氯化三苯四氮唑校正纸片扩散法检测天然抗菌成分的误差

Adjusting Error of Current K-B Method to Detect Natural Antibacterial Ingredients by TTC

目的:对现行纸片扩散法(K-B法)检测天然抗菌成分存在显著误差的原因进行分析,提出改进方法。方法:采用氯化三苯四氮唑(TTC)对指示菌显色、分析天然产物乙醇浸膏中抗菌成分的极性、样品在平板培养前适当扩散等方法,对K-B法检测天然抗菌成分存在显著误差的原因进行了研究。结果:天然产物中存在中极性、弱极性甚至非极性抗菌成分,在培养基中扩散较慢,现行K-B法以透明抑菌圈为判读抗菌活性依据,会低估样品抗菌活性,甚至出现假阴性结果,造成漏筛。以不能被TTC显色的指示菌范围和透明抑菌圈之和来判读天然产物抗菌活性,提高了K-B法检测天然抗菌成分的准确性和可靠性。结论:现行K-B法不能直接应用于由有机溶剂提取的天然抗菌成分的活性检测,TTC显色K-B法可有效消除由样品扩散速度较慢引起的显著误差。

Objective： To analyze significant error＇s reasons of current K-B method for detecting antimicrobic activity of natural product, and introduce modified method. Method： The reasons for significant error were studied by adopting TIC chromogenic method, analyzing alcohol extract of natural antimicrobic component＇ s polarity and making sample appropriate diffusion before plate cultivated. Result： There were many semipolar, low-polar and nonpolar antimicrobic components in natural products, they diffused slowly in medium, it was possible for false negative and leaked screening by inhibition zone size judging only, but TIC method was better precise and reliable with the sum of indicator size without dyed by TIC and inhibition zone size. Conclusion： It wasn＇s applied for current K-B method to detect antibacterial activity of organic solvent extracts until it was improved with TIC chromogenic method.