Antioxidant properties of hymatomelanic acids from brown coal

The antioxidant activity of a low-temperature fraction of hymatomelanic acids from brown coal in a model process of the radical chain oxidation of cumene was determined using a gas-volumetric method. Their antiradical activity was evaluated by spectrophotometry using a reaction with 2,2-diphenyl-1-picrylhydrazyl (DPPH). The pronounced ability of hymatomelanic acids to cause antioxidant and antiradical effects in model systems was demonstrated. It was found that the antioxidant and antiradical activities increased with the concentration of hymatomelanic acids. The determined properties of hymatomelanic acids from brown coal can be useful for technical and biomedical applications.