Study On Inhibitory Effect Of Dihydromyricetin

In this paper, the antibacterial activity and antibacterial mechanism of dihydromyricetin were studied.Based on the test tube dilution method, the antibacterial effect of dihydromyricetin was investigated. The results showed that the minimum inhibition concentration(MIC) of dihydromyricetin in Escherichia coli, S.paratyphi B, P.aeruginosa, Bacillus sabtilis, Canidia albicans, and Staphylococcus aureus were 0.3125, 0.625, 0.3125, 1.25, 0.3125, 0.625 mg/mL; and the minimum bactericidal concentration(MBC) were 2.5, 2.5, 2.5, 10, 2.5, 2.5 mg/mL. Thus, the dihydromyricetin has a broad-spectrum antibacterial activity, and lower MIC. The dihydromyricetin has obvious effect of antibacterial and bactericidal. Moreover, compared with berberine hydrochloride, dihydromyricetin showed stronger antibacterial and bactericidal effect.To further evaluation of antibacterial mechanism of dihydromyricetin, S. aureusand and E. coil were selected as indicator strains. The results of environmental scanning electron microscopy(SEM) showed that the normal cultivation of S.aureus has smooth surface, full of bacteria and good refraction. After treatment by dihydromyricetin for 4 h, bacteria surface began to produce drape, and become coarse; 14 h later, the bacteria began to shrink, surface depression, vesicles and irregular protuberance structure.The bacteria which normal cultured for 24 h, was slightly rough, but no abnormal structure, the bacteria still saturated molding. However, the bacteria which treated by dihydromyricetin for 24 h, become serious shrinkage, dry, and twisted, some bacteria has obvious atrophy. Thus, the bacteria became obvious compared with control group after treatment with dihydromyricetin.Cell membrane, cell wall permeability experimental results showed that the dihydromyricetin has a certain influence on the cell walls of bacteria cell membranes, but minimal effects on cell wall. Thus, the action target of dihydromyricetin was not on the cell wall. Dihydromyricetin can increase the permeability the bacterial cell membrane to small molecular substances, such as ions, electrolyte, but the effect on the permeability of macromolecular material such as enzyme coLTD was limited, indicating that dihydromyricetin could influence the permeability of the bacterial cell membrane, but it can’t make the bacteria completely loss of selective permeability. Breathing metabolic inhibition of the experimental results showed that the dihydromyricetin has inhibitory effect on S. aureus, it is induced that dihydromyricetin inhibit the bacteria respiratory metabolism by inhibiting TCA way.