Evaluation of the Dietetic and Therapeutic Potential of a High Molecular Weight Hydroxycinnamate-Derived Polymer fromSymphytum asperumLepech. Regarding Its Antioxidant, Antilipoperoxidant, Antiinflammatory, and Cytotoxic Properties

Abstract

A water-soluble hydroxycinnamate-derived polymer (>1000 kDa) from Symphytum asperum Lepech. (Boraginaceae) strongly reduced the diphenylpicrylhydrazyl radical (IC₅₀ ≈ 0.7 μg/mL) and inhibited the nonenzymatic lipid peroxidation of bovine brain extracts (IC₅₀ ≈ 10 ng). This polymer exhibited only a low hydroxyl radical scavenging effect in the Fe³⁺−EDTA−H₂O₂ deoxyribose system (IC₅₀ > 100 μg/mL) but strongly decreased superoxide anion generation in either the reaction of phenazine methosulfate with NADH and molecular oxygen (IC₅₀ ≈ 13.4 μg/mL) or in rat PMA-activated leukocytes (IC₅₀ ≈ 5 μg/mL). The ability to inhibit both degranulation of azurophil granules and superoxide generation in primed leukocytes indicates that the NADPH oxidase responsible for this later effect is inhibited, pointing to the Symphytum asperum polymer as a potent antiinflammatory and vasoprotective agent. At all concentrations tested (0−200 μg/mL), we observed no cytotoxicity on normal human fibroblasts and neither antiproliferative effects nor proliferation activation on neoplastic cells. Keywords: Symphytum asperum; hydroxycinnamates; DPPH assay; lipid peroxidation; hydroxyl radical generation; superoxide anion generation; degranulation; neutrophils; growth-inhibition; growth-proliferation; human fibroblast; colon adenocarcinoma; breast adenocarcinoma