Biotransformation of geniposide by human intestinal microflora on cytotoxicity against HepG2 cells

Genipin, a natural blue colorant precursor: Source, extraction, properties, and applications

Natural cross-linkers are extensively employed due to their low toxicity and biocompatibility benefits. Genipin acts as a precursor for producing blue colorants. The formation of these colorants involves the cross-linking reaction between genipin and primary amines present in amino acids, peptides, and proteins. Genipin is extracted from Gardenia jasminoides and Genipa americana. This article explains the cross-linking mechanism of genipin with proteins/polysaccharides to provide an overall understanding of its properties. Furthermore, it explores new sources of genipin and innovative methodologies to make the genipin recovery process efficient. Genipin increases food products' texture, gel strength, stability, and shelf life. The antibacterial, anti-inflammatory, and antioxidant properties of chitosan, gelatin, alginate, and hyaluronic acid increased after genipin cross-linking. Lastly, drawbacks, toxicity, and directions regarding the genipin cross-linking have also been addressed. The review article covers how to recover and cross-link genipin with biopolymers for industrial applications.

Unraveling a Combined Inactivation Mechanism of Cytochrome P450s by Genipin, the Major Reactive Aglycone Derived from Gardeniae Fructus

Genipin (GP) is the reactive aglycone of geniposide, the main component of traditional Chinese medicine Gardeniae Fructus (GF). The covalent binding of GP to cellular proteins is suspected to be responsible for GF-induced hepatotoxicity and inhibits drug-metabolizing enzyme activity, although the mechanisms remain to be clarified. In this study, the mechanisms of GP-induced human hepatic P450 inactivation were systemically investigated. Results showed that GP inhibited all tested P450 isoforms via distinct mechanisms. CYP2C19 was directly and irreversibly inactivated without time dependency. CYP1A2, CYP2C9, CYP2D6, and CYP3A4 T (testosterone as substrate) showed time-dependent and mixed-type inactivation, while CYP2B6, CYP2C8, and CYP3A4 M (midazolam as substrate) showed time-dependent and irreversible inactivation. For CYP3A4 inactivation, the kinact/KI values in the presence or absence of NADPH were 0.26 or 0.16 min-1 mM-1 for the M site and 0.62 or 0.27 min-1 mM-1 for the T site. Ketoconazole and glutathione (GSH) both attenuated CYP3A4 inactivation, suggesting an active site occupation- and reactive metabolite-mediated inactivation mechanism. Moreover, the in vitro and in vivo formation of a P450-dependent GP-S-GSH conjugate indicated the involvement of metabolic activation and thiol residues binding in GP-induced enzyme inactivation. Lastly, molecular docking analysis simulated potential binding sites and modes of GP association with CYP2C19 and CYP3A4. We propose that direct covalent binding and metabolic activation mediate GP-induced P450 inactivation and alert readers to potential risk factors for GP-related clinical drug-drug interactions.

Glutathione S-Transferases Mediate In Vitro and In Vivo Inactivation of Genipin: Implications for an Underlying Detoxification Mechanism

Genipin (GP), the reactive metabolite of geniposide (GE), is responsible for GE-induced hepatotoxicity. As a potential detoxification pathway, the inactivation of GP by glutathione S-transferases (GSTs) has not yet been characterized. In this study, the thiol-GSH conjugates of GP, M532-1 and M532-2 were first identified and the catalytic activities of GSTs were investigated both in vitro and in vivo. GSTA1-1 and GSTA4-4 showed high activity in the formation of both thiol-GSH conjugates, whereas GSTA4-4 specifically catalyzed M532-2 formation in vitro. The active GST isoforms protect against alkylation of N-acetylcysteine (NAC), a classic model nucleophile. GST inhibition attenuated M532-1 formation in rat bile, confirming the in vivo catalytic role of GSTs. In conclusion, this study demonstrated the inactivation of GP by GSTs and implied that interindividual variability of GSTs may be a risk factor for susceptibility to GE-induced hepatotoxicity.

Zanthoxylum armatum DC. extract induces liver injury via autophagy suppression and oxidative damage by activation of mTOR/ULK1 pathway

Zanthoxylum armatum DC. (ZADC) has anti-inflammatory, antioxidative, and antibacterial effects. The cytotoxicity of methanol extract of Zanthoxylum armatum DC. (MZADC) has been reported for BRL 3 A cell lines. However, whether MZADC can induce liver damage in vivo remains unclear. Therefore, it is essential to explore whether ZADC causes liver injury and, if the results confirm hepatotoxicity, to further study the potential mechanisms for the in-vitro cytotoxicity of the BRL 3 A cell lines. In vivo, different doses (0.346, 0.519, and 1.038 g/kg/day) of MZADC treatment were given by intragastric administration among male Sprague Dawley rats for 28 days. Levels of serum alanine transaminase (ALT), aspartate transaminase (AST), and alkaline phosphatase (ALP) in the high dose group increased. Steatosis and focal necrosis were found in liver cells in rats in the high dose group. In vitro, BRL 3 A cells were cultivated with MZADC at different concentrations (30, 50, and 70 μg/mL) for 24 h. The cell viability, the number of autophagosomes, and the expression levels of LC3 and Beclin-1 were on a decreasing trend. Besides, proportions of p-mTOR/mTOR and p-ULK1/ULK1 increased. Meanwhile, reactive oxygen species (ROS) accumulation and the content of malondialdehyde (MDA) were on the rise while the activity of superoxide dismutase (SOD) and the content of glutathione (GSH) was on the decline. This research suggests that MZADC may cause rats liver injury and inhibit autophagy in BRL 3 A cells by the mTOR/ULK1 pathway, and further induce intracellular oxidative damage.

Genipin induces developmental toxicity through oxidative stress and apoptosis in zebrafish

Genipin, an iridoid substance, is mainly derived from Gardenia jasminoides Ellis of the traditional Chinese medicine and is widely used in raw materials for the food additive gardenia blue and biological materials. The developmental toxicity of genipin has not been investigated, and its underlying mechanism is unclear. Therefore, in this study we attempt to investigate the potential developmental toxicity of genipin in zebrafish embryos/larvae. The results showed zebrafish embryos treated with 50 μg/ml dose of genipin display inhibited hatching rates and body length. The pericardial edema was observed. It was also found that genipin could induce cardio-toxicity, hepatotoxicity and nephrotoxicity in zebrafish larvae. After genipin treatment, the suppression of antioxidant capacity and increase of oxidative stress were showed for the triggered generation of ROS and MDA, and decreased activity of SOD. Compared with the 0.5% DMSO group, a number of apoptotic cells in zebrafish were increased after genipin exposure. By measuring marker gene expression with the using of qRT-PCR, we proposed that developmental toxicity after genipin treatment might be associated with oxidative stress and apoptosis increase. Our research offers a better understanding for developmental toxicity of genipin.

Assessing the Anti-inflammatory Mechanism of Reduning Injection by Network Pharmacology

Reduning Injection (RDNI) is a traditional Chinese medicine formula indicated for the treatment of inflammatory diseases. However, the molecular mechanism of RDNI is unclear. The information of RDNI ingredients was collected from previous studies. Targets of them were obtained by data mining and molecular docking. The information of targets and related pathways was collected in UniProt and KEGG. Networks were constructed and analyzed by Cytoscape to identify key compounds, targets, and pathways. Data mining and molecular docking identified 11 compounds, 84 targets, and 201 pathways that are related to the anti-inflammatory activity of RDNI. Network analysis identified two key compounds (caffeic acid and ferulic acid), five key targets (Bcl-2, eNOS, PTGS2, PPARA, and MMPs), and four key pathways (estrogen signaling pathway, PI3K-AKT signaling pathway, cGMP-PKG signaling pathway, and calcium signaling pathway) which would play critical roles in the treatment of inflammatory diseases by RDNI. The cross-talks among pathways provided a deeper understanding of anti-inflammatory effect of RDNI. RDNI is capable of regulating multiple biological processes and treating inflammation at a systems level. Network pharmacology is a practical approach to explore the therapeutic mechanism of TCM for complex disease.

Genipin enhances the antitumor effect of elesclomol in A549 lung cancer cells by blocking uncoupling protein-2 and stimulating reactive oxygen species production

The uncoupling protein-2 (UCP2) serves a role in tumor aggressiveness and anticancer resistance, which is considered to be associated with its ability to attenuate reactive oxygen species (ROS) production. We hypothesized that UCP2 may protect cancer cells from elesclomol-induced cytotoxicity, and that this may be overcome by blocking UCP2 function with genipin. In A549 lung cancer cells that exhibited high UCP2 expression, treatment with elesclomol alone induced limited changes in glucose uptake, ROS production and cell survival. By contrast, both UCP2 knockdown and genipin treatment mildly reduced glucose uptake, increased ROS production and decreased cell survival. Combining genipin and elesclomol further reduced glucose uptake and increased cellular and mitochondrial ROS production. Moreover, co-treatment with genipin and elesclomol reduced the colony forming capacity to 50.6±7.4% and the cell survival to 42.0±3.4% of that in the control cells (both P<0.001). Suppression of cell survival by treatment with elesclomol and genipin was enhanced in the presence of an exogenous ROS inducer and attenuated by a ROS scavenger. The cytotoxic effects of combining genipin and elesclomol were accompanied by reduced mitochondrial membrane potential and occurred through apoptosis as demonstrated by Annexin V assay and increased protein cleavage of PARP and caspase-3. Finally, in an A549 ×enograft mouse model, tumor growth was only modestly retarded by treatment with elesclomol or genipin alone, but was markedly suppressed by combining the two drugs compared with that in the control group (P=0.008). Therefore, high UCP2 expression may limit the antitumor effect of elesclomol by attenuating ROS responses, and this may be overcome by co-treatment with genipin; combining elesclomol and genipin may be an effective strategy for treating cancers with high UCP2.

Isoflavones' effects on pharmacokinetic profiles of main iridoids from Gardeniae Fructus in rats

Gardeniae Fructus (GF) and Semen Sojae Praeparatum (SSP) are both medicine food homologies and widely used in Chinese clinical prescriptions together. The research investigated the pharmacokinetics of four iridoids in normal rats and isolfavones-fed rats, which were administered with isolfavones from SSP for 7, 14, 21 and 28 consecutive days. A validated LC-MS/MS method was developed for determining shanzhiside, genipin-1-gentiobioside, geniposide and their metabolite genipin in rat plasma. Plasma samples were pretreated by solid-phase extraction using paeoniflorin as the internal standard. The chromatographic separation was performed on a Waters Atlantis T3 (4.6 mm × 150 mm, 3 μm) column using a gradient mobile phase consisting of acetonitril and water (containing 0.06% acetic acid). The mass detection was under the multiple reaction monitoring (MRM) mode via polarity switching between negative and positive ionization modes. The calibration curves exhibited good linearity (r > 0.997) for all components. The lower limit of quantitation was in the range of 1–10 ng/mL. The intra-day and inter-day precisions (RSD) at three different levels were both less than 12.2% and the accuracies (RE) ranged from −10.1% to 16.4%. The extraction recovery of them ranged from 53.8% to 99.7%. Pharmacokinetic results indicated the bioavailability of three iridoid glycosides and the metabolite, genipin in normal rats was higher than that in rats exposed to isoflavones. With the longer time of administration of isoflavones, plasma concentrations of iridoids decreased, while genipin sulfate, the phase Ⅱ metabolite of genposide and genipin-1-gentiobioside, appeared the rising exposure. The pharmacokinetic profiles of main iridoids from GF were altered by isoflavones.

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A LC-MS/MS method for determination of four iridoids in rat plasma was developed and applied.

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The bioavailability of four iridoids decreased in rats with their increasing isoflavones exposure time.

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Isoflavones could alter the fate of iridoids in vivo when GF and SSP were prescribed together to obtain toxicity-reducing.

Screening of the Hepatotoxic Components in Fructus Gardeniae and Their Effects on Rat Liver BRL-3A Cells

Fructus Gardeniae (FG) is a common Chinese medicine and food. However, the toxicity of FG has drawn increasing concern, especially its hepatotoxicity. The purpose of this study was to screen the hepatotoxic components of FG and evaluate their effects on rat liver BRL-3A cells. The chemical composition of FG was determined by HPLC-ESI-MS. CCK-8 assay was used to evaluate the cytotoxicity of ten chemical components from FG, and then the toxic components with significant inhibitory activity were selected for further study. The results showed that geniposide, genipin, genipin-1-gentiobioside, gardenoside, and shanzhiside all suppress cells viability. Apoptosis assays further indicated that geniposide and its metabolite genipin are the main hepatotoxic components of FG. Pretreatment of cells with geniposide or genipin increased the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP). The activities of superoxide dismutase (SOD) and glutathione (GSH) were decreased, while the malondialdehyde (MDA) level was increased. The cell contents of tumor necrosis factor (TNF-α), interleukin-6 (IL-6), and nitric oxide (NO) were also increased. Molecular docking simulations were used to investigate the mechanism of FG-induced hepatotoxicity, revealing that geniposide and genipin bind strongly to the pro-inflammatory factor TNFR1 receptor of the NF-κB and MAPK signaling pathways. The obtained results strongly indicate that the hepatotoxicity of FG is caused by iridoids compounds. Genipin had the most significant hepatotoxic effect. These toxic substances destroy the cell antioxidant defense system, increasing inflammatory injury to the liver cells and leading to apoptosis and even necrosis. Thus, this study lays a foundation for toxicology research into FG and its rational application.

Intestinal Microbiota-Associated Metabolites: Crucial Factors in the Effectiveness of Herbal Medicines and Diet Therapies

Although the efficacy of herbal medicines (HMs) and traditional Chinese medicines (TCMs) in human diseases has long been recognized, their development has been hindered in part by a lack of a comprehensive understanding of their mechanisms of action. Indeed, most of the compounds extracted from HMs can be metabolized into specific molecules by host microbiota and affect pharmacokinetics and toxicity. Moreover, HMs modulate the constitution of host intestinal microbiota to maintain a healthy gut ecology. Dietary interventions also show great efficacy in treating some refractory diseases, and the commensal microbiota potentially has significant implications for the high inter-individual differences observed in such responses. Herein, we mainly discuss the contribution of the intestinal microbiota to high inter-individual differences in response to HMs and TCMs, and especially the already known metabolites of the HMs produced by the intestinal microbiota. The contribution of commensal microbiota to the inter-individual differences in response to dietary therapy is also briefly discussed. This review highlights the significance of intestinal microbiota-associated metabolites to the efficiency of HMs and dietary interventions. Our review may help further identify the mechanisms leading to the inter-individual differences in the effectiveness of HM and dietary intervention from the perspective of their interactions with the intestinal microbiota.

Exploration of the hepatoprotective chemical base of an orally administered herbal formulation (YCHT) in normal and CCl4-intoxicated liver injury rats. Part 1: Metabolic profiles from the liver-centric perspective

ETHNOPHARMACOLOGICAL RELEVANCE

Yin-Chen-Hao Tang (YCHT), derived from "Treatise on Febrile Diseases" in ancient China, has been a very popular hepatoprotective three-herb formula in China and Japan, although its chemical base remains unclear.

AIM OF THIS STUDY

As the first step in revealing the hepatoprotective chemical base of YCHT, we aimed to clarify the absorbed ingredients and associated metabolic pathways for orally dosed YCHT in both normal and liver injury rats from a liver-centric perspective.

MATERIALS AND METHODS

With the aid of 10 reference compounds, the absorbed ingredients and generated metabolites were systematically characterized by high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF) in the portal vein plasma (the plasma before hepatic disposition) - liver - systemic plasma (the plasma after hepatic disposition), following oral administration of YCHT in normal and CCl₄-induced liver injury rats.

RESULTS

A total of 38 compounds with six chemical structures, consisting of 10 prototypes and 28 metabolites generated through 9 biotransformations, were absolutely or tentatively identified, and 25 compounds were first reported on YCHT treatments. Among them, 8 compounds were absolutely confirmed by comparing with standard substances, and some had published hepatoprotective activities. Compared with the 35, 15, and 29 compounds identified in the portal vein plasma, liver, and systemic plasma of normal rats, respectively, the corresponding numbers of characterized compounds were 37, 13 and 29 in the liver injury rats.

CONCLUSIONS

Sulfation and glucuronidation were the predominant biotransformations, and intestinal metabolism, prior to hepatic metabolism, occurred for most compounds. CCl₄-induced liver injury caused only slight changes in the metabolic profiles of rats orally administered YCHT. These results provided the precondition for further quantitative analysis and pharmacodynamic screening of compounds in YCHT.

Exploration of the hepatoprotective chemical base of an orally administered herbal formulation (YCHT) in normal and CCl4-intoxicated liver injury rats. Part 2: Hepatic disposition in vivo and hepatoprotective activity in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Yin-Chen-Hao Tang (YCHT) has been a very popular, hepatoprotective three-herb formula with an unclear chemical base.

AIM OF THIS STUDY

To reveal the hepatoprotective chemical base of oral-dosed YCHT, we bridged the hepatic disposition of six compounds in vivo and their hepatoprotection in vitro.

MATERIALS AND METHODS

In vivo, following the oral administration of YCHT in normal and CCl₄-induced liver injury rats, the determinations of chlorogenic acid, 4-hydroxyacetophenone, geniposide, genipin, rhein and emodin were conducted in the portal vein plasma, the liver, and the systemic plasma. In vitro, the hepatoprotective activities of these compounds were determined in the CCl₄-induced HepG2 cells.

RESULTS

Consistent with the highest content in YCHT, geniposide had the highest exposure in vivo. Inconsistent with the negligible content, rhein, 4-hydroxyacetophenone, emodin and genipin showed substantial hepatic accumulations. In contrast, chlorogenic acid, an ingredient that has a high content in YCHT, elicited no hepatic exposure. In normal rats, the hepatic disposition prevented the compounds entering into the systemic plasma from the portal vein plasma by 44.9-100%, except for rhein. CCl₄-induced liver injury caused a decreased hepatic exposure of 4-hydroxyacetophenone, rhein and emodin by 50%. In vitro, all six compounds exerted the hepatoprotection by increasing cell viability, decreasing hepatic marker enzymes and inhibiting lipid peroxidation at varying levels.

CONCLUSION

Geniposide, rhein, emodin, 4-hydroxyacetophenone and genipin directly resisted liver injury in oral-dosed YCHT, while chlorogenic acid likely played an indirect role. This study proved that YCHT exerted hepatoprotection through multiple components and multiple actions. However, close attention should be paid to the possible side effects and oral dosage of YCHT in clinics.

Evaluation of the Hepatotoxicity of the Zhi-Zi-Hou-Po Decoction by Combining UPLC-Q-Exactive-MS-Based Metabolomics and HPLC-MS/MS-Based Geniposide Tissue Distribution

With traditional Chinese medicine (TCM) becoming widespread globally, its safety has increasingly become a concern, especially its hepatoxicity. For example, Gardenia jasminoides Ellis is a key ingredient in the Zhi-Zi-Hou-Po decoction (ZZHPD), which is a commonly-used clinically combined prescription of TCM that may induce hepatoxicity. However, the underlying toxicity mechanism of ZZHPD is not fully understood. In this study, a plasma metabolomics strategy was used to investigate the mechanism of ZZHPD-induced hepatotoxicity through profiling entire endogenous metabolites. Twenty-four Sprague-Dawley rats were randomly assigned into four groups, which were orally administered with 0.9% saline, as well as 2.7 g/kg/day, 8.1 g/kg/day, or 27 g/kg/day of ZZHPD for 30 consecutive days, respectively. Biochemical assay and metabolomics assay were used to detect serum and plasma samples, whilst histopathological assay was used for detecting liver tissues, and the geniposide distribution in tissues was simultaneously measured. The results showed that the concentration of 20 metabolites linked to amino acid, lipid, and bile acid metabolism had significant changes in the ZZHPD-treated rats. Moreover, toxic effects were aggravated with serum biochemical and histopathological examines in liver tissues as the dosage increased, which may be associated with the accumulation of geniposide in the liver as the dosage increased. Notably, our findings also demonstrated that the combined metabolomics strategy with tissue distribution had significant potential for elucidating the mechanistic complexity of the toxicity of TCM.

1H NMR-based metabolomics approach to investigating the renal protective effects of Genipin in diabetic rats

Diabetic nephropathy is one of the various complications of diabetes mellitus, affecting patients for lifetime. Earlier studies have revealed that genipin can not only improve diabetes, but also induce cytotoxicity. Therefore, it is not clear which effect of genipin on kidneys occurs, when it is used in the treatment of diabetes. In the present study, we performed nuclear magnetic resonance (NMR)-based metabolomics analysis of urine and kidney tissue samples obtained from diabetic rats to explore the change of endogenous metabolites associated with diabetes and concomitant kidney disease. Nine significant differential metabolites that were closely related to renal function were screened. They were mainly related to three metabolic pathways: synthesis and degradation of ketone bodies, glycine, serine and threonine metabolism, and butanoate metabolism, which are involved in methylamine metabolism, energy metabolism and amino acid metabolism. In addition, after the intervention of genipin, the metabolic levels of all the metabolites tended to be normal, indicating a protective effect of genipin on kidneys. Our results may be helpful for understanding the antidiabetic effect of genipin.

Drug pharmacomicrobiomics and toxicomicrobiomics: from scattered reports to systematic studies of drug-microbiome interactions

INTRODUCTION

Pharmacomicrobiomics and toxicomicrobiomics study how variations within the human microbiome (the combination of human-associated microbial communities and their genomes) affect drug disposition, action, and toxicity. These emerging fields, interconnecting microbiology, bioinformatics, systems pharmacology, and toxicology, complement pharmacogenomics and toxicogenomics, expanding the scope of precision medicine. Areas covered: This article reviews some of the most recently reported pharmacomicrobiomic and toxicomicrobiomic interactions. Examples include the impact of the human gut microbiota on cardiovascular drugs, natural products, and chemotherapeutic agents, including immune checkpoint inhibitors. Although the gut microbiota has been the most extensively studied, some key drug-microbiome interactions involve vaginal, intratumoral, and environmental bacteria, and are briefly discussed here. Additionally, computational resources, moving the field from cataloging to predicting interactions, are introduced. Expert opinion: The rapid pace of discovery triggered by the Human Microbiome Project is moving pharmacomicrobiomic research from scattered observations to systematic studies focusing on screening microbiome variants against different drug classes. Better representation of all human populations will improve such studies by avoiding sampling bias, and the integration of multiomic studies with designed experiments will allow establishing causation. In the near future, pharmacomicrobiomic testing is expected to be a key step in screening novel drugs and designing precision therapeutics.

Biotransformation of Geniposide into Genipin by Immobilized Trichoderma reesei and Conformational Study of Genipin

Trichoderma reesei QM9414, Trichoderma viride 3.316, Aspergillus niger M85, and Aspergillus niger M92 were screened for hydrolyzing geniposide into genipin. T. reesei was selected according to the β-glucosidase activity of the fermentation broths using geniposide as a substrate. T. reesei was immobilized by embedding method using sodium alginate as the carrier. Geniposide was hydrolyzed by immobilized T. reesei at 28°C (200 rpm) for 34 h, and the yield of genipin was 89%. The product was purified and identified by UV, IR, EIMS, and ¹H-NMR. Since there were two sets of signals in ¹H-NMR spectra, a series of experiments were performed and verified that the existence of two conformations was the main reason. Generally, biotransformation of geniposide into genipin by immobilized T. reesei provides a promising solution to the genipin production.

Mechanistic insights into geniposide regulation of bile salt export pump (BSEP) expression

Geniposide (GE) is a major component isolated from Gardenia jasminoides Ellis, which has been used to treat cholestasis liver diseases. Our previous study has shown that GE could notably increase mRNA and protein expressions of BSEP in cholestatic rats. BSEP plays a critical role in maintenance of the enterohepatic circulation of bile acids. BSEP could be regulated by the transactivation pathway of farnesoid X receptor (FXR) and nuclear factor erythroid 2-related factor (Nrf2). Here the mechanisms for BSEP regulation by GE were investigated. GE induced the mRNA levels of BSEP in HepG2 cells and cholestatic mice, and knockdown of FXR and Nrf2 reduced the mRNA expression of BSEP at varying degrees after treatment of GE. FXR acts as the major regulator of BSEP transcription. The involvement of FXR regulated BSEP expression by GE was further investigated. An enhancement was observed in FXR-dependent BSEP promoter activation using luciferase assay. ChIP assay further confirmed the interaction between FXR and BSEP after GE treatment. Using siRNA and ChIP assays, we demonstrated that peroxisome-proliferator-activated receptor γ co-activator-1α (PGC-1α) and co-activator-associated arginine methyltransferase 1 (CARM1) were predominantly recruited to the BSEP promoter upon FXR activation by GE. In conclusion, GE regulated the expression of BSEP through FXR and Nrf2 signaling pathway. The FXR transactivation pathway was enhanced by increasing recruitment of coactivators PGC-1α and CARM1 upon GE treatment, coupled with an increased binding of FXR to the BSEP promoter.

PGC-1α and CARM1 interact with FXR to increase FXR-dependent BSEP expression upon GE treatment.

Proteomic investigation of signatures for geniposide-induced hepatotoxicity

Evaluating the safety of traditional medicinal herbs and their major active constituents is critical for their widespread usage. Geniposide, a major active constituent with a defined structure from the traditional medicinal herb Gardenia jasminoides ELLIS fruit, exhibits remarkable anti-inflammatory, antiapoptotic, and antifibrotic properties and has been used in a variety of medical fields, mainly for the treatment of liver diseases. However, geniposide-induced hepatotoxicity and methods for the early detection of hepatotoxicity have yet to be reported. In this study, geniposide-induced hepatotoxicity was investigated. In addition, candidate biomarkers for the earlier detection of geniposide-induced hepatotoxicity were identified using a label-free quantitative proteomics approach on a geniposide overdose-induced liver injury in a rat model. Using an accurate intensity-based, absolute quantification (iBAQ)-based, one-step discovery and verification approach, a candidate biomarker panel was easily obtained from individual samples in response to different conditions. To determine the biomarkers' early detection abilities, five candidate biomarkers were selected and tested using enzyme-linked immunosorbent assays (ELISAs). Two biomarkers, glycine N-methyltransferase (GNMT) and glycogen phosphorylase (PYGL), were found to indicate hepatic injuries significantly earlier than the current gold standard liver biomarker. This study provides a first insight into geniposide-induced hepatotoxicity in a rat model and describes a method for the earlier detection of this hepatotoxicity, facilitating the efficient monitoring of drug-induced hepatotoxicity.

Evaluation of genipin on human cytochrome P450 isoenzymes and P-glycoprotein in vitro

Genipin is obtained from the fruit of Gardenia jasminoides Ellis and acts as an herbal medicine or functional food in East Asia. In addition to produce natural colorant, it possesses widely antiinflammatory, antithrombotic, antidepressive and anticarcinogenic activities. However, little research focuses on the potential of genipin for drug-drug interactions. In this study, effects of genipin on mRNA and protein expression of cytochrome P450 (CYP) 2C19, CYP2D6 and CYP3A4 were detected by real-time reverse-transcription polymerase chain reaction (real-time RT-PCR) and Western blot, respectively, in human hepatoma HepG2 cells. Enzyme activities of which were detected by luminogenic CYP assay in vitro. Moreover, effect of genipin on P-glycoprotein expression was analyzed by Western blot. Results showed that genipin possessed a significant induction on CYP2D6 and a remarkable inhibition on CYP2C19 and CYP3A4 not only from the expression of mRNA and protein (P<0.05 or P<0.01), but the level of enzyme activity. Moreover, a concentration-dependent induction of genipin on P-glycoprotein expression was observed. In conclusion, caution should be exercised with respect to the induction or inhibition of genipin on CYP isoenzymes and the strong induction on P-glycoprotein.

Genipin induces cyclooxygenase-2 expression via NADPH oxidase, MAPKs, AP-1, and NF-κB in RAW 264.7 cells

Genipin is a compound found in gardenia fruit extract with diverse pharmacological activities. However, the mechanism underlying genipin-induced cyclooxygenase-2 (COX-2) expression remains unknown. In this study, we investigated the effects of genipin on COX-2 expression and determined that exposure to genipin dose-dependently enhanced the production of prostaglandin E2 (PGE2), a major COX-2 metabolite, in RAW 264.7 cells. These effects were mediated by genipin-induced activation of the COX-2 promoter, as well as AP-1 and NF-κB luciferase constructs. Phosphatidylinositol-3-kinase/Akt and MAPKs were also significantly activated by genipin, and Akt and MAPKs inhibitors (PD98059, SB20358, SP600125, and LY294002) inhibited genipin-induced COX-2 expression. Moreover, genipin increased production of the ROS and the ROS-producing NAPDH-oxidase (NOX) family oxidases, NOX2 and NOX3. Inhibition of NADPH with diphenyleneiodonium attenuated ROS production, COX-2 expression and NF-κB and AP-1 activation. These results suggest that the molecular mechanism mediating ROS-dependent COX-2 up-regulation and PGE2 production by genipin involves activation of Akt, MAPKs and AP-1/NF-κB.

An effective solution to discover synergistic drugs for anti-cerebral ischemia from traditional Chinese medicinal formulae

Recently, the pharmaceutical industry has shifted to pursuing combination therapies that comprise more than one active ingredient. Interestingly, combination therapies have been used for more than 2500 years in traditional Chinese medicine (TCM). Understanding optimal proportions and synergistic mechanisms of multi-component drugs are critical for developing novel strategies to combat complex diseases. A new multi-objective optimization algorithm based on least angle regression-partial least squares was proposed to construct the predictive model to evaluate the synergistic effect of the three components of a novel combination drug Yi-qi-jie-du formula (YJ), which came from clinical TCM prescription for the treatment of encephalopathy. Optimal proportion of the three components, ginsenosides (G), berberine (B) and jasminoidin (J) was determined via particle swarm optimum. Furthermore, the combination mechanisms were interpreted using PLS VIP and principal components analysis. The results showed that YJ had optimal proportion 3(G): 2(B): 0.5(J), and it yielded synergy in the treatment of rats impaired by middle cerebral artery occlusion induced focal cerebral ischemia. YJ with optimal proportion had good pharmacological effects on acute ischemic stroke. The mechanisms study demonstrated that the combination of G, B and J could exhibit the strongest synergistic effect. J might play an indispensable role in the formula, especially when combined with B for the acute stage of stroke. All these data in this study suggested that in the treatment of acute ischemic stroke, besides restoring blood supply and protecting easily damaged cells in the area of the ischemic penumbra as early as possible, we should pay more attention to the removal of the toxic metabolites at the same time. Mathematical system modeling may be an essential tool for the analysis of the complex pharmacological effects of multi-component drug. The powerful mathematical analysis method could greatly improve the efficiency in finding new combination drug from TCM.

Protective Effects of Geniposide and Genipin against Hepatic Ischemia/Reperfusion Injury in Mice

Geniposide is an active product extracted from the gardenia fruit, and is one of the most widely used herbal preparations for liver disorders. This study examined the cytoprotective properties of geniposide and its metabolite, genipin, against hepatic ischemia/reperfusion (I/R) injury. C57BL/6 mice were subjected to 60 min of ischemia followed by 6 h of reperfusion. Geniposide (100 mg/kg) and genipin (50 mg/kg) were administered orally 30 min before ischemia. In the I/R mice, the levels of serum alanine aminotransferase and hepatic lipid peroxidation were elevated, whereas hepatic glutathione/glutathione disulfide ratio was decreased. These changes were attenuated by geniposide and genipin administration. On the other hand, increased hepatic heme oxygenase-1 protein expression was potentiated by geniposide and genipin administration. The increased levels of tBid, cytochrome c protein expression and caspase-3 activity were attenuated by geniposide and genipin. Increased apoptotic cells in the I/R mice were also significantly reduced by geniposide and genipin treatment. Our results suggest that geniposide and genipin offer significant hepatoprotection against I/R injury by reducing oxidative stress and apoptosis.

The effect of gut microbiota on drug metabolism

INTRODUCTION

Numerous drugs and toxicants must be metabolized to an active form. Metabolic activation by host tissues, such as the liver, has been well studied. However, drug and toxicant metabolism by the intestinal microbiota is an unexplored, but essential, field of study in pharmacology and toxicology. The taxonomic diversity and sheer numbers of the intestinal microbiota, and their capacity to metabolize xenobiotics, underscore the importance of this mode of metabolism.

AREAS COVERED

Metabolism by the intestinal microbiota has focused on the natural products of glycosides hydrolyzed by intestinal microbiota enzymes, but not by host tissues. Metabolism of synthetic drugs by the intestinal microbiota has been less-intensively investigated. This review provides an overview of xenobiotic metabolism by the intestinal microbiota of both natural products and synthetic drugs.

EXPERT OPINION

Metabolism by the intestinal microbiota might result in a different metabolite profile than that produced by host tissues. This could potentially result in either activation or inactivation of the pharmacological and/or toxicological actions of the compound in question. The contribution of the intestinal microbiota to drug metabolism remains relatively unexplored. Therefore, studies of xenobiotic metabolism by the intestinal microbiota need to be included in new drug development as well as classical studies of host tissue metabolism.

Application of Scutellariae radix, Gardeniae fructus, and Probiotics to Prevent Salmonella enterica Serovar Choleraesuis Infection in Swine

Salmonella enterica serovar Choleraesuis, a host-adapted pathogen of swine, usually causes septicemia. Lactic acid bacteria (LAB) strains have been widely studied in recent years for their probiotic properties. In this study, a mouse infection model first screened for potential agents against infection, then a pig infection model evaluated effects of LAB strains and herbal plants against infection. Scutellariae radix (SR) and Gardeniae fructus (GF) showed abilities to reduce bacteria shedding and suppressing serum level of TNF-α induced by infection in swine. Bioactivities of SR and GF were enhanced by combining with LAB strains, which alone could speed up the bacteria elimination time in feces and boost immunity of infected pigs. Baicalein and genipin exhibited stronger cytotoxicity than baicalin and geniposide did, as well as prevent Salmonella from invading macrophages. Our study suggests LAB strains as exhibiting multiple functions: preventing infection, enhancing immunity to prepare host defenses against further infection, and adjusting intestinal microbes' enzymatic activity in order to convert herbal compounds to active compounds. The SR/GF-LAB strain mixture holds potential infection-prevention agents supplied as feed additives.

Role of intestinal microflora in xenobiotic-induced toxicity

In addition to its role in digestion of food in the gastrointestinal tract, the intestinal microflora is also capable of biotransforming numerous drugs. Likewise, the intestinal microflora may significantly modulate xenobiotic-induced toxicity by either activating or inactivating xenobiotics via metabolism. To date, most investigations of xenobiotic metabolism have focused not only on metabolism in host tissues, but the modulation of the pharmacological activity of drugs by the intestinal microflora. Despite its importance, the presumed role of intestinal microflora metabolism in xenobiotic-induced toxicity has been understudied. Therefore, it is appropriate to briefly review our current situation, and state which research in xenobiotic metabolism by intestinal microflora, particularly in the field of toxicology, is needed.