bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of anti-inflammatory potential of Bergenia ciliata Sternb. rhizome extract in rats
Authors: Sinha Sanghamitra , Murugesan T , Maiti Kuntal , Gayen Jiaur Rahaman , Pal M , Saha B P
Published: July 2003

The methanol extract of the rhizome of Bergenia ciliata Sternb. (Saxifragaceae) has been evaluated for anti-inflammatory potential using two acute rat models (carrageenan- and serotonin (5-HT)-induced rat paw oedema) and a chronic rat model (cotton pouch-induced granuloma). Phenylbutazone (100 mg kg−1), a non-steroidal anti-inflammatory agent, was used as a standard. The methanol extract (100, 200 or 300 mg kg−1) exhibited significant (P < 0.05) anti-inflammatory activity in all the animal models. At 300 mg kg−1 the methanol extract exhibited maximum inhibition of 32.4 ± 2.89% in carrageenan-induced rat paw oedema while the standard showed an inhibition of 44.1 ± 2.7% after 3 h of drug treatment. In the serotonin-induced rat paw oedema model, 300 mg kg−1 methanol extract suppressed oedema by 45.33 ± 2.09%, whereas the standard produced an inhibition of 53.5 ± 4.3%. In the cotton pouch granuloma model the methanol extract inhibited significantly (P < 0.001) the granuloma weight in a dose-dependent manner. In this model, 300 mg kg−1 extract produced a maximum inhibition of 31.4 ± 1.09% in granuloma weight compared with 41.1 ± 1.32% reduction in granuloma weight for the standard. The methanol extract of B. ciliata exhibited significant anti-inflammatory potential at the dose levels examined.
Anti-fibrotic effects of a hot-water extract from Salvia miltiorrhiza roots on liver fibrosis induced by biliary obstruction in rats
Authors: Nan Ji-Xing , Park Eun-Jeon , Kang Hee-Chul , Park Pil-Hoon , Kim Ji-Young , Sohn Dong Hwan
Published: July 2003

The anti-fibrotic effects of a hot-water extract form the traditional Chinese medicinal herb Salvia miltiorrhiza (Labiatae) on liver fibrosis induced by biliary obstruction was studied in rats. Liver fibrosis was induced in male Sprague-Dawley rats by bile duct ligation and scission (BDL). After surgery, the hot-water extract of S. miltiorrhiza roots (100 mg kg−1, p.o.) was administered daily for 28 days. The concentrations of aspartate transaminase, alanine transaminase, alkaline phosphatase, total bilirubin and total cholesterol in serum and hydroxyproline and malondialdehyde contents in liver were significantly increased in BDL rats. Treatment with the extract of S. miltiorrhiza significantly reduced (P < 0.01) the serum aspartate transaminase, alanine transaminase, alkaline phosphatase, and total cholesterol concentrations in BDL rats. The liver hydroxyproline content in BDL rats treated with extract was also reduced to 68% of that in BDL control rats (P < 0.01). The liver malondialdehyde content in BDL rats treated with the extract was also reduced to 47% of that in BDL control rats (P < 0.01). The morphological characteristics of fibrotic livers were improved in BDL rats treated with extract. Immunohistochemical examination of fibrotic liver showed that the extract of S. miltiorrhiza markedly reduced protein expression of α-smooth muscle cell-like actin, which indicates that hepatic stellate cell activation was inhibited during liver fibrosis development. The results indicate that the hot-water extract of S. miltiorrhiza roots inhibits fibrosis and lipid peroxidation in rats with liver fibrosis induced by biliary obstruction.
Potency, affinity constants and receptor reserves for noradrenaline and adrenaline on aortae from aged normo- and hypertensive rats
Authors: Doggrell Sheila A , Chen Ying-Yu
Published: July 2003

Previously we have determined the potency, affinity constants (KA values), and α1-adrenoceptor reserves for noradrenaline and adrenaline on the thoracic aortae of 20-week-old Wistar Kyoto normotensive (WKY) and spontaneously hypertensive rats (SHRs). This study has investigated whether these parameters were altered on the thoracic aortae by ageing, and in hypertension/heart failure. The effects of phenoxybenzamine on the contractile responses of the aortae of 20-month-old WKYs and SHRs were determined. The pD2 values for noradrenaline and adrenaline were 7.1 and 7.0, respectively, on the aortae of 20-month-old WKYs, and similar values were obtained on age-matched SHRs. On the aortae of 20-month-old WKYs, the KA values for noradrenaline and adrenaline were 1.85 and 1.95 × 10−6 M, and the receptor occupancies required for 50% maximum responses were 16 and 24%, respectively. There were lower affinities, by approximately twofold, but similar receptor reserves for noradrenaline and adrenaline on the aortae of age-matched SHRs. In comparison with the aortae of 20-week-old WKYs and SHRs, there was a 5-fold loss of sensitivity to noradrenaline and adrenaline between 20 weeks and 20 months. Between 20 weeks and 20 months there was a 50-fold loss of affinity with ageing and a further twofold loss with hypertension/heart failure, and an increase in α1-adrenoceptor reserves for noradrenaline and adrenaline between 20 weeks and 20 months. There were no differences in the sensitivity and affinity, and minor changes in the α1-adrenoceptor reserves for noradrenaline and adrenaline between the aortae of 20-month-old WKYs and SHRs. In contrast there were major changes in these parameters in the ageing of the WKY aorta from 20 weeksto 20 months. There were no additional changes in the sensitivity and α1-adrenoceptor reserves, but a small additional change in affinity for noradrenaline and adrenaline in hypertension/heart failure on the aortae of 20-month-old SHRs.
Acetylcholine induces cytosolic Ca2+ mobilization in isolated distal colonic crypts from normal and cystic fibrosis mice
Authors: Klaren P H M , Hardcastle J , Evans S , Colledge W H , Evans M J , Taylor C J , Hardcastle P T , White S J
Published: July 2003

In intestinal biopsies from cystic fibrosis (CF) patients acetylcholine fails to elicit a chloride secretion response, and this observation can be explained by a defect in the Ca2+ signalling pathway in CF secretory cells. We tested the hypothesis that in CF intestine, the generation of an intracellular Ca2+ signal upon cholinergic stimulation is absent. A transgenic CF mouse model was used. Electrical measurements on intact jejunum and unstripped colon were performed in Ussing chambers. Intact distal colonic crypts were isolated, and the intracellular Ca2+ concentration was monitored using the Ca2+-sensitive dye fura-2. Acetylcholine increased the short-circuit current generated by wild-type jejunum and colon, but failed to induce a response in CF tissues. Acetylcholine caused a transient elevation in the intracellular Ca2+ concentration in colonic crypts from both wild-type and CF mice; the amplitude and timing of the response in CF crypts was indistinguishable from that in wild-type crypts. The response to acetylcholine was also observed in the absence of extracellular calcium, indicating intracellular stores as the source from which the cytosolic Ca2+ concentration increased. We conclude that the absence of a cholinergically-induced secretory response in CF intestine is not due to a defect in the generation of a Ca2+ signal in intestinal cells upon cholinergic stimulation.
Cellular characterization of an in-vitro cell culture model of seal-induced cardiac ischaemia
Authors: Takahashi Kyoko , Ohyabu Yuko , Schaffer Stephen W , Azuma Junichi
Published: July 2003

The lack of a well-characterized in-vitro cell culture model of load-induced cardiac ischaemia has hampered investigations into the mechanism of ischemic injury. We therefore developed a new in-vitro model of cardiac ischaemia that mimics distinct features of ischaemic injury.

Neonatal rat heart cells were cultured in a sealed flask for 24–72 h. In this environment, the cells were exposed to stresses of hypoxia, acidosis and stagnant incubation medium. The pO2 and pH of the medium gradually decreased during the ischaemic insult and ultimately fell to a level of 14 mmHg and pH 6.8, respectively. The model triggered severe cell injury, including morphological degeneration, CPK release, beating impairment and ATP depletion. Apoptosis occurred in some cardiomyocytes as early as 24 h after onset of seal-induced ischaemia. This was evidenced by positive nuclear staining using Hoechst 33258 and by the induction of caspase-3 mRNA. By 72 h, internucleosomal DNA fragmentation was observed in 45% of the myocytes; however, a non-myocyte preparation subjected to the same ischaemic insult exhibited no evidence of DNA fragmentation.

These results demonstrate that neonatal cardiomyocytes subjected to the new simulated ischaemia model exhibit several similarities to cardiac ischaemia, including the simultaneous appearance of necrosis, breakdown of cellular ATP, beating cessation and apoptosis. The new model should prove useful in unravelling the molecular alterations underlying ischaemic injury and myocardial apoptosis.
Prevention of neuronal cell damage induced by oxidative stress in-vitro: effect of different Ginkgo biloba extracts
Authors: Guidetti Cristina , Paracchini Silvano , Lucchini Serena , Cambieri Maurizio , Marzatico Fulvio
Published: July 2003

The effect of two different Ginkgo biloba extracts (GB1 and GB4) was studied in-vitro on cultured neurons exposed to oxidative stress caused by H2O2 (50 μmol L−1) and FeSO4 (100 μmol L−1). Only about 50% of the neurons were still viable at the end of the experiment (8 h) in control conditions, while the two extracts dose dependently increased the number of viable cells, in the concentration range 10–200 μg mL−1. The two Ginkgo biloba extracts differed in their effect on hydroxyl-radical-scavenging capacity: GB1 and GB4 had an IC50 (50% inhibiting concentration) value of 78 μg mL−1 and 186 μg mL−1, respectively. However, both extracts inhibited apoptosis in cortical neurons after oxidative stress in-vitro. These observations make one suppose that different preparations of Ginkgo biloba have quantitatively different actions and outline the importance of the contribution of apoptosis prevention toward their neuroprotective action.
The effects of freeze-drying on the stability of liposomes to jet nebulization
Authors: Bridges Paul A , Taylor Kevin M G
Published: July 2003

Egg phosphatidylcholine liposomes were freeze-dried in the presence and absence of trehalose. The lyophilized liposomes were rehydrated and aerosolized using a Pari LC jet nebulizer. The size of the aerosols generated was determined by laser diffraction, which was also used to determine the size distribution of the liposomes before lyophilization, post-rehydration, in the nebulizer post-aerosolization and those deposited in the two stages of a twin impinger. In the absence of trehalose, large liposomes and vesicle aggregates were produced on rehydration, which were rapidly reduced in size on nebulization. Liposomes with a mean size of 1 or 2.5 μm, freeze-dried with trehalose, had a mean size less than 3 μm following rehydration and exhibited enhanced stability to nebulization. Liposomes of 1 μm before freeze-drying were evenly distributed within aerosols generated by the nebulizer, whilst aerosols generated from 2.5 μm liposomes were fractionated in the twin impinger with the largest liposomes collected in the upper stage.
The urinary excretion of γ-hydroxybutyric acid in man
Authors: Kavanagh P V , Kenny P , Feely J
Published: July 2003

γ-Hydroxybutyric acid (GHB) has been widely associated with drug-facilitated sexual assault (DFSA). However, its excretion profile in man has not been well characterized. To assess the detectability of GHB for forensic cases and to correlate urinary levels with dose, we have examined the excretion profiles of 1- and 2-g doses of GHB (sodium salt) in a healthy male volunteer. The urinary levels were measured by a novel, simple and highly reproducible method. The drug was found to be excreted in small amounts in the free form (0.86 and 1.16% for 1- and 2-g doses, respectively) rapidly in urine (≤ 10 h). The urinary levels were found to be in the low mg L−1 range (up to 29.1 mg L−1). The work presented demonstrates that it is of the utmost importance to collect the samples as soon as possible following the alleged assault.
Formation of a defluorinated metabolite of a quinoxaline antiviral drug catalysed by human cytochrome P450 1A2
Authors: Mutch Peter J , Dear Gordon J , Ismail Issy M
Published: July 2003

The in-vitro metabolism of GW420867X ((S)-2-ethyl-7-fluoro-3-oxo-3, 4-dihydro-2H-quinoxaline-1-carboxylic acid isopropyl ester), a quinoxaline drug for the potential treatment of HIV, has been studied with singly expressed human cytochromes P450 (CYP 450). No biotransformation of [14C]GW420867X was evident in the presence of any of the CYP 450 isoforms, with the exception of CYP 450 1A2, where a single metabolite was observed in the HPLC radiochromatograms of enzyme incubations with the test compound. The structure of this metabolite was determined by nuclear magnetic resonance spectroscopy and mass spectrometry, and was shown to correspond to the replacement of the aromatic fluorine of GW420867X with a hydroxyl group. Thus, it appeared that CYP 450 1A2 catalysed the specific defluorination of GW420867X, presumably during formation of an arene oxide intermediate during aromatic hydroxylation.
Effect of indinavir on the pharmacokinetics of rifampicin in HIV-infected patients
Authors: Jaruratanasirikul Sutep , Sriwiriyajan Somchai
Published: July 2003

Indinavir, an antiretroviral agent, has an influence on the pharmacokinetics of other drugs by acting as an inhibitor of cytochrome P450-mediated drug metabolism. The incidence of tuberculosis has increased dramatically in the past decade because of an epidemic of HIV infection. Rifampicin is still one of the most valuable drugs for the standard treatment of tuberculosis. The objective of this study was to investigate the effects of indinavir on the pharmacokinetics of rifampicin in man. Our study was conducted in eleven HIV-infected patients. All patients received a 600-mg single dose of oral rifampicin on day 1 and 15- and 800-mg oral indinavir three times a day from day 2 to day 15. Rifampicin pharmacokinetic studies were carried out on day 1 and day 15. The results showed that rifampicin concentrations were higher when it was administered with indinavir than when it was administered alone. With concomitant indinavir medication, the mean AUC0–24 of rifampicin was increased by 73%. Therefore, we conclude that indinavir has an inhibitory effect on the metabolism of rifampicin.
A rapid and sensitive method for the determination of the amount of theophylline in blood spots
Authors: Watson D G , Oliveira E J , Boyter A C , Dagg K D
Published: July 2003

Monitoring of drugs (such as theophylline) with a narrow therapeutic window could be simplified if patients were able to submit blood spots for analysis. This could reduce clinic attendance for venous blood sampling and save staff time. A rapid sensitive method utilizing liquid chromatography-mass spectrometry has been developed to determine the amount of theophylline in blood spots. The lowest level of theophylline analysed in a blood spot was 15 ng extracted into 250 μL and this was still considerably above the limit of quantification (3 ng in 250 μL). The levels of theophylline in blood spots correlated well with theophylline levels in plasma samples obtained from the same patients. The assay might be of use in therapeutic drug monitoring of theophylline and blood spot sampling could be applied to other drugs where therapeutic monitoring is required.
Synthesis of N-Pyridinyl(methyl)-1,2-dihydro-4-hydroxy-2-oxoquinoline-3-carboxamides and analogues and their anti-inflammatory activity in mice and rats
Authors: Collin X , Robert J M , Duflos M , Wielgosz G , Baut G Le , Robin-Dubigeon C , Grimaud N , Lang F , Petit J Y
Published: July 2003

The topical anti-inflammatory activity of a series of N-pyridinyl(methyl)1,2-dihydro-4-hydroxy-2-oxoquinoline-3-carboxamides, analogues of roquinimex, has been evaluated by measuring their inhibitory effect in the phorbol myristate acetate (PMA)-induced mouse ear swelling test, used as a screening test.

All the eight carboxamides tested (9–16) exhibited significant inhibitory activity at 0.4 and 0.2 mm kg−1. The most potent compound, the 6-bromo derivative 12, induced a 73% inhibition at 0.2 mm kg−1. Pharmacomodulation was carried out by heterocycle opening and molecular simplification leading to pentafluorobenzoylacetamide 17, pentafluorocinnamamides 18 and 19, and pentafluorobenzaldimines 20 and 21. All the five compounds exerted a reduction in swelling (49–63% at 0.2 mm kg−1) comparable with ibuprofen (56%). Anti-inflammatory activity of the most efficient compounds was evaluated by carrageenan-induced rat paw oedema inhibition. The pentafluorobenzaldimine 20 showed the highest activity with an inhibition percentage of 85% at 0.2 mm kg−1.
Overcoming antimicrobial resistance by targeting resistance mechanisms
Authors: Poole Keith
Published: July 2003

Three mechanisms of antimicrobial resistance predominate in bacteria: antibiotic inactivation, target site modification, and altered uptake by way of restricted entry and/or enhanced efflux. Many of these involve enzymes or transport proteins whose activity can be targeted directly in an attempt to compromise resistance and, thus, potentiate antimicrobial activity. Alternatively, novel agents unaffected by these resistance mechanisms can be developed. Given the ongoing challenge posed by antimicrobial resistance in bacteria, targeting resistance in this way may be our best hope at prolonging the antibiotic era.
A novel and simple type of liposome carrier for recombinant interleukin-2
Authors: Kanaoka Eri , Takahashi Kouji , Yoshikawa Takayoshi , Jizomoto Hiroaki , Nishihara Yoshitaka , Hirano Koichiro
Published: July 2003

The strong interaction between recombinant interleukin-2 (IL-2) and liposome was characterized and its possible application to drug-delivery control considered. The liposomes were prepared with egg phosphatidylcholine, distearoyl-phosphatidylglycerol (DSPG), dipalmitoyl-phosphatidylcholine, dipalmitoyl-phosphatidylglycerol or distearoyl-phosphatidylcholine (DSPC). Small and hydrophobic liposomes were selected, which were composed of saturated and long-fatty-acid-chain phospholipids. When the composition and the mixture ratio of IL-2 and the liposome were optimized, more than 95% of the lyophilized IL-2 (Imunace, 350000, JRU) was adsorbed consistently onto the DSPC-DSPG liposome (molar ratio, 10:1; 25 μmol mL−1; 30 nm in size). Merely mixing IL-2 lyophilized with liposome suspension is convenient pharmaceutically. After intravenous administration to mice, liposomal IL-2 was eliminated half as slowly from the systemic circulation as free IL-2, with more than 13 and 18 times more IL-2 being delivered to the liver and spleen, respectively. After subcutaneous administration of liposomal IL-2 to mice, the mean residence time of IL-2 in the systemic circulation was 8 times that of free IL-2. These results show that IL-2 consistently adsorbs onto the surface of liposomes after optimization of its composition and mixing ratio. Intravenous and subcutaneous administration to mice demonstrates the gradual release of IL-2. Further trials are warranted using these liposomes.
Characterization of glass solutions of poorly water-soluble drugs produced by melt extrusion with hydrophilic amorphous polymers
Authors: Forster Angus , Hempenstall John , Rades Thomas
Published: July 2003

Indomethacin, lacidipine, nifedipine and tolbutamide are poorly soluble in water and may show dissolution-related low oral bioavailability. This study describes the formulation and characterization of these drugs as glass solutions with the amorphous polymers polyvinylpyrrolidone (PVP) and polyvinylpyrrolidone-co-vinyl acetate by melt extrusion. The extrudates were compared with physical mixtures of drug and polymer. X-ray powder diffraction, thermal analysis, infrared spectroscopy, scanning electron microscopy, HPLC, moisture analysis and dissolution were used to examine the physicochemical properties and chemical stability of the glass solutions prepared by melt extrusion at a 1:1 drug/polymer ratio. Depending on the temperature used, melt extrusion produced amorphous glass solutions, with markedly improved dissolution rates compared with crystalline drug. A significant physicochemical interaction between drug and polymer was found for all extrudates. This interaction was caused by hydrogen bonding (H-bonding) between the carbonyl group of the pyrrole ring of the polymer and a H-donor group of the drug. Indomethacin also showed evidence of H-bonding when physical mixtures of amorphous drug and PVP were prepared. After storage of the extrudates for 4–8 weeks at 25°C/75% relative humidity (RH) only indomethacin/polymer (1:1) extrudate remained totally amorphous. All extrudates remained amorphous when stored at 25°C/< 10% RH. Differences in the physical stability of drug/polymer extrudates may be due to differences in H-bonding between the components.
Distribution of the methylpiperazinopyridobenzoxazepine derivative JL13, a potential antipsychotic, in rat brain
Authors: Guiso Giovanna , Caccia Silvio
Published: July 2003

The brain uptake and distribution of the potential antipsychotic 5-(4-methylpiperazin-1-yl)-8-chloro-pyrido[2,3][1,5]benzoxazepine fumarate (JL13) was examined in rats after neuropharmacologically active doses. Plasma and brain concentrations of the compound were measured by reversed-phase HPLC with UV detection (210 nm). Clozapine was used as an internal standard. After an intraperitoneal dose of 10 mg kg−1, the compound attained mean maximum plasma concentrations within 5 min of dosing, then declined with a mean elimination half-life of approximately 1 h. It rapidly crossed the blood-brain barrier and equilibrated with plasma, achieving mean maximum concentrations and area under the curve approximately 20-times those in plasma, with slight regional differences. Disappearance from whole brain almost paralleled its disappearance from plasma. There was a linear relationship between JL13 concentrations in plasma and brain regions, and in all tissues the concentrations of the compound increased almost linearly with the dose over the range of 5–20 mg kg−1. It thus appears that JL13 brain pharmacokinetics parallels that in plasma, and that plasma concentrations accurately predict brain concentrations in rats.
Control of impurities in diphenhydramine hydrochloride by an ion-pairing, reverse-phase liquid chromatographic method
Authors: Henderson L , Miller J H McB , Skellern G G
Published: July 2003

A precise, sensitive, repeatable and robust reverse-phase liquid chromatographic method has been developed for the control of seven possible impurities of diphenhydramine hydrochloride. The robustness of the method was examined by varying, in turn, each of four mobile-phase parameters (acetonitrile content, buffer salt concentration, ion-pair reagent concentration and pH). The method was linear in the range 0–0.14 mg mL−1 for diphenhydramine hydrochloride with an acceptable precision and accuracy, and a limit of detection of 0.17 μg mL−1. Five samples of diphenhydramine hydrochloride from two sources were analysed with the developed liquid chromatographic method.
A study of the anti-invasive properties of N-α-phthalimidomethyl-ketomethylene tripeptide-based metalloprotease inhibitors
Authors: Martin S Lorraine , McDowell Andrew , Lynas John F , Nelson John , Walker Brian
Published: July 2003

We have developed matrix metalloprotease (MMP) inhibitors based on synthetic peptides incorporating a non-cleavable peptide-bond isostere at the site of the putative scissile bond. These inhibitors, N-α-phthaloyl-Gly-Ψ(CO-CH2)-Leu-Tyr-Ala-NH2 (Pht-G-CH2-LYA-NH2) and N-α-phthaloyl-Gly-Ψ(CO-CH2)-Leu-Tic-Ala-NH2 (Pht-G-CH2-LTcA-NH2) were kinetically evaluated against the type IV collagenases, gelatinase A (MMP-2) and B (MMP-9), and compared with an exactly analogous chelating-based inhibitor, N-α-mercaptoacetyl-Leu-Tyr-Ala-NH2 (HSCH2CO-LYA-NH2). The peptide inhibitors were also tested for their anti-invasive effects on breast carcinoma cell lines using a modification of the Boyden chamber assay. Gelatin zymography was utilized to identify gelatinolytic activities present in media removed from cultured breast cancer cells. Of the two N-α-phthalimidomethyl-ketomethylene peptide-based inhibitors, Pht-G-CH2-LYA-NH2 proved the more effective inhibitor of MMP-2 and MMP-9 (Ki 34.27 and 45.75 μm, respectively). However, when tested against two breast cancer cell lines, T47D and MDA-MB-231, both inhibitors were able to effectively reduce tumour cell invasion through a type IV collagen matrix by up to 91.2%. Of particular interest was the observation that Pht-G-CH2-LYA-NH2 was the most potent inhibitor of invasion by the highly aggressive MDA-MB-231 cells, despite the cells' relative lack of active secreted metalloprotease activity. The results obtained from this kinetic and anti-invasive analysis of the new inhibitors suggest that compounds incorporating the N-α-phthalimidomethyl-ketomethylene peptide-bond isostere may have potential for development as new agents with anti-metastatic properties.
Synthesis and hydrolytic behaviour of glycerol-1,2-diibuprofenate-3-nitrate, a putative pro-drug of ibuprofen and glycerol-1-nitrate
Authors: Ingram Matthew J , Moynihan Humphrey A , Powell Mark W , Rostron Chris
Published: July 2003

Nitroxylated derivatives of non-steroidal anti-inflammatory drugs appear to offer protection against the gastrotoxicity normally associated with non-steroidal anti-inflammatory drugs, ostensibly via local production of nitric oxide. A diester of ibuprofen and glycerol-1-mononitrate has been prepared via the condensation of ibuprofen with 3-bromopropan-1,2-diol, followed by silver-(I)-nitrate-mediated nitroxylation. The release of ibuprofen from this diester has been studied in a simulated gastric fluid model with direct analysis by reverse-phase HPLC, using an acetonitrile-water (80%:20%) mobile phase containing trifluoroacetic acid (0.005%). n-Propyl ibuprofen was found to undergo pH-dependent hydrolysis, ranging from negligible hydrolysis at pH 5 to 52% hydrolysis at pH 3, over a 2-h period in this model. The ibuprofen-glycerol mononitrate diester was subjected to the most vigorous model hydrolytic conditions and was found to undergo 50% hydrolysis during the study period. This study shows that pro-drugs of ibuprofen and glycerol mononitrate can be obtained, and can undergo degradation to the parent drugs under conditions simulating those likely to be encountered in the stomach.
Clonidine-induced antinociception and locomotor hypoactivity are reduced by dexamethasone in mice
Authors: Capasso Anna , Loizzo Alberto
Published: July 2003

The effects of dexamethasone pretreatment on clonidine-induced antinociception and locomotor hypoactivity were investigated in mice. In the hot-plate and the tail-flick tests, dexamethasone administered intraperitoneally at a dose of 1 mg kg−1, 30, or 60 min before clonidine, reduced clonidine antinociception in both tests and reduced clonidine-induced locomotor hypoactivity in the activity cage. When administered 15 min before clonidine, dexamethasone had no effect on clonidine antinociception. A higher dexamethasone dose (10 mg kg−1) induced the same effects observed at a dose of 1 mg kg−1 in the hot-plate and the tail-flick tests, but the former dose had a stronger effect on locomotor hypoactivity. Dexamethasone (10 ng/mouse) administered intracerebroventricularly 30 min before clonidine was also able to reduce both clonidine-induced antinociception and locomotor hypoactivity. The protein synthesis inhibitor, cycloheximide, administered intraperitoneally at the dose of 10 mg kg−1, 2, h before clonidine, was able to prevent dexamethasone effects on clonidine-induced antinociception. The glucocorticoid receptor antagonist RU-38486, administered intracerebroventricularly at the dose of 1 ng/mouse, was also able to block dexamethasone effects on clonidine-induced antinociception and locomotor hypoactivity, whereas both cycloheximide and RU-38486 per se did not influence pain sensitivity or locomotor activity. These results suggest that the dexamethasone effects on clonidine-induced antinociception and locomotor hypoactivity depend on the stimulating effects that dexamethasone exert, on the protein synthesis via the glucocorticoid receptor in the brain.
The development and in-vitro evaluation of novel mixed metal hydroxy-carbonate compounds as phosphate binders
Authors: Rankin B J , Zhu H , Webb M , Roberts N B
Published: July 2003

The currently available phosphate binders are relatively inefficient and suffer from clinical side-effects of increased absorption of calcium and aluminium and the diarrhoea-inducing effects of magnesium. A new class of compounds based on mixed metal hydroxides has been developed and evaluated for their potential as phosphate binders. The mixed metal hydroxides were prepared using a standard procedure for hydrotalcite (Al2Mg6(OH)16. CO3. 4H2O) by substituting Fe3+ for Al3+ with Mg3+ or Ca2+ as the divalent metal ion. Phosphate precipitation (binding) was examined at different pH values in aqueous solution and in various food mixtures in comparison with hydrotalcite, Al(OH)3, CaCO3 and Mg(OH)2 on the same weight-to-weight basis. A series of compounds with differing ratios of metal ions (Fe:Mg/Ca 1:2 or 1:3) gave analytically similar ratios to those predicted from the initial amounts added. CTFeCa bound > 90% phosphate in aqueous solution compared with 65% binding with CTFeMg, 85% binding with Mg(OH)2, and less than 30% binding for CaCO3 and Al(OH)3. The mixed metal compounds also bound up to 80 % phosphate in various food matrices, which was relatively independent of changes in pH, compared with Mg(OH)2, where binding decreased from 85% at pH 3.0 to 25% at pH 8.0. Al(OH)3 and CaCO3 were relatively ineffective phosphate binders under all the conditions tested. The mixed metal hydroxides compounds show considerable promise as phosphate binders over those currently available and warrant further patient-based in-vivo testing.
1,8-Cineole protects against liver failure in an in-vivo murine model of endotoxemic shock
Authors: Santos Flávia A , Silva Regilane M , Tomé Adriana R , Rao Vietla S N , Pompeu Margarida M L , Teixeira Maria J , De Freitas Luiz A R , De Souza Valderes L
Published: July 2003

The effects of 1,8-cineole on d-galactosamine/lipopolysaccharide (GalN/LPS)-induced shock model of liver injury was investigated in mice. The co-administration of GalN (700 mg kg−1, i.p.) and LPS (5 μg kg−1, i.p.) greatly elevated serum concentrations of tumour necrosis factor-α (TNF-α), alanine aminotransferase and aspartate aminotransferase, and induced massive hepatic necrosis and lethality in 100% of control mice. Pretreatment with 1,8-cineole (400 mg kg−1, p.o.) and dexamethasone (1 mg kg−1, s.c.),60 min before GalN/LPS, offered complete protection (100%) against the lethal shock and acute elevation in serum TNF-α and serum transaminases. Hepatic necrosis induced by GalN/LPS was also greatly reduced by both 1,8-cineole and dexamethasone treatment. The results indicate that 1,8-cineole protects mice against GalN/LPS-induced liver injury through the inhibition of TNF-α production, and suggest that 1,8-cineole may be a promising agent to combat septic-shock-associated pathologies.
The evaluation of novel mixed metal hydroxy-carbonates as phosphate binders: an in-vivo study in the rat
Authors: Rankin B J , Thewles A , Lote C J , Webb M , Roberts N B
Published: July 2003

A number of novel phosphate binders based on mixed metal hydroxide structures incorporating Fe and Ca, or Fe and Mg (classified as CT, Crosfield test compounds), were compared with the established phosphate binders Mg(OH)2, Al(OH)3, CaCO3 and a commercial hydrotalcite (Al- and Mg-based) using a rat model. The changes in urine and soluble faecal phosphate were used to evaluate efficacy of phosphate binding. The binders were mixed into a standard rat maintenance food at a concentration of 1% (w/w). Four rats were used for each binder study group and fed over 7 days. Urine and faeces were collected (in a metabolic cage) over the last 24-h study period and the phosphate content measured. The urinary phosphate was significantly reduced (P < 0.001) with CTFeCa (72 ± 44 μm), CTFeMg (13 ± 4 μm), CT100 (26 ± 11 μm), and Mg(OH)2 (65 ± 53 μm), compared with control (766 ± 188 μm), Al(OH)3 (1256 ± 279 μm), and CaCO3 (857 ± 25 μm). The soluble phosphate content of the faeces was significantly reduced (P < 0.05) by up to 60% with CTFeCa, CTFeMg and Mg(OH)2, and up to 40% with CT100 and Al(OH)3, compared with 30% in controls and 10% with CaCO3. The new mixed metal hydroxy-carbonate compounds based on FeCa or FeMg are effective phosphate binders in-vivo and warrant further testing in patients.
Antinociceptive effect of U-50488H, a κ-opioid agonist, in streptozotocin-induced diabetic mice
Authors: Suzuki Yasuyuki , Goto Kazuhiro , Shiizaki Kazuhiro , Omiya Yuji , Ishige Atsushi , Komatsu Yasuhiro , Kamei Junzo
Published: July 2003

We compared the antinociceptive activity of a κ-opioid agonist, U-50488H, in streptozotocin-induced diabetic mice with that in non-diabetic mice. Subcutaneously administered U-50488H (3 and 10 mg kg−1) showed a more potent antinociceptive effect, as evaluated by the tail-pressure method, in diabetic mice than in non-diabetic mice. Increased antinociceptive activity of U-50488H observed in diabetic mice was also observed in mice given U-50488H intrathecally (3 and 10 μg). However, there were no differences observed between diabetic and non-diabetic mice given U-50488H intracerebroventricularly (3 and 10 μg). Although the antinociceptive effect of U-50488H (3 mg kg−1, s.c.) in non-diabetic mice was increased by treatment with PD135158 (100 ng, i.c.v.), a cholecystokininB (CCKB) antagonist, the antinociceptive activity of U-50488H which was enhanced in diabetic mice was not influenced by PD135158. Moreover, the increased antinociceptive activity of U-50488H (3 mg kg−1, s.c.) in diabetic mice diminished when desulfated octapeptide of cholecystokinin (3–100 ng, i.c.v.), a CCKB agonist, was administered. These results suggested that diabetic mice were selectively hyper-responsive to spinal κ-opioid receptor-mediated antinociception. The function of the analgesia inhibitory system in which cholecystokinin is used as a transmitter might be diminished in diabetic mice.
Effect of γ-butyrobetaine on fatty liver in juvenile visceral steatosis mice
Authors: Higashi Yasuhiko , Yokogawa Koichi , Takeuchi Noriko , Tamai Ikumi , Nomura Masaaki , Hashimoto Noriyoshi , Hayakawa Jun-Ichiro , Miyamoto Ken-Ichi , Tsuji Akira
Published: July 2003

We pharmacokinetically examined the effect of γ-butyrobetaine, a precursor of l-carnitine, on the change of fatty acid metabolism in juvenile visceral steatosis (JVS) mice, which have systemic l-carnitine deficiency due to lack of l-carnitine transporter activity. The concentrations of total free fatty acid (FFA), palmitic acid and stearic acid in the liver of JVS mice were significantly higher than those in wild-type mice. After intravenous administration of γ-butyrobetaine (50 mg kg−1), the concentration of l-carnitine in the plasma of JVS mice reached about twice that of the control level and levels in the brain, liver and kidney were also significantly increased, whereas those in wild-type mice hardly changed. Although the plasma concentrations of FFA in both types of mice were unchanged after administration of γ-butyrobetaine, the concentrations of palmitic acid and stearic acid were significantly decreased. In particular, the liver concentration of FFA in JVS mice was decreased to the wild-type control level, accompanied by significant decreases in long-chain fatty acids, palmitic acid and stearic acid, whereas those in wild-type mice were not changed. These results suggest that γ-butyrobetaine can be taken up into organs, including the liver, of JVS mice, and transformed to l-carnitine. Consequently, administration of γ-butyrobetaine may be more useful than that of l-carnitine itself for treatment of primary deficiency of carnitine due to a functional defect of the carnitine transporter.
The lipid-lowering effect of trans-dehydrocrotonin, a clerodane diterpene from Croton cajucara Benth. in mice fed on high-fat diet
Authors: Silva Regilane M , Santos Flávia A , Rao Vietla S N , Maciel Maria A M , Pinto Angelo C
Published: July 2003

The clerodane diterpene trans-dehydrocrotonin extracted and isolated from the stem bark of Croton cajucara Benth. was investigated for its lipid-lowering effect in mice fed on a high-fat diet. Mice fed on a high-fat diet for a two-week period demonstrated significantly increased blood levels of total cholesterol and triglycerides, compared with normal controls. Oral treatment with trans-dehydrocrotonin at a dose of 25 or 50 mg kg−1 daily markedly suppressed the high-fat-diet associated rise in total cholesterol and triglyceride levels. The hypocholesterolaemic effect of trans-dehydrocrotonin was more prominent at the dose of 50 mg kg−1 with significant decreases in high-density lipoprotein, very-low-density lipoprotein and low-density lipoprotein cholesterol levels. The lower atherogenic index of the trans-dehydrocrotonin-treated groups suggests the hypolipidaemic potential of this plant-based drug. These results indicate that orally administered trans-dehydrocrotonin is effective in suppressing high-fat-diet-induced hyperlipidaemia in mice and suggest its likely beneficial use as anti-atherogenic agent.
Interactions among proteins and hydrophobically modified polyelectrolytes
Authors: Bromberg L E
Published: July 2003

A special class of hydrophobically modified polyelectrolytes was studied wherein poly(acrylic acid) (PAA) was conjugated with Pluronic F127 NF surfactant. The Pluronic-PAA copolymer solutions form gels at low concentrations when exposed to body temperature. Such gels possess enhanced retention in topical applications. Circular dichroism spectra indicate that tertiary structures of human insulin, haemoglobin, and albumin were stabilized in solutions of Pluronic-PAA. Aggregation of insulin in gelled solutions of Pluronic-PAA was impeded as demonstrated in shaking tests. The presence of Pluronic-PAA hindered the insulin degradation by α-chymotrypsin by at least 7-fold. Extraction of calcium ions from trypsin by Pluronic-PAA led to the dramatic changes in the tertiary structure and total loss of enzymatic activity, suggesting that Pluronic-PAA could inhibit tryptic degradation of proteins.
Turbidimetric and HPLC assays for the determination of formulated lysozyme activity
Authors: Liao Yong-Hong , Brown Marc B , Martin Gary P
Published: July 2003

In several studies lysozyme has been employed as a model protein to investigate the effects of formulation factors upon biological activity. The aim of this work was to develop and validate an HPLC technique to assay lysozyme and to compare the results with biological activity determined from a validated turbidimetric assay. The turbidimetric assay was based upon the lytic action of lysozyme on Micrococcus lysodeikticus cells, whilst the reverse-phase HPLC assay employed an acetonitrile gradient in 0.1% trifluoroacetic acid. The limits of detection and quantification were 3.84 and 6.24 μg mL−1 for HPLC assay, whilst the corresponding values for turbidimetric assay were 1.94 and 3.86 μg mL−1. The methods were used to monitor the loss of enzyme activity after heating. Lysozyme concentrations determined from HPLC peak height were found to correlate (r2 = 0.9963) with those obtained from turbidimetric assay.
Pro-inflammatory activity of contaminating DNA in hyaluronic acid preparations
Authors: Filion Mario C , Phillips Nigel C
Published: July 2003

Hyaluronic acid (HA), an abundant non-sulfated glycosaminoglycan component of the extracellular matrix, has applications in drug delivery, tissue engineering and as an ingredient in cosmetics. HA preparations containing high-molecular-weight polymers are also used in the treatment of inflammatory disorders such as arthritis and interstitial cystitis. Low-molecular-weight fragments derived from HA have been reported to induce pro-inflammatory cytokines such as IL-12 and TNF-α, and could therefore potentially exacerbate existing inflammation. We therefore examined the pro-inflammatory activity of HA preparations, since inflammatory reactions are known to occur following administration of HA. We tested low-molecular-weight fragments obtained from seven different HA preparations, either by sonication (≅ 3 times 105 Da) or by hyaluronidase digestion (≅ 1 times 104 Da), for the ability to induce the synthesis of IL-12 and TNF-α by human monocytic cells. We found that two of the seven HA preparations tested stimulated the synthesis of IL-12 and TNF-α by human monocytic cells. We unexpectedly found that the induction of IL-12 and TNF-α by these HA preparations was not due to their degradation to low-molecular-weight fragments, since their native high-molecular-weight forms possessed the same ability to stimulate IL-12 and TNF-α synthesis, but was due to the presence of contaminating DNA. Treatment of these two HA preparations with deoxyribonuclease I abrogated or reduced the induction of IL-12 and TNF-α. It is clear from this study that HA preparations can induce the synthesis of pro-inflammatory cytokines by monocytes. The ability of HA to act as a pro-inflammatory mediator may not, however, be related to the presence of low-molecular-weight HA fragments, but to the presence of DNA. The presence of pro-inflammatory DNA in HA preparations should be evaluated before its use, not only for the treatment of patients with inflammatory disorders, but also before many other applications.
Cryptofolione derivatives from Cryptocarya alba fruits
Authors: Schmeda-Hirschmann Guillermo , Astudillo Luis , Bastida Jaume , Codina Carles , De Arias Antonieta Rojas , Ferreira María Elena , Inchaustti Alba , Yaluff Gloria
Published: July 2003

Cryptofolione (1) and the new cryptofolione derivative 6-(4,6-dimethoxy-8-phenyl-octa-1,7-dienyl)-4-hydroxy-tetrahydro-pyran-2-one (2) were isolated from the fruits of Cryptocarya alba. The structures were elucidated by spectroscopic methods. Cryptofolione showed activity towards Trypanosoma cruzi trypomastigotes, reducing their number by 77% at 250 μg mL−1. Cryptofolione showed moderate cytotoxicity in both macrophages and T. cruzi amastigotes. It also displayed a mild inhibitory effect on the promastigote form of Leishmania spp. As both cytotoxic and trypanocidal effects are similar, the compound presented little selectivity in our assay models.
Tea consumption modulates hepatic drug metabolizing enzymes in Wistar rats
Authors: Maliakal Pius P , Coville Peter F , Wanwimolruk Sompon
Published: July 2003

The antioxidant, antimutagenic and anticarcinogenic activities of green tea and its polyphenols have been reported. As bioactivation of the precarcinogens and detoxification of ultimate carcinogens are mainly carried out by hepatic metabolizing enzymes, we have investigated the modulation of these enzyme activities subsequent to tea consumption in rats. Female Wistar rats were divided into eight groups (n = 5). Six groups were given aqueous solutions (2%, w/v) of six different teas (New Zealand green tea, Australian green tea, Java green tea, Dragon green tea, Gunpowder green tea or English Breakfast black tea) as the sole source of fluid. One group was given a standard green tea extract (0.5%, w/v) while the control group had free access to water. At the end of four-weeks treatment, different cytochrome P450 (CYP) isoform and phase II enzyme activities were determined by incubation of the liver microsomes or cytosols with appropriate substrates. CYP 1A2 activity was markedly increased in all the tea treatment groups (P < 0.05). CYP 1A1 activity was increased significantly in most of the groups except for the Madura, Gunpowder, and Java green tea-treatment groups. Cytosolic glutathione-S-transferase activity was significantly increased (P < 0.05) in the New Zealand, Gunpowder, and Java green tea-treatment groups. The microsomal UDP-glucuronosyl transferase activity remained unchanged or was moderately increased in most of the groups. The balance between the phase I carcinogen-activating enzymes and the phase II detoxifying enzymes could be important in determining the risk of developing chemically-induced cancer.
Buchu (Agathosma betulina and A. crenulata, Rutaceae) essential oils: their pharmacological action on guinea-pig ileum and antimicrobial activity on microorganisms
Authors: Lis-Balchin M , Hart S , Simpson E
Published: July 2003

The mode of action of essential oils from two buchu species (Agathosma betulina and A. crenulata, Rutaceae) from the Cape region of South Africa has been studied on smooth muscle in-vitro using guinea-pig ileum. At high concentration, the oils had an initial spasmogenic activity followed by spasmolysis. The spasmolytic action was post-synaptic, not atropine-like and did not involve adrenoceptor or guanylyl cyclase activation. In the presence of the phosphodiesterase inhibitor rolipram, the spasmolytic action of A. betulina was significantly increased whilst that due to A. crenulata was also increased but not to a significant level. These results suggested a mode of action for the oils involving cyclic adenosine monophosphate. In addition, A. betulina appeared to block calcium channels but this was not seen with A. crenulata, possibly because the initial spasmogenic activity complicated the study of its spasmolytic action. Neither essential oil (10 μL, undiluted) demonstrated antimicrobial action against Enterococcus hirae and Pseudomonas aeruginosa but very low activity was observed against Escherichia coli, Saccharomyces cerevisiae and Staphylococcus aureus, suggesting little potential for these oils as antimicrobial agents/preservatives.
Ethnopharmacology in drug discovery: an analysis of its role and potential contribution
Authors: Heinrich Michael , Gibbons Simon
Published: July 2003

In this paper we discuss some examples of ethnopharmacological research as it has been conducted during the last two centuries and look at the current role of this discipline in drug discovery (especially with respect to the American and European markets) and the further development of these phytotherapeutical resources for local use in the countries of origin (ethnopharmacology). Examples from 19th century research on curare (Humboldt and Bernard), from the 20th century on hallucinogenic mushrooms (Wasson), on Mexican Indian indigenous plants (our own research) and of current industry based research are used to illustrate the development of this discipline and to highlight the challenges for the future.