Study On Antioxidant Activity And Antibacterial Mechanism Of Volatile Oil From Artemisia Argyi Leaves

Peroxidation and bacterial invasion have caused serious threats to human life and health.The wide use of chemical antioxidants endangers human health.At the same time,the use of antibiotics leads to the enhancement of bacterial drug resistance.Therefore,it is urgent to seek non-toxic and pollution-free natural products to replace chemical drugs.It is found that the volatile oil of aromatic plants,as a good natural active substance,has good antioxidant activity and antibacterial activity.However,at present,the relevant reports on the antioxidation and bacteriostasis of the volatile oil of Artemisia argyi leaves(Aal Vo)are relatively simple.Therefore,a comprehensive and systematic study on the antioxidant activity and antibacterial mechanism of the Aal Vo is of great significance for the further development and utilization of the Aal Vo.In this study,the basic physical and chemical properties of the Aal Vo were clarified through the extraction and component analysis of the Aal Vo.The antioxidant activity of Aal Vo was evaluated by measuring the total reducing power,inhibition rate of lipid peroxidation and scavenging rate of different free radicals.In addition,the antibacterial activity of the Aal Vo was evaluated by measuring the antibacterial diameter,thermal stability,UV stability,acid-base stability,minimum inhibitory concentration,minimum bactericidal concentration and antibacterial time curve of the Aal Vo.Finally,the effects of the Aal Vo on bacterial enzyme activity,protein,nucleic acid,conductivity,biofilm and cell morphology were measured,and the antibacterial mechanism of the Aal Vo was studied combined with metabonomics.The results are as follows:(1)The color of the Aal Vo was different in different periods,and the content of main chemical components was different.The yields of the Aal Vo was the highest in July,which was 0.50%.The results of infrared spectroscopy and GC-MS showed that the Aal Vo mainly contained alcohols and terpenes,among which Eucalyptol was the main characteristic component,cis-Chrysanthenol,Caryophyllene,(-)-4-terpenol andα-Terpineol is its main chemical component.(2)The antioxidant activity of the Aal Vo was positively correlated with its concentration within a certain concentration range.The antioxidant capacity of the Aal Vo is less than that of VC and BHT,but when the Aal Vo reaches a certain concentration,its antioxidant capacity is comparable to both.(3)The Aal Vo has good antibacterial activity and stability.The antibacterial activity of the Aal Vo was the best in July,the diameter of antibacterial against S.aureus and E.coli were(24.00±1.00)mm and(19.67±1.53)mm respectively,and the minimum inhibitory concentrations were 3.75 and 7.5 μL/m L respectively,the minimum bactericidal concentrations were 7.5 and 15 μL/m L respectively.The inhibitory effect of the Aal Vo against two bacteria showed a dose effect,0.5×MIC concentration of the Aal Vo can delay the growth of two bacteria,1×MIC concentration of the Aal Vo can inhibit the growth of two kinds of bacteria.(4)The Aal Vo could inhibit the formation of bacterial biofilm,damage the bacterial membrane structure in certain extent,reduce the activity of energy and respiratory related metabolic enzymes in the bacteria,lead to the leakage of key biological macromolecules such as protein and nucleic acid in the cells,and increase the conductivity in the bacterial solution.(5)The effect of the Aal Vo against bacteria could chang its metabolic pathway and produce differential metabolites.The Aal Vo performed biological effects on S.aureus and E.oli by regulating the biosynthesis pathways of secondary metabolites and monobactams.