Barley protective activity against rat liver microsome lipid peroxidation

Based on the finding that reactive oxygen species (ROS), in particular free radicals, play an important role in initiating and accelerating lipid peroxidation and that are involved in a number of chronic diseases and that plant materials contain antioxidant compounds, we have evaluated the antioxidant activity of three different barley samples: an unroasted barley sample, a roasted barley sample prepared in a pilot roaster apparatus and a commercial instant barley coffee. The antioxidant activity of barley samples has been determined in a chemical system, based on coupled oxidation of linoleic acid and beta-carotene and expressed as antioxidant activity percentage, and in a biological system as protective activity percentage against lipid peroxidation of microsome membrane hepatocytes induced by CCl4. The unroasted barle ysample has shown weak activity in the chemical system and no activity in the biological system. Conversely, the same barley after roasting and the instant barley sample are very active in the two systems. In particular, the tested roasted barley solutions are abe to completely protect lipid microsomes from peroxidation. The three barley solutions were dialysed using membrane with cut-offs 3500Da. The dialysate and the retentate of the unroasted barley sample showed scarce activity, while the dialysates and the retentates of roasted and instant barley samples showed high antioxidant activity both in the chemical and in the biological systems. These results indicate that during roasting process high molecular weight dark brown compounds with remarkable antioxidant and protective properties are formed.