Corydalis Rhizoma as a model for herb-derived trace metabolites exploration: A cross-mapping strategy involving multiple doses and samples

Investigation of red clover (Trifolium pratense) isoflavonoid residual complexity by off-line CCS-qHNMR

The importance of Trifolium pratense L. as a dietary supplement and its use in traditional medicine prompted the preparation of a thorough metabolite profile. This included the identification and quantitation of principal constituents as well as low abundant metabolites that constitute the residual complexity (RC) of T. pratense bioactives. The purity and RC of isoflavonoid fractions from standardized red clover extract (RCE) was determined using an off-line combination of countercurrent separation (CCS) and two orthogonal analytical methodologies: quantitative ¹H NMR spectroscopy with external calibration (EC-qHNMR) and LC-MS. A single-step hydrostatic CCS methodology (Centrifugal Partition Chromatography [CPC]) was developed that fractionated the isoflavonoids with a hexanes-ethyl acetate-methanol-water (HEMWat) 5.5/4.5/5/5, v/v solvent system (SS) into 75 fractions containing 3 flavonolignans, 2 isoflavonoid glycosides, as well as 17 isoflavonoids and related compounds. All metabolites were identified and quantified by qHNMR spectroscopy. The data led to the creation of a complete isoflavonoid profile to complement the biological evaluation. For example, fraction 69 afforded 90.5% w/w biochanin A (17), with 0.33% w/w of prunetin (16), and 0.76% w/w of maackiain (15) as residual components. Fraction 27 with 89.4% w/w formononetin (13) as the major component had, in addition, a residual complexity consisting of 3.37%, 0.73%, 0.68% w/w of pseudobaptigenin (11), kaempferol (10) and pratensein (8), respectively. Despite the relatively high resolving power of CPC, and not unexpectedly, the chromatographic fractions retained varying degrees of the original metabolomic diversity. Collectively, the extent of metabolomic diversity should be recognized and used to guide the development of isolation strategies, especially when generating samples for bioactivity evaluation. The simultaneous structural and quantitative characterization enabled by qNMR, supported by LC-MS measurements, enables the evaluation of a relatively large number of individual fractions and, thereby, advances both the chemical and biological evaluation of active principles in complex natural products.

An integrated strategy for comprehensive characterization of metabolites and metabolic profiles of bufadienolides from Venenum Bufonis in rats

Comprehensive characterization of metabolites and metabolic profiles in plasma has considerable significance in determining the efficacy and safety of traditional Chinese medicine (TCM) in vivo. However, this process is usually hindered by the insufficient characteristic fragments of metabolites, ubiquitous matrix interference, and complicated screening and identification procedures for metabolites. In this study, an effective strategy was established to systematically characterize the metabolites, deduce the metabolic pathways, and describe the metabolic profiles of bufadienolides isolated from Venenum Bufonis in vivo. The strategy was divided into five steps. First, the blank and test plasma samples were injected into an ultra-high performance liquid chromatography/linear trap quadrupole-orbitrap-mass spectrometry (MS) system in the full scan mode continuously five times to screen for valid matrix compounds and metabolites. Second, an extension-mass defect filter model was established to obtain the targeted precursor ions of the list of bufadienolide metabolites, which reduced approximately 39% of the interfering ions. Third, an acquisition model was developed and used to trigger more tandem MS (MS/MS) fragments of precursor ions based on the targeted ion list. The acquisition mode enhanced the acquisition capability by approximately four times than that of the regular data-dependent acquisition mode. Fourth, the acquired data were imported into Compound Discoverer software for identification of metabolites with metabolic network prediction. The main in vivo metabolic pathways of bufadienolides were elucidated. A total of 147 metabolites were characterized, and the main biotransformation reactions of bufadienolides were hydroxylation, dihydroxylation, and isomerization. Finally, the main prototype bufadienolides in plasma at different time points were determined using LC-MS/MS, and the metabolic profiles were clearly identified. This strategy could be widely used to elucidate the metabolic profiles of TCM preparations or Chinese patent medicines in vivo and provide critical data for rational drug use.

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Extension-mass defect filter model could reduce about 39% interfering ions.

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The optimized acquisition mode enhanced about 4 times acquisition capability than regular DDA mode.

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147 metabolites were characterized with metabolic network prediction, and the metabolic pathways were deduced in plasmas.

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The quantitative method of 14 prototypes was established by LC-MS/MS for metabolic profiles study.

Processing methods and mechanisms for alkaloid-rich Chinese herbal medicines: A review

The processing of Chinese herbal medicine is a form of pharmaceutical technology developed over thousands of years, in order to increase efficiency and decrease toxicity of herbs in traditional Chinese medicine (TCM). Herbal processing is essential for safe and effective application of TCM in clinical practice, as it alters the active chemical components and therefore the functions of herbal medicines. Alkaloid-rich herbal medicines in TCM are commonly processed by cleansing, cutting, processing by dry stir-frying, stir-frying with liquid adjuvants, and processing by water decoction. In addition, commonly used adjuvants for processing alkaloid-rich herbal medicines are river sand, wine, vinegar, brine, honey and herbal juice. For alkaloid-rich herbal medicines, the main chemical reactions that occur during processing include hydrolysis, oxidation, replacement, decomposition and condensation. This paper aimed to summarize the processing methods and mechanisms for alkaloid-rich Chinese herbal medicines, and provide much-needed theoretical support and scientific evidence for understanding those mechanisms and effects. Information on processing methods for alkaloid-rich herbal medicines was collected from classic books of herbal medicine, PhD and MSc dissertations, online scientific databases including PubMed, SciFinder, Scopus, Web of Science, Baidu Scholar and Google Scholar. This paper should help to advance our knowledge of the processing mechanisms and aid in the development of processing methods for alkaloid-rich Chinese herbal medicines.