| Artemisia argyi is the mature leaves of Artemisia argyi Levl.,a plant of the Compositae family,and is widely used in food,medicine and other fields.Artemisia argyi polysaccharide is a kind of heteropolysaccharide with anti-oxidation,anti-inflammation,immune regulation,anti-coagulant activity and other functions,and has broad development prospects.In this paper,two solvents were used to extract the active ingredients of mugwort leaves,and their antioxidant and antibacterial effects were compared,and the antibacterial mechanism was clarified.In this paper,two solvents were used to extract the active ingredients of Artemisia argyi,and their antioxidant and antibacterial effects were compared,and the antibacterial mechanism was clarified.The study found that the polysaccharide content in the two extracts of Artemisia argyi was higher.The structure and antioxidant activity of polysaccharides from Artemisia argyi were further explored,and it was found that the extraction of citric acid aqueous solution was more suitable for the extraction of active ingredients from Artemisia argyi than the traditional water extraction method.The main findings are as follows:（1）The citric acid aqueous solution and deionized water were used to prepare the extract of Artemisia argyi,the study found that the contents of total flavonoids,total polyphenols and polysaccharides in the water extracts of Artemisia argyi were 208.03mg/g,51.77mg/g and 398.72mg/g,respectively.The extracts of Artemisia argyi were80.39mg/g、25.44mg/g、453.45mg/g,respectively.both the water and acid extracts of Artemisia argyi have strong antioxidant capacity,and the median inhibition concentration(IC50)of DPPH free radical scavenging rate is 33.10μg/m L and 54.52μg/m L,respectively;The IC50 values of free radical scavenging rate were 2.92mg/g and1.63mg/mL;the IC50 values of free radical scavenging rate of ABTS were 0.17mg/g and 0.32mg/mL,respectively.（2）The Oxford cup method was used to compare the antibacterial activities of the two Artemisia argyi extracts.The results showed that:the water extract of Artemisia argyi has no obvious antibacterial activity,but the acid extraction has significant antibacterial activity.The minimum inhibitory concentration（MIC）against Staphylococcus aureus and Shigella is 0.1g/mL,and the minimum inhibitory concentration for Salmonella is 0.2g/mL.And the antibacterial effect on the three food-borne pathogenic bacteria is:Staphylococcus aureus>Shigella>Salmonella.Combining scanning electron microscopy,gel electrophoresis and other techniques to further explore the antibacterial mechanism of the acid extraction,the acid extraction can change the permeability of the cell membrane,destroy the integrity of the cell wall,and inhibit the synthesis of bacterial protein,thereby destroying the structure of the bacterial body and causing bacteria to fail to grow and reproduce normally.（3）The structure of polysaccharides was analyzed by infrared spectroscopy,particle size,potential,molecular weight,and monosaccharide composition.The results showed that:the citric acid extracts Artemisia argyi polysaccharides with higher content,larger molecular weight,smaller particle size and more stable solution.Infrared spectroscopy results show that the two Artemisia argyi polysaccharides both contain pyranose ring structures,The two Artemisia argyi polysaccharides are mainly composed of mannose,rhamnose,glucuronic acid,galacturonic acid,galactose,arabinose,fucose and anhydrous Glucose composition;The molar ratio of HUA-P monosaccharides is15.52:3.92:5.55:9.10:71.68:15.38:1.40:1.00,and the molar ratio of AUA-P monosaccharides is 6.67:2.88:2.06:4.08:24.17:7.88:1.00:1.56.The extraction of citric acid solution will affect the molar ratio of monosaccharide composition of Artemisia argyi polysaccharide.Scanning electron microscopy observed the difference in the microstructure composition of the two Artemisia argyi polysaccharides.（4）The antioxidant results showed that:AUA-P and HUA-P have strong antioxidant capacity,and the IC50 for the DPPH free radical scavenging rate is 0.36mg/m L and 0.38mg/mL,respectively;the hydroxyl free radical scavenging rate is the IC50 values were 4.56mg/mL and 17.56mg/mL,respectively;the IC50 values for the ABTS free radical scavenging rate were 1.18mg/mL and 1.95mg/mL,respectively.（5）By constructing a mouse skin melanoma cell model to determine the toxic and side effects of icosaccharin,the results showed that:the acid extraction of Artemisia argyi has no toxic and side effects on the growth of mouse skin melanoma cells.In summary,this article systematically explored the effects of two solvents on the extracts of Artemisia argyi and polysaccharides from Artemisia argyi,and found that the citric acid aqueous solution extraction is more suitable for the extraction of active ingredients from Artemisia argyi,At the same time,it provides a theoretical basis for the extraction,structural analysis and functional activity of Artemisia argyi polysaccharides,provides technical support for the development and utilization of Artemisia argyi resources,and provided new ideas for the development and utilization of polysaccharides in cosmetics and functional products in the future. |
