Evaluation of antioxidant properties of marine microalga Chlorella marina

In recent years, the use of photosynthetic micro-organisms, such as microalgae, in life sciences has received increasing attentions due to their diverse phytometabolic contents with various chemical structures and biological activities[1]. Use of microalgae for human consumption as a source of high value health food, functional foods and for production of biochemical products, such as vitamins, carotenoids, phycocyanin and polyunsaturated fatty acids including the omega-3 fatty acids have been developed[2-4]. Among the various microalgae that have been explored for their suitability for commercial potential: Dunaliella species, Chlorella species and Spirulina species are three major type that have been used successfully to produced high concentrations of valuable compounds such as lipids, protein and pigments[5-7]. They also have nutritionally potential applications as functional foods which are able to provide additional physiological and pharmacological benefits for human health[1,8,9]. Polyunsaturated fatty acids, sulfated polysaccharides, phycosterols, heat-induced proteins, phenolic compounds, and pigments including carotenoids are the naturally origin functional ingredients which have positive effects on the health of man and animals[10]. A large number of studies on the microalgal bioactive compounds have oriented to the anti-inflammatory, antiviral, antimicrobial, antihelmintic, cytotoxic, immunological, and enzyme inhibition properties[11-13]. 毬-carotene and other carotenoids (astaxanthin & lutein) are integral part of the photosynthetic apparatus in algae and functions as accessory pigments in the harvesting complex and as protective agents against the active oxygen products (AOS) that are formed from photo-oxidation. These oxygen radicals can react with macromolecules and lead to cellular damages[14,15]. The mechanism of biological effect of illumination (including near-UV-B) appear to involve endogenous photosensitization and formation of AOS, such as from singlet oxygen (1O2), superoxide radical (O), hydroxyl radical (-OH) and hydrogen peroxide (H2O2)[15,16]. The algae have developed defiance system against photo-oxidative damage by antioxidative mechanisms to detoxify and eliminate these highly reactive oxygen species. Moreover, because of phototropic life of microalgae and their ARTICLE INFO ABSTRACT