evaluation of antioxidant stability of arbutin and pyrus boissieriana buhse leaf extract

with regard to the importance of antioxidants in foods, cosmetics and pharmaceutics, there are several studies on natural resources for finding rich sources of antioxidants and their role in protecting the body against oxidative stress injuries. the purpose of this study was to investigate the antioxidant stability of arbutin and the pyrus boissieriana buhse leaf extract and their effects on lipid oxidation in different conditions of temperature and time. arbutin and the pyrus boissieriana buhse leaf extract were stored for 14 days in the different conditions of temperature including room, refrigerator and freezer. total phenolic compounds were measured by the folin-ciocaltea method. flavonoid compounds were evaluated by aluminum chloride method. their total antioxidant activity was measured by frap (ferric reducing antioxidant power) method and their protection effect on lipid oxidation was measured by tbars (thiobarbituric acid reactant substances) method. also, the amount of sustainability for peroxide activities was measured by tmb (tetra methyl benzedrine) method. polyphenol formed 1.96 mg/g dry weight of pyrus boissieriana buhse leaf extract and the amount of flavonoid complex was 0.125 mg/g dry weight of pyrus boissieriana buhse leaf extract. the amount of frap was decreased by increasing temperature and time. the amount of lipid oxidation had increased in all samples with time (0-14). the stability of peroxide activities decreased in the different conditions of temperature and time. the results of this study show the existence of antioxidant activities with higher stability in storage time and the protective effect of arbutin and pyrus boissieriana buhse leaf extract on lipid oxidation. therefore, using arbutin and pyrus boissieriana buhse leaf extract as a natural resource of antioxidant is suggested for substituting synthetic antioxidants.