ABSTRACT
Objective To investigate the relationship between the calcium ion and the effects of ECA on the contraction of the smooth muscles of Oncomelania foot, and explore the mechanism of ECA in decreasing the snail climbing adhesion and increasing snail-killing. Method The in vitro experiment was used to observe the effects of ECA on contraction activities of foot smooth muscles of Oncomelania. Results ECA 5. 0, 10. 0, 20. 0 mg/L. enhanced the resting tension, decreased the contraction range and increased the contraction frequency of the foot smooth muscles of Oncomelania in Ringer's solution with or without Ca2+ , with a characteristic of the dose-dependent, but stronger in solution with Ca2+ than that in solution without Ca2+. Conclusions ECA can enhance the resting tension, decrease the contraction range and increase the contraction frequency of the foot smooth muscles of Oncomelania. This suggested that ECA could be related to increasing the intracellular Ca2+ release and influx of the extracellular Ca2+. This could provide an explanation why ECA decreases the rate of Oncomelania climbing adhesion and enhances snail-killing.
ABSTRACT
Objective To extract the molluscicidal active component, Eomecon Chionantha Hance Alkaloids (ECA)from Eomecon Chionantha Hance. Methods The molluscicidal active component from the rootstalk of Eomecon Chionantha Hance was extracted and purified by using the method, 70% alcohol percolation, decompress concentrating, salting-out and so on. Results The final product rate of ECA was 1.009%. Conclusion This method is economic, simple and reliable, and suitable to industrialized production.
ABSTRACT
Objective To understand the molluscicidal effects of Eomecon Chionantha Alkaloids (ECA) on Oncomelania hupensis.Methods By using immersion methods for different durations of time the molluscicidal effects of ECA and the rate of snails climbing-upward were observed. Results While the solution concentrations and temperatures of ECA were at 1.25 mg/L,30℃;2.5 mg/L,25℃;5 mg/L and 10 mg/L,25℃ respectively,and the snails were immersed for 72 hours,the mortality of Oncomelania snails were 100%. The hatching rates of Oncomelania eggs after immersed for 72 h in the solution of 5 mg/L were 0～10%. ECA showed an inhibiting effect on the snails' climbing-upward in the concentrations of 5 mg/L. Conclusion ECA has molluscicidal effect on Oncomelania and is one of the potential plant molluscicides.
ABSTRACT
Objective To understand the acute toxicity of a plant-derived molluscicide Eomecon Chionantha Hance alkaloids ECA to fish. Methods The conventional tests of acute toxicity to fish were carried out at the laboratory. Results The Hypophthalmichthys molitrix mortality was zero under the concentration of 1. 25 mg/L for 96 hours, and 100% under the concentration of 20. 0 mg/ L. for 2 hours. LC50 of ECA to Hypophthalmichthys molitrix was 6. 457 mg/L for 2 h and the 95% confidence interval was 5. 289-7. 882 mg/L. The Cyprinus carpio mortality was zero under the con centration of 2. 5 mg/L for 96 hours, and 100% under the concentration of 20. 0 mg/L for 2 hours. LC50 of ECA to the Cyprinus carpio was 7. 244 mg/L for 2 hours and the 95% confidence interval was 5. 278-9. 954 mg/L. The Carassius auratus mortality was zero under the concentration of 1. 25 mg/L for 96 hours, and 100 % under the concentration of 20. 0 mg/L for 5 hours. LC50 of EGA to the Carassius auratus was 7. 080 mg/L for 5 hours and the 95% confidence interval was 5. 202 -9. 635 mg/L. Conclusion Toxicity of ECA to fish is lower than that of niclosamide. The EGA thus represents a promising plant-derived molluscicide which is worthy of further investigation.