The Rapid Discrimination Of Molds In Traditional Chinese Medicine Based On The Mass Spectrometry

Objective It has been demonstrated that the microbial contamination might affect the quality of herbs,which could adverse the human health.More and more attention has been payed to the microbial contamination of herbs.However,The traditional methods for the microbial identification were time-consuming.There is an urgent need for the development of a rapid and simple techniques for microbial identification.This study detected the moldy traditional Chinese medicin by matrix-assisted laser desorption/ionization time of flight mass spectrometry(MALDI-TOF MS).Furthermore,in order to determine whether the molds from the moldy herbs could adverse the human health,the molds has been discriminated.It could provide an alternative method for the quality control of the herbs.Methods This study combined the MALDI-TOF MS with the NAPIQ to detect the sterols of the herbs.The kinds of the sterols detected could be used as an indicator to identify the microbial contamination of herbs.Subsequently,the molds from the moldy herbs were separated and purified.Their extraction were analyzed by MALDI-TOF MS.According to the ribosomal protein mass spectra and the high resolution mass spectra in600-2000 Da,the species and subspecies of the microorganism could be successfully identified.The specificity and the repeatability of this method calculated by three similarity calculation methods.And this method has been applied into actual samples.Results According to the NAPIQ method,the ionization efficiency of the sterols in MALDI-TOF MS has been enhanced.The kinds of sterols in the fresh herbs were generally phytosterols which were important components of plant cellular membranes.In the moldy herbs,there were more zoosterols because of the presence of microorganism.The zoosterols including lanosterol and ergosterol are usually minor components of herbs,thus zoosterols in the herbs show that the traditional chinese medicine could be contaminated by microorganism.Sterols could be used as an indicator to identify the microbial contamination of herbs by detecting the kinds of zoosterols and phytosterols.Many different species of molds were separated from the moldy herbs.And they were identify by MALDI-TOF MS.The molds could be identified into species-level group based on the ribosomal protein mass spectra.But for some microbial subspecies,their ribosomal protein spectra displayed high levels of similarity,which made it problematic to discriminate them.Based on the specialized metabolite production,there are obvious differences between the high resolution spectra in 600-2000 Da.This study combines the ribosomal protein spectra with the high resolution mass spectra in 600-2000 Da,which offers a perspective tool for the identification of molds.Conclusion In this study,NAPIQ coupled with MALDI-TOF MS provided a perspective tool for the identification of the moldy herbs.And the rapid identification of molds separated from moldy herbs is importran for the quality control of the herbs.The ribosomal protein mass spectra in 2000-20000 Da was coupled with the high resolution mass spectra in 600-2000 Da for the rapid identification of molds at species-level and subspecies-level.The utilization of the similarity calculation methods could improve the accuracy of the microbial identification.This method showed obvious advantages for the rapid identification of molds in traditional Chinese medicine matrices compared with the conventional method...