Green Synthesis Of Antioxidant Silver Nanoparticles With Sulfated Polysacarides From The Red Seaweed Crassiphycus Birdiae

Sulfated polysaccharides (SPs) from the edible red seaweed Crassiphycus birdiae have antioxidant activity. Previous studies have shown that SPs, when in the form of silver nanoparticles (AgNps), had better antioxidant activity than in its original form. However, there is no data about AgNps synthesized with the SPs from C. birdiae. Then, AgNps synthesized with the SPs from C. birdiae were obtained and evaluated as antioxidant agents. The AgNps detection and size measurement were made by dynamic light scattering (DLS). The PS reducing capacity was evaluated by the total antioxidant capacity test (TAC). The antioxidant capacity of AgNps and SPs was also determined by ferric chelation test. In addition, their protein and sugar content were determined spectrophotometrically. The PS showed TAC, and this allowed the synthesis of AgNps. The AgNps showed an average size of 117.6 nm. No protein contamination was found in the SPs neither AgNps. The sugar content in the AgNps suspension was higher (55.7%) than that found in the SPs solution (49.7%). The AgNps suspension presented an iron chelating activity 25% higher than the of SPs solution. The results showed that the SPs from C. birdiae, in the form of nanoparticles, had their iron chelating activity enhanced, indicating that the silver nanoparticles can be subject of further studies to identify their potential as antioxidants agents in different applications.