Metabolism of Genipin in Rat and Identification of Metabolites by Using Ultraperformance Liquid Chromatography/Quadrupole Time-of-Flight Tandem Mass Spectrometry

Chromosomal-level Genome Assembly of the Coffee Bee Hawk Moth Reveals the Evolution of Chromosomes and the Molecular Basis of Distinct Phenotypes

Cephonodes hylas, the coffee bee hawk moth is a hawk moth species with unique characteristics, such as larvae feeding on gardenia, overcoming the toxicity of its iridoid glycosides, diurnal adults, and transparent wings. Although C. hylas is a fascinating model for molecular biological research, genome sequence analysis-based genetic approaches to elucidate these peculiarities have not yet been undertaken. We successfully achieved de novo genome assembly at the chromosome level of C. hylas comparable to the Lepidoptera model organism, silkworm. Additionally, 16,854 protein-coding genes were annotated, and the constructed genome sequence and annotated genes were of the highest quality BUSCO completion compared to closely related species. Comparative genome analysis revealed the process of chromosomal evolution from the Bombycoidea ancestral (n = 31) genome and changes in turnover at the chromosome level associated with chromosomal fusion events, such as the rate of repetitive sequence insertion. These analyses were only possible because the genome was constructed at the chromosome level. Additionally, increased the nonsynonymous/synonymous rate (dN/dS) ratios were observed in multiple photoreceptor-related genes that were strongly associated with the acquisition of diurnal activity. Furthermore, tandemly duplicated expanded genes containing many digestive and other enzymes and larval midgut-specific expression were also confirmed. These genes may be involved in the metabolism of genipin, a toxin found in gardenias. Using the genome sequence of C. hylas determined at the chromosome level, we have successfully identified new insights into the chromosomal evolution of Bombycoidea, as well as the relationship between the genome sequence and its characteristic traits.

Comprehensive Metabolite Identification of Genipin in Rats Using Ultra-High-Performance Liquid Chromatography Coupled with High Resolution Mass Spectrometry

Genipin, an aglycone of geniposide, is a rich iridoid component in the fruit of Gardenia jasminoides Ellis and has numerous biological activities. However, its metabolic profiles in vivo and vitro remain unclear. In this study, an effective analytical strategy based on ultra-high-performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS) in positive and negative ion modes was developed to analyze and identify genipin metabolites in rat urine, blood, feces, and fecal fermentation in combination with many methods including post-collection data mining methods, high-resolution extracted ion chromatography (HREIC), and multiple mass defect filtering (MMDF). Simultaneously, the metabolites of genipin in vivo were verified by fecal fermentation of SD rats at different times. Finally, based on information such as reference substances, chromatographic retention behavior, and accurate mass determination, a total of 50 metabolites (including prototypes) were identified in vivo. Among them, 7, 31 and 28 metabolites in vivo were identified in blood, urine, and feces, respectively. Our results showed that genipin could generate different metabolites that underwent multiple metabolic reactions in vivo including methylation, hydroxylation, dehydroxylation, hydrogenation, sulfonation, glucuronidation, demethylation, and their superimposed reactions. Forty-six metabolites were verified in vitro. Meanwhile, 2 and 19 metabolites identified in blood and urine were also verified in fecal fermentation at different times. These results demonstrated that metabolites were produced in feces and reabsorbed into the body. In conclusion, the newly discovered metabolites of genipin can provide a new perspective for understanding its pharmacological effects and build the foundation for thee toxicity and safety evaluations of genipin.

Impacts of crosslinking conditions on Pickering emulsions stabilized by genipin-crosslinked chitosan-caseinophosphopeptides nanocomplexes

Polysaccharide-polypeptide nanocomplexes are promising colloidal Pickering stabilizers. The resulting Pickering emulsions, however, are susceptible to pH and ionic strength changes. This phenomenon was also observed in our recently developed Pickering emulsions stabilized by the chitosan (CS)-caseinophosphopeptides (CPPs) nanocomplexes. To improve the stability of these Pickering emulsions, we herein crosslinked the CS-CPPs nanocomplexes with a natural crosslinker genipin. The genipin-crosslinked CS-CPPs nanocomplexes (GCNs) were used to prepare Pickering emulsions. The impacts of genipin concentration, crosslinking temperature, and duration on the characteristics of GCNs and the GCNs-stabilized Pickering emulsions (GPEs) were systemically investigated. GCNs showed crosslinking strength-dependent variations in their physical properties. Crosslinking at a weak or strong condition weakened the emulsification ability of GCNs at low concentrations. A strong crosslinking condition also compromised the capacity of GCNs to stabilize a high fraction of oil. GPEs were oil-in-water type and gel-like. GCNs crosslinked at a lower temperature and for a shorter crosslinking duration stabilized stronger gel-like GPEs. Moreover, GPEs had high pH and ionic strength stabilities. This work provided a feasible way to enhance the stability and regulate the physical properties of Pickering emulsions stabilized by polysaccharide-polypeptide nanocomplexes.

Updated Pharmacological Effects, Molecular Mechanisms, and Therapeutic Potential of Natural Product Geniposide

At present, the potential of natural products in new drug development has attracted more and more scientists’ attention, and natural products have become an important source for the treatment of various diseases or important lead compounds. Geniposide, as a novel iridoid glycoside compound, is an active natural product isolated from the herb Gardenia jasminoides Ellis (GJ) for the first time; it is also the main active component of GJ. Recent studies have found that geniposide has multiple pharmacological effects and biological activities, including hepatoprotective activity, an anti-osteoporosis effect, an antitumor effect, an anti-diabetic effect, ananti-myocardial dysfunction effect, a neuroprotective effect, and other protective effects. In this study, the latest research progress of the natural product geniposide is systematically described, and the pharmacological effects, pharmacokinetics, and toxicity of geniposide are also summarized and discussed comprehensively. We also emphasize the major pathways modulated by geniposide, offering new insights into the pharmacological effects of geniposide as a promising drug candidate for multiple disorders.

Detection and Identification of Catalpol Metabolites in the Rat Plasma, Urine and Faeces Using Ultra-high Performance Liquid Chromatography-Q Exactive Hybrid Quadrupole-orbitrap High-resolution Accurate Mass Spectrometry

BACKGROUND

Catalpol, an iridoid glycoside, is one of the richest bioactive components present in Rehmannia glutinosa. More and more metabolites of drugs have exhibited various pharmacological effects, thus providing guidance for clinical application. However, few researches have paid attention to the metabolism of catalpol.

OBJECTIVE

This study aimed to establish a rapid and effective method to identify catalpol metabolites and evaluate the biotransformation pathways of catalpol in rats.

METHODS

In this study, catalpol metabolites in rat urine, plasma and faeces were analyzed by UHPLC-Q-Exactive MS for the characterization of the metabolism of catalpol. Based on high-resolution extracted ion chromatograms (HREICs) and parallel reaction monitoring mode (PRM), metabolites of catalpol were identified by comparing the diagnostic product ions (DPIs), chromatographic retention times, neutral loss fragments (NLFs) and accurate mass measurement with those of catalpol reference standard.

RESULTS

A total of 29 catalpol metabolites were detected and identified in both negative and positive ion modes. Nine metabolic reactions, including deglycosylation, hydroxylation, dihydroxylation, hydrogenation, dehydrogenation, oxidation of methylene to ketone, glucuronidation, glycine conjugation and cysteine conjugation, were proposed.

CONCLUSION

A rapid and effective method based on UHPLC-Q-Exactive MS was developed to mine the metabolism information of catalpol. Results of metabolites and biotransformation pathways of catalpol suggested that when orally administrated, catalpol was firstly metabolized into catalpol aglycone, after which phase I and phase II reactions occurred. However, hydrophilic chromatography-mass spectrometry is still needed to further find the polar metabolites of catalpol.

Synthesis of [3 H] and [14 C]genipin

[3 H]Genipin was synthesized in a single step by Ir(I) catalyzed hydrogen isotope exchange. Conditions for selective exchange of the sp2 CH bond ortho to the methyl ester functionality were developed through deuterium modeling studies through a catalyst screen. Optimized conditions so obtained were then utilized with tritium gas to generate [3 H]genipin at a specific activity of 18.5 Ci/mmol. Racemic [14 C]genipin was prepared in eight steps in overall 5.4% radiochemical yield from potassium [14 C]cyanide.

Comprehensive investigation of in-vivo ingredients and action mechanism of iridoid extract from Gardeniae Fructus by liquid chromatography combined with mass spectrometry, microdialysis sampling and network pharmacology

Gardeniae Fructus is a widely used Traditional Chinese Medicines in treating various diseases. However, the absorbed components and metabolites of its main bioactive iridoid ingredients from iridoid extract of the fruits of Gardeniae Fructus in rat plasma need further study. In this study, a systematic method based on ultra-performance liquid chromatography-quadrupole-time-of-flight/mass spectrometry (UPLC-Q-TOF/MS) technique was developed to speculate the absorbed components and metabolites of iridoid extract in rat plasma after oral administration. A total of 19 compounds, including 9 prototype components and 10 metabolites were identified in plasma. 5 metabolites containing 4 new metabolites (M1, M2, M7, M10) were tentatively determined in rat plasma. Besides, Microdialysis-intensity-fading mass spectrometry (MD-IF-MS) method was originally employed to reveal the binding affinities with α-glucosidase for in-vivo prototype components and their metabolites. Finally, the absorbed constituents and the corresponding target proteins were used to generate compound-target network to find the related diseases and action pathways by a network pharmacology method. The results provide useful information for further study of pharmacology and in vivo mechanism of action of iridoid extract from the fruits of Gardeniae Fructus.

Exploration of serum biomarkers for predicting the response to Inchinkoto (ICKT), a Japanese traditional herbal medicine

INTRODUCTION

In patients with obstructive jaundice, biliary drainage sometimes fails to result in improvement. A pharmaceutical-grade choleretic herbal medicine, Inchinkoto (ICKT), has been proposed to exert auxiliary effects on biliary drainage; however, its effects are variable among patients.

OBJECTIVES

The aim of this study is to explore serum biomarkers that are associated with pharmaceutical efficacy of ICKT.

METHODS

Obstructive jaundice patients who underwent external biliary decompression were enrolled (n = 37). ICKT was given orally 3 times a day at daily dose of 7.5 g. Serum and bile samples were collected before, 3 h after, and 24 h after ICKT administration. The concentrations of total bilirubin, direct bilirubin, and total bile acid in bile specimens were measured. Metabolites in serum samples were comprehensively profiled using LC-MS/MS and GC-MS/MS. Pharmacokinetic analysis of major ICKT components was also performed.

RESULTS

ICKT administration significantly decreased serum ALT and increased bile volume after 24 h. The serum concentrations of ICKT components were not well correlated with the efficacy of ICKT. However, the ratio of 2-hydroxyisobutyric acid to arachidonic acid and the ratio of glutaric acid to niacinamide, exhibited good performance as biomarkers for the efficacy of ICKT on bile flow and ALT, respectively. Additionally, comprehensive correlation analysis revealed that serum glucuronic acid was highly correlated with serum total bilirubin, suggesting that this metabolite may be deeply involved in the pathogenesis of jaundice.

CONCLUSIONS

The present study indicates that ICKT is efficacious and provides candidates for predicting ICKT efficacy. Further validation studies are warranted.

Simultaneous quantification method for comparative pharmacokinetics studies of two major metabolites from geniposide and genipin by online mircrodialysis-UPLC-MS/MS

Genipin-1-o-glucuronic acid and genipin-monosulfate are two major metabolites from geniposide and genipin. Based on diabetic rat model, we developed a simultaneous quantification method to investigate their comparative pharmacokinetics by online mircrodialysis-ultra performance liquid chromatography-mass spectrometry (MD-UPLC-MS/MS) without their standard compounds. Online microdialysis sampling could avoid unexpected contamination or degradation of the analytes during the storage and transfer steps. Combined with good sensitivity, selectivity and selectivity of UPLC-MS/MS, online MD-UPLC-MS/MS method could real-timely monitor metabolites in rat blood for quantitative analysis. Our research found that AUC_0→t of genipin-1-o-glucuronic acid and genipin-monosulfate in blood of diabetic group were 17.68 and 7.58 times than those in normal group, respectively, and AUC_0→t of genipin-1-o-glucuronic acid was 2.28 times than that of genipin-monosulfate in blood of diabetic group, which revealed the effect of diabetes on the pharmacokinetic properties of the two metabolites. This study not only provides an approach for pharmacokinetic studies for various metabolites from herb medicines, but also can predict druggability of their bioactive metabolites. The insight obtained should facilitate drug development and toxicity research.

Disintegration of wheat aleurone structure has an impact on the bioavailability of phenolic compounds and other phytochemicals as evidenced by altered urinary metabolite profile of diet-induced obese mice

BACKGROUND

Phenolic acids are covalently bound to the arabinoxylan fibre matrix of wheat aleurone layer. In order to be bioavailable they need to be released by endogenous or bacterial enzymes and absorbed within the intestinal lumen. The intestinal microbiota can metabolize phenolic acids and other food-born phytochemicals. However, the effect of structure of the cereal bran or aleurone layer on these processes is not comprehensively studied.

METHODS

The structure of aleurone layer was modified either by dry-grinding or by enzymatic treatments with xylanase alone or in combination with feruloyl esterase. Diet induced obese C57BL6/J mice were fed with high-fat diets containing either pure ferulic acid, or one of the four differentially treated aleurone preparations for 8 weeks. The diets were designed to be isocaloric and to have similar macronutrient composition. The urinary metabolite profiles were investigated using non-targeted LC-qTOF-MS-metabolomics approach.

RESULTS

The different dietary groups were clearly separated in the principal component analysis. Enzymatic processing of aleurone caused increased excretion of ferulic acid sulfate and glycine conjugates reflecting the increase in unbound form of readily soluble ferulic acid in the diet. The urinary metabolite profile of the diet groups containing native and cryo-ground aleurone was more intense with metabolites derived from microbial processing including hippuric acid, hydroxyl- and dihydroxyphenylpropionic acids. Furthermore, aleurone induced specific fingerprint on the urinary metabolite profile seen as excretion of benzoxazinoid metabolites, several small dicarboyxlic acids, and various small nitrogen containing compounds.

CONCLUSIONS

The structural modifications on wheat aleurone fraction resulted in altered metabolism of aleurone derived phenolic acids and other phytochemicals excreted in urine of diet-induced obese mice.

A validated HPLC-MS/MS method for determination of genipin-1-o-glucuronic acid in rat plasma after administration of genipin and its application to a pharmacokinetic study

A sensitive and specific method was developed and validated for the quantitation of one major metabolite of genipin in rats plasma. The major metabolite was isolated from rat bile via semi-preparative HPLC technology and its chemical structure was identified as genipin-1-o-glucuronic acid (GNP-GLU), which was for the first time used as a standard compound for quantitative analysis in rat plasma after administration of genipin. The application of high-performance liquid chromatography-tandem mass spectrometry in negative mode in multiple reaction monitoring mode was investigated. Chromatographic separation was achieved on an Eclipse XDB-C18 column using a mobile phase consisting of water with 0.1% formic acid (A)-acetonitrile (B). The limit of detecation was 0.214 ng/mL and the lower limit of quantification was 0.706 ng/mL. The calibration curve was linear from 1.27 to 3810 ng/mL for plasma samples, with a correlation coefficient of 0.9924. The intra- and inter-day precisions and accuracy were all within 15%. The recoveries of GNP-GLU and puerarin were above 90.0 and 76.2%, respectively. The highly sensitive method was successfully applied to estimate pharmacokinetic parameters of GNP-GLU following oral and intravenous administration of genipin to rats.