| Chemical pesticides have always played an important role in the prevention and control of crops and pests.They are widely used because of their low price and high insecticidal rate.With the development of the economy and the improvement of people's quality of life,a series of problems such as chemical pesticide residues,drug resistance of pathogens and environmental pollution caused by spraying chemical pesticides have gradually attracted people's attention.Therefore,the development of natural green pesticides with high environmental protection,high insecticidal rate and easy degradation is widely favored by people.As the most important marine plant in the ocean,seaweed contains many compounds with novel structure and unique biological activity.In this paper,the most common Phytophthora in the coastal waters of Qingdao is studied.It is separated by pulverization,extraction,concentration,gradient elution and various column chromatography separation and purification techniques.The obtained monomer compounds are correspondingly Biological activity screening yielded meaningful experimental results.Firstly,more than 30 monomer compounds were obtained by repeated column chromatography methods such as silica gel column and gel column with repeated activity of the polar components of different polarities,and these compounds were determined by modern spectroscopic techniques.structure.Secondly,the activity of monomeric compounds was screened by using three biological activity screening models: filter paper,red nematode and Artemia.The results are as follows:Antibacterial activity screening: The five samples of samples Z1,Z3,Z4,Z7,Z28,Z23 were very weak in inhibiting the six indicator bacteria,and the diameter of the inhibition zone was about9mm-10mm(the positive control was 26mm);Sample Z6 only has a certain inhibitory effect on the indicator strain of B.thuringiensis,the diameter of the inhibition zone is 15mm(the positive control was 30mm);Z15 ??has a certain inhibitory effect on S.aureus,and the diameter of the inhibition zone is 16mm(The positive control was 28mm);Z20 only had a certain inhibitory effect on E.coli,and the inhibition zone diameter was 15mm(the positive control was 25mm).Thethree samples inhibited the other five indicator bacteria very weakly,and the inhibition zone was very weak.The diameter is about 9-10mm(the positive control is 26mm),which has a certain selectivity;the sample Z27 is opposite to six indicator bacteria(B.subtilis,B.thuringiensis,E.coli,S.aureus,P.aeruginosa,X.Campestris)showed strong inhibition.The diameter of the inhibition zone was 18 mm,20mm,16 mm,15mm,22 mm and 22 mm,which is worthy of further study.Red nematode activity screening: The five samples of samples Z4,Z12,Z19,Z22,Z30 showed strong inhibitory activity against red nematodes at each concentration,and the semi-lethal concentrations of these five samples were: 50.456 ug/ m L,47.41 ug/m L,58.683 ug/m L,39.013ug/m L,and 55.132 ug/m L,with very strong biological activity;samples Z15 and Z20 did not inhibit any red nematode at each concentration.The activity is weak;the other components have a certain inhibitory effect on the red nematode,and the semi-lethal concentration is between 100ug/m L and 200 ug/m L,which has certain biological activity.Artemia activity: Both samples of Z4 and Z12 showed strong inhibitory effects on Artemia at each concentration,and the semi-lethal concentrations of the two samples were 3.337 mg/m L and2.852 mg/m L,respectively.The Artemia showed strong inhibition,and the two samples also have significant inhibitory effects on the red nematode.It can be judged that these two substances have excellent biological activity and can be further studied. |
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