基于响应面优化中药单体组合及其对仔猪腹泻产肠毒素大肠杆菌的抑菌作用OA

This study aimed to optimize the composite ratio of three Chinese medicine monomers-quercetin,baicalin,and berberine-using response surface methodology and to evaluate their antibacterial effect against enterotoxigenic Escherichia coli(ETEC)causing piglet diarrhea.The minimum inhibitory concentration(MIC)of each monomer against ETEC was determined by the microbroth dilution method,and the combined effect was assessed using the fractional inhibitory concentration index(FICI).The optimal mass ratio of the monomers was obtained through response surface optimization using response surface methodology.The effects of the optimized monomer combination on bacterial growth curve,conductivity,alkaline phosphatase(AKP)activity,and DNA fluorescence signal were measured.The results showed that the MIC of quercetin,baicalin,and berberine against ETEC was 5.00,3.00,and 3.75 g/L,respectively.FICI tests indicated that the combined effects of these monomers were additive.Response surface optimization revealed the optimal mass ratio of quercetin:baicalin:berberine to be 1∶2∶2.Compared with the control group,bacterial growth in all treatment groups was inhibited.The conductivity and AKP activity in the treatment groups were significantly higher than those in the control group(P<0.05),with the 2 MIC group showing significantly higher conductivity than the MIC and 0.5 MIC groups(P<0.05).The DNA fluorescence signal in the treatment groups was significantly lower than that in the control group(P<0.05).The study shows that the optimized Chinese medicine monomer combination exerts its antibacterial effect by disrupting the integrity of the cell wall and cell membrane of ETEC and affecting its genetic material,providing a reference for developing novel herbal preparations as alternatives to antibiotics.