| Abstract
| - Botryococcus braunii is a green colonial microalga that is used mainly for the production ofhydrocarbons, exopolysaccharides, and carotenoids. In the present study, the antioxidant propertiesof acetone extracts of B. braunii were evaluated using in vitro model systems such as 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxy radical scavenging, and lipid peroxidation in human low-densitylipoprotein and rat tissues. Acetone extracts of B. braunii (equivalent to 10 ppm total carotenoid)exhibited 71 and 67% antioxidant activity in DPPH and hydroxyl radical scavenging model systems,respectively. Similarly, the extract also showed 72, 71, and 70% antioxidant activity in the liver, brain,and kidney of rats. Low-density lipoprotein oxidation induced by Cu2+ ions was also protected (22,38, and 51%) by the algal extract in a dose-dependent manner (4, 6, and 8 ppm levels of totalcarotenoid). Thiobarbituric acid reactive substances concentration in the blood, liver, and kidney ofrats was also significantly decreased in B. braunii treated samples compared with those of control.Carotenoids (violaxanthin, astaxanthin, lutein, zeaxanthin, chlorophylls a and b, and α, β-carotene)identified in the B. braunii acetone extract may be exhibiting antioxidant activity. Among thecarotenoids, lutein represents more than 75% of the total carotenoids. B. braunii extract was shownto be effective for protecting biological systems against various oxidative stresses in vitro. This is thefirst report on the antioxidant properties of B. braunii. Keywords: Botryococcus braunii; antioxidant activity; microalga; lipid peroxidation; carotenoids
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