Studies On Antibacterial Activity And Mechanism Of Chloroform Fraction Obtained From The Aqueous Extracts Of The Leaves Of Artemisia Argyi Levl

The official record of Artemisia argyi as a medicine was first seen in "Famous Doctors" written by Tao Hongjing in Liang dynasty.The effects included warming the meridian,dispelling cold and relieving pain.A large number of studies have shown that the volatile oil in Artemisia argyi had obvious antibacterial activity.However,the antibacterial effect of the non-volatile components in the leaves of Artemisia argyi Levl is still unclear.In order to further explore the antibacterial components of the leaves of Artemisia argyi Levl,it was extracted by decocting method,and the antibacterial activity of the extracted solution was studied.1.Antibacterial activity of the aqueous extracts from the leaves of Artemisia argyi Levl: The leaves of Artemisia argyi Levl was extracted by decoction method with water as solvent,and the antibacterial activity of the extracts was compared by the drug sensitive paper method.The results showed that the extraction rates of the aqueous extracts was 21.17%.Besides,the antibacterial activity of the extract was studied by experimental strains(Staphylococcus aureus,Micrococcus luteus,Bacillus subtilis,Escherichia coli and Stenotrophomonas maltophilia)and it was found that the aqueous extract had certain antibacterial activity against the five strains,of which the best antibacterial activity was against Staphylococcus aureus.2.Antibacterial activity of different effective fractions of the aqueous extract from the leaves of Artemisia argyi Levl: In order to further identify the effective antibacterial parts of the aqueous extract fractions,it was sequentially extracted with petroleum ether,chloroform,ethyl acetate and n-butanol to obtain the different extract components,and the extraction rate and antibacterial activity of each fraction were determined.Among them,the petroleum ether extract yield was 0.92%,the chloroform extract yield was6.23%,the ethyl acetate extract yield was 5.03%,and the n-butanol extract yield was6.24%.The results of antibacterial experiments showed that the extracts had certain antibacterial activity.By contrast,the chloroform fraction obtained from the aqueous extracts of the leaves of Artemisia argyi Levl had the strongest antibacterial activity against Staphylococcus aureus and Escherichia coli,whose minimum inhibitory concentration is 3 mg/m L and 5 mg/m L,respectively.3.Antibacterial Activity and mechanism of chloroform fraction obtained from the aqueous extracts of the leaves of Artemisia argyi Levl: the results showed that chloroform fraction could maintain antibacterial activity for a long time and had obvious inhibitory effect on the growth curves of Staphylococcus aureus and Escherichia coli.The chloroform fraction can obviously destroy the cell wall of bacteria and change the permeability of cell membrane.Although it does not effectively destroy the cell membrane,the bacteria are in a semi apoptotic state,which further affects protein synthesis,the activities of related enzymes on the respiratory metabolic pathway,such as malate dehydrogenase and succinate dehydrogenase,and genes expression related to bacterial growth,such as cell viability(clp P)and cell wall synthesis(mtg A,ica A),stress response(sig B)and oxidative stress(din F)genes.The mutual effects eventually lead to cell apoptosis.This study provides a scientific basis for revealing the antibacterial activity of the non-volatile components of the leaves of Artemisia argyi Levl,and lays an experimental foundation for further development and utilization of the leaves of Artemisia argyi Levl.