followed by sequential acetone precipitation. Biochemical analysis of these fractions showed that they were enriched with sulfated galactans. The viability and proliferative capacity of 3T3 fibroblasts exposed to FeSO4 (2 µM), CuSO4 (1 µM) or ascorbate (2 mM) was not affected. However, these cells were exposed to oxidative stress in the presence of FeSO4 or CuSO4 and ascorbate, which caused the activation of caspase-3 and caspase-9, resulting in apoptosis of the cells. We also observed increased lipid peroxidation, evaluated by the detection of malondialdehyde and decreased glutathione and superoxide dismutase levels. Treating the cells with the ultrafiltrate fractions (UF) fractions protected the cells from the oxidative damage caused by the two salts and ascorbate. The most effective protection against the oxidative damage caused by iron was provided by UF-0.7 (1.0 mg/mL); on treatment with UF-0.7, cell viability was 55%. In the case of copper, cell viability on treatment with UF-0.7 was ~80%, but the most effective fraction in this model was UF-2.0, with cell viability of more than 90%. The fractions, mainly UF-0.7 and UF-2.0, showed low iron chelating activity, but high copper chelating activity and total antioxidant capacity (TAC). These results suggested that some of their protective mechanisms stem from these properties.

Low Molecular Weight Dextran Sulfate (ILB®) Administration Restores Brain Energy Metabolism Following Severe Traumatic Brain Injury in the Rat

“…Attenuation of oxidative/nitrosative stress may be the basis of the overall positive effect of ILB ® on brain metabolism. In fact, studies using various experimental models of cell toxicity have shown that different sulfated polysaccharides (SP) are able to attenuate oxidative stress by acting as efficient antioxidants [62], with scavenging properties directed towards superoxide anions and hydroxyl radicals [63] and some chelating capacity shown towards iron and, more evident, copper [64], as well as decreasing ROS formation thanks to their marked reducing potential [65]. Our results with ILB ® suggest that the concomitant decrease in lipid peroxidation (evidenced by the decrease in cerebral MDA) and NO production (decrease in nitrite + nitrate), and the increase in cell antioxidant defenses (increase in ascorbate and GSH) are mediated, at least in part, by the ability of ILB ® to act as an efficient ROS scavenger.…”

Chemical characterization of sulfated polysaccharides from Gracilaria gracilis and Ulva lactuca and their radical scavenging, metal chelating, and cholinesterase inhibitory activities

“…However, previous report revealed that green seaweed (Udotea flabellum) exhibited low metal chelating capacity below 20%. [31] The observed radical and metal chelating activities of PGCL and PULV suggest they are potent antioxidants. Antioxidants are radical scavengers and metal chelators with a capacity to donate an electron.…”

Valuing Bioactive Lipids from Green, Red and Brown Macroalgae from Aquaculture, to Foster Functionality and Biotechnological Applications

“…Overall, their growing interest is powered by their bioactive molecules with several industrial applications [ 16 ]. The most well-studied macroalgae bioactive compounds include abundant molecules such as polysaccharides and peptides, although minor constituents, such as alkaloids and lipids, have also been recognized for their nutritional and bioactive values [ 17 , 18 ]. Even though macroalgae have a low lipid content (which is variable among macroalgal species [ 19 , 20 , 21 , 22 , 23 ]), these compounds are recognized as an important source of polyunsaturated fatty acids (PUFA) including long-chain omega-3 FA, such as α-linolenic acid (18:3 n -3), eicosapentaenoic acid (20:5 n -3) and docosahexaenoic acid (22:6 n -3), that have been addressed as essential modulators to reduce the risk of cancer and cardiovascular diseases [ 24 ].…”