海洋微藻β-葡聚糖的生物活性分析

BIOACTIVITIES OF Β-GLUCAN IN SIX MARINE MICROALGAE

为研究微藻来源的β-葡聚糖生物活性以及是否存在种间差异,从6种海洋硅藻和定鞭藻(Haptophyte)中制备了β-葡聚糖,进行了抗肿瘤、抗氧化、抑菌活性的分析和比较。6种微藻分别为:中肋骨条藻(Skeletonema costatum)、三角褐指藻(Phaeodactylum tricornutum)、假微型海链藻(Thalassiosira pseudonana)、柔弱角刺藻(Chaetoceros debilis)、球等鞭金藻(Isochrysis galbana)、颗石藻(Pleurochrysis sp.)。研究结果显示:1.微藻β-葡聚糖对Hela肿瘤细胞有细胞毒性:浓度为50—100μg/mL时,假微型海链藻β-葡聚糖的活性最高;200μg/mL时,颗石藻的最高,但活性均未超过50%。2.以DPPH和DCFH-DA两种方法检测抗氧化活性发现,6种微藻β-葡聚糖均有浓度相关的抗氧化活性,并且对氧自由基的清除率相对较高;当β-葡聚糖浓度为400μg/mL时,其清除率可达72%—74%。3.对不同菌的作用有差异:有浓度相关的抑制大肠杆菌的作用,浓度为400μg/mL时,抑菌率可达60%;有促进金黄色葡萄球菌生长的作用,其中,仅中肋骨条藻的β-葡聚糖有浓度相关的作用。结果表明,几种硅藻和定鞭藻的β-葡聚糖生物活性功能相同,都具有抗肿瘤、抗氧化以及抑菌或促菌作用,活性大小与浓度有明显的相关性。相同浓度或作用时间下,其活性大小及活性饱和性具有微藻种间差异。这为研究和利用微藻及其天然产物提供了参考。

The biological activity of β-glucan in different organisms varies significantly. We studied the bioacitivity, in terms of cytotoxicity, antioxidation, and antimicrobe, of β-glucans extracted from mass cultures of six strains of marine diatom and haptophyte, namely, Skeletonema costatum, Phaeodactylum tricornutum, Thalassiosira pseudonana, Chaetoceros debilis, Isochrysis galbana, and Pleurochrysis sp. The results show that β-glucan from each microalgal strain showed moderate cytotoxicity on Hela cells. The most potent β-glucan was from T. pseudonana in concentration ranged 50-100 μg/ml, and Pleurochrysis sp. at 200 μg/ml. β-glucan from I. galbana and Pleurochrysis sp. show good positive concentration-cytotoxcitiy correlation. Moreover, β-glucan from all the strain was concentration-relevant in antioxidation against reactive oxygen and DPPH; for example, at 400μg/ml, β-glucan could remove 72% to 74% reactive oxygen. However, the effects on microorganism by β-glucan differed among the strains. For instances, β-glucan from marine microalga could inhibit the growth of E. coli up to 60% at the concentration of 400 μg/ml, but promote the growth of Staphylococcus aureus(best for β-glucan from S. costatum). The activities were concentration- and time- dependent. Significant difference may exist among the microalga at the same glucan concentration, calling for more works in the future.