Effect of in vitro and in vivo aerosolized treatment with geniposide on tracheal permeability in ovalbumin-induced guinea pigs

Alleviative Effect of Geniposide on Lipopolysaccharide-Stimulated Macrophages via Calcium Pathway

In this study, we investigated how geniposide (a bioactive ingredient of gardenia fruit) acts on lipopolysaccharide (LPS)-stimulated macrophages. Griess reagent assay, Fluo-4 calcium assay, dihydrorhodamine 123 assay, multiplex cytokine assay, quantitative RT-PCR, and flow cytometry assay were used for this study. Data showed that geniposide at concentrations of 10, 25, and 50 μM reduced significantly the levels of nitric oxide, intracellular Ca2+, and hydrogen peroxide in LPS-activated RAW 264.7. Multiplex cytokine assay showed that geniposide at concentrations of 10, 25, and 50 μM meaningfully suppressed levels of IL-6, G-CSF, MCP-1, and MIP-1α in RAW 264.7 provoked by LPS; additionally, geniposide at concentrations of 25 and 50 μM meaningfully suppressed the levels of TNF-α, IP-10, GM-CSF, and MIP-1β. Flow cytometry assay showed that geniposide reduces significantly the level of activated P38 MAPK in RAW 264.7 provoked by LPS. Geniposide meaningfully suppressed LPS-induced transcription of inflammatory target genes, such as Chop, Jak2, Fas, c-Jun, c-Fos, Stat3, Nos2, Ptgs2, Gadd34, Asc, Xbp1, Nlrp3, and Par-2. Taken together, geniposide exerts alleviative effects in LPS-stimulated macrophages via the calcium pathway.

Geniposide-mediated protection against amyloid deposition and behavioral impairment correlates with downregulation of mTOR signaling and enhanced autophagy in a mouse model of Alzheimer's disease

Geniposide, an iridoid glycoside extract from the gardenia fruit, is used in traditional Chinese medicine to alleviate symptoms of liver and inflammatory diseases. Geniposide activates GLP-1 receptors, known to modulate the activity of mechanistic target of rapamycin (mTOR), a key kinase regulating energy balance, proliferation, and survival in cells. mTOR activation inhibits autophagy, which is often disrupted in age-related diseases. Modulation of mTOR function to increase autophagy and inhibit apoptosis is involved in the protective effects of pharmacologic agents targeting diabetes and Alzheimer’s disease (AD). We investigated whether such mechanism could mediate geniposide’s neuroprotective effects in the APP/PS1 mouse model of AD. Eight-week treatment with geniposide improved cognitive scores in behavioral tests, reduced amyloid-β 1-40 plaque deposition, and reduced soluble Aβ1-40 and Aβ1-42 levels in the APP/PS1 mouse brain.This also showed increased p-Akt/Akt, p-mTOR/mTOR and decreased p-4E-BP1/4E-BP1 expression, and these patterns were partially reversed by geniposide. Evidence for enhanced autophagy, denoted by increased expression of LC3-II and Beclin1, was also seen after treatment with geniposide. Our data suggests that down regulation of mTOR signaling, leading to enhanced autophagy and lysosomal clearance of Aβ fibrils, underlies the beneficial effects of geniposide against neuropathological damage and cognitive deficits characteristic of AD.

Synergistic Use of Geniposide and Ginsenoside Rg1 Balance Microglial TNF-α and TGF-β1 following Oxygen-Glucose Deprivation In Vitro: A Genome-Wide Survey

Ischemia-activated microglia are like a double-edged sword, characterized by both neurotoxic and neuroprotective effects. The aim of this study was to reveal the synergistic effect of geniposide and ginsenoside Rg1 based on tumor necrosis factor- (TNF-) α and transforming growth factor- (TGF-) β1 balance of microglia. BV2 microglial cells were divided into 5 groups: control, model (oxygen-glucose deprivation (OGD)), geniposide-treated, ginsenoside-Rg1-treated, and combination-treated. A series of assays were used to detect on (i) cell viability; (ii) NO content; (iii) expression (content) of TNF-α and TGF-β1; and (iv) gene expression profiles. The results showed that integrated use of geniposide and ginsenoside Rg1 significantly inhibited NO level and protected cell viability, improved the content and expression of TGF-β1, and reduced the content and expression of TNF-α. Separated use of geniposide or ginsenoside Rg1 showed different effects at different emphases. Next-generation sequencing showed that Fcγ-receptor-mediated phagocytosis pathway played a key regulatory role in the balance of TNF-α and TGF-β1 when cotreated with geniposide and ginsenoside Rg1. These findings suggest that synergistic drug combination of geniposide and ginsenoside Rg1 in the treatment of stroke is a feasible avenue for the application.

Effects of intestinal microbiota on the bioavailability of geniposide in rats

This study investigated the effects of intestinal microbiota on the metabolism of geniposide by using a rat model treated with a mixture of antibiotics. The plasma concentration of geniposide was determined after oral administration in control and antibiotics-treated rats by using liquid chromatography-tandem mass spectrometry. The maximum plasma concentrations (Cmax) of geniposide in control and antibiotics-treated rats were 0.91 ± 0.26 and 1.01 ± 0.04 μg/mL, respectively, and the area under the curve (AUC) values were 7.34 ± 3.32 and 11.9 ± 2.1 μg·h/mL (p < 0.05), respectively. The levels of geniposide in rat feces were 0.64 and 15.6 mg, respectively, in the control and antibiotics-treated groups. Thus, the systemic exposure of geniposide was greater in the antibiotics-treated rats. This may be due to the antibiotic-induced suppression of the metabolic activities of the intestinal microbiota. These results suggest that the gut microbiota may have an impact on the bioavailability of geniposide.

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.

Influence of borneol and muscone on geniposide transport through MDCK and MDCK-MDR1 cells as blood-brain barrier in vitro model

The objective of this study was (1) to characterize geniposide transport through MDCK and MDCK-MDR1 cell lines to confirm its transport mechanism and (2) to evaluate the effect of borneol and muscone as enhancers of geniposide transport in the BBB models so as to explore the enhancement mechanism. Transport studies of geniposide were performed in both directions, from apical to basolateral and from basolateral to apical sides. Drug concentrations were analyzed by HPLC. Geniposide showed relatively poor absorption in MDCK and MDCK-MDR1 cells, apparent permeability coefficients ranging from 0.323×10(-6) to 0.422×10(-6) cm/s. The in vitro experiments showed that geniposide transport in both directions was not concentration dependent and saturable, indicating purely passive diffusion. The efflux ratio of geniposide was less than 2 in the two cell models, which suggested that geniposide was not P-gp substrates. Geniposide transport in both directions significantly increased when co-administrated with increasing concentrations of borneol and muscone. Actin staining results indicated that borneol and muscone increased geniposide transport in the BBB models may attribute to disassembly effect on tight junction integrity.

Geniposide inhibits airway inflammation and hyperresponsiveness in a mouse model of asthma

Our group recently reported the strong anti-inflammatory effects of geniposide (Gen), a bioactive iridoid glucoside derived from gardenia jasminoides, in a mouse acute lung injury model. Herein, we hypothesized that Gen might also have potential therapeutic benefits in treatment of asthma, which was tested in a mouse model of ovalbumin (Ova)-induced allergic airway inflammation. Ova-sensitized and -challenged BALB/c mice, as compared with control animals, displayed airway hyperresponsiveness (AHR), bronchoalveolar lavage eosinophilia, mucus hypersecretion, and increased T help 2 (Th2)-associated cytokine and chemokine amounts, as well as serum Ova-specific immunoglobulin E (IgE) level. Being compared with the Ova-induced hallmarks of asthma, intraperitoneal Gen treatment prevented eosinophilic pulmonary infiltration, attenuated the increases in interleukin (IL)-4, IL-5, and IL-13, and reduced eotaxin and vascular cell adhesion molecule 1 (VCAM-1) expression. Also, Gen significantly ameliorated the Ova-driven airway hyperresponsiveness, mucus hypersecretion, and allergen-specific IgE level, which are the cardinal pathophysiological symptoms in allergic airway diseases. In addition, the efficacy of Gen was comparable to that of dexamethasone (Dex), a currently available anti-asthmatic drug. Collectively, our findings reveal that the development of immunoregulatory strategies based on Gen may be considered as an effective adjuvant therapy for allergic asthma.

A sensitive liquid chromatographic-mass spectrometric method for simultaneous quantification of six iridoid glycosides from Zhi-zi-chi Decoction in rat plasma and its application to a pharmacokinetic study

A sensitive liquid chromatographic-mass spectrometric (LC-MS) method was developed and validated for simultaneous determination of geniposide, geniposidic acid, scandoside methyl ester, gardenoside, deacetyl asperulosidic acid methyl ester and genipin-1-β-gentiobioside after oral administration of Zhi-zi-chi Decoction in rat plasma. The six iridoid glycosides were extracted from plasma samples by protein precipitation, and then separated on an Apollo C18 column (250 mm × 4.6mm, 5 μm) through the application of a gradient elution. The analytes were monitored in positive electrospray ionization by selected ion monitoring mode (SIM). The lower limits of quantitation (LLOQ) of the six analytes were all lower than 6 ng/mL. The accuracy (relative error, RE%) was between -7.0% and 9.9%, while the intra- and inter-day precisions (relative standard deviation, RSD%) were less than 6.3% and 9.8% for the six analytes, respectively. The developed method was successfully applied to a comparative pharmacokinetic study of the six iridoids in rat plasma after oral administration of Zhi-zi-chi Decoction and Gardenia jasminoides extract.

Neuroprotective effects of tongluojiunao in neurons exposed to oxygen and glucose deprivation

ETHNOPHARMACOLOGICAL RELEVANCE

Tongluojiunao (TLJN) is an herb extract that mainly contains ginsenoside Rg1 and geniposide, which are clinically used for treating ischemic damages in the brain.

AIM OF THE STUDY

In the stroke, cerebral ischemia followed by oxygen reperfusion induced apoptosis in hippocampal neurons, while extension of axons and dendrites in neurons may compensate for and repair damages of neuronal network in the hypoxia brain. In this study, we investigated whether TLJN can protect neurons against damages by ischemia in brain vasculature.

MATERIALS AND METHODS

We measured cell viability and lactate dehydrogenase (LDH) release from primary culture of rat hippocampal neurons before and after the neurons were deprived of oxygen and glucose (OGD). In addition, the effects were evaluated with cell viability and neurite outgrowth before or after OGD.

RESULTS

We found that TLJN could play a neuroprotective role to cultured primary rat hippocampal neurons under both normal and oxygen/glucose-deprivation (OGD) conditions. TLJN could protect both cultured primary rat hippocampal neurons and brain microvascular endothelial cells (BMECs) from cell death under both normal and oxygen/glucose-deprivation (OGD) conditions. Moreover, under the same conditions, BMECs-conditioned media pretreated by TNJN could also promote neuron viability and neurite outgrowth, indicating that TLJN stimulated BMECs to secret some neuroprotective/neurotrophic factors.

CONCLUSION

These findings suggest that TLJN has a marked neuroprotective and neurotrophic roles by either direct or indirect operation, and provide insight into the mechanism of clinical efficacy of this drug against stroke.

Genipin up-regulates heme oxygenase-1 via PI3-kinase-JNK1/2-Nrf2 signaling pathway to enhance the anti-inflammatory capacity in RAW264.7 macrophages

Genipin, an aglycon of geniposide, has been reported to exhibit diverse pharmacological functions such as antitumor and anti-inflammatory effects. This study aimed to elucidate the anti-inflammatory mechanism of genipin, focusing particularly on the role of heme oxygenase-1 (HO-1), a potent anti-inflammatory enzyme. In RAW264.7 cells, genipin increased HO-1 expression and its enzyme activity via a NF-E2-related factor 2 (Nrf2)-antioxidant response element (ARE) pathway. These effects were significantly inhibited by exposure to the phosphatidylinositol 3-kinase (PI 3-kinase) inhibitor, LY294002, or by expression of a dominant negative mutant of PI 3-kinase. Additional experiments showed that the activation of c-Jun NH(2)-terminal kinase 1/2 (JNK1/2) is required for genipin-induced phosphorylation and nuclear translocation of Nrf2 and antioxidant response element (ARE)-driven induction of HO-1, and acts as a downstream effector of PI 3-kinase. Furthermore, functional significance of HO-1 induction was revealed by genipin-mediated inhibition of lipopolysaccharide-stimulated inducible nitric oxide synthase expression or cyclooxygenase-2 promoter activity, the response was reversed by the blocking of HO-1 protein synthesis or HO-1 enzyme activity. Therefore, identification of PI 3-kinase-JNK1/2-Nrf2-linked signaling cascade in genipin-mediated HO-1 expression defines the signaling event that could participate in genipin-mediated anti-inflammatory response.

Brain microvascular endothelial cells mediate neuroprotective effects on ischemia/reperfusion neurons

AIM OF THE STUDY

The permeability of the blood-brain barrier (BBB) is a bottleneck for the development of new cerebropathy medications because the medication must be transmitted across the BBB to achieve its curative function. To explore a new approach to the treatment of brain disease, this study investigated the mediating effects of brain microvascular endothelial cells (MVECs) on injured neurons.

MATERIALS AND METHODS

MVECs and cortical neurons were cultured and damage by cerebral ischemia/reperfusion (I/R) was simulated. The conditioned media from four groups of MVECs - normal cells (N-CM), normal cells treated with Tong Luo Jiu Nao (TLJN) (NT-CM), simulated cerebral I/R cells (I/R-CM), and simulated cells treated with TLJN (I/RTCM) - were then collected. These conditioned media were added to neuronal cultures and the viability of the neurons was examined.

RESULTS

The results demonstrated that N-CM could alleviate I/R damage to neurons, and this capacity could be improved by TLJN treatment. However, I/R-CM could cause damage to normal and I/R neurons, while I/RT-CM could significantly alleviate the damage to I/R neurons.

CONCLUSIONS

We propose that MVECs secrete active substances that influence the survival of neurons, and so MVECs may mediate a neuroprotective effect on ischemia/reperfusion neurons.

Ethanol enhanced in vivo gene delivery with non-ionic polymeric micelles inhalation

Modifications of both carriers and host barriers have been investigated for efficient inhalation gene delivery to lung. Here we used a biocompatible, non-ionic poly(ethyleneoxide)-poly(propyleneoxide)-poly(ethyleneoxide) (PEO-PPO-PEO) polymeric micelles (PM) as a carrier and combined it with ethanol to enhance membrane penetration of delivered DNA. The inhalation delivery with six 100 microg doses of pCMV-Lac Z with PM co-formulated with 10%-40% ethanol to nude mice in 2 days at 8 h interval was performed. The beta-galatosidase (beta-Gal) activity was assessed using chlorophenol red-beta-d galactopyranoside (CPRG) and X-gal staining for quantitative and qualitative analysis in tissues. The results showed that beta-Gal activity was significantly increased by 38% in lung around bronchioles when inhalation with PM and 10% ethanol was given. The 10% ethanol also increased the intracellular apparent permeability by 42% in stomach and by 141% in intestine at 48 h after the first dosage of delivery. Also delivery of DNA encoding a functional human cystic fibrosis transmembrane protein (CFTR) using the same inhalation delivery method co-formulated with 10% ethanol, an increased expression of CFTR in lung was detected by immunostaining. We concluded that 10% ethanol co-formulated with the PM system could enhance inhaled gene delivery to airway and gastrointestinal (GI) tract.

Anti-inflammatory evaluation of gardenia extract, geniposide and genipin

Gardenia fruit has been traditionally used as a folk medicine for centuries in Asian countries. Extraction with ethanol was used to obtain an extract (GFE) that contains two known constituents, geniposide and genipin, which were subsequently evaluated for anti-inflammatory activity. GFE, genipin, and geniposide showed acute anti-inflammatory activities in carrageenan-induced rat paw edema. In a dose-dependent manner, GFE also inhibited vascular permeability induced by acetic acid. Both genipin and geniposide inhibited production of exudate and nitric oxide (NO) in the rat air pouch edema model. However, genipin possessed stronger anti-inflammatory activity than geniposide, as demonstrated by the results with carrageenan-induced rat paw edema, carrageenan-induced air pouch formation, and measurement of NO content in the exudates. GFE caused a dose-dependent inhibition of acetic acid-induced abdominal writhing in mice. Collectively, genipin, rather than geniposide, is the major anti-inflammatory component of gardenia fruit.

Antiinflammatory effects of genipin, an active principle of gardenia

Genipin, the aglycone of geniposide, is metabolically produced from the geniposide in body tissues. The purpose of this study is to clarify some pharmacological actions of genipin. Genipin showed concentration-dependent inhibition on lipid peroxidation induced by Fe++/ascorbate in rat brain homogenate. Genipin exhibited significant topical antiinflammatory effect shown as an inhibition of croton oil-induced ear edema in mice. Nitric oxide (NO) synthesis by inducible nitric oxide synthase (iNOS) is increased in inflammatory diseases and leads to cellular injury. Genipin concentration-dependently (50-300 microM) inhibited NO production and iNOS expression upon stimulation by lipopolysaccharide/interferon-gamma (IFN-gamma) in RAW 264.7, a murine macrophage cell line. Genipin markedly blocked lipopolysaccharide-evoked degradation of inhibitor-kappaB-beta (IkappaB-beta), indicating that it exhibits inhibitory effect on NO production through the inhibition of nuclear factor-kappaB (NF-kappaB) activation. It was also shown to contain potent antiangiogenic activity in a dose-dependent manner, which was detected by chick embryo chorioallantoic membrane assay. In summary, we demonstrate that genipin possesses antiinflammatory and is a specific hydroxyl radical scavenger. Its antiangiogenic and NO production-inhibitory properties are also presented.