Antibacterial and Antidiarrheal Activities of Houttuynia Cordata Thunb. And Portulaca Oleracea L. Extracts Against Enterotoxigenic Escherichia Coli

Houttuynia cordata Thunb. and Portulaca oleracea L. have been used as medicinal and food homologous plants. This research focused on evaluating the possibilities of the combination of H. cordata and P.  oleracea extracts as alternatives to antibiotics. The antimicrobial and antidiarrheal activities of the combination of ethanol extract and essential oil from H. cordata (HEE and HEO) and ethanol extract from P. oleracea (PEE) against enterotoxigenic Escherichia coli were studied. Results showed the combination (CB-HHP) of HEE, HEO, and PEE indicated synergistic effect on E. coli , and the concentration consist when HEE, HEO, and PEE were at a concentration of 1, 0.56, and 0.5 mg/mL, respectively, was regarded as minimal inhibitory concentration (MIC) of CB-HHP. CB-HHP increased the permeability of cell wall and cell membrane and affected the integrity of cell membrane, as evidenced by the leakage of alkaline phosphatase (AKP), potassium ion (K+), and protein, and changes in cell morphology further proved the damage to the cell wall and membrane of E. coli by CB-HHP. In addition, CB-HHP treatment significantly inhibited formation of E. coli bacterial biofilm. In vivo, gavaging with CB-HHP (HEE:HEO:PEE = 1:0.56:0.5, 800 mg/kg body weight) could significantly relieve the weight loss and diarrhea rate and protect the duodenal villi of mice infected by E. coli , as well as increasing the concentration of immunoglobulin (Ig) G, IgM, and IgA in serum. Therefore, CB-HHP was demonstrated remarkable antibacterial activity, antidiarrheal activity, and intestinal protective function, with potential to be used as food-derived additives.