Antioxidant Activity of Some Polyphenolic Extracts Obtained from Plants with Antitumoral Potential on Linoleic Acid Emulsion

Abstract

Polyphenols consist in a wide range of biological molecules present in plants and they have a variety of biological and chemical activities in vitro and in vivo. The most important classes of polyphenols are flavonoids and phenolic acids. Plant polyphenols are especially known for their important antioxidant activity; for instance, lipid peroxidation is implicated in the pathogenesis of cancer, atherosclerosis and toxic cell injuries. In this study, air dried aerial parts of European Mistletoe (Viscum album), European Birthwort (Aristolochia clematitis), Greater Celandine (Chelidonium majus) and Stag’s-horn Clubmoss (Lycopodium clavatum) were powdered and extracted with 60% ethanol (v/v). The total polyphenols content of the ethanolic extracts was estimated by a spectrophotometric method. The ethanolic extracts were investigated for antioxidant activity in linoleic acid/water emulsion system. The progression of the oxidation processes was monitored at 80°C for 7 days by measuring conjugated dienes, hydroperoxides and thiobarbituric acid reactive substances (TBARS) formation. The antioxidant activity of the sample extracts was expressed as inhibition percentage, comparatively to controls containing no antioxidant. The obtained results revealed that the vegetal extracts inhibited the formation of conjugated dienes, lipid hydroperoxides and thiobarbituric acid reactive substances (TBARS); the dynamics of lipid peroxidation inhibition is different from one plant to another