Isolation Of Active Antibacterial Components From Artemisia Argyi And Preparation And Application Of Its Starch Nanofiber

Artemisia argyi is one of the traditional herb-medicines with the longest history in China.Modern researches show that the extracts,such as volatile oil(essential oil)and total flavonoids,of Artemisia argyi have good antibacterial activity against Staphylococcus aureus,Escherichia coli and other bacteria.In this paper,natural antibacterial components are separated from Artemisia argyi folium by green and environmentally friendly extraction method,and antibacterial nanofibers are prepared by electrospinning together with starch,which can be a foundation for the application of natural products such as Artemisia argyi and starch in biomedicine and other fields.(1)The total flavonoids were extracted from A argyi folium by microwave-assisted extraction method,and the extraction process was optimized by using the response surface experiment design.Under the optimum conditions,the total flavonoids in extraction of Artemisia argyi folium were 167.02 mg /g.By using NAK-9 macroporous resin to remove polysaccharide from the extraction,the antimicrobial activities of the purified total flavonoids extraction against three microorganism(Staphylococcus aureus,Escherichia coli,Candida albicans)had been greatly improved in different concentrations.The order of antimicrobial activities was C.albicans>S.aureus>E.coli.The total flavonoids viscose fibers of Artemisia argyi folium were prepared by wet spinning.The input of total flavonoids of Artemisia argyi folium increased the mechanical strength of the viscose fibers.Nonwovens were prepared from viscose fiber by spunlaced method.The nonwovens had good antimicrobial properties and the antimicrobial properties did not decrease after water washing,which could meet the commercial requirements.Using2,2-dimethyl-1,3-propanediol acrylamide methoxy phosphate(DPAMP)as a flame retardant,the flame retardant finishing of Artemisia argyi folium viscose nonwovens were carried out.The flammability increased with the increase of the grafting ratio of DPAMP.When the grafting ratio was 8.5%,the limiting oxygen index could reach27.4 % and the limiting oxygen index does not change after water washing.(2)The essential oil was extracted from Artemisia argyi folium by ultrasonic-assisted hydrodistillation and the extraction process of Artemisia argyi folium essential oil was optimized by response surface experiment design.the yield of essential oil was 0.92±0.1 % under the optimum conditions.The chemical composition of the obtained essential oil of Artemisia argyi folium was analyzed by gas chromatography-mass spectrometry(GC-MS).The results indicated that at least21 components were identified and the main components were eucalyptol,camphor,1-caryophyllene,etc.The obtained essential oil has excellent antimicrobial activities against C albicans,S aureus and E coli.The order of antimicrobial activities was E.coli > C.albicans > S.aureus.The inhibition zone of E.coli reaches 19.5±0.7 mm.(3)In order to investigate the compatibility of Artemisia argyi folium essential oil with natural polysaccharide compounds,three different cyclodextrins were selected to load Artemisia argyi folium essential oil.The loading performance,in vitro release performance,thermal stability and crystalline state of Artemisia argyi folium essential oil-cyclodextrins were investigated.The results indicated thatβ-cyclodextrins were the most hydrophobic,which resulted in the highest essential oil loading capacity.The release performance of essential oil from essential oil-cyclodextrin inclusion complexes were demonstrated for a slowly controlled release.The compatibilities of Artemisia argyi folium essential oil-cyclodextrin inclusion complexes with amylose were investigated and the results indicated that the Artemisia argyi folium essential oil-β-cyclodextrin inclusion complexes had a good compatibility with amylose.(4)The dissolution mechanism of common corn starch and high amylose starch in water and formic acid was studied in depth.It was shown that there were big differences in the molecular conformation,orientation and intermolecular hydrogen bonds of ordinary starch and high amylose starch in different solutions.The molecular conformation of high amylose starch changes from multi-helix structure to single-helix structure,which was more conducive to subsequent spinning.The high amyloses tarch nanofibers were prepared by electrospinning when total flavonoids and essential oil of Artemisia argyi folium were as natural antimicrobial materials,respectively,amylose as raw material and formic acid(FA)as solvent.When the total flavonoids of Artemisia argyi folium were used as the antibacterial agent,the diameters of the obtained starch nanofibers were 0.10-0.57 μm and the average diameter was 0.30 μm.When the essential oil of Artemisia argyi folium were as the antibacterial agent,the diameters of the obtained starch nanofibers were 0.15 to 0.54μm and the average diameter was 0.31 μm.When glutaraldehyde was used to cross-link the two kind of starch nanofibers,the average diameters and water sensitivity of the two kinds of nanofibers were slightly decreased while the slow-release performance,antimicrobial activities and mechanical strength were improved.These results indicate that the obtained starch fiber film with the antimicrobial components of Artemisia argyi folium have a good application prospect for the further application in biomedical fields.