Study On The Extraction Of Dihydroquercetin And Its Antibacterial Effect In Combination With Leucovorin

Dihydroquercetin is a plant extract that has antibacterial,anti-tumor,anti-inflammatory,anti-viral,and immune-regulating effects.Chelidonine is a natural component extracted from celandine,which belongs to the isoquinoline-like benzophenanthridine-type alkaloid,which is widely used in clinical practice.significant effect on bacteria.In this experiment,Gram-positive bacteria Staphylococcus aureus（S.aureus）and Gram-negative bacteria Escherichia coli（E.coli）were used as research objects,and dihydroquercetin was extracted from larch tree roots to explore the effects of dihydroquercetin respectively.The inhibitory effect of cortex and chelerythrine on E.coli and S.aureus and the antibacterial effect of the combination of dihydroquercetin and chelerythrine.The main content and results of the paper are as follows:（1）Dihydroquercetin extracted from larch tree roots was extracted by ultrasonic-assisted ethanol hot-dip extraction,and then purified by methyl tert-butyl ether extraction.The result is a dihydroquercetin refined product with a purity of 90%.（2）First,the antibacterial results showed that the MIC of dihydroquercetin against S.aureus and E.coli were 1.2 mg/m L,and the MIC of chelerythrine against S.aureus and E.coli were 0.025 mg/m L.m L,0.02 mg/m L.Second,with the increase of drug concentration,the growth rate of the two bacteria decreased significantly.When the concentration of dihydroquercetin and chelerythrine reached 1 MIC,the growth of the two bacteria was rapidly inhibited.S.aureus and E.coli are above 1/2 MIC,causing damage and causing a large amount of nucleotide leakage.The osmotic pressure of E.coli increased with the increase of the concentration of dihydroquercetin,but the concentration advantage of S.aureus only appeared at the end of the culture.The detection results ofβ-galactosidase showed that the enzyme activities of E.coli and S.aureus were 79.15%and 70.1%respectively at 120 min,and theβ-galactosidase was leaked due to the destruction of the bacteria by dihydroquercetin.Final,scanning electron microscopy（SEM）and transmission electron microscopy（TEM）were used to explore the inhibitory effect of dihydroquercetin on the two strains of bacteria,which showed that the bacterial cells were extended,with folds and depressions on the outside,and even the cells showed signs of ablation.（3）The antibacterial effect of dihydroquercetin combined with chelerythrine on S.aureus and E.coli was evaluated.The results showed that when dihydroquercetin and chelerythrine were added to S.aureus,the OD₆₀₀values after 24 h were 0.645 and 0.646 respectively,and the OD₆₀₀value after combined use was 0.581.Through the combined evaluation of drugs calculated on the growth rate of S.aureus and E.coli at 24 hours,the two strains were 0.0142（positive number indicates synergistic effect）and-0.0279（negative number indicates antagonistic effect）.The OD₂₆₀and OD₂₈₀values of the experimental group measured by the combination of drugs on S.aureus were significantly higher than those of dihydroquercetin alone,even 1.04 times and 1.6 times of the 24 h 2 MIC concentration of dihydroquercetin,respectively.The activity ofβ-galactosidase increased by 16.91%,and the enzyme activity of POD,CAT and SOD increased by 1.11 times,1.28 times and 1.25 times respectively compared with 1 MIC of dihydroquercetin on S.aureus.More fluorescent parts can be seen when used for bacteria,indicating that a large number of bacteria are damaged,and the permeability conductivity is also significantly enhanced.The antibacterial effect of the combination of drugs on the bacteria is more significant.