ABSTRACT
Deciphering the metabolites of multiple components in herbal medicine has far-reaching significance for revealing pharmacodynamic ingredients.However,most chemical components of herbal medicine are secondary metabolites with low content whose in vivo metabolites are close to trace amounts,making it difficult to achieve comprehensive detection and identification.In this paper,an efficient strategy was proposed:herb-derived metabolites were predicted according to the structural characteristics and metabolic reactions of chemical constituents in Corydalis Rhizoma and chemical structure screening tables for metabolites were conducted.The fragmentation patterns were summarized from represen-tative standards combining with specific cleavage behaviors to deduce structures of metabolites.Ion abundance plays an important role in compound identification,and high ion abundance can improve identification accuracy.The types of metabolites in different biological samples were very similar,but their ion abundance might be different.Therefore,for trace metabolites in biological samples,we used the following two methods to process:metabolites of high dose herbal extract were analyzed to char-acterize those of clinical dose herbal extracts in the same biological samples;cross-mapping of different biological samples was applied to identify trace metabolites based on the fact that a metabolite has different ion abundance in different biological samples.Compared with not using this strategy,44 more metabolites of clinical dose herbal extract were detected.This study improved the depth,breadth,and accuracy of current methods for herb-derived metabolites characterization.
ABSTRACT
Objective To investigate the maximum allowable deviation of ion abundance ratios of characteristic fragment ions in common drugs （poisons） in blood by gas chromatography-mass spectrometry （GC-MS） method. Methods Four common drugs （poisons） （dichlorvos, phorate, diazepam and estazolam） were detected by GC-MS full scan mode after liquid-liquid extraction in two laboratories and under three chromatographic conditions. The deviations of ion abundance ratios of the four common drugs （poisons） in marked blood samples with concentrations of 0.5, 1.0, 2.0, 5.0 and 10.0 μg/mL were analyzed. At the same time, the false negative rates of ion abundance ratios were analyzed when the mass concentration was limit of detection （LOD）, 2LOD, limit of quantitation （LOQ） and 2LOQ, and the false positive rates of ion abundance ratios were analyzed with blank blood samples. Results Under the two laboratories, four common drugs （poisons） and three kinds of chromatography conditions, the differences in deviations of the ion abundance ratios of marked blood samples were not statistically significant （P>0.05）. More than 95% of the absolute deviations of the ion abundance ratios of the marked blood samples were within the range of ±10%, and more than 95% of the relative deviations were within the range of ±25%. In cases of low concentration （concentration less than 2LOQ） or low signal to noise ratio （3-15）, the false negative rate was less than 5% and the false positive rate was 0% when the relative deviation was greater than 50%. Conclusion The absolute deviations of ion abundance ratios of four common drugs （poisons） in marked blood samples are advised to have a determination range within ±10%, and the determination range of relative deviations within ±25%.