A STUDY ON POSSIBILITY OF APPLICATION AS PHARMACEUTICAL USE OF ANTIOXIDANTS EXTRACTED FROM TWO BENTHIC DIATOMS Amphora coffeaeformis AND Achnanthes longipes FROM KOREA

Abstract

This study reports the possibility on pharmaceutical uses of two benthic diatoms, Amphora coffeaeformis and Achnanthes longipes which are commonly found as dominant benthic microalgae in Korea. Single species was isolated and subcultured with artificial seawater media which was enriched with F/2 media, trace metal solution and meta-silicate anhydrous crystal, and growth characteristics were also determined. Biomass was collected after two weeks of mass culture based on the maximum growth condition, and lyophilized for later analysis. The antioxidant properties of different fractions (n-hexane, chloroform and ethylacetate) obtained by 80% methanolic extract of two microalgae were investigated for free radical, reactive oxygen species scavenging (Super oxide, Hydrogen peroxide, Hydroxyl radical and Nitric oxide), metal chelating and lipid peroxidation inhibition activities. All fractions of A. longipes and A. coffeaeformis showed higher DPPH• (free radical) scavenging activities in n-hexane fraction (89.0% and 67.5%). N-hexane fraction of A. longipes showed significantly higher activity (49.0%) on nitric-oxide. Metal chelating activities from ethyl acetate fraction of A. longipes and A. coffeaeformis exhibited 64.0% and 75.6% which were higher than commercial antioxidants (-tocopherol: 18.0% and BHT: 16.0). H2O2 scavenging effects from chloroform and n-hexane fractions of A. coffeaeformis exhibited 46.2% and 47.6% which were closely similar to the commercial antioxidants. Chloroform and ethyl acetate fractions of A. longipes and fractions of n-hexane and chloroform of A. coffeaeformis showed better lipid peroxidation activities than commercial -tocopherol. Both organic and aqueous fractions have good antioxidative compounds with different antioxidant properties, suggesting that the mass culture of two diatoms have an important possibility in order to develop a new aquaculture industry for pharmaceutical use.