矽藻培養及抗氧化活性分析

矽藻是自然界中種類最多的單細胞藻類，已有研究指出矽藻多醣具有抗氧化、抗癌之活性。本研究使用台中港取得之矽藻TPC14 (Odontella sinensis) ，首先以f/2培養基在溫度25 ℃、光照/黑暗週期為14/10小時下培養14天，建立其生長曲線。接著使用不同培養基f、3/2f、2f、5f及L1培養，每天取樣、計數細胞數並繪製生長曲線圖，並在培養第14天萃取總醣，利用酚硫酸法測量醣類含量並以DPPH、ABTS自由基清除能力測定其抗氧化活性。結果顯示f培養基所培養之TPC14其細胞數最高，在培養第14天約達到8.1 × 106 ± 1.5 cells/L。矽藻培養所得到之胞外可溶性聚合物其含量約8.43 ± 1.54 mg/g 乾藻、胞外附著性聚合物0.23 ± 0.01 mg/g 乾藻、胞內碳水化合物0.21 ± 0.04 mg/g 乾藻及殘餘碳水化合物14.10 ± 0.25 mg/g乾藻。我們的實驗證實粗萃之殘餘碳水化合物具有抗氧化活性，當其濃度為500 ppm時，DPPH自由基清除率約可達93.48 % (EC50= 89 ppm) ，當殘餘碳水化合物濃度達400 ppm時，ABTS自由基清除率約為85.74 % (EC50= 140 ppm) 。

關鍵字

矽藻； Odontella sinensis ；多醣；抗氧化

並列摘要

Diatoms are the most abundant species among the unicellular algae. Researches had shown that polysaccharides from diatoms have the effects of anti-oxidation and anti-cancer. TPC14 (Odontella sinensis) , diatoms collected from port of Taichung, was cultured using f/2 medium in the condition of 25 ℃, light/dark cycle 14/10 hours to establish its growth curve. They were also grown at various culture medium f、3/2f、2f、5f and L1 to find out the optimal culture condition and estimate its total carbohydrate contents by a phenol-sulfuric acid method. The methods of DPPH and ABTS for free radical scavenging effect were used to test the antioxidant activity of the carbohydrates. Our results showed that the highest cell numbers were reached 8.1 × 106 ± 1.5 cells/L at day 14 in medium f. The amount of extracellular soluble polysaccharides and extracellular adhesive polysaccharides obtained from diatom TPC14 were about 8.43 ± 1.54 mg/g biomass and 0.23 ± 0.01 mg/g biomass respectively. The amount of intracellular carbohydrates and the residual carbohydrates were 0.21 ± 0.04 mg/g biomass and 14.10 ± 0.25 mg/g biomass, respectively. Our results further demonstrated that the residual carbohydrates of diatom TPC14 had strong scavenging activities on DPPH radical (EC50= 89 ppm) and on ABTS radical (EC50= 140 ppm) in vitro.