条斑紫菜提取物对4种赤潮微藻生长的抑制作用

The growth inhibition of the four species of red tide microalgae by the extracts from Porphyra yezoensis

研究条斑紫菜水溶性抽提液对前沟藻、中肋骨条藻、米氏凯伦藻和塔玛亚历山大藻等4种赤潮微藻生长的影响,在此基础上,利用甲醇、丙酮、乙酸乙酯、氯仿和石油醚等有机溶剂浸泡条斑紫菜干粉,经抑藻圈方法检测条斑紫菜水溶性抽提液的抑藻活性。通过测定藻细胞密度和细胞体积,观察藻细胞形态,分析藻细胞内叶绿素、蛋白质和多糖等生理生化指标的变化,对抑藻活性最大的提取物对前沟藻、米氏凯伦藻、中肋骨条藻和塔玛亚历山大藻赤潮微藻生长的抑制作用进行分析,并依次以石油醚、乙酸乙酯和正丁醇为提取溶剂,采用液液分离法对此提取物做了进一步分离。结果表明,当条斑紫菜水溶性抽提液浓度超过16g/L时能显著抑制4种赤潮微藻的生长,尤其是对前沟藻和米氏凯伦藻具有很强的抑制作用。在5种有机溶剂提取物中,甲醇提取物的抑制作用最为明显。进一步研究发现此提取物对4种赤潮微藻的生长抑制显著且具有浓度效应,在16g/L时,此提取物对前沟藻、米氏凯伦藻、中肋骨条藻和塔玛亚历山大藻的生长抑制率分别为70.5%、79.9%、67.1%和65.1%。同时,致使米氏凯伦藻、中肋骨条藻和塔玛亚历山大藻等3种赤潮微藻体积变小,运动能力下降,藻细胞出现空洞、细胞破碎和色素减褪等现象;4种赤潮微藻细胞内的叶绿素、可溶性蛋白质和多糖含量显著减低。通过液液分离法甲醇提取物进一步分离为石油醚相、乙酸乙酯相、正丁醇相和水相等4种提取物。其中,石油醚相和乙酸乙酯相具有较强的抑制作用。

A kind of aqueous extracts of Porphyra yezoensis was extracted with distilled water,and its inhibitory activity against four species of red tide microalgae,Amphidinium hoefleri,Karenia mikimitoi, Skeletonema costatum and Alexandrium tamarense was tested. The extracts were extracted with five solvents （methanol,acetone,ethyl acetate,chloroform and petroleum ether）,respectively,to probe their inhibitory effects on the growth of those microalgae. Based on the observation of microalgal morphology and density,cell size and the contents of some key physiological indicators （chlorophyll,proteins and polysaccharides）,the inhibitory effect of the solvent extract that had strongest inhibition on all tested microalgae was investigated. Thereafter,the extracts mentioned above were separated again with petroleum ether phase,ethyl acetate phase,n-butanol phase and distilled water phase by the method of liquid-liquid fractionaction. The results showed that the growth of the four microalgae was significantly inhibited by the aqueous extracts of P. yezoensis at the concentration of 16 g/L. The inhibitory effect of the aqueous extracts of P. yezoensis for A. hoefleri and K. mikimitoi was stronger than that for A. tamarense and S. costatum. The methanol extracts of P. yezoensis dry powder had the strongest effect,and at the concentration of 16 g/L its growth inhibitory effect on A. hoefleri,K. mikimitoi,A. tamarense and S. costatum was 70. 5% ,79. 9% ,67. 1% and 65. 1% on day 12, respectively. At the same time,the cell size and athletic ability of the cells decreased,and cavities,pieces and pigment faded in cells were caused. The further investigation found that under the effect of the methanol extracts the contents of chlorophyll,proteins and polysaccharides in the cells of those microalgae significantly decreased. The methanol extracts were partitioned to petroleum ether phase,ethyl acetate phase,n-butanol phase and distilled water phase by liquid-liquid fractionaction,among which those extracted with petroleum ether and ethyl acetate had the strongest effect.