诃子提取物对3种致病菌的体外抑菌效果及其机制研究

In vitro antibacterial effect and mechanism of Terminalia chebula extract on three pathogenic bacteria

为探究诃子在畜禽疫病防控中的作用及应用潜力,以大肠埃希菌、肺炎克雷伯菌和阴沟肠杆菌3种常见致病菌为对象,对比诃子和其他11种中药提取物的抑菌圈直径和最小抑菌浓度(MIC),分析诃子培养上清液的总漏出率和电导率、蛋白浓度及诃子对细菌DNA和蛋白含量的影响。结果显示:诃子比其他11种中药的抑菌效果更强,表现为抑菌圈直径更大,MIC更低。培养上清液的电导率和漏出率增加,用2倍MIC诃子药液处理8 h后,大肠埃希菌和肺炎克雷伯菌上清液蛋白浓度显著增加(P<0.05)。诃子抑制大肠埃希菌蛋白合成,使分子质量约为80 ku的蛋白缺失;对肺炎克雷伯菌和阴沟肠杆菌蛋白质合成影响不明显,对细菌DNA也没有明显的凝胶阻滞作用,但能降解DNA。以上结果表明:诃子具有较好的抑菌效果,其作用机制是通过破坏细菌细胞膜通透性,抑制细菌核酸和蛋白合成而发挥抑菌作用。

In order to investigate the role and application potential of Terminalia chebula in the pre⁃vention and control of livestock and poultry diseases,three species of common pathogenic bacteria,Esche⁃richia coli,Klebsiella pneumoniae and Enterobacter cloacae were selected as test organisms.The inhibition circle diameter and minimum inhibitory concentration(MIC)of T.chebula and 11 other Chinese herbal ex⁃tracts were compared,the total leakage rate,electrical conductivity,protein concentration in the superna⁃tant,and the effects of T.chebula on the DNA and protein content of bacteria were analyzed.The results showed that T.chebula had stronger antibacterial effect than other Chinese herbs,with larger circle diame⁃ter and lower concentration of bacteriostatic.The conductivity and leakage rate of culture supernatant in⁃creased.The protein concentration of the supernatant of E.coli and K.pneumoniae significantly increased(P<0.05)after 2-fold MIC T.chebula treatment for 8 h.T.chebula inhibited the protein synthesis of E.coli,resulting in the deletion of a protein with a molecular weight of about 80 ku.However,T.chebula had no obvious effect on protein synthesis of K.pneumoniae and E.cloacae.T.chebula had no significant gel-blocking effect on bacterial DNA,but could degrade DNA.The above results indicate that T.chebula could exert its antibacterial effect by disrupting the permeability of bacterial cell membrane and inhibiting the synthesis of bacterial nucleic acid and protein.Therefore,the rational application of the T.chebula ex⁃tract is a new idea for the prevention and control of livestock and poultry infectious diseases in China.