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
Mycobacterium tuberculosis (M. tuberculosis), the causative agent of tuberculosis, still causes higher mortality than any other bacterial pathogen until now. With the emergence and spread of multidrug-resistant (MDR) and extensively drug-resistant (XDR-TB) strains, it becomes more important to search for alternative targets to develop new antimycobacterial drugs. Lupulone is a compound extracted from Hops (Hurnulus lupulus), which exhibits a good antimicrobial activity against M. tuberculosis with minimal inhibitory concentration (MIC) value of 10 µg/mL, but the response mechanisms of lupulone against M. tuberculosis are still poorly understood. In this study, we used a commercial oligonucleotide microarray to determine the overall transcriptional response of M. tuberculosis H37Rv triggered by exposure to MIC of lupulone. A total of 540 genes were found to be differentially regulated by lupulone. Of these, 254 genes were upregulated, and 286 genes were downregulated. A number of important genes were significantly regulated which are involved in various pathways, such as surface-exposed lipids, cytochrome P450 enzymes, PE/PPE multigene families, ABC transporters, and protein synthesis. Real-time quantitative RT-PCR was performed for choosed genes to verified the microarray results. To our knowledge, this genome-wide transcriptomics approach has produced the first insights into the response of M. tuberculosis to a lupulone challenge.