bluuebunny/crossref_metadata_2025 huggingface dataset:
Montmorillonite adsorbs creatinine and accelerates creatinine excretion from the intestine
Authors: Zhang Yan-ting , Wang Xiu-fang , Long Li-hui , Liu Tong , Cao Yong-xiao
Published: October 2010

Objectives

This study aims to evaluate the sorption by montmorillonite of creatinine and the accelerating effect of montmorillonite on creatinine excretion from the intestine.

Methods

The sorption of montmorillonite was observed in vitro. Also, rat intestinal tract and blood vessels were perfused circularly with perfusate with or without creatinine, respectively, to study the promotion of creatinine diffusion from the blood vessel to the intestine and the inhibition of creatinine absorption in the intestinal tract. The effect of decreasing the serum concentration of creatinine was studied in an acute hypercreatininaemia mouse model. The concentration of creatinine was determined by the basic picric acid method.

Key findings

Montmorillonite adsorbed creatinine markedly in the simulated intestinal solution in a concentration-dependent manner. The sorption–time curve of montmorillonite with creatinine showed that the sorption was fast. The adsorption rate reached a maximum in 10 min. The pH of the solution influenced the sorption, the rate of which was higher at a low pH than at a high pH. Creatinine could diffuse from the blood vessel to the intestine and was reabsorbed in the intestine. Montmorillonite promoted the diffusion and inhibited the absorption. Montmorillonite decreased the serum creatinine level of hypercreatininaemia mice prepared by injecting creatinine intraperitoneally.

Conclusions

Montmorillonite adsorbs creatinine and accelerates its excretion from the intestine.
Effects of co-administration of bupropion and nicotine ord-amphetamine on the elevated plus maze test in mice
Authors: Biala Grazyna , Kruk Marta
Published: October 2010

Objectives

A variety of abused drugs, including psychostimulants, can modulate the expression of anxiety. Although the effect of nicotine and d-amphetamine on anxiety-related behaviour in animal models has been investigated, the mechanisms underlying the anxiogenic or anxiolytic actions of these drugs have not been clarified. Bupropion is an antidepressant drug which may alleviate some symptoms of nicotine withdrawal, although its effects on anxiety are not clear. We have investigated the effect of nicotine and d-amphetamine on anxiety in the elevated plus maze test in mice.

Methods

We examined the influence of acute administration of nicotine (0.1 mg/kg, s.c.) and d-amphetamine (2 mg/kg, i.p.) on anxiety level. We then evaluated the anxiety-related response after subchronic injection of both psychostimulants, including crossover effects. For this purpose, nicotine (0.1 mg/kg, s.c.) was administered daily for six days, and on the seventh day mice were challenged with nicotine (0.1 mg/kg, s.c.) or d-amphetamine (2 mg/kg, i.p.). A distinct group of mice was pretreated with d-amphetamine (2 mg/kg, i.p., 8 days), and subjected to d-amphetamine (2 mg/kg, i.p.) or nicotine (0.1 mg/kg, s.c.) challenge on the ninth day. Moreover, we investigated acute and subchronic effects of co-administration of bupropion (5, 10 and 20 mg/kg; i.p.) and nicotine or d-amphetamine.

Key findings

We observed that acute anxiogenic effects of nicotine and d-amphetamine as well as the development of tolerance and cross-tolerance to their effects were blunted by a pretreatment with a nonactive dose of bupropion (5 mg/kg, i.p.).

Conclusions

These results demonstrated that similar neural mechanisms were involved in the regulation of nicotine and d-amphetamine anxiety-like behaviour in mice. The results have provided new findings to support the use of bupropion in the treatment of nicotine and/or amphetamine addiction.
Cytochrome P450-mediated metabolism in the human gut wall
Authors: Thelen Kirstin , Dressman Jennifer B
Published: October 2010

Objective

Although the human small intestine serves primarily as an absorptive organ for nutrients and water, it also has the ability to metabolise drugs. Interest in the small intestine as a drug-metabolising organ has been increasing since the realisation that it is probably the most important extrahepatic site of drug biotransformation.

Key findings

Among the metabolising enzymes present in the small intestinal mucosa, the cytochromes P450 (CYPs) are of particular importance, being responsible for the majority of phase I drug metabolism reactions. Many drug interactions involving induction or inhibition of CYP enzymes, in particular CYP3A, have been proposed to occur substantially at the level of the intestine rather than exclusively within the liver, as originally thought. CYP3A and CYP2C represent the major intestinal CYPs, accounting for approximately 80% and 18%, respectively, of total immunoquantified CYPs. CYP2J2 is also consistently expressed in the human gut wall. In the case of CYP1A1, large interindividual variation in the expression levels has been reported. Data for the intestinal expression of the polymorphic CYP2D6 are conflicting. Several other CYPs, including the common hepatic isoform CYP2E1, are expressed in the human small intestine to only a very low extent, if at all. The distribution of most CYP enzymes is not uniform along the human gastrointestinal tract, being generally higher in the proximal regions of the small intestine.

This article reviews the current state of knowledge of CYP enzyme expression in human small intestine, the role of the gut wall in CYP-mediated metabolism, and how this metabolism limits the bioavailability of orally administered drugs. Possible interactions between drugs and CYP activity in the small intestine are also discussed.
Amitriptyline inhibits the activity of the rat glutamate transporter EAAT3 expressed in Xenopus oocytes
Authors: Baika Hee-Jung , Lee Soon-Ae , Washington Jacqueline M , Zuo Zhi-yi
Published: October 2010

Objectives

Evidence suggests that glutamatergic systems may be involved in the pathophysiology of major depression and the mechanism of action of antidepressants. We have investigated the effects of amitriptyline, a tricyclic antidepressant, on the activity of the excitatory amino acid transporter type 3 (EAAT3), a protein that can regulate extracellular glutamate concentrations in the brain.

Methods

EAAT3 was expressed in Xenopus oocytes. Using a two-electrode voltage clamp, membrane currents were recorded after application of 30 μM l-glutamate in the presence or absence of various concentrations of amitriptyline or after application of various concentrations of l-glutamate in the presence or absence of 0.64 μM amitriptyline.

Key findings

Amitriptyline concentration-dependently reduced EAAT3 activity. This inhibition reached statistical significance at 0.38–1.27 μM amitriptyline. Amitriptyline 0.64 μM reduced the pharmacokinetic parameter Vmax, but did not affect the pharmacokinetic parameter Km, of EAAT3 for l-glutamate. The amitriptyline inhibition disappeared after a 4-min washout. Phorbol-12-myristate-13-acetate, a protein kinase C activator, increased EAAT3 activity. However, 0.64 μM amitriptyline induced a similar degree of decrease in EAAT3 activity in the presence or absence of phorbol-12-myristate-13-acetate.

Conclusions

Our results suggested that amitriptyline at clinically relevant concentrations reversibly reduced EAAT3 activity via decreasing its maximal velocity of glutamate transporting function. The effects of amitriptyline on EAAT3 activity may have represented a novel site of action for amitriptyline to increase glutamatergic neuro-transmission. Protein kinase C may not have been involved in the effects of amitriptyline on EAAT3.
Effects of quinidine on antinociception and pharmacokinetics of morphine in rats
Authors: Okura Takashi , Morita Yuki , Ito Yoshihiko , Kagawa Yoshiyuki , Yamada Shizuo
Published: October 2010

Aim

The aim of this study was to investigate the effect of quinidine, a P-glycoprotein inhibitor, on the pharmacokinetics and pharmacodynamics of morphine in rats.

Methods

Rats were given morphine (30 mg/kg p.o. or 30 mg/kg over 10 min i.v.) 30 min after pretreatment with quinidine (30 mg/kg p.o.). Antinociceptive effects were determined using the tail immersion test. Concentrations of morphine in plasma and brain were also determined.

Key findings

The antinociception of morphine was significantly enhanced by oral administration of quinidine, with a 3.1-fold greater area under the effect–time curve than that in vehicle-treated rats. Morphine concentrations in plasma and brain were significantly increased by quinidine. The area under the plasma concentration–time curve after oral or intravenous administration of morphine was increased 5.2- and 1.7-fold, respectively, in quinidine-pretreated rats compared with vehicle-pretreated rats. Quinidine caused a 40% decrease in the total clearance of morphine and increased the concentration of morphine in the brain, although the brain-to-plasma concentration ratio was not changed.

Conclusions

Oral administration of quinidine increases the absorption of morphine from the gastrointestinal tract and subsequently enhances the concentration in the brain and its antinociceptive effect. Enhanced intestinal absorption of morphine may be due largely to inhibition of intestinal P-glycoprotein by quinidine.
Pharmacological and metabolic characterisation of the potent σ1 receptor ligand 1′-benzyl-3-methoxy-3H-spiro[[2]benzofuran-1,4′-piperidine]
Authors: Wiese Christian , Maestrup Eva Große , Schepmann Dirk , Vela Jose Miguel , Holenz Jörg , Buschmann Helmut , Wünsch Bernhard
Published: October 2010

Objectives

The pharmacology and metabolism of the potent σ1 receptor ligand 1′-benzyl-3-methoxy-3H-spiro[[2]benzofuran-1,4′-piperidine] were evaluated.

Methods

The compound was tested against a wide range of receptors, ion channels and neurotransmitter transporters in radioligand binding assays. Analgesic activity was evaluated using the capsaicin pain model. Metabolism by rat and human liver microsomes was investigated, and the metabolites were identified by a variety of analytical techniques.

Key findings

1′-Benzyl-3-methoxy-3H-spiro[[2]benzofuran-1,4′-piperidine] (compound 1) is a potent σ1 receptor ligand (Ki 1.14 nM) with extraordinarily high σ1/σ2 selectivity (>1100). It was selective for the σ1 receptor over more than 60 other receptors, ion channels and neurotransmitter transporters, and did not interact with the human ether-a-go-go-related gene (hERG) cardiac potassium channel. Compound 1 displayed analgesic activity against neuropathic pain in the capsaicin pain model (53% analgesia at 16 mg/kg), indicating that it is a σ1 receptor antagonist. It was rapidly metabolised by rat liver microsomes. Seven metabolites were unequivocally identified; an N-debenzylated metabolite and a hydroxylated metabolite were the major products. Pooled human liver microsomes formed the same metabolites. Studies with seven recombinant cytochrome P450 isoenzymes revealed that CYP3A4 produced all the metabolites identified. The isoenzyme CYP2D6 was inhibited by 1 (IC50 88 nM) but did not produce any metabolites.

Conclusions

1′-Benzyl-3-methoxy-3H-spiro[[2]benzofuran-1,4′-piperidine] is a potent and selective σ1 receptor antagonist, which is rapidly metabolised. Metabolically more stable σ1 ligands could be achieved by stabilising the N-benzyl substructure.
Endothelium-independent vasorelaxation by the selective alpha estrogen receptor agonist propyl pyrazole triol in rat aortic smooth muscle
Authors: Alda José O , Valero Marta S , Pereboom Desiree , Gros Pilar , Garay Ricardo P
Published: October 2010

Objectives

This study investigated the signalling mechanism of the relaxant responses to the estrogen receptor alpha (ERα) agonist PPT (propyl pyrazole triol) in endothelium-denuded rat aortic rings.

Methods

Several compounds, including protein kinase G (PKG) inhibitors and potassium channel inhibitors, were tested against PPT-dependent rat aortic relaxation. Cyclic GMP and cytosolic calcium responses to PPT in isolated aortic smooth muscle were investigated in parallel.

Key findings

PPT vasorelaxation was largely reduced by the selective ERα antagonist methyl-piperidinopyrazole (MPP; −91.6 ± 2.5%), by the selective PKG inhibitor Rp-8-Br-cGMP (−78.6 ± 4.9%), by the specific soluble guanylyl cyclase inhibitor ODQ (1H-(1,2,4)-oxadiazolo[4,3-a]quinoxalin-1-one; −85.3 ± 5.2%) and to a lesser extent by the selective BKCa (large-conductance calcium- and voltage-activated potassium channel) inhibitor iberiotoxin (−59.3%), the selective IKCa (intermediate-conductance calcium-activated potassium channel) inhibitor TRAM-34 (1-[(2-chlorophenyl)diphenylmethyl]-1H-pyrazole; −50.7%) and the voltage-gated potassium channel inhibitor 4-aminopyridine (−40.8%). In isolated aortic smooth muscle, PPT strongly enhanced the cyclic GMP content (+144%) and Rp-8-Br-cGMP largely reduced the PPT-dependent calcium signal (−80.8%).

Conclusions

ERα receptor stimulation in rat aortic smooth muscle evokes a PKG-signalling pathway, likely triggering relaxation by BKCa and IKCa channel opening.
Identification of in-vivo and in-vitro metabolites of palmatine by liquid chromatography–tandem mass spectrometry
Authors: Yang Qian C , Wu Wen H , Han Feng M , Chen Yong
Published: October 2010

Objectives

Despite its important therapeutic value, the metabolism of palmatine is not yet clear. Our objective was to investigate its in-vivo and in-vitro metabolism.

Methods

Liquid chromatography–tandem electrospray ionization mass spectrometry (LC-ESI/MSn) was employed in this work. In-vivo samples, including faeces, urine and plasma of rats, were collected after oral administration of palmatine (20 mg/kg) to rats. In-vitro samples were prepared by incubating palmatine with intestinal flora and liver microsome of rats, respectively. All the samples were purified via a C18 solid-phase extraction procedure, then chromatographically separated by a reverse-phase C18 column with methanol–formic acid aqueous solution (pH 3.5, 70: 30 v/v) as mobile phase, and detected by an on-line MSn detector. The structure of each metabolite was elucidated by comparing its molecular weight, retention time and full-scan MSn spectra with those of the parent drug.

Key findings

The results revealed that 12 metabolites were present in rat faeces, 13 metabolites in rat urine, 7 metabolites in rat plasma, 10 metabolites in rat intestinal flora and 9 metabolites in rat liver microsomes. Except for six of the metabolites in rat urine, the other in-vivo and in-vitro metabolites were reported for the first time.

Conclusions

Seven new metabolites of palmatine (tri-hydroxyl palmatine, di-demethoxyl palmatine, tri-demethyl palmatine, mono-demethoxyl dehydrogen palmatine, di-demethoxyl dehydrogen palmatine, mono-demethyl dehydrogen palmatine, tri-demethyl dehydrogen palmatine) were reported in this work.
Novel action of 7-O-galloyl-d-sedoheptulose isolated from Corni Fructus as a hypertriglyceridaemic agent
Authors: Yokozawa Takako , Park Chan Hum , Noh Jeong Sook , Tanaka Takashi , Cho Eun Ju
Published: October 2010

Objectives

We investigated the lipid-lowering activity of 7-O-galloyl-d-sedoheptulose, an active component of Corni Fructus, and related mechanisms.

Methods

Rats were fed a high-fructose diet for 6 days, followed by treatment with 7-O-galloyl-d-sedoheptulose, 5, 10 or 20 mg/kg per day, or fenofibrate (positive control).

Key findings

The high-fructose diet induced an increase in body weight, hypertriglyceridaemia, hyperglycaemia and hypertension. Administration of 7-O-galloyl-d-sedoheptulose significantly reduced the levels of triglyceride in the serum and liver (being more effective than fenofibrate) but did not lead to changes in liver weight or hepatic function, whereas fenofibrate increased the liver weight markedly. The preventive effect of 7-O-galloyl-d-sedoheptulose against the accumulation of triglyceride and cholesterol was related to the up-regulation of peroxisome proliferator-activated receptor α expression.

Conclusions

The present study supports the role of 7-O-galloyl-d-sedoheptulose as a promising agent against hypertriglyceridaemia without hepatic side-effects.
Silymarin inhibits melanin synthesis in melanocyte cells
Authors: Choo Soo-Jin , Ryoo In-Ja , Kim Young-Hee , Xu Guang-Hwa , Kim Won-Gon , Kim Ki-Ho , Moon Seong-Joon , Son Eui-Dong , Bae KiHwan , Yoo Ick-Dong
Published: October 2010

Objectives

The aim was to search for inhibitors of melanogenesis from natural resources.

Methods

The inhibitory effect of silymarin on melanogenesis in a spontaneously immortalized mouse melanocyte cell line, Mel-Ab, was studied.

Key findings

Silymarin significantly prevented melanin production in a dose-dependent manner with an IC50 value (concentration producing 50% maximal inhibition) of 28.2 μg/ml, without effects on cell viability. Also, silymarin inhibited l-DOPA oxidation activity of tyrosinase, the rate-limiting melanogenic enzyme, in cell based-systems but it did not directly affect cell-free tyrosinase activity. Furthermore, Western blot analysis indicated that silymarin decreased the expression of tyrosinase protein.

Conclusions

This study suggests that the depigmenting effect of silymarin might be attributable to inhibition of tyrosinase expression and that silymarin may be useful as a natural skin-lightening agent.
Brain targeting studies on buspirone hydrochloride after intranasal administration of mucoadhesive formulation in rats
Authors: Khan Ms Shagufta , Patil Kundan , Yeole Pramod , Gaikwad Rajiv
Published: October 2010

Objectives

The purpose of this study was to find out whether nasal application of buspirone could increase its bioavailability and directly transport the drug from nose to brain.

Methods

A nasal formulation (Bus-chitosan) was prepared by dissolving 15.5 mg buspirone hydrochloride, 1% w/v chitosan hydrochloride and 5% w/v hydroxypropyl β-cyclodextrin (HP-β-CD) in 5 ml of 0.5% sodium chloride solution. The formulation was nasally administered to rats and the plasma and brain concentration compared with that for buspirone hydrochloride solution after intravenous and intranasal (Bus-plain) administration. The brain drug uptake was also confirmed by gamma scintigraphic study.

Key findings

The nasal Bus-chitosan formulation improved the absolute bioavailability to 61% and the plasma concentration peaked at 30 min whereas the peak for nasal Bus-plain formulation was 60 min. The AUC0-480 in brain after nasal administration of Bus-chitosan formulation was 2.5 times that obtained by intravenous administration (711 ± 252 ng/g vs 282 ± 110 ng/g); this was also considerably higher than that obtained with the intranasal Bus-plain formulation (354 ± 80 ng/g). The high percentage of direct drug transport to the brain (75.77%) and high drug targeting index (>1) confirmed the direct nose to brain transport of buspirone following nasal administration of Bus-chitosan formulation.

Conclusions

These results conclusively demonstrate increased access of buspirone to the blood and brain from intranasal solution formulated with chitosan and HP-β-CD.
Application of a novel symmetrical shape factor to gastroretentive matrices as a measure of swelling synchronization and its impact on drug release kinetics under standard and modified dissolution conditions
Authors: Liu Quan , Fassihi Reza
Published: October 2010

Objectives

We have assessed the kinetics of drug release in relation to the full or partial hydration and swelling of matrices under standard and modified United States Pharmacopeia (USP) apparatus II using a novel index, defined as the symmetrical shape factor. The symmetrical shape factor describes the regularity of the hydration rate of the matrix perimeter relative to its central regions.

Methods

Monolithic and three-layer matrices based on hypromellose, polyethylene oxide, Kollidon SR, theophylline, diltiazem hydrochloride and alfuzosin hydrochloride were subjected to dissolution testing.

Key findings

Our results indicated that Kollidon SR matrices and the three-layer composite systems with and without effervescing components were not significantly affected by the dissolution conditions. However, in the case of the floating monolithic systems based on hypromellose and polyethylene oxide, both release profiles and swelling dynamics in accordance with the similarity factor (f2) and symmetrical shape factor values were significantly influenced.

Conclusions

The symmetrical shape factor values were positively impacted. Consequently the drug release kinetics were more predictable and reproducible. The modified USP method resulted in a more synchronized axial and radial swelling with symmetrical shape factor values approaching unity. Data further indicated that the modified USP method provided for complete matrix hydration and swelling as the dosage form remained fully submerged, allowing for more reliable release mimicking the in-vivo conditions.
An improved primary human nasal cell culture for the simultaneous determination of transepithelial transport and ciliary beat frequency
Authors: Mallants Roel , Vlaeminck Valerie , Jorissen Mark , Augustijns Patrick
Published: October 2010

Objectives

The aim was to establish a preclinical in-vitro system of the nasal mucosa for the simultaneous evaluation of nasal absorption and effects on ciliary activity.

Methods

Human nasal epithelial cells were grown in collagen-coated transport inserts with transparent polyethylene terephthalate membranes (3 μm). Transepithelial transport and ciliary beat frequency values were measured every 15 min for 1 h.

Key findings

The apparent permeability coefficients (Papp) for atenolol (mainly paracellular transport) and propranolol (transcellular transport) amounted to 0.1 ± 0.1 and 23.7 ± 0.6 × 10−6 cm/s, respectively, illustrating that the system can be used to discriminate between high permeability and low permeability compounds. Transport of talinolol (substrate for the P-glycoprotein efflux carrier) did not reveal polarity (0.3 ± 0.2 and 0.2 ± 0.1 × 10−6 cm/s for absorptive and secretory transport, respectively) and was not affected by verapamil (10 μm), suggesting the absence of P-glycoprotein in the nasal cell culture. No significant effects of atenolol, propranolol and talinolol on ciliary beat frequency were observed (98 ± 20% of the control condition after 60 min). Chlorocresol significantly decreased the ciliary activity but this decrease was not accompanied by effects on the transepithelial transport of atenolol, propranolol and talinolol.

Conclusions

A new system was developed which offers possibilities as a fast screening tool for studying the potential of compounds for nasal drug administration, since permeability and a possible cilio-toxic effect can be assessed simultaneously.
Site-specific contribution of proton-coupled folate transporter/haem carrier protein 1 in the intestinal absorption of methotrexate in rats
Authors: Yokooji Tomoharu , Mori Nobuhiro , Murakami Teruo
Published: October 2010

Objectives

Methotrexate is reportedly a substrate for proton-coupled folate transporter/haem carrier protein 1 (PCFT/HCP1) and reduced folate carrier 1 (RFC1). In this study, we examined the contribution of PCFT/HCP1 and RFC1 in the intestinal absorption of methotrexate in rats.

Methods

Western blot analysis was carried out to evaluate the protein levels of PCFT/HCP1 and multidrug resistance-associated protein 2 in brush-border membrane of rat small intestine. Mucosal uptake of methotrexate was studied in the rat everted small intestine and an in-situ intestinal perfusion study of methotrexate was also carried out in rats.

Key findings

In transport studies using everted intestine, the mucosal methotrexate influx rate in proximal intestine at pH 5.5 was significantly greater than that at pH 7.4. Coadministration of folate or its analogues, such as folinate and 5-methyltetrahydrofolate, substrates for both PCFT/HCP1 and RFC1, significantly suppressed the methotrexate influx at pH 5.5, whereas thiamine pyrophosphate, an inhibitor for RFC1 alone, exerted no significant effect. Western blot analysis showed higher PCFT/HCP1 expression in proximal than distal small intestine. In distal small intestine, methotrexate influx rate was low and was not pH dependent. Also, folate and its analogues exerted no significant effect on methotrexate absorption.

Conclusions

Based on the present and our previous results, the site-specific contributions of various transporters including PCFT/HCP1 in methotrexate intestinal absorption were discussed. The variation in luminal pH and the involvement of multiple transporters in methotrexate absorption may cause variation in oral bioavailability among patients.
Monoketocholate can decrease transcellular permeation of methotrexate across Caco-2 cell monolayers and reduce its intestinal absorption in rat
Authors: Chen Gong , Fawcett J Paul , Mikov Momir , Tucker Ian G
Published: October 2010

Objectives

Bile salts have been shown to decrease the absorption of methotrexate in the rat intestine by an unknown mechanism. We aimed to examine this effect.

Methods

We assessed apical-to-basolateral (AP-BL) permeation of methotrexate (5 μM) across Caco-2 cell monolayers pretreated with various concentrations (0, 0.25, 0.5, 1, 3 and 5 mm) of sodium cholate or its semisynthetic analogue, sodium 12-monoketocholate. We also determined the effect of orally administered 12-monoketocholate on the intestinal absorption of methotrexate in rats to evaluate a possible in-vitro–in-vivo correlation.

Key findings

It was found that sodium cholate and sodium 12-monoketocholate decreased the AP-BL permeation of methotrexate at low concentrations (maximal inhibition at 0.25 and 1 mm, respectively) and increased it at higher concentrations. Determination of [14C] mannitol permeation and electrical resistance of monolayers during experiments showed that membrane integrity was not compromised at low concentrations of bile salts but was disrupted at higher concentrations. Subsequently, we examined the effect of the simultaneous oral administration of sodium 12-monoketocholate (4, 20, 40 and 80 mg/kg) on the intestinal absorption of methotrexate in rats after an oral dose (5 mg/kg). The pharmacokinetic study showed that 12-monoketocholate at 4 and 20 mg/kg did not change the methotrexate area under the serum concentration–time curve whereas sodium 12-monoketocholate at 40 and 80 mg/kg significantly reduced it.

Conclusions

Sodium 12-monoketocholate appears to decrease the intestinal absorption of methotrexate in rats by inhibition of transcellular active transport.
Effect of St John's wort on the disposition of fexofenadine in the isolated perfused rat liver
Authors: Turkanovic Jasmina , Ngo Suong N T , Milne Robert W
Published: October 2010

Objectives

This study examined the effects of St John's wort (Hypericum perforatum) on the disposition of fexofenadine, a substrate of P-glycoprotein/organic anion transporting polypeptide, in the isolated perfused rat liver.

Methods

Male Sprague-Dawley rats were given St John's wort, 1000 mg/kg, by intragastric gavage once daily for 14 days. On day 15, livers were isolated surgically and perfused in a recirculating system with fexofenadine (2 μg/ml), either alone or following addition of ciclosporin (0.5 μg/ml) 5 min before the addition of fexofenadine. Perfusate samples and bile were collected for 60 min. Fexofenadine in perfusate, bile and the homogenised livers was measured by HPLC.

Key findings

Administration of St John's wort significantly increased biliary clearance with respect to perfusate and biliary clearance with respect to the concentration in the liver, by 74% and 71%, respectively. This was reversed by ciclosporin.

Conclusions

St John's wort enhanced the elimination of fexofenadine into the bile. This could be because it increases the activity of P-glycoprotein on the canalicular membrane of hepatocytes.
Anti-inflammatory effects of Artemisia princeps in antigen-stimulated T cells and regulatory T cells
Authors: HoChang Sung , Jung Eun Jung , Park Youn Hee , Lim Dong Gyun , Ko Na Young , Choi Wahn Soo , Her Erk , Kim Soo Hyun , Choi Kang Duk , Bae Jae Ho , Kim Sun Hee , Kang Chi Dug , Han Duck Jong , Kim Song Cheol
Published: October 2010

Objectives

The aim was to investigate the anti-inflammatory effects of Artemisia princeps extract on the activity of anti-CD3/CD28-stimulated CD4+CD25- T cells and antigen-expanded regulatory T cells.

Methods

CD4+CD25- T cells were activated with coated anti-CD3 and anti-CD28 and cultured in the presence or absence of various concentrations of A. princeps extract. The cultures were pulsed on Day 6 with [3H]thymidine and, after harvesting the cells, [3H] thymidine incorporation was measured. For analysis of interleukin-2 and interferon-γ secreted from CD4+CD25- T cells, culture supernatants were collected on Days 2 and 6. For the analysis of interleukin-10 secreted from the CD4+CD25- T cells and expanded regulatory T cells, supernatants were collected after 2 and 7 days, respectively. Cytokine levels were determined using an enzyme-linked immunosorbent assay. Potential medicinal components of the A. princeps extract were determined using gas chromatography–mass spectrometry.

Key findings

A. princeps (30 μg/ml) effectively suppressed proliferation of CD4+CD25- T cells that were stimulated with anti-CD3/CD28 without causing cytotoxicity in spleen cells incubated under conditions lacking antigen stimulation. A. princeps inhibited production of the pro-inflammatory cytokines interleukin-2 and interferon-γ in anti-CD3/CD28-stimulated CD4+CD25- T cells. Also, the extract slightly increased production of the anti-inflammatory cytokine interleukin-10 in these cells. In regulatory T cells expanded by anti-CD3/CD28, A. princeps increased production of interleukin-10 and Foxp3.

Conclusions

The results suggest that A. princeps may be useful in the treatment of autoimmune diseases and organ transplantation rejection by inhibiting proliferation of inflammatory T cells, suppressing inflammatory processes in antigen-stimulated CD4+CD25- T cells and increasing activity of expanded regulatory T cells.
A novel compound from celery seed with a bactericidal effect against Helicobacter pylori
Authors: Zhou Yong , Taylor Brian , Smith Thomas J , Liu Zhong-ping , Clench Malcolm , Davies Noel W , Rainsford K D
Published: October 2010

Objectives

The aim was to purify and characterise an antimicrobial component from celery (Apium graveolens) seeds, which have been used for centuries as a herbal medicine with reported antibacterial effects.

Methods

A crude alcoholic extract of celery seeds was fractionated by organic solvent extractions, column chromatography and HPLC. Fractions were assayed for antimicrobial activity against the gastric pathogen Helicobacter pylori and other bacteria. The purified antibacterial component was characterised via MS and NMR. Preliminary investigation of its mechanism of action included morphological studies, incorporation of macromolecular precursors, membrane integrity and two-dimensional protein electrophoresis.

Key findings

The purified component, termed ‘compound with anti-Helicobacter activity’ (CAH), had potent bactericidal effects against H. pylori; the minimum inhibitory concentration and minimum bactericidal concentration were 3.15 μg/ml and 6.25–12.5 μg/ml, respectively. CAH (Mr = 384.23; empirical formula C24H32O4) had specific inhibitory effects on H. pylori and was not active against Campylobacter jejuni or Escherichia coli. MS and NMR data were consistent with a dimeric phthalide structure. The results appeared to rule out mechanisms that operated solely by loss of membrane integrity or inhibition of protein or nucleic acid synthesis.

Conclusions

CAH may be suitable for further investigation as a potent agent for treating H. pylori infections.
Anti-inflammatory activity and possible mechanism of extract from Mikania laevigata in carrageenan-induced peritonitis
Authors: Alves Claudiney F , Alves Vanessa B F , de Assis Izabel P , Clemente-Napimoga Juliana T , Uber-Bucek Elizabeth , Dal-Secco Daniela , Cunha Fernando Q , Rehder Vera L G , Napimoga Marcelo H
Published: October 2010

Objectives

The aim was to test the potential use of an extract of Mikania laevigata (popularly known in Brazil as guaco), made from leaves harvested in different months of the year, on neutrophil migration after an inflammatory stimulus and investigate the underlying molecular mechanisms.

Methods

We examined the effect of guaco on vascular permeability and leucocyte function in carrageenan-induced peritonitis in mice.

Key findings

Our results demonstrated that guaco extract administered subcutaneously (3 mg/kg) decreased the vascular permeability and also leucocyte rolling and adhesion to the inflamed tissues by a mechanism dependent on nitric oxide. Specifically, inhibitors of nitric oxide synthase remarkably abrogated the guaco extract-mediated suppression of neutrophil migration to the inflammatory site. In addition, guaco extract-mediated suppression of neutrophil migration appeared to be dependent on the production of the cytokines interleukin-1β and tumour necrosis factor-α. One of the major constituents of the guaco extract, coumarin, was able to inhibit the neutrophil migration towards the inflammatory focus.

Conclusions

In conclusion the anti-inflammatory effect induced by guaco extract may be by inhibition of pro-inflammatory cytokine production at the inflammatory site.
Characterisation of a novel conjugate of ibuprofen with 3-hydroxybutyric acid oligomers
Authors: Stasiak Pawel , Ehrhardt Carsten , Juzwa Maria , Sznitowska Malgorzata
Published: October 2010

Objectives

A conjugate of ibuprofen with 3-hydroxybutyric acid oligomers has been evaluated as a novel drug delivery model system.

Methods

This paper focuses on the synthesis and the characterisation of the physicochemical properties of this conjugate, and on hydrolysis studies in aqueous buffers and simulated intestinal fluid. We also describe the development of an analytical method (HPLC) for hydrolysis studies of this compound.

Key findings

The conjugate had high stability in aqueous solutions of pH 6–8 and underwent slow enzymatic hydrolysis.

Conclusions

This conjugate is not well suited for oral administration but might be considered a candidate for development of prodrug preparations for parenteral or topical sustained release.
Altered expression of MRP2, MRP3 and UGT2B1 in the liver affects the disposition of morphine and its glucuronide conjugate in a rat model of cholestasis
Authors: Hasegawa Yoshitaka , Kishimoto Shuichi , Takahashi Hirokazu , Inotsume Nobuo , Takeuchi Yoshikazu , Fukushima Shoji
Published: October 2010

Objectives

The aim was to investigate the disposition of morphine and morphine-3-glucuronide (M3G) in a rat model of cholestasis induced by bile duct ligation (BDL).

Methods

Morphine (15 mg/kg) was administered intravenously, and morphine and M3G concentrations in the plasma and urine measured by HPLC. Changes in the mRNA expression of multidrug resistance-associated protein (MRP)2, MRP3 and UDP-glucuronosyltransferase (UGT)2B1 in the liver were estimated using RT-PCR.

Key findings

Although the plasma morphine concentrations declined exponentially, the elimination was delayed 3 and 5 days after BDL. Plasma M3G concentrations on day 1 after BDL were similar to those in the untreated control group, but were increased 3 and 5 days after BDL. Expression of MRP3 and UGT2B1 mRNA increased after BDL. The urinary excretion of M3G was increased significantly after BDL.

Conclusions

Enhanced glucuronidation of morphine and transportation of M3G into the blood increased the plasma M3G concentration in the BDL groups. However, M3G disposition 1 day after BDL was similar to that in the untreated control group because urinary excretion of M3G increased.
Enhancement of amlodipine cardioprotection by quercetin in ischaemia/reperfusion injury in rats
Authors: Ahmed Lamiaa A , Salem Hesham A , Attia Amina S , El-Sayed Mostafa E
Published: October 2010

Objectives

To investigate the possible modification of the cardioprotective effect of amlodipine when co-administered with quercetin in myocardial ischaemia/reperfusion-induced functional, metabolic and cellular alterations in rats.

Methods

Oral doses of amlodipine (15 mg/kg) and quercetin (5 mg/kg), alone or in combination, were administered once daily for 1 week. Rats were then subjected to myocardial ischaemia/reperfusion (35min/10min). Heart rates and ventricular arrhythmias were recorded during ischaemia/reperfusion progress. At the end of reperfusion, activities of plasma creatine kinase (CK) and cardiac myeloperoxidase were determined. In addition, cardiac contents of lactate, ATP, thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH) and total nitrate/nitrite (NOx) were estimated. Finally, histological examination was performed to visualize the protective cellular effects of different pretreatments.

Key findings

Combined therapy provided significant improvement in the amlodipine effect toward preserving cardiac electrophysiologic functions, ATP and GSH contents as well as reducing the elevated plasma CK, cardiac TBARS and NOx contents.

Conclusion

Quercetin could add benefits to the cardioprotective effect of amlodipine against injury induced in the heart by ischaemia/reperfusion.
Boswelliaresin: from religious ceremonies to medical uses; a review of in-vitro, in-vivo and clinical trials
Authors: Moussaieff Arieh , Mechoulam Raphael
Published: October 2010

Objectives

Despite its historical-religious, cultural and medical importance, Boswellia has not been thoroughly studied, and gaps still exist between our knowledge of the traditional uses of the resin and the scientific data available. Here we review the pharmacology of Boswellia resin and of the small molecules identified as the active ingredients of the resin.

Key findings

The resin of Boswellia species (‘frankincense’, ‘olibanum’) has been used as incense in religious and cultural ceremonies since the beginning of written history. Its medicinal properties are also widely recognized, mainly in the treatment of inflammatory conditions, as well as in some cancerous diseases, wound healing and for its antimicrobial activity. Until recently, work on Boswellia focused on the immunomodulatory properties of the resin and boswellic acids were considered to be the main, if not the only, active ingredients of the resin. Hence, this family of triterpenoids was investigated by numerous groups, both in vitro and in vivo. These compounds were shown to exert significant anti-inflammatory and pro-apoptotic activity in many assays: in vitro, in vivo and in clinical trials. We recently found incensole acetate and its derivatives, which are major components of Boswellia resin, to be nuclear factor-κB inhibitors, thus suggesting that they are, at least in part, responsible for its anti-inflammatory effects. Incensole acetate also exerts a robust neuroprotective effect after brain trauma in mice. Furthermore, it causes behavioural as well as anti-depressive and anxiolytic effects in mice. It is also a potent agonist of the transient receptor potential (TRP)V3 channel. It thus seems that incensole acetate and its derivatives play a significant role in the effects that Boswellia resin exerts on biological systems.

Conclusions

Altogether, studies on Boswellia resin have provided an arsenal of bio-active small molecules with a considerable therapeutic potential that is far from being utilized.
In-vitro and in-vivo metabolic studies of the candidate chemopreventative pentamethylchromanol using liquid chromatography/tandem mass spectrometry
Authors: Gorman Gregory S , Coward Lori , Kerstner-Wood Corenna , Freeman Lea , Hebert Charles D , Kapetanovic Izet M
Published: October 2010

Objectives

This study focuses on the in-vitro metabolic profiles of pentamethyl-chromanol in human, rat, dog and non-human primates, and characterizes the associated metabolic kinetics and specific human isozymes responsible for metabolism. Additional investigations compare in-vitro data with in-vivo metabolic data from rats and dogs.

Methods

In-vitro metabolites were generated from commercially available microsomes, S9 fractions and cytochrome P450 isozymes. Reaction mixtures were analysed using liquid chromatography/tandem mass spectrometry for metabolite identification, stability, pheno-typing and kinetic profiles. Plasma samples were collected from 28-day toxicology studies in rats and dogs, and analysed using the same methodology as for the identification of in-vitro metabolites.

Key findings

Samples from in-vitro experiments produced a total of eight identified metabolites while five were observed in the in-vivo samples. Kinetic analysis of metabolites in human microsomes generated Michaelis constants (KM) ranging from 10.9 to 104.9 μM. Pentamethylchromanol metabolic stability varied by species and multiple isozymes were identified for the observed biotransformation pathways. Pentamethylchromanol is susceptible to multiple metabolic pathways and differential metabolic stability, which is species dependent.

Conclusions

In-vitro metabolism was not a strong predictor of in-vivo metabolism for the samples assays but showed glucuronidation and sulfation as common biotransformation pathways.
Faster clearance of mirodenafil in rats with acute renal failure induced by uranyl nitrate: contribution of increased protein expression of hepatic CYP3A1 and intestinal CYP1A1 and 3A1/2
Authors: Choi Young H , Lee Young S , Kim Tae K , Lee Bong-Y , Lee Myung G
Published: October 2010

Objectives

It has been reported that mirodenafil is primarily metabolized via hepatic cytochrome P450 (CYP) 1A1/2, 2B1/2, 2D1 and 3A1/2 in rats. It has also been reported that the protein expression of hepatic CYP3A1 and intestinal CYP1A1 and 3A1/2 increases and that of hepatic CYP2D1 decreases in rats with acute renal failure induced by uranyl nitrate (U-ARF rats). Thus, the pharmacokinetics of mirodenafil were studied in control and U-ARF rats.

Methods

The pharmacokinetic parameters of mirodenafil and SK3541 (a metabolite of mirodenafil) were compared after the intravenous and oral administration of mirodenafil at a dose of 20 mg/kg to U-ARF and control rats.

Key findings

After interavenous administration of mirodenafil to U-ARF rats, the total area under the concentration–time curve (AUC) of mirodenafil was significantly smaller (36.5% decrease) than controls, possibly due to the significantly faster non-renal clearance (66.1% increase; because of increase in the protein expression of hepatic CYP3A1) than controls. After the oral administration of mirodenafil to U-ARF rats, the AUC of mirodenafil was also significantly smaller (47.8% decrease) due to the increase in the protein expression of hepatic CYP3A1 and intestinal CYP1A1 and 3A1/2 compared with controls.

Conclusions

After both intravenous and oral administration of mirodenafil to U-ARF rats, the AUCSK3541/AUCmirodenafil ratios were comparable with that in controls and this could be due to further metabolism of SK3541 in rats.
Evaluation of anti-angiogenic, anti-inflammatory and antinociceptive activity of coenzyme Q10 in experimental animals
Authors: Jung Hyun-Joo , Park Eun-Hee , Lim Chang-Jin
Published: October 2010

Objectives

This work aimed to assess some pharmacological activities of coenzyme Q10 (CoQ10) in animal experimental models.

Methods

The chick chorioallantoic membrane assay was used to evaluate anti-angiogenic activity of CoQ10. Anti-inflammatory activity of CoQ10 was confirmed using two animal models of inflammation. These were the vascular permeability and air pouch models, models of acute and sub-acute inflammation, respectively. Antinociceptive activity was assessed by the acetic acid-induced abdominal constriction response.

Key findings

CoQ10 dose-dependently displayed inhibition of chick chorioallantoic membrane angiogenesis. In the acetic acid-induced vascular permeability model in mice, CoQ10 at 50, 100 and 200 mg/kg reduced vascular permeability from 0.74 ± 0.01 (A590) to 0.67 ± 0.01 (P < 0.01), 0.46 ± 0.02 (P < 0.01) and 0.30 ± 0.01 (P < 0.01), respectively. In the carrageenan-induced inflammation in the air pouch, CoQ10 was able to diminish exudate volume, the number of polymorphonulcear leucocytes and nitrite content in the air pouches. CoQ10 at 25, 50 and 100 mg/kg significantly reduced acetic acid-induced abdominal constriction in mice from 27.0 ± 2.00 (number of abdominal constrictions) to 17.7 ± 0.33 (P < 0.01), 9.3 ± 0.67 (P < 0.01) and 1.3 ± 0.33 (P < 0.01), respectively, suggesting a strong antinociceptive activity.

Conclusions

CoQ10 possessed considerable anti-angiogenic, anti-inflammatory and antinociceptive activity, possibly via down-regulating the level of nitric oxide, which partly supported its use as a dietary supplement and in combination therapy.
Quercetin and naringenin transport across human intestinal Caco-2 cells
Authors: Chabane Meriem Nait , Ahmad Abraham Al , Peluso Jean , Muller Christian D , Ubeaud-Séquier Geneviève
Published: October 2010

Objectives

Flavonoids are phenolic compounds found in most edible fruits and vegetables. Previous studies have demonstrated their biological and beneficial effects on human health. However, their bioavailability and, in particular, their intestinal absorption mechanism have not yet been clearly identified. The aim of our work was to quantify and to characterize in vitro the nature of the transport of two flavonoids distinguished by their physicochemical and pharmacological properties: quercetin, a flavan-3-ol, and naringenin, a flavanone.

Methods

Differentiated and polarized Caco-2 human intestinal epithelial cell lines were used for this purpose.

Key findings

In our experimental conditions, quercetin and naringenin were poorly absorbed by Caco-2 cells. Quercetin was absorbed by passive diffusion and a pH-dependent mechanism mediated by the organic anion transporting protein B (OATP-B). It was not a multidrug resistance associated protein (MRP)1 substrate, but was substrate of the MRP2 efflux transporter and not P-glycoprotein (P-gp). Intestinal permeability from the apical to the basolateral side was higher for naringenin than for quercetin, which was partly explained by naringenin's physicochemical characteristics. Naringenin, partially absorbed by passive diffusion, was also an ATP-dependent transport substrate mediated by MRP1, but was not an OATP-B substrate. However, naringenin was secreted via active P-gp and MRP2 efflux transporters.

Conclusions

The contribution of ATP-dependent efflux transporters (MRP2 and P-gp) to the permeability of these compounds in the apical side could explain their low bioavailability. In conclusion, knowledge of the absorption mechanism of these two flavonoids was used to determine the intake level that has a beneficial effect on human health and their putative role in food—drug interactions.