A Blend Consisting of Agaran from Seaweed Gracilaria birdiae and Chromium Picolinate Is a Better Antioxidant Agent than These Two Compounds Alone.

A blend refers to the combination of two or more components to achieve properties that are superior to those found in the individual products used for their production. Gracilaria birdiae agaran (SPGb) and chromium picolinate (ChrPic) are both antioxidant agents. However, there is no documentation of blends that incorporate agarans and ChrPic. Hence, the objective of this study was to generate blends containing SPGb and ChrPic that exhibit enhanced antioxidant activity compared to SPGb or ChrPic alone. ChrPic was commercially acquired, while SPGb was extracted from the seaweed. Five blends (B1; B2; B3; B4; B5) were produced, and tests indicated B5 as the best antioxidant blend. B5 was not cytotoxic or genotoxic. H2O2 (0.6 mM) induced toxicity in fibroblasts (3T3), and this effect was abolished by B5 (0.05 mg·mL-1); neither ChrPic nor SPGb showed this effect. The cells also showed no signs of toxicity when exposed to H2O2 after being incubated with B5 and ChrPic for 24 h. In another experiment, cells were incubated with H2O2 and later exposed to SPGb, ChrPic, or B5. Again, SPGb was not effective, while cells exposed to ChrPic and B5 reduced MTT by 100%. The data demonstrated that B5 has activity superior to SPGb and ChrPic and points to B5 as a product to be used in future in vivo tests to confirm its antioxidant action. It may also be indicated as a possible nutraceutical agent.

In Vitro Antitumor Potential of Sulfated Polysaccharides from Seaweed Caulerpa cupressoides var. flabellata.

Seaweeds are important source of bioactive compounds, including sulfated polysaccharides (SP). Because of their structural heterogeneity, these compounds are promising sources of anticancer compounds. SP from brown and red seaweeds have shown antimelanoma activity in different in vitro and in vivo models. However, SP from green seaweed are still poorly evaluated. Therefore, SP were extracted from the green alga Caulerpa cupressoides var. flabellata, and their antiproliferative, anti-migratory, and inhibitory effect on melanin production on B16-F10 melanoma cells was evaluated. Cell assays, including flow cytometry, demonstrated that SP (100-1000 µg mL-1) are non-cytotoxic, do not induce apoptosis or necrosis, and do not interfere with cell cycle. However, SP (1000 µg mL-1) were found to significantly inhibit cell colony formation (80-90%), cell migration (40-75%), and melanin production (~ 20%). In summary, these results showed that SP inhibited important melanoma development events without cytotoxicity effects, suggesting that C. cupressoides may be an important source of SP with antitumor properties.

Immunostimulatory Effect of Sulfated Galactans from the Green Seaweed Caulerpa cupressoides var. flabellata.

Sulfated polysaccharides (SPs) obtained from green seaweeds are structurally heterogeneous molecules with multifunctional bioactivities. In this work, two sulfated and pyruvated galactans were purified from Caulerpa cupressoides var. flabellata (named SP1 and SP2), and their immunostimulatory effect was evaluated using cultured murine macrophage cells. Both SPs equally increased the production of nitric oxide, reactive oxygen species, and the proinflammatory cytokines TNF-α and IL-6. NMR spectroscopy revealed that both galactans were composed primarily of 3)-ß-d-Galp-(1→3) units. Pyruvate groups were also found, forming five-membered cyclic ketals as 4,6-O-(1'carboxy)-ethylidene-ß-d-Galp residues. Some galactoses are sulfated at C-2. In addition, only SP2 showed some galactose units sulfated at C-4, indicating that sulfation at this position is not essential for the immunomodulatory activity of these galactans. Overall, the data showed that the galactans of C. cupressoides exhibited immunostimulating activity with potential therapeutic applications, which can be used in the development of new biomedical products.

Antioxidant Fucoidans Obtained from Tropical Seaweed Protect Pre-Osteoblastic Cells from Hydrogen Peroxide-Induced Damage.

Some antioxidant compounds decrease the amount of intracellular reactive oxygen species (ROS) and consequently reduce the deleterious effects of ROS in osteoblasts. Thus, these compounds fight against osteoporosis. Brown seaweeds are a rich source of antioxidant fucose-containing sulfated polysaccharides (fucans and fucoidans). We obtained six fucoidans (FRFs)-F0.3, F0.5, F0.7, F1.0, F1.5, and F2.1-from Dictyota mertensii by proteolytic digestion followed by sequential acetone precipitation. Except for F0.3, all FRFs showed antioxidant activity in different in vitro tests. In pre- osteoblast-like cells (MC3T3-L1) exposed to H2O2-oxidative stress, caspase-3 and caspase-9 were activated, resulting in apoptosis of the cells. We also observed a decrease in superoxide dismutase (SOD) and alkaline phosphatase (ALP) activity. The antioxidant FRFs protected the cells from the oxidative damage caused by H2O2, decreasing intracellular ROS and caspase activation, and increasing SOD activity. The most effective protection against damage was provided by F0.7, F1.5, and F2.1. At 0.5 mg/mL, these FRFs also suppressed the H2O2-mediated inhibition of ALP activity. The data indicated that FRFs F0.7, F1.5, and F2.1 from D. mertensii were antioxidants that protected bone tissue from oxidative stress and could represent possible adjuvants for the treatment of bone fragility through counteracting oxidative phenomena.