The Mechanical Discussion Of Dihydromyricetin Inhibit Vibrio Parahaemolyticus

Dihydromyricetin (DMY) is a kind of polyphenol hydroxyl dihydroflavonol abound in the vitaceae ampelopsin genus. It has many physiological activities such as anti-inflammatory analgesic, anti-allergy, cough expectorant, hepatoprotective, hypoglycemic, lipid-lowering, anti-lipid peroxidation, anti-bacterial and anticancer etc. DMY has a strong inhibitory effect on bacillus and vibrio as a kind of flavonoids with broad-spectrum antibacterial effect. This paper study on the bacteriostat action of DMY on several common food pathogens to determine the minimal inhibitory concentrations (MIC) of DMY, probe into the antimicrobial properties of DMY, analyze the antibacterial target with the sybyl software of computer-aided drug screening targets, and study on its antibacterial activity on vibrio parahaemolyticus, thus providing a theoretical basis for the development of a powerful aquatic antibacterial agent. Specific contents as follows:(1) DMY has a good antibacterial effect on gram positive bacteria and negative bacteria but mold. DMY and citric acid has good synergy bacteriostatic effect on deputy hemolytic vibrio. With the concentration of5g/L, the DMY has obvious antibacterial effect on the deputy hemolytic vibrio in TSB culture medium and with the addition of1%, the citric acid has the best antibacterial effect on deputy hemolytic vibrio. The MIC is only0.625g/L, and the citric acid together with DMY with concentration of5g/L have better antibacterial effect than potassium sorbate with the same concentration.It mainly inhibit the growth of deputy hemolytic vibrio specially in the period of logarithmic phase. The citric acid and DMY with concentration of5g/L have no inhibiting effect on deputy hemolytic vibrio in South America white shrimp which may be related to the prolyl acid metabolism pathway of deputy hemolytic vibrio. DMY has a variety of biological activity against human prostate cancer cells DU145, but have a strong inhibitory effect reproduction, but almost don’t strengthen the anticancer with organic acids. (2) The vibrio parahaemolyticus affected by DMY has been significantly changed through scanning electron microscopy compared with the control group. The Vibrio parahaemolyticus was arc, smooth in rod surface and rounded plump appearance in the control group. But the vibrio parahaemolyticus treated by DMY for24h, showed serious bacterial wrinkled, shriveled, distorted, and a clear structure of depression or irregular protrusions. The results showed that the conductivity coefficient of1.5MIC group and10MIC group had a rise and DMY conductivity coefficient of10MIC group treated after24h showed a sharp rise, indicating that the effects of low concentrations of DMY increase in membrane permeability treated for certain time and molecules penetrating into the membrane acted on other substances, resulting in the destruction of membrane integrity and leakage of intracellular ions.The increase of concentration of inhibitory substance further increased the membrane permeability. Therefore, antibacterial substances were easier access to the plasma membrane, acting on the cell membrane and macro molecules began to fester and the content material is completely penetrate it, resulting in a sharp increase in conductance coefficient. Cell damage detection results also confirmed that1.5MIC group was hard to reach full kill effect on vibrio parahaemolyticus in short time, just caused some cell damage or necrosis. When increase the concentration of DMY (10MIC), it can be achieved the effect of damage or necrotic, and the necrotic cell ratio reached high as80%.(3) When the relationship between Vibrio parahaemolyticus bacteria cell surface hydrophobicity and sterilization rate are further studied, we found that the bactericide rate of DMY depends on the microbial cell surface hydrophobicity. Within a certain range, the higher hydrophobic surface of coefficients, the better suppression bacteria effect which may be due to a strong hydrophobic DMY acting on the cell surface, causing an increase in surface hydrophobicity of microbial cell membranes, resulting the penetration increasement of DMY into the cell membrane. By measuring proline, ProDH, and y-glutamyl kinase activity, we found that when DMY and citric acid both worked on vibrio parahaemolyticus, the content of proline accumulated in a short period. The molecular docking results further indicate that when DMY molecule entered into the plasma membrane in ionic form,the effect target was the active center of FDA, leading to the enzyme inactivation, interfering with the normal metabolism of proline, and resulting in the cell damage or death. It can be initially determine that DMY and citric acid have synergistic effect on ProDH interferring with the normal metabolism of proline, which caused the cell damage and the critical kinase y-glutamyl kinase inactivation achieving an antibacterial effect.