Antioxidant and prooxidant properties of a polyphenol-rich extract from Geranium sanguineum L. in vitro and in vivo.

A polyphenol-rich extract from Geranium sanguineum L. (PC) protected biological membranes due to its antioxidant capacity. PC caused a dose-dependent decrease of the osmotic hemolysis of human erythrocytes and increased their resistance against the toxic effect of H(2)O(2); no effect on catalase activity was observed.