Study On The Mechanism Of Purslane Decoction In Inhibiting E.coli And Dysenteryn In Vitro

Antibiotics and chemically synthesized antibacterial drugs have played a positive role in the prevention and treatment of animal bacterial diseases.However,due to its long-term application in animal disease prevention and control in animal husbandry,bacterial resistance increases and bacterial diseases become more and more difficult to treat.In addition,the residue of antibiotics and chemically synthesized antibacterial drugs has become an important factor of food safety.Traditional Chinese medicine is the treasure of China’s traditional culture.It has the advantages of environmental protection,low side effects and resistance to drug resistance in animal epidemic prevention and control,and has attracted more and more attention.Portulaca oleracea is a kind of medicine food homologous plant,which has good pharmacological activities such as antibacterial,antiviral,anti ulcer,anti-inflammatory,anti-oxidation and promoting wound healing,but its mechanism of action and corresponding active components are not clear.Based on the method of network pharmacology analysis,this experiment systematically expounds the pharmacological activity and target of Portulaca oleracea,and validates its efficacy in the treatment of bacterial diarrhea and dysentery in vitro and at the cellular level.Ten active components of Portulaca oleracea,such as arachidonic acid,β-sitosterol,kaempferol,luteolin,isobeet element and quercetin,were screened by network pharmacology analysis,with 187 corresponding targets and 62 core targets.KEGG enrichment analysis showed that the core targets were closely related to colitis,virus infection,cancer and other pathways,among which the pathways related to the treatment of colitis were ABCC4,ABCG2,ACAT1,ALOX5,CYP3A4,IFNG,IKKA,MPO,NOS2,NQO1,PPARG,PTGS1,PTGS2,TNF,XDH and so on.In view of the above results of network pharmacology analysis,the study aimed at the antibacterial mechanisms of Portulaca oleracea against Escherichia coli and Shigella for both Escherichia coli and Shigella can cause colitis.The results of bacteriostatic test in vitro showed that compared with the extract of purslane obtained by water ultrasound,methanol ultrasound and ethanol ultrasound,purslanewater extract had the best bacteriostatic effect,and its MIC was 125 mg/ml.Purslane water decoctions with different concentrations can inhibit the normal growth of E.coli and dysentery bacteria and destroy their cell morphology;can destroy the cell wall and cell membrane of bacteria,resulting in the increase of AKP,nucleic acid and soluble protein content in the culture medium;can inhibit the expression of some bacterial proteins,and the above effects of purslane water decoctions on bacteria are positively correlated with the concentration and the action time.RT-PCR results showed that the effect of MIC concerntration on the transcription level of virulence genes IpaB and VirB of Shigella dysenteriae at 12 h was more obvious,and the inhibitory effect was more obvious at 1/2 MIC concentration at 6 h.Colonic inflammation model was established by infecting human normal colon epithelial cells(NCM460)with dysentery bacillus,and 12.5 mg/mL purslane decoction can effectively inhibit the expression of inflammatory factors TNF-a and IL-6,and relieve dysentery bacillus on cells damage caused by activity.