Study On Antibacterial And Antifungal Activity Of Extracts From Selected Plants

Plant diseases is one of the major hazards affect agricultural production yields,however,control of plant diseases caused overusing chemical pesticides,the environmental issues,as well as pesticide residues and resistance issues,botanical pesticides provide a good way to solve those problem.This paper studied on rapid high-throughput screening methods,26 plant extracts determined antibacterial activity by resazurin colorimetric – microdilution method.Better activity of plant extracts were measured further activity.Aphananthe aspera ethyl acetate extract had good antibacterial activity,and to tract antibacterial active ingredient.Aphananthe aspera n-butanol fraction extract was separacted and tested,the main findings were as follows:1.Using aqueous ethanol extraction method at room temperature,processed 26 kinds of plant,and liquid-liquid extracted them by the organic solvent that basis of polarity from low to high,obtained several different polar extracts.Using resazurin colorimetric–microdilution method,determinated two common bacteria inhibitory activity of ethyl acetate and n-butanol extracts.The results show:Phoebe sheareri ethyl acetate,Sapium sebiferum ethyl acetate,Phyllostachys vivax ethyl acetate,Sinobambusa tootsik ethyl acetate,Rhus chinensis ethyl acetate and Aphananthe aspera ethyl acetate inhibited Staphylococcus aureus,MICs were 12.5 ?g/mL,12.5 ?g/mL,25.0 ?g/mL,25.0 ?g/mL,25.0?g/mL and 25.0?g/mL.Phoebe sheareri ethyl acetate,Sapium sebiferum ethyl acetate,Rosmarinus officinalis ethanol extract,P.maculatus ethyl acetate,Sinobambusa tootsik ethyl acetate,Phyllostachys vivax ethyl acetate,Pleioblastus amarus ethyl acetate and Aphananthe aspera ethyl acetate inhibited Xanthomonas oryzae,MICs were 12.5?g/mL,12.5 ?g/mL,12.5 ?g/mL,25.0 ?g/mL,25.0 ?g/mL,25.0 ?g/mL,25.0 ?g/mL,25.0?g/mL.2.The inhibitory activity against three fungi of plant extracts were evaluated with resazurin colorimetric – microdilution method,and higher biological activity of plant extracts were determined toxicity.The results show:A.aspera ethyl acetate inhibited Botrytis cinerea,MIC was 5 ?g/mL and EC50 was 484.897 ?g/mL.A.aspera ethyl acetate,K.Bipinnata ethyl acetate and R.officinalis ethanol extract inhibited G.sanbinetti,MICs were5 ?g/mL and EC50 were 552.221 ?g/mL,345.636 ?g/mL and 995.569 ?g/mL.R.officinalis ethanol extract and A.aspera ethyl acetate inhibited C.Cda,MICs were5 ?g/mL and EC50 were 1086.927 ?g/mL and 667.010 ?g/mL.3.Tracking the active ingredient of A.aspera ethyl acetate fraction.With the antibacterial activity test,the biological activity of each fraction was extracted with A.aspera comparison,ethyl acetate fraction inhibited bacteria and fungi that much higher than other fractions.Ethyl acetate fraction was further fractioned by medium-pressure separate to obtain 10 fractions.F6 inhibited Staphylococcus aureus and Xanthomonas oryzae,and MICs were 50 ?g/mL and 100 ?g/mL;F7 inhibited them,and MICs were both200 ?g/mL.F7 inhibited Fusarium solani and Botrytis cinerea,EC50 were 1992.947 ?g/mL and 2773.169 ?g/mL;F8 inhibited Fusarium solani and Botrytis cinerea,EC50 were2558.705 ?g/mLand 3126.421 ?g/mL?4.Separating of chemical ingredients from A.aspera butanol fraction.A.aspera butanol fraction was separated with AB-8 macroporous resin first,then separated with dextran gel,separated with high pressure liquid preparative chromatography finally.4 kinds of known ingredient were isolated.The purity of the 4 compounds is both exceed 98%which was determined by HPLC.4 compounds were identified by means of NMR analysis.They were first isolated in the A.aspera.