Ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry for rapid analysis of the metabolites of morroniside produced by human intestinal bacteria

Gut microbiota: A potential enhancing factor for the therapeutic efficacy of bioactive compounds in herbal medicines

The therapeutic efficacy of herbal medicines (HMs) is often compromised by the low bioavailability of their bioactive compounds. However, emerging evidence highlights the crucial role of gut microbiota in enhancing their effectiveness. This review summarizes gut microbiota-mediated metabolism of key herbal components, including terpenoids, flavonoids, alkaloids, and quinones. Particular emphasis is placed on the diverse gut microbiota, enzymes, and metabolites that participate in the biotransformation pathways of these active components of HMs. Exploring the metabolism between the gut microbiota and bioactive compounds gives a better understanding of HMs with multiple components against multiple targets, complex mechanisms of action, and diverse physiological activities. This review underscores the critical importance of gut microbiota in modulating and potentially enhancing the pharmacological effects of HMs, which offers new insights into gut microbiota-mediated transformation pathways and molecular mechanisms of bioactive compounds and deepens the understanding of the therapeutic effects of HMs. Moreover, it suggests new research directions for studying HMs based on gut microbiota-mediated biotransformation.

In vivo and in vitro metabolism study of traditional Chinese medicine formula Dingkun Dan in rats by using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry

Dingkun Dan (DKD), a reputable traditional Chinese medicine formula, has been used to treat gynecological diseases and showed significant clinical effects since ancient times. However, the application and development of DKD are seriously hampered by the unclear active substances. Structural characterization of compounds absorbed in vivo and their corresponding metabolites is significant for clarifying the pharmacodynamic material basis. In this study, an integrated strategy using ultra-performance liquid chromatography, coupled with quadrupole time-of-flight mass spectrometry and UNIFI™ software, was used to identify prototypes and metabolites after oral administration of DKD in rats. As a result, a total of 261 compounds, including 140 prototypes and 121 metabolites, were tentatively characterized in rat plasma, urine, and feces. The metabolic pathways of prototypes have been studied to clarify their possible transformation process in vivo. Moreover, an in vitro metabolism study was applied for verifying the metabolites under simulating the metabolic environment in vivo. This first systematic metabolic study of DKD is important for elucidating the metabolites and metabolic pathways and could provide a scientific basis for explaining the integrative mechanism in further pharmacology study.

Dietary phytochemicals that influence gut microbiota: Roles and actions as anti-Alzheimer agents

The last decide has witnessed a growing research interest in the role of dietary phytochemicals in influencing the gut microbiota. On the other hand, recent evidence reveals that dietary phytochemicals exhibit properties of preventing and tackling symptoms of Alzheimer's disease, which is a neurodegenerative disease that has also been linked with the status of the gut microbiota over the last decade. Till now, little serious discussions, however, have been made to link recent understanding of Alzheimer's disease, dietary phytochemicals and the gut microbiota together and to review the roles played by phytochemicals in gut dysbiosis induced pathologies of Alzheimer's disease. Deciphering these connections can provide insights into the development and future use of dietary phytochemicals as anti-Alzheimer drug candidates. This review aims at presenting latest evidence in the modulating role of phytochemicals in the gut microbiota and its relevance to Alzheimer's disease and summarizing the mechanisms behind the modulative activities. Limitations of current research in this field and potential directions will also be discussed for future research on dietary phytochemicals as anti-Alzheimer agents.

Biotransformation of betulinic acid by Circinella muscae and Cunninghamella echinulata to discover anti-inflammatory derivatives

Biotransformation of betulinic acid was carried out with Circinella muscae CGMCC 3.2695 and Cunninghamella echinulata CGMCC 3.970, yielded six previously undescribed hydroxylated metabolites and four known compounds. C. muscae could catalyze the regioselecitve hydroxylation and carbonylation at C-3, C-7, C-15 and C-21 to yield seven products. C. echinulata could catalyze the C-1, C-7 and C-26 regioselecitve hydroxylation and acetylation to yield five metabolites. The structures of the metabolites were established based on extensive NMR and HR-ESI-MS data analyses. Furthermore, most of the metabolites exhibited pronounced inhibitory activities on lipopolysaccharides-induced NO production in RAW264.7 cells.

A novel strategy for the characterization of glaucocalyxin A metabolites in vivo and in vitro by UHPLC-Q-TOF-MS based on DDA and DIA data acquisitions

Glaucocalyxin A (GLA) belongs to the natural ent-kauranoid diterpenoids family with antitumor, antifibrotic, anticoagulative, antioxidant, and anti-AD effects. In this study, ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) system was applied to observe probable metabolites of GLA in vitro and in vivo firstly. The mass data were respectively obtained by two typical acquisition methods, ‘data-dependent acquisition’ (DDA) and ‘data-independent acquisition’ (DIA) modes. The combinations can not only guarantee sensitivity but also capture more precursor ions and MS/MS spectra. Then, multiple data processing techniques were applied to hunt metabolites rapidly. As a result, 32 phase I metabolites of different structures and 6 phase II metabolites were identified, including 25, 18, 17 and 7 in rat urine, feces, bile, and plasma, respectively. Besides, under the action of rat intestinal flora (RIF), 7 metabolites were detected. In the study, the main bio-transformations were oxidation and demethylation. Conjugation with methylation, sulfate, and glucuronide produced phase II metabolites. This study laid the foundation for the further study of the pharmacological effects of GLA and was conducive to mechanism research.

The experimental process flow.

Study on the metabolites of betulinic acid in vivo and in vitro by ultra high performance liquid chromatography with time-of-flight mass spectrometry

Betulinic acid is a triterpenoid organic acid with remarkable antitumor properties and is naturally present in many fruits, condiments and traditional Chinese medicines. Currently, a strategy was developed for the identification of metabolites following the in vivo and in vitro biotransformation of Betulinic acid with rat intestinal bacteria utilizing ultra high performance liquid chromatography with time-of-flight mass spectrometry with polymeric solid-phase extraction. As a result, 46 metabolites were structurally characterized. The results demonstrated that Betulinic acid is universally metabolized in vivo and in vitro, and Betulinic acid could undergo general metabolic reactions, including oxidation, methylation, desaturation, loss of O and loss of CH₂ . Additionally, the main metabolic pathways in vivo and in vitro were determined by calculating the relative content of each metabolite. This is the first study of Betulinic acid metabolism in vivo, whose results provide novel and useful data for better understanding of the safety and efficacy of Betulinic acid.

Metabolic profile elucidation of Zhi-Zi-Da-Huang decoction in rat intestinal bacteria using high-resolution mass spectrometry combined with multiple analytical perspectives

1. Zhi-Zi-Da-Huang decoction (ZZDHD) has been widely used for the treatment of alcoholic jaundice, alcoholic liver disease, and acute hepatitis in China for thousands of years. Conventionally decoctions are administered orally, after which the metabolism caused by the enzymes in intestinal bacteria may influence significantly on the curative effects or toxicity. 2. In this work, the comprehensive metabolic process of ZZDHD in intestinal bacteria was investigated reliably using high-resolution HPLC-DAD-ESI-TOF/MS. Besides, a novel strategy for major-to-trace metabolites identification which integrated information derived from diagnostic fragment ions, mass spectral similarity filter strategy, dynamic metabolic change of target compounds and relevant behavior in LC-MS was adopted. 3. As a result, 45 compounds, including 26 bio-converted prototypes and 19 newly generated metabolites were detected and tentatively identified. The metabolic profile of ZZDHD in gastro-intestinal was subsequently elucidated. Deglycosylation, oxidation, reduction, acetylation, and ring cleavage were all observed in the biotransformation of the decoction. Among the rest, deglycosylation was found to be the predominant metabolic pathway. 4. The results obtained herein provided a practical strategy for metabolic profile elucidation of traditional herbal medicines. Moreover, it would be helpful to unravel how the oral decoctions play the therapeutic role in vivo.

Understanding the Molecular Mechanisms of the Interplay Between Herbal Medicines and Gut Microbiota

Herbal medicines (HMs) are much appreciated for their significant contribution to human survival and reproduction by remedial and prophylactic management of diseases. Defining the scientific basis of HMs will substantiate their value and promote their modernization. Ever-increasing evidence suggests that gut microbiota plays a crucial role in HM therapy by complicated interplay with HM components. This interplay includes such activities as: gut microbiota biotransforming HM chemicals into metabolites that harbor different bioavailability and bioactivity/toxicity from their precursors; HM chemicals improving the composition of gut microbiota, consequently ameliorating its dysfunction as well as associated pathological conditions; and gut microbiota mediating the interactions (synergistic and antagonistic) between the multiple chemicals in HMs. More advanced experimental designs are recommended for future study, such as overall chemical characterization of gut microbiota-metabolized HMs, direct microbial analysis of HM-targeted gut microbiota, and precise gut microbiota research model development. The outcomes of such research can further elucidate the interactions between HMs and gut microbiota, thereby opening a new window for defining the scientific basis of HMs and for guiding HM-based drug discovery.

Identification, bioactivity evaluation and pharmacokinetics of multiple components in rat serum after oral administration of Xian-Ling-Gu-Bao capsule by ultra performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry

The Xian-Ling-Gu-Bao capsule (XLGB) is a famous traditional Chinese medicine prescription (TCMP), which has proven effective in osteoporosis treatment. However, due to the lack of a dynamic XLGB profile, the in vivo pharmacokinetics of multiple bioactive components within this medicine remains unknown. In the present study, ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF-MS) identified a total of eighteen prototypes (using reference standards) in rat serum after oral administration of XLGB. These prototypes were subsequently evaluated to ascertain their effects on the proliferation and alkaline phosphatase activity of UMR106 cells and the adipogenesis of 3T3-L1 cells. Furthermore, a rapid and sensitive UPLC/Q-TOF-MS method was developed and validated for simultaneous quantitative analysis of 11 prototypes in rat serum. Chromatographic separation was achieved using a Waters Acquity BEH C18 column (2.1×100mm, 1.7μm) and linear gradient elution employing a mobile phase consisting of water and acetonitrile (both containing 0.1% formic acid). All calibration curves showed excellent linearity (r²>0.99) within the sampling ranges considered. The assay was accurate, precise and reproducible, as demonstrated by the obtained intra- and inter-day precisions (less than 12.3%) and accuracies (between -12.7% and 11.0%), and the matrix effects, extraction recoveries and stabilities were all satisfactory. Moreover, pharmacokinetic parameters were calculated from the plasma concentration-time data. Compared to single-compound dosing, significantly enhanced responses were obtained when several analytes were administered simultaneously, indicating possible drug-drug interactions among the complex ingredients of TCMP. This work provides an experimental baseline regarding the clinical applications and medicinal effectiveness of XLGB in the treatment of osteoporosis.

Design, synthesis and preliminary evaluation of the anti-inflammatory of the specific selective targeting druggable enzymome cyclooxygenase-2 (COX-2) small molecule

CONTEXT

Development of a reliable and selective anti-inflammatory agent of cyclooxygenase-2 (COX-2), induced or up-regulated by inflammatory/injury stimulus such as IL-1β, TNF-α and LPS in the various types of organs, tissues and cells, with low side effects is a long-standing medicinal chemistry problem with significant social implications.

OBJECTIVE

To target druggable enzymome COX-2 by exploiting NSAIDs and genipin (GEP) in anti-inflammatory infection.

MATERIALS AND METHODS

The compound aspirin GEP ester (AGE) was designed by computer-assisted screening, synthesized in the esterification of the acylate derivative and the methylate derivative with Et₃N, and evaluated with 20, 40 and 60 mg/kg from days 18 to 24 after immunization in collagen-induced arthritis (CIA) rats by the sequential enzymatic experiments, western-blot analysis and pathological observation methods.

RESULTS

AGE exhibited higher binding affinity with COX-1 and displayed the lowest estimated free energy with COX-2 than other ligands built by hanging NSAIDs with GEP, and was characterized by ¹H NMR, ¹³C NMR and HRMS. AGE was competed against COX-2 with molecule-dependent potencies and selectivity (IC₅₀: 0.36 mM; selectivity index: 275) in the sequential enzymatic experiments and decreased the expression of COX-2 in peripheral blood lymphocytes of CIA rats. AGE (40 and 60 mg/kg) could significantly relieve the secondary hind paw swelling and arthritis index, along with observing AGE attenuated histopathological changes of fibroblast like synovial tissue (FLST) and mesenteric lymph node lymphocytes (MLNL) in CIA rats.

DISCUSSION AND CONCLUSION

AGE pharmacophore reported herein may be an effective strategy to develop a novel anti-inflammatory agent and potential inhibitor of COX-2.

Recent development in liquid chromatography stationary phases for separation of Traditional Chinese Medicine components

Traditional Chinese Medicine (TCM) is an ancient medical practice which has been used to prevent and cure diseases for thousands of years. TCMs are frequently multi-component systems with mainly unidentified constituents. The study of the chemical compositions of TCMs remains a hotspot of research. Different strategies have been developed to manage the significant complexity of TCMs, in an attempt to determine their constituents. Reversed-phase liquid chromatography (RPLC) is still the method of choice for the separation of TCMs, but has many problems related to limited selectivity. Recently, enormous efforts have been concentrated on the development of efficient liquid chromatography (LC) methods for TCMs, based on selective stationary phases. This can improve the resolution and peak capacity considerably. In addition, high-efficiency stationary phases have been applied in the analysis of TCMs since the invention of ultra high-performance liquid chromatography (UHPLC). This review describes the advances in LC methods in TCM research from 2010 to date, and focuses on novel stationary phases. Their potential in the separation of TCMs using relevant applications is also demonstrated.