Commercial Fucoidans from Fucus vesiculosus Can Be Grouped into Antiadipogenic and Adipogenic Agents

Abstract

Fucus vesiculosus is a brown seaweed used in the treatment of obesity. This seaweed synthesizes various bioactive molecules, one of them being a sulfated polysaccharide known as fucoidan (FF). This polymer can easily be found commercially, and has antiadipogenic and lipolytic activity. Using differential precipitation with acetone, we obtained four fucoidan-rich fractions (F0.5/F0.9/F1.1/F2.0) from FF. These fractions contain different proportions of fucose:glucuronic acid:galactose:xylose:sulfate, and also showed different electrophoretic mobility and antioxidant activity. Using 3T3-L1 adipocytes, we found that all samples had lipolytic action, especially F2.0, which tripled the amount of glycerol in the cellular medium. Moreover, we observed that FF, F1.0, and F2.0 have antiadipogenic activity, as they inhibited the oil red staining by cells at 40%, 40%, and 50%, respectively. In addition, they decreased the expression of key proteins of adipogenic differentiation (C/EBPα, C/EBPβ, and PPARγ). However, F0.5 and F0.9 stimulated the oil red staining at 80% and increased the expression of these proteins. Therefore, these fucoidan fractions have an adipogenic effect. Overall, the data show that F2.0 has great potential to be used as an agent against obesity as it displays better antioxidant, lipolytic and antiadipogenic activities than the other fucoidan fractions that we tested.

Keywords: 3T3-L1 cells; brown seaweed; fucan; lipolytic; obesity.

Figure 1

Staining pattern of the polysaccharides after agarose gel electrophoresis, stained with toluidine blue. About 5 µL (50 µg) of each sample was applied in agarose gel prepared in diaminopropane acetate buffer and subjected to electrophoresis, as described in methods. OR—origin. This figure is representative of three separate tests made independently.

Figure 2

The effects of FF, F0.5, F0.9, F1.1, and F2.0 on 3T3-L1 cell viability. (A) 24 h; (B) 48 h; (C) 72 h. Each value is the mean ± SD of three determinations and from three independent assays. Different letters (^a,b) indicate a significant difference (p < 0.05) between different concentrations of the same sample; Different numbers (^1,2,3) indicate a significant difference (p < 0.05) between the same concentration of each sample; Different letters (^x,y,z) indicate a significant difference (p < 0.05) between the same concentration in different times (24, 48 and 72 h). Asterisks (*) indicate a significant difference (p < 0.05) between the concentrations of any sample and the control.

Figure 3

Adipocytes stained with the dye, oil red O. 10× magnification. (A) Control; (B) FF; (C) F0.5; (D) F0.9; (E) F1.1; (F) F2.0. Bar = 60 µm. This figure is representative of three separate tests made independently.

Figure 4

Oil red O content. Each value is the mean ± SD of three determinations and from three independent assays. Different letters (^a,b,c,d) indicate a significant difference (p < 0.05) between the concentration tested (200 µg/mL) of all samples. O.D. (Optical density).

Figure 5

(A) The effects of FF, F0.5, F0.9, F1.1, and F2.0 on the expression of adipocyte markers. Equal amounts of protein (50 μg) were used for Western blot analysis, for the detection of β-actin, C/EBPα, C/EBPβ, and PPARγ. These gels are representative of three separate tests made independently; (B) Represents the expression relative to the control value. Different letters (^a,b,c,d,e,f) indicate a significant difference (p < 0.05) between the expression of the same marker for different samples. The control corresponds to cells that were not exposed to fucoidans. Each value is the mean ± SD of three determinations and from three independent assays.

Figure 5

(A) The effects of FF, F0.5, F0.9, F1.1, and F2.0 on the expression of adipocyte markers. Equal amounts of protein (50 μg) were used for Western blot analysis, for the detection of β-actin, C/EBPα, C/EBPβ, and PPARγ. These gels are representative of three separate tests made independently; (B) Represents the expression relative to the control value. Different letters (^a,b,c,d,e,f) indicate a significant difference (p < 0.05) between the expression of the same marker for different samples. The control corresponds to cells that were not exposed to fucoidans. Each value is the mean ± SD of three determinations and from three independent assays.

Figure 6

The content of glycerol released into the medium. Each value is the mean ± SD of three determinations and from three independent assays. Different letters (^a,b,c,d) indicate a significant difference (p < 0.05) between the changes of the medium for same sample; Different numbers (^1,2,3,4) indicate a significant difference (p < 0.05) between the same change of the medium in the different samples.