Evaluation of the dietetic and therapeutic potential of a high molecular weight hydroxycinnamate-derived polymer from Symphytum asperum lepech. Regarding its antioxidant, antilipoperoxidant, antiinflammatory, and cytotoxic properties

A water-soluble hydroxycinnamate-derived polymer (> 1000 kDa) from Symphytu m asperum Lepech. (Boraginaceae) strongly reduced the diphenylpicrylhydrazy l radical (IC50 approximate to 0.7 mug/mL) and inhibited the nonenzymatic l ipid peroxidation of bovine brain extracts (IC50 approximate to 10 ng). Thi s polymer exhibited only a low hydroxyl radical scavenging effect in the Fe 3+-EDTA-H2O2 deoxyribose system (IC50 > 10 mug/mL) but strongly decreased s uperoxide anion generation in either the reaction of phenazine methosulfate with NADH and molecular oxygen (IC50 approximate to 13.4 mug/mL) or in rat PMA-activated leukocytes (IC50 approximate to 5 mug/mL). The ability to in hibit both degranulation of azurophil granules and superoxide generation in primed leukocytes indicates that the NADPH oxidase responsible for this la ter effect is inhibited, pointing to the Symphytum asperum polymer as a pot ent antiinflammatory and vasoprotective agent. At all concentrations tested (0-200 mug/mL), we observed no cytotoxicity on normal human fibroblasts an d neither antiproliferative effects nor proliferation activation on neoplas tic cells.