2.6.2. Hydroxyl Radical Scavenging Assay

The hydroxyl radical scavenging capacity of polysaccharide samples was evaluated on a microplate analytical assay according to a previous method [26] with some modifications. First, 50 µL of ferrous sulfate (1.5 mM) and 50 µL of H₂O₂ (0.01%) were mixed with 100 µL of samples. Finally, 50 µL of 1,10-phenanthroline (1.5 mM) was added. The reaction mixture was then incubated in the dark for 30 min at 37 °C, and the absorbance was measured at 536 nm. Vc was used as a positive control. The hydroxyl radical scavenging rate was calculated using the following formula:

where A_sample is the absorbance of the tested sample, A_control is the absorbance of the ultrapure water instead of the tested sample, and A₀ is the absorbance of the ultrapure water instead of H₂O₂ and the tested sample.