Optimal Extraction Process Of Myriophyllum Spicatum Allelochemical And Its Acute Toxicity

In recent years, with the increasing of pollution, eutrophication of water body and water frequently, Microcystis aeruginosa as common cyanobacteria posed a serious threat for people’s lives and industrial-agricultural development. This research focused on allelochemicals from Myriophyllum spicatum stems to analysis of the optimum extraction process of allelochemicals and to explore the influence of extraction on antioxidant enzyme system and acute toxicity in Brachydanio rerio. The study found that extraction can quickly and effectively inhibited the growth of Microcystis aeruginosa with destroying antioxidant enzyme system of the algae, but for Brachydanio rerio as a low toxic substance, in order to provide some theoretical support for further research in the future.Extraction process of inhibitory components from Myriophyllum spicatum with the ultrasonic-cellulase method was studied. Based on one-way and orthogonal test, and regarding growth inhibition rate of extraction on M. aeruginosa as index of evaluation, an optimal extraction process of Myriophyllum spicatum allelochemicals was obtained as following: enzymatic hydrolysis of time was 4h, p H was 3.0, optimal temperature was 30℃, cellulase dosage(mass of cellulase to Myriophyllum spicatum powder) was 21%, ultrasonic power was 120 W and ultrasonic time was 1h. Ethanol reagent blank had no significant effect on the growth of Microcystis aeruginosa.The inhibition rate of extraction which were obtained with water extraction method and ultrasonic-cellulase method indicated that the latter showed better effect and had obvious difference with the water extraction(P<0.05) under the optimal condition. Compared with water extraction, only the lowconcentration groups(5g/L, 10g/L) after 7d disappeared the inhibition of Microcystis aeruginosa, and the other groups still retained the higher ability of inhibitition, especially at concentration of 40g/L and reaction time for 24 h, meanwhile the biggest growth inhibition rate of ultrasonic-cellulase extraction was 271.74%, while growth inhibition rate of water extraction was only 129.78%.After extraction which was obtained with ultrasonic-cellulase method from Myriophyllum spicatum acting on M. Aeruginosa, with reaction time and concentration of extraction increased, T-SOD activity,CAT activity and MDA dosage decreased rapidly in 12 h, and after 12 h the rate of decrease slowed down. T-SOD activity, CAT activity and MDA dosage tended to 0 in the high concentration group(30g/L, 40g/L)at 96 h, which were negatively correlated with concentration of extraction. Compared with the control group, each group showed significant differences(P<0.05).The study of water extraction and extraction of ultrasonic-cellulase from Myriophyllum spicatum on the acute toxicity of Brachydanio rerio showed that survival rate of Brachydanio rerio in each concentration group of water extraction and ultrasonic-cellulase extraction were higher than the control group, and especially survival rate of Brachydanio rerio in each concentration group of ultrasonic-cellulase extraction were all100% in the reaction time of 120 h, and on Brachydanio rerio survival were there no effects. According to Criteria for evaluating and grading toxicity of chemicals to fish and daphnia, we knew that water extraction and ultrasonic-cellulase extraction were low toxic substances on Brachydanio rerio. Therefore, ultrasonic-cellulase extraction was safe for ecosystem, and it could be used for the removal of water bloom in the production practice, the protection of aquatic ecosystem, Protect environment.