| Endophytic fungi refers to a large number of microorganisms that are symbiotic or parasitic in the tissues and organs of the host plant and do not cause significant lesions of the host and complete the whole life cycle.As a result of long-term coexistence with the host,will produce the same or similar active plants with the host metabolites,has become an important source of new drug screening.In this experiment,we selected Limonium bicolor as plant material,and studied the bioactivity of its endophytic fungi metabolites,and provided the basic data for the comprehensive development and utilization of endophytic fungi resources.A total of 32 isolates of endophytic fungi were isolated from the whole strain of Limonium bicolor by tissue block separation.Of which 6 leaves,11 stems,15 roots.Through the morphological characterization,21 strains were identified,belonging to 2 genera,3 orders,7 families and 11 genera.The fungi were fermented by PD medium,fermentation solid-liquid separation,fermentation liquid were extracted with ethyl acetate and n-butanol,obtained the ethyl acetate extract(EAE)and n-butanol extract(NBE),mycelium by methanol extraction of methanol extract(MME),96 samples for screening of fermentation products biological activity.Study on the antioxidant activity results showed that 74 samples showed the total reducing capacity,accounting for 77.08% of the total sample,Vc equivalent of more than 100?g/mg total of 1,S 102(NBE)the total reducing power of the strongest,Vc equivalent to 108.20ug/mg;DPPH free radical scavenging activity results showed that 94 samples exhibited DPPH free radical scavenging activity,accounting for 97.92% of the total samples,the clearance rate of more than 80% of the total of 5,R 301(EAE)activity was the strongest,the clearance rate was 94.23%;88 samples showed hydroxyl radical scavenging activity,accounting for 91.67% of the total samples,the clearance rate of more than 20% of the total 7,R 201(NBE)activity was the strongest,the removal rate was 35.34%.The results antibacterial activity showed that 75 samples had inhibitory activity against Escherichia coli,accounting for 78.13% of the total samples,A total of 4 samples with a diameter of 16 mm or more,S 101(NBE)had the strongest inhibitory activity,MIC was 0.625mg/m L;77 samples had inhibitory activity against Staphylococcus aureus,accounting for 80.21% of the total samples,A total of 2 samples with a diameter of 16 mm or more,R 403(EAE)had the strongest inhibitory activity,MIC was 1.250mg/mL;62 samples had inhibitory activity against Klebsiella pneumoniae,accounting for 64.58% of the total samples,A total of 6 samples with a diameter of 16 mm or more,L 301(EAE)had the strongest inhibitory activity,MIC was 0.625mg/m L;54 samples had inhibitory activity against Bacillus licheniformis,accounting for 56.25% of the total samples,A total of 3 samples with a diameter of 16 mm or more R 401(EAE)had the strongest inhibitory activity,MIC was 0.156mg/m L;55 samples had inhibitory activity against Pseudomonas aeruginosa,accounting for 57.29% of the total sample,but the overall inhibitory activity is weak,in order to achieve re-screening standards.Alpha glucosidase inhibitory activity results showed that 84 samples of ?-glucosidase exhibited inhibitory activity,accounting for 87.50% of the total samples,the inhibition rate in more than 80% of the total of 11,accounting for 11.46% of the total sample,S 303(EAE)the highest inhibiting activity,the inhibition rate was 96.38%.The results of insect resistant experiment indicated that 8 samples have certain insecticidal activity against Tribolium castaneum,accounting for 8.33% of the total samples,R 302(NBE)had the strongest activity,LC50 was 24.268mg/m L(positive control drug fenvalerate LC50=0.279mg/m L);10 samples had a certain contact activity against Lasioderma serricorne,accounting for 10.41% of the total samples,S 303(NBE)activity was the strongest,LC50 was 14.831 mg/mL(positive control drug fenvalerate LC50 = 0.140mg/m L).The fumigant activity of endophytic fungi was weak,and 5 samples showed fumigation activity,accounting for 5.01% of the total samples.S 303(EAE)had the strongest fumigation activity,LC50 was 29.304mg/mL,(positive drug dichlorvos LC50=0.023mg/mL);L 301(EAE)had the strongest fumigation activity against Lasioderma serricorne,LC50 was 43.414mg/m L,(positive drug dichlorvos LC50=0.141mg/mL).The repellent activity results showed that five samples had strong repellent activity against Tribolium castaneum,accounting for 5.21% of the total number of samples,6 samples showed strong repellent activity against Lasioderma serricorne,accounting for 6.25% of the total number of samples.Among them,R 304(NBE)had strong repellent activity against two kinds of test insects.In 10000 ppm,2h and repellent rate were 94% and 84%,respectively.Repellent activity was equivalent to positive substance DEET under the same conditions.Study on the extraction and antioxidant activity of Endophytic Fungi Polysaccharides from Limonium bicolor.The results showed that the contents of 64 polysaccharides in 32 endophytic fungi were different.A total of 10 samples with polysaccharide content of 0.5 mg/mL or more,accounting for 10.42% of the total sample,the highest polysaccharide content of R 202 was 0.91 mg / m L.The results of antioxidant showed that 58 samples showed certain reduction ability,accounting for 90.63% of the total samples;55 samples showed DPPH scavenging activity,accounting for 85.94% of the total number of samples;54 samples showed hydroxyl radical scavenging activity,Accounting for 84.37% of the total number of samples.In this experiment,the endophytic fungi were isolated from the whole plant of Limonium bicolor,the species and species distribution of endophytic fungi were clarified,and the endophytic fungi fermentation products were tested for antibacterial and antioxidant,?-glucosidase inhibition and insect-resistant activity screening,to obtain high activity strains,to find a new natural antioxidants,antimicrobial agents and natural pesticides to lay the foundation,but also for the integrated development and utilization of endophytic fungi to provide a scientific basis. |
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