bluuebunny/crossref_metadata_2025 huggingface dataset:
Cardioprotective actions of two bioflavonoids, quercetin and rutin, in experimental myocardial infarction in both normal and streptozotocin-induced type I diabetic rats
Authors: Annapurna Akula , Reddy Challa S , Akondi Raju B , Rao Sangana R C
Published: October 2010

Objectives

Revascularization therapy is the mainstay of treatment in the management of myocardial infarction in normal and diabetic patients. We attempted to evaluate the cardioprotective actions of quercetin and rutin in ischaemia-reperfusion-induced myocardial infarction in both normal and diabetic rats.

Methods

Myocardial infarct size was measured using the staining agent 2,3,5-triphenyltetrazoliumchloride. Serum and tissue malondialdehyde levels and superoxide dismutase and catalase in heart tissue were estimated spectrophotometrically. A lead II electrocardiogram was monitored at various intervals throughout the experiment.

Key findings

Results demonstrated the larger infarct size, enhanced lipid peroxidation, partial depletion of antioxidant enzymes and drastic drop in heart rate in diabetic hearts subjected to in-vivo ischaemia-reperfusion in comparison to normal rats subjected to ischaemia-reperfusion. Furthermore, quercetin and rutin significantly limit the infarct size in both normal and diabetic animals in a similar fashion. However, rutin offered complete cardioprotection at a dose of 10 mg/kg in terms of limiting infarct size. Both flavonoids could partially but significantly attenuate the lipid peroxidation. In addition, treatment has shown moderate improvement in heart rate in both normal and diabetic rats.

Conclusions

Our data suggest the possible cardioprotective effects of quercetin and rutin in ischaemia-reperfusion injury in both normal and diabetic rats, and that protection might be in part due to the attenuation of oxidative stress and moderate increment in antioxidant reserves.
Potential beneficial effect of naringenin on lipid peroxidation and antioxidant status in rats with ethanol-induced hepatotoxicity
Authors: Jayaraman Jayachitra , Veerappan Muniappan , Namasivayam Nalini
Published: October 2010

Objectives

The aim was to study the effect of naringenin, a biologically active compound, on tissue antioxidant status and lipid peroxidation in ethanol-induced hepatotoxicity in rats.

Methods

Rats were divided into four groups: Groups 1 and 2 received isocaloric glucose and 0.5% carboxymethyl cellulose; groups 3 and 4 received 20% ethanol equivalent to 6 g/kg daily for 60 days. In addition, groups 2 and 4 were given naringenin (50 mg/kg) daily for the last 30 days of the experiment.

Key findings

The results showed significantly elevated levels of serum aspartate and alanine transaminases, γ-glutamyl transpeptidase, tissue thiobarbituric acid reactive substances, conjugated dienes, lipid hydroperoxides and protein carbonyl content, and significantly lowered activities/levels of antioxidants such as superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase, reduced glutathione and vitamins C and E in ethanol-treated rats compared with control rats. Administration of naringenin to rats with ethanol-induced liver injury significantly decreased the levels of serum aspartate and alanine transaminases, γ-glutamyl transpeptidase, tissue thiobarbituric acid reactive substances, conjugated dienes, lipid hydroperoxides and protein carbonyl content and significantly elevated the activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione-S-transferase, and the levels of reduced glutathione and vitamins C and E in the tissues compared with unsupplemented ethanol-treated rats. Histological changes observed in the liver correlated with the biochemical findings.

Conclusions

Taken together these findings suggest that naringenin has a therapeutic potential in the abatement of ethanol-induced hepatotoxicity.
Modelling of diclofenac sodium diffusion from swellable and water-soluble polyethylene oxide matrices
Authors: Petrović Jelena , Jocković Jelena , Ibrić Svetlana , Ɖurić Zorica
Published: October 2010

Objectives

The main objective of this study was to develop a mathematical model for the characterization of diclofenac sodium diffusion from polyethylene oxide (PEO) matrices. A model was developed on the basis of the diffusion theory accounting for the characteristics of the polymer: swelling with subsequent dissolution in water. The concentration-dependent diffusion of drug and water was taken into account. Experimental data were analysed using a computer software program as an aid for solving partial differential equations.

Methods

Six formulations of matrix tablets with different drug-excipient ratios were prepared using low-molecular-weight PEO as a matrix-forming material. For obtaining drug release data, dissolution studies were performed and water uptake by pure PEO matrices was studied as well.

Key findings

A good agreement of the developed model with experimental results was demonstrated. Some anomalies in drug diffusion were observed and their origin was questioned. Changes in the parameters characterizing the process of diffusion are attributed to glassy-rubbery polymer transitions. Additional interpretation of this phenomenon on the basis of percolation theory is also provided.

Conclusions

The obtained model has the ability to predict the required characteristics of matrices for desired drug release. The composition of batches with undesirable release properties can be predetermined and avoided in manufacturing.
Effective vaginal DNA delivery with high transfection efficiency is a good system for induction of higher local vaginal immune responses
Authors: Kanazawa Takanori , Takashima Yuuki , Shibata Yasunori , Tsuchiya Miki , Tamura Toshiaki , Okada Hiroaki
Published: October 2010

Objectives

To investigate the local vaginal and systemic immune responses of effective vaginal DNA delivery with high transfection efficiency, we determined the effects on Th1-dependent cytokine (interferon-γ) production in spleen and inguinal lymph node cells and antibody responses of vaginal pDNA immunization with a cell-penetrating peptide, and compared our vaginal immunization with intradermal and intranasal immunizations.

Methods

Mice were immunized by vaginal, nasal or dermal administration of pCMV-OVA with or without peptide carriers, and serum, vaginal fluids, spleen and inguinal cells were harvested. The serum immunoglobulin (Ig)G2a and vaginal IgA antibody responses were determined by sandwich enzyme-linked immunosorbent assay (ELISA). The interferon-γ production from spleen cells or inguinal lymph node cells was determined by an ELISA kit.

Key findings

The direct vaginal immunization strongly induced IgA in the vaginal fluids and interferon-γ production in the local lymph node draining from the vagina. In addition, co-vaccination with the peptide carriers elevated these immune responses compared with vaccination with pCMV-OVA alone. Vaginal immunization with high transfection efficiency promoted vaginal IgA production to a significantly greater extent than intradermal or nasal immunization.

Conclusions

These results suggested that direct vaginal DNA vaccines under high transfection conditions induced higher local vaginal antibody than that by intranasal or intradermal administration, and peptide carriers effectively elevated mucosal immune responses. Therefore, this vaginal DNA vaccination method may be expected to be useful in the prevention and treatment methods for vaginal infectious diseases such as HIV infection.
Evaluation of molecular pharmaceutical and in-vivo properties of spray-dried isolated andrographolide—PVP
Authors: Bothiraja C , Shinde Mukesh B , Rajalakshmi S , Pawar Atmaram P
Published: October 2010

Objectives

Andrographolide, a natural lipophilic molecule, has a wide range of pharmacological actions. However, due to low aqueous solubility, it has low oral bioavailability. The purpose of the study was to increase the solubility and dissolution rate of isolated andrographolide by formulating its solid dispersion.

Method

Solid dispersions were obtained by a spray-drying technique using different ratios of drug to polyvinylpyrrolidine (PVP K-30). Solid dispersions in compression with isolated drug and corresponding physical mixtures were characterized for various molecular pharmaceutical properties and subjected to stability study for up to 3 months.

Key findings

A five-fold increase in saturation solubility of andrographolide with higher values of Q5min (cumulative percentage release in 5 min) and lower values of t75% (time required for 75% w/w drug release) for solid dispersion was observed in different dissolution mediums. This was attributed to the formation of amorphous nature and intermolecular hydrogen bonding between drug and PVP K-30. The stability study showed there to be no significant change in molecular pharmaceutical properties and dissolution profile over the period of 3 months. Moreover, the in-vivo study in Wistar albino rats also justified improvement in the therapeutic efficacy of andrographolide after solid dispersion.

Conclusions

This study demonstrates the utility of solid dispersion to improve primary and secondary pharmaceutical properties of andrographolide using PVP K-30 as a carrier.
Preparation and pharmacokinetics of docetaxel based on nanostructured lipid carriers
Authors: Li Xiang , Wang Dongkai , Zhang Jing , Pan Weisan
Published: October 2010

Objectives

This study describes the preparation and pharmacokinetics of docetaxel based on freeze-dried nanostructured lipid carriers (NLCs).

Methods

The docetaxel-incorporated NLCs were developed using hot high-pressure homogenisation, and lyophilised to obtain freeze-dried docetaxel NLCs. The influences of different concentrations of lipid matrices, ratio of drug to lipid, and different cryoprotectants on the characteristics of the NLCs were investigated.

Key findings

Freeze-dried docetaxel NLCs were spherical, with 5% (w/w) docetaxel loading efficiency and were stable for at least 6 months at 25°C. X-ray powder diffraction and differential scanning calorimetry analysis suggested that docetaxel was distributed in a molecular or amorphous status. In-vitro release studies showed sustained drug release, with the cumulated release rate of 13% within 24 h without burst release. The freeze-dried docetaxel NLCs also showed sustained-release properties after intravenous injection into rats. The area under the plasma–concentration time curve and mean residence time were increased 4.90 and 2.82 times compared with docetaxel solution. The concentration of docetaxel in the lungs was significantly higher in rats treated with the NLCs than in those given docetaxel solution.

Conclusions

Docetaxel NLCs have an organ-targeting effect and prolonged mean retention time and have potential for the treatment of lung cancer.
Involvement of adipokines in rimonabant-mediated insulin sensitivity in ob/ob mice
Authors: Mohapatra Jogeswar , Sharma Manoranjan , Singh Satinder , Pandya Gaurav , Chatterjee Abhijit , Balaraman Ramachandran , Patel Pankaj R , Jain Mukul R
Published: October 2010

Objectives

It has been recently reported that blockade of type 1 cannabinoid (CB1) receptors by specific antagonists or genetic manipulation alleviates dyslipidaemia, hyperglycaemia and insulin resistance in animal models of obesity and type 2 diabetes. However, the precise role of adipokines in the insulin-sensitising effects of the CB1 antagonist rimonabant is not clear.

Methods

ob/ob mice were treated with different doses of rimonabant and then subjected to an oral glucose tolerance test. The expression of different adipokines in white adipose tissue was analysed by quantitative real-time PCR.

Key findings

Rimonabant (30 mg/kg) significantly inhibited body weight and fat pad weight gain (P < 0.05) and improved glucose tolerance. Gene expression analysis indicated that tumour necrosis factor-α, visfatin and retinol binding protein-4 were downregulated in the adipose tissue of ob/ob mice treated with rimonabant compared with controls, whereas adiponectin was significantly upregulated.

Conclusions

Rimonabant-mediated alteration of adipokines in white adipose tissues may play a role in improving insulin sensitivity in obese animals.
Nootropic activity of lipid-based extract of Bacopa monniera Linn. compared with traditional preparation and extracts
Authors: Lohidasan Sathiyanarayanan , Paradkar Anant R , Mahadik Kakasaheb R
Published: October 2010

Objectives

The aim was to design an alternative solvent-free extraction method using the hydrophilic lipid Gelucire (polyethylene glycol glycerides) for herbal extraction and to confirm the efficacy of extraction using biological screening.

Methods

Bacopa monniera Linn. (BM) was selected for the study. Conventional methanolic extract (MEBM), Ayurvedic ghrita (AGBM) and lipid extracts (LEBM) were prepared and standardised by high-performance thin-layer chromatography (HPTLC). Nootropic activity in rats was evaluated using the two-trial Y-maze test and the anterograde amnesia induced by scopolamine (1 mg/kg i.p.) determined by the conditioned avoidance response. The extracts were administered daily at doses of 100, 200 and 400 mg/kg orally. At the end of the conditioned avoidance response test, brain monoamine levels were estimated by HPLC.

Key findings

The LEBM, MEBM and AGBM contained 3.56%, 4.10% and 0.005% bacoside A, respectively. Significantly greater spatial recognition was observed with LEBM (P < 0.001 at 400 and 200 mg/kg) and MEBM (P < 0.001 at 400 mg/kg, P < 0.01 at 200 mg/kg) than AGBM. The conditioned avoidance response was significantly higher in the groups treated with high doses of LEBM and MEBM than AGBM. There were significant decreases in brain noradrenaline (P < 0.001) and 5-hydroxytryptamine (P < 0.01) levels and an increase in dopamine levels (P < 0.05) in the LEBM-treated groups compared with the stress control group.

Conclusions

The proposed LEBM is solvent free, does not have the shortcomings associated with conventional extraction, and had comparable nootropic activity to the MEBM.
The relation between moisture-induced aggregation and structural changes in lyophilized insulin
Authors: Flores-Fernández Giselle M , Solá Ricardo J , Griebenow Kai
Published: October 2010

Objectives

Long-term stability is a critical factor in the successful development of protein pharmaceuticals. Due to the relative instability of proteins in aqueous solutions, they are formulated frequently and stored as lyophilized powders. Exposure of such powders to moisture constitutes a substantial storage problem leading to aggregation and inactivation. We have investigated the structural consequences of moisture sorption by lyophilized insulin under controlled humidity conditions by employing Fourier transform-infrared (FT-IR) microscopy.

Methods

Lyophilized insulin samples were stored in humidity chambers under controlled conditions at 50°C. Protein aggregation studies were carried out by redissolving the insulin samples and measuring the amount of both soluble protein and insoluble aggregates. Near-UV circular dichroism spectra were collected to assess the tertiary structure. FT-IR microscopy studies were carried out to investigate secondary structural changes in solid-state insulin after incubation at different relative humidities.

Key findings

It was found that sorption of moisture was accompanied by small structural changes in lyophilized insulin at low levels of relative humidity (i.e. 11%). At higher relative humidity levels, structural changes were becoming more pronounced and were characterized by a loss in the α-helix and increase in β-sheet content. The magnitude of the structural changes in tendency paralleled the solid-state instability data (i.e. formation of buffer-insoluble aggregates and loss in tertiary structure upon reconstitution).

Conclusions

The results support the hypothesis that water sorption by lyophilized proteins enables structural transitions which can lead to protein aggregation and other deleterious phenomena.
Protective effects of sodium para-amino salicylate on manganese-induced neuronal death: the involvement of reactive oxygen species
Authors: Yoon Hyonok , Kim Do-Sung , Lee Geum-Hwa , Kim Ji Ye , Kim Diana H , Kim Kee-Won , Chae Soo-Wan , You Wan-Hee , Lee Yong Chul , Park Seoung Ju , Kim Hyung-Ryong , Chae Han-Jung
Published: October 2010

Objectives

This study tested whether sodium para-amino salicylic dihydrate, an antibacterial drug for tuberculosis, could block manganese-induced apoptosis in SK-N-MC neurons.

Methods

Cell viability, Hoechst staining, dichlorofluorescin diacetate analysis for reactive oxygen species measurement, and immunoblotting were performed.

Key findings

In vitro, manganese chloride significantly decreased the viability of SK-N-MC cells, accompanied by apoptotic features such as changes in nuclear morphology. Sodium para-amino salicylic dihydrate inhibited these apoptotic characteristics through reducing intracellular reactive oxygen species generation, protecting mitochondrial membrane potential and caspase-3 activation.

Conclusions

Sodium para-amino salicylic dihydrate inhibits manganese-induced apoptosis in neurons and may reduce manganese-mediated neurodegeneration.
Chitosan-tripolyphosphate nanoparticles as a possible skin drug delivery system for aciclovir with enhanced stability
Authors: Hasanovic Amra , Zehl Martin , Reznicek Gottfried , Valenta Claudia
Published: October 2010

Objectives

The aim of the present study was to create a skin delivery system based on chitosan-tripolyphosphate nanoparticles for aciclovir with enhanced chemical stability.

Methods

Nanoparticles were formed spontaneously using ionotropic gelation with tripolyphosphate. Two different sizes of aciclovir-loaded nanoparticles were characterised in terms of zeta potential, particle size and polydispersity index.

Key findings

Standard diffusion experiments using Franz-type diffusion cells showed reasonable skin permeability that depended on particle size and chitosan content. The larger the nanoparticle, having a higher chitosan content, the better the aciclovir permeation through porcine skin. Differential scanning calorimetry studies showed a remarkable decrease in the typical transition temperature, indicating an interaction between skin lipid bilayer and the nanoparticles. Moreover, the chemical stability of aciclovir was significantly increased by the nanoparticle system. After the observation period of 5 weeks, aciclovir incorporated into nanoparticles had undergone photo-oxidation to a significantly lower extent than pure aqueous solution. This degradation product of aciclovir was analysed using LC/MS, and its identity established.

Conclusions

These studies demonstrate that incorporation of aciclovir into chitosan-tripolyphosphate nanoparticles significantly improves its chemical stability. Moreover, skin diffusion studies in vitro showed improved permeation of aciclovir from the nanoparticle system, especially from nanoparticles with higher chitosan content.
Collagen-based wound dressing for doxycycline delivery: in-vivo evaluation in an infected excisional wound model in rats
Authors: Adhirajan Natarajan , Shanmugasundaram Natesan , Shanmuganathan Seetharaman , Babu Mary
Published: October 2010

Objectives

A novel collagen-based dressing consisting of 2,3-dihydroxybenzoic-acid-modified gelatin microspheres loaded with doxycycline has previously been reported to address both infection and matrix degradation. In the present study the potential benefits of the dressing were investigated in an excisional wound model in rats challenged with Pseudomonas aeruginosa.

Methods

A full-thick excisional wound (1.5 times 1.5 cm) was created on the dorsum of the rats and infection induced by injecting 105 colony-forming units (CFU) of P. aeruginosa. The healing pattern was assessed from wound reduction, matrix metalloprotease (MMP) levels, CFU reduction and histological and biochemical analysis.

Key findings

The treated group exhibited complete healing by day 15, compared with day 24 in the control group. Early subsidence of infection (99.9% by day 9) resulted in faster epidermal resurfacing and fibroplasias, whereas the microbial load exceeded 103 CFU even on day 15 in the control group and caused severe inflammation. Biochemical analysis showed that the expression of both collagen and hexosamine was significantly increased in the treated group. Gelatin zymography revealed prolonged expression of MMPs 2, 8 and 9 in the control group compared with the treated group.

Conclusions

The study indicates that the developed dressing attenuated both infection and metalloprotease levels, and may therefore have potential application in wound healing.
Evaluation of supercritical fluid engineered budesonide powder for respiratory delivery using nebulisers
Authors: Amani Amir , Chrystyn Henry , Clark Brian J , Abdelrahim Mohamed E , York Peter
Published: October 2010

Objectives

Currently, suspensions prepared from micronised drug substances are the only delivery system marketed for nebulisation of steroids, and reported inconsistent or low bioavailability arising from their use provides a rationale for researching alternative formulations. Supercritical fluid processing of drug substances to obtain respirable-sized particles has been used over the last decade to formulate dry powder inhalers. We aimed thus to process budesonide powder to improve its deposition characteristics.

Methods

In an attempt to overcome the limitations of nebuliser suspensions when prepared from micronised drug particles, budesonide powder was processed using a supercritical fluid based process and suspended using Tween 80 as a surfactant to provide an aqueous nebuliser formulation. The in-vitro characteristics of the emitted dose on nebulisation for the prepared suspension were then compared to a commercially available suspension formulation of budesonide using a jet and a vibrating mesh nebuliser.

Key findings

The results showed a significant improvement of the in-vitro deposition properties of the suspension containing supercritical fluid engineered budesonide particles.

Conclusions

The results indicated the benefit of such materials compared with traditionally micronised drug powders.
Preparation, characterization and taste-masking properties of microspheres containing azithromycin
Authors: Hu Liandong , Pan Jianbin , Liu Ci , Xu Hongxin , Luo Liangzhao
Published: October 2010

Objectives

The aim of this study was to prepare a microsphere formulation in order to mask the bitter taste of azithromycin.

Methods

Microspheres of azithromycin with ethyl cellulose were prepared by the modified solvent diffusion method. The microspheres were mixed with other excipients to form orally dry suspensions and the sensory test for taste masking was evaluated.

Key findings

Results demonstrated that the suspension could significantly mask the bitter taste of azithromycin and the relative bioavailability of suspensions to reference preparations was 102.7%.

Conclusions

The results indicate that the microsphere formulation can be a promising drug carrier for masking the bitter taste of azithromycin.
An investigation of the ability of elemene to pass through the blood-brain barrier and its effect on brain carcinomas
Authors: Wu Xue Shen , Xie Tian , Lin Jing , Fan Hai Zhu , Huang-Fu Hong Jiao , Ni Li Feng , Yan Hui Fang
Published: October 2010

Objectives

Elemene is a chemical extracted from plants. It has demonstrated anti-tumour capability. Although widely studied, there has been little reported regarding its tissue distribution. Our aim was to rectify this.

Methods

The tissue distribution of elemene was studied after intragastric or intravenous administration in rats. The effectiveness of elemene in treating brain tumours was studied using the G-422 tumour cell model in mice.

Key findings

Elemene had a higher concentration in the lungs, spleen and livers than other tissues of normal rats after intragastric and intravenous administration, while the concentration in the gastrointestinal tract was greater after intragastric administration. Elemene molecules were also detected in the rats' brain tissue. Elemene had a therapeutic effect on mice inoculated with G-422 cells both intracranially and subcutaneously. The best life-extending rate and the best tumour-inhibiting rate of elemene were 64.43% and 34.46%, respectively, when 80 mg/kg elemene was used for treatment.

Conclusions

The results from the tissue distribution study showed that elemene can pass through the blood-brain barrier. The therapeutic experiments showed that elemene is effective in treating cerebral malignancy.
Effect of chronic treatment of carvedilol on oxidative stress in an intracerebroventricular streptozotocin induced model of dementia in rats
Authors: Kumar Prakash Atish , Kumar Anil
Published: October 2010

Objectives

Oxidative stress is emerging as an important issue in the pathogenesis of dementia. This study was conducted to investigate the possible neuroprotective effects of carvedilol against streptozotocin induced behavioural alterations and oxidative damage in rats.

Methods

An intracerbroventricular cannula was implanted in the lateral ventricles of male Wistar rats. Various behavioural (locomotor activity, Morris water maze task) and biochemical parameters (lipid peroxidation, nitrate concentration, catalase, acetylcholinesterase, reduced glutathione and protein) were assessed.

Key findings

Intracerebroventricular administration of streptozotocin caused a significant memory deficit as evaluated in the Morris water maze task paradigms, and caused marked oxidative damage as indicated by significant increases in malondialdehyde and nitrite levels, and depletion of superoxide dismutase, catalase and reduced glutathione levels. It also caused a significant increase in acetylcholinesterase activity. Chronic administration of carvedilol (1 and 2 mg/kg, i.p.) for a period of 25 days starting 4 days before streptozotocin administration resulted in an improvement in memory retention, and attenuation of oxidative damage and acetylcholinesterase activity.

Conclusions

This study demonstrates the effectiveness of carvedilol in preventing cognitive deficits as well as the oxidative stress caused by intracerbroventicular administration of streptozotocin in rats. Carvedilol may have potential in the treatment of neurodegenerative diseases.
Ketorolac trometamol topical formulations: release behaviour, physical characterization, skin permeation, efficacy and gastric safety
Authors: El-Setouhy Doaa Ahmed , Ahmed El-Ashmony Sahar Mohy
Published: October 2010

Objectives

The objective of this study was to improve systemic delivery of the highly analgesic ketorolac trometamol (ketorolac tromethamine) via the transdermal route, through cost-effective topical formulations, to avoid most of the problems associated with ketorolac trometamol therapy.

Methods

In-vitro release behaviour of the drug from different microemulsion and emulgel formulations was evaluated. E2 emulgel (based on isopropyl myristate as penetration enhancer) and E7 emulgel (based on Brij 92 as penetration enhancer) were evaluated for their physical properties, rat skin permeation, in-vivo analgesic effect (hot-plate test and the paw pressure test), acute and chronic anti-inflammatory activity and gastric safety.

Key findings

Isopropyl myristate and the synergistic effect of the two known penetration enhancers (propylene glycol and Brij 92) significantly modulated drug permeation and may be a promising approach for the transdermal delivery of ketorolac trometamol and other drugs. Selected in-vivo tested formulae (E2 and E7) caused significantly less ulcer score and less gastric erosion compared with oral ketorolac trometamol. E7 showed significantly higher analgesic and anti-inflammatory activity compared with E2 with no significant difference compared with oral ketorolac trometamol.

Conclusions

The developed ketorolac trometamol E7 emulgel appeared promising for dermal and transdermal delivery of ketorolac trometamol, which would circumvent most of the problems associated with drug therapy.
A bioassay for mosquito repellency against Aedes aegypti: method validation and bioactivities of DEET analogues
Authors: Jahn Alexander , Kim Seok Yong , Choi Joon-Ho , Kim Dae-Duk , Ahn Young-Joon , Yong Chul Soon , Kim Jung Sun
Published: October 2010

Objectives

Vector-borne diseases are still a major mortality factor in Africa and South-east Asia and effective mosquito repellents are therefore needed. An efficient and safe in-vitro assay system using artificial blood and skin substitute could facilitate the development of novel repellents, as most assays currently rely on human subjects or vertebrate whole blood. Moreover, examining the skin permeation profiles could provide safer mosquito repellents. The new assay system could serve as an initial system for testing new repellent candidates upon validation with DEET and its analogues.

Methods

N,N-Diethyl-meta-toluamide (DEET) and five analogues were synthesised and used to validate a novel in-vitro bioassay using artificial blood and collagen membrane. Repellency against Aedes aegypti was correlated with lipophilicity and skin permeation.

Key findings

The new in-vitro assay showed good reproducibility (interday relative standard deviation <10% at high concentrations). Four of the five DEET analogues showed repellency similar or superior to that of DEET. Repellency correlated linearly with lipophilicity but stronger repellents tended to permeate skin better.

Conclusions

The new in-vitro assay using blood substitute and collagen membrane significantly simplifies screening of possible mosquito repellents. Lipophilicity as well as skin permeation profiles should be considered before testing of compounds that are candidates for mosquito repellents.
Enhanced oral bioavailability of etodolac by self-emulsifying systems: in-vitro and in-vivo evaluation
Authors: Barakat Nahla S
Published: October 2010

Objectives

The objective of this study was to prepare a self-emulsifying drug delivery system (SEDDS) for oral bioavailability enhancement of a poorly water-soluble drug, etodolac. The SEDDS formulations were optimized by evaluating their ability to self-emulsify when introduced to an aqueous medium under gentle agitation, and by determination of the particle size of the resulting emulsion.

Methods

An optimized formulation of SEDDS (composed of 20% etodolac, 30% oil Labrafac WL1349, 10% Lauroglycol 90 and 40% Labrasol) was selected for bioavailability assessment in rabbits. The anti-inflammatory effect was also determined in rats, and compared with powder drug and etodolac suspension in water (50 mg/kg).

Key findings

The peak plasma concentration of 16.4 ± 1.1 μg/ml appeared after 1.3 ± 0.2 h, whereas with powder drug and etodolac suspension the values were 7.5 ± 0.5 and 10.6 ± 0.7 μg/ml at 4.2 ± 0.4 and 2.4 ± 0.2 h, respectively. The AUC0–8 of the etodolac SEDDS formulation was 2.3 times that of the pure drug and 1.4 times that of the suspension form. SEDDS formulation exhibits a 21% increase in paw thickness compared with a 39% increase on oral administration of etodolac suspension after 4 h at the same dose of the drug (20 mg/kg).

Conclusions

The result indicates the utility of SEDDS for the oral delivery of etodolac and potentially other lipophilic drugs.
Sphingosylphosphorylcholine inhibits melanin synthesis via pertussis toxin-sensitive MITF degradation
Authors: Kim Dong-Seok , Park Seo-Hyoung , Kwon Sun-Bang , Kwon Nyoun Soo , Park Kyoung-Chan
Published: October 2010

Objectives

Sphingolipids act as structural components in cell membranes, and form lipid intermediates that have functional roles as signalling molecules in various cellular processes. Our previous findings have suggested that sphingolipid metabolites are deeply involved in the regulation of melanogenic processes. In this study we aimed to examine sphingosylphosphorylcholine-mediated signalling pathways related to melanogenesis.

Methods

We determined the hypopigmenting effects and the related signalling pathways of sphingosylphosphorylcholine in Mel-Ab cells. In particular, we analysed the involvement of the G-protein-coupled receptor in sphingosylphosphorylcholine-induced MITF degradation.

Key findings

Western blotting revealed that sphingosylphosphorylcholine induced the activation of extracellular signal-regulated kinase (ERK), as well as Akt. Moreover, the specific Akt pathway inhibitor LY294002 blocked the hypopigmenting effect of sphingosylphosphorylcholine and abrogated the sphingosylphosphorylcholine-mediated down-regulation of microphthalmia-associated transcription factor (MITF), showing that the Akt pathway is involved in sphingosylphosphorylcholine-mediated melanin inhibition. Treatment with the proteasome inhibitor MG132 blocked the decrease in MITF by sphingosylphosphorylcholine, but sphingosylphosphorylcholine did not decrease the level of MITF mRNA, indicating that the reduction in the level of MITF results from MITF degradation. Furthermore, pre-incubation of Mel-Ab cells with pertussis toxin completely abolished the hypopigmenting effects and the activation of ERK and Akt by sphingosylphosphorylcholine, suggesting that the effects of sphingosylphosphorylcholine are mainly dependent on the G-protein-coupled receptor).

Conclusions

Together, these results suggest that sphingosylphosphorylcholine reduces melanin synthesis via pertussis toxin-sensitive ERK and Akt activation, and subsequent MITF degradation.
The involvement of endoplasmic reticulum stress in flavonoid-induced protection on cardiac cell death caused by ischaemia/reperfusion
Authors: Kim Do-Sung , Kwon Dae-Young , Kim Myung-Sunny , Kim Hye Kyung , Lee Yong Chul , Park Seong Ju , Yoo Wan Hee , Chae Soo-Wan , Chung Myoung-Ja , Kim Hyung-Ryong , Chae Han-Jung
Published: October 2010

Objectives

We have investigated whether endoplasmic reticulum stress and Bcl-2 proteins were linked to the protective effect exerted by flavonoids on ischaemia/reperfusion-induced cardiac damage.

Methods

Cell viability and immunoblotting were performed.

Key findings

H9c2 cardiac muscle cells were exposed to flavonoids such as biochanin A, daidzein, genistein, luteolin, quercetin and rutin, followed by ischaemia 12 h/reperfusion 4 h. The flavonoids protected against cell death induced by ischaemia/reperfusion. Flavonoid treatment significantly increased the expression level of the anti-apoptotic protein, Bcl-2, but decreased that of the proapoptotic protein, Bax. The flavonoids down-regulated the expression levels of endoplasmic reticulum stress proteins, glucose-regulated protein-78, activating transcription factor 6α, X-box binding protein 1, inositol-requiring protein-1, phosphor-eukaryotic initiation factor 2α, and C/EBP-homologous protein.

Conclusions

This study suggested that the protective mechanisms of flavonoids included regulation of Bcl-2/Bax proteins as well as the endoplasmic reticulum stress proteins.
Cardiovascular effects induced by Cymbopogon winterianus essential oil in rats: involvement of calcium channels and vagal pathway
Authors: De Menezes Igor Alexandre Côrtes , Moreira Ítalo José Alves , De Paula José Welton Azevedo , Blank Arie Fitzgerald , Antoniolli Angelo Roberto , Quintans-Júnior Lucindo José , Santos Márcio Roberto Viana
Published: October 2010

Objectives

This study has investigated the cardiovascular effects of the Cymbopogon winterianus essential oil (EOCW) in rats. C. winterianus is a plant used in folk medicine for the treatment of hypertension.

Methods

For the measurement of haemodynamic and ECG parameters, male Wistar rats under anaesthesia were cannulated in the abdominal aorta and lower vena cava and electrodes were subcutaneously implanted in their paws. For an in-vitro approach, the rats were killed and the superior mesenteric artery was removed and cut into rings (1–2 mm). These rings were then mounted in organ baths containing Tyrode's solution at 37 °C and gassed with carbogen.

Key findings

In rats, EOCW (1–20 mg/kg, i.v.) induced dose-dependent hypotension and tachycardia. These effects were not affected by L-NAME or indometacin, but were partially reduced after atropine administration. EOCW (20 mg/kg only) also induced bradycardia-associated sinoatrial blockade, junctional rhythm, and first-degree atrioventricular block, which was abolished after atropine administration or vagotomy. In arterial rings, EOCW (0.1–3000 μg/ml) induced relaxation of phenylephrine tonus that was not affected by removal of the endothelium. These relaxations were similar to those observed in rings without endothelium precontracted with KCl 80 mm. EOCW was able to antagonize the CaCl2 (30–300 μm) induced contractions in depolarizing solution (KCl 60 mm).

Conclusions

These results demonstrated that EOCW induced hypotension and vasorelaxation. These effects appeared to be mainly mediated by Ca+2-channel blocking. Furthermore, the higher dose of EOCW induced transient bradycardia and arrhythmias due to a cardiac muscarinic activation secondary to a vagal discharge.
Potential protective effects of a traditional Chinese herb, Litsea coreana Levl., on liver fibrosis in rats
Authors: Huang Cheng , Ma Taotao , Meng Xiaoming , Lv Xiongwen , Zhang Lei , Wang Jianqing , Li Jun
Published: October 2010

Objectives

It was found that total flavonoids from Litsea coreana Levl. (TFLC), which is a traditional Chinese medicine, had a preventive effect against hepatic steatosis in our previous study. This study was designed to evaluate whether TFLC could improve liver fibrosis in rats.

Methods

The liver fibrosis model rats were treated with composite factors of high-fat emulsion (10 ml/kg) via gavage accompanied by a subcutaneous injection of low-dose CCl4. Thirty rats were given composite factors plus TFLC (100, 200, 400 mg/kg), respectively, for 8 weeks.

Key findings

The results showed that TFLC (200 and 400 mg/kg) treatment significantly reduced the elevation of liver index (liver weight/body weight) and spleen index (spleen weight/body weight), alanine transaminase, aspartate aminotransferase, hyaluronic acid, laminin, procollagen III N-terminal peptide, procollagenase IV and hydroxyproline. In addition, TFLC treatment improved the morphologic changes of hepatic fibrosis, suppressed expression of α-smooth muscle actin, collagen I, transforming growth factor (TGF)-β1 and TGFβ receptor (TGFβR)1, and increased peroxisome proliferator-activated receptor-γ expression in the liver of hepatic fibrosis rats.

Conclusions

In conclusion, TFLC is able to ameliorate liver injury and protect rats from liver fibrosis. This process may be related to inhibiting the expression of transforming growth factor-β1 and increasing the expression of peroxisome proliferator-activated receptor-γ.
In-vitro free radical scavenging, antiproliferative and anti-zearalenone cytotoxic effects of 4-(methylthio)-3-butenyl isothiocyanate from TunisianRaphanus sativus
Authors: Salah-Abbès Jalila Ben , Abbès Samir , Abdel-Wahhab Mosaad A , Oueslati Ridha
Published: October 2010

Objectives

The aim of this study was to investigate the antiradical and antioxidant properties of 4-(methylthio)-3-butenyl isothiocyanate (MTBITC) extracted from Raphanus sativus and to assess the effects of MTBITC on tumour cell growth, cytotoxicity induced by zearalenone, an oestrogenic mycotoxin, and modulation of the expression of the genes involved in these aspects of cell behaviour.

Methods

A murine leukaemia cell line (L1210) was grown in vitro and supplemented with MTBITC (2, 4, 8, 16 and 32 μm) for 48 h. Cell growth was evaluated by the MTT assay. The chemopreventive role of MTBITC on the cytotoxic effect of zearalenone in a Balb/c mice keratinocyte cell line (C5-O) was also evaluated. Apoptosis and lipid peroxidation were assessed, as well as the expression of genes involved following zearalenone treatment alone or in combination with MTBITC.

Key findings

MTBITC showed a significant ability to inhibit nitroblue tetrazolium reduction by superoxide radicals in a non-enzymatic superoxide generating system, to scavenge free radicals and to cause a decrease in L1210 cell growth. The C5-O cells treated with zearalenone alone showed a high frequency of apoptotic cells and lipid peroxidation, typical of oxidative stress generated by zearalenone. The cotreatment with MTBITC reduced the cytotoxicity of zearalenone and the subsequent gene expression analysis demonstrated that MTBITC decreased the expression of caspase 8, implicated in the physiological mechanism to eliminate injured or abnormal cells.

Conclusions

The results suggest that MTBITC was able to inhibit L1210 cell growth and counteract the zearalenone oxidative stress to C5-O cells through caspase 8 inhibition of apoptosis.
Nonlinear mixed effects models applied to cumulative concentration–response curves
Authors: Thorin Chantal , Mallem Mohamed Yassine , Noireaud Jacques , Gogny Marc , Desfontis Jean-Claude
Published: October 2010

Objectives

In experimental pharmacology, drug effect studies currently establish and analyse cumulative concentration–response curves (CCRC) under repeated measurements designs. Usually the CCRC parameters are estimated using the Hill's function in a nonlinear regression for independent data. The two-way analysis of variance is generally used to identify a statistical difference between the responses for two treatments but that analysis does not take into account the nonlinearity of the model and the heteroscedasticity (uneven distribution) of the data. We presently tested the possibility of finding a statistical solution for the nonlinear response in repeated measurements data using the nonlinear mixed effects (nlme) models.

Methods

Experimental data sets, originating from studies on β-adrenoceptor-induced relaxation in rat thoracic aorta ring, were analysed using the nlme methods.

Key findings

Comparison with classical methods showed the superiority of the nlme models approach. For each pharmacological parameter (Em, n, pD2), a point estimate, a standard error and a confidence interval are returned by the nlme procedures respecting the assumption of independency and normality of the residuals.

Conclusions

Using the method presently described, it is now possible to detect significant differences for each pharmacological parameter estimated in different situations, even for designs with small samples size (i.e. at least six complete curves).
Dose-dependent effects of sildenafil on post-ischaemic left ventricular function in the rat isolated heart
Authors: Kolettis Theofilos M , Kontaras Konstantinos , Spartinos Ioannis , Maniotis Christos , Varnavas Varnavas , Koutouzis Michael , Mourouzis Iordanis , Papalois Apostolos , Pantos Constantinos , Kyriakides Zenon S
Published: October 2010

Objectives

Sildenafil may be beneficial during myocardial ischaemia/reperfusion, but this effect may be dose-dependent, accounting for previous conflicting results. We have explored the effects of two acute and one chronic administration regimen on left ventricular function.

Methods

The study was conducted on 36 Wistar rats (290 ± 7 g). Sildenafil was administered 30 min before ischaemia at a low (0.7 mg/kg, n= 8) or high (1.4 mg/kg, n= 8)dosage. The chronic treatment arm (n= 8) consisted of two daily injections of sildenafil (0.7 mg/kg) for three weeks. The control group was formed by 12 rats. Ischaemic contracture, post-ischaemic recovery and hypercontracture were measured in isolated, Langendorff-perfused preparations.

Key findings

Ischaemic contracture tended to be lower after high-dose sildenafil, while remaining unchanged after low-dose or chronic sildenafil administration. Compared with controls (62.9 ± 2.0% of baseline developed pressure), post-ischaemic recovery was higher (P= 0.0069) after low dose (75.1 ± 2.4%), unchanged (P= 0.13) after high dose (69.1 ± 2.1%), but lower (P < 0.001) after chronic (42.9 ± 4.5%) sildenafil administration. Compared with controls (71.8 ± 3.9 mmHg), hypercontracture was higher (P= 0.0052) after chronic sildenafil administration (89.5 ± 4.1 mmHg), but similar after acute low dose (65.7 ± 3.3 mmHg, P= 0.33) or high dose (67.1 ± 4.7 mmHg, P= 0.43).

Conclusions

The effects of sildenafil after ischaemia/reperfusion were strongly dose-dependent. Beneficial actions on left ventricular function were evident after acute pretreatment with a low dosage, but were lost after doubling the dose. Chronic sildenafil administration deteriorated left ventricular function during ischaemia and reperfusion.
Effects of morroniside isolated from Corni Fructus on renal lipids and inflammation in type 2 diabetic mice
Authors: Park Chan Hum , Noh Jeong Sook , Tanaka Takashi , Yokozawa Takako
Published: October 2010

Objectives

The effects of morroniside isolated from Corni Fructus on renal lipids and inflammation provoked by hyperglycaemia were investigated using type 2 diabetic mice.

Methods

Morroniside was administered orally to db/db mice at 20 or 100 mg/kg daily for 8 weeks, and its effects were compared with those in vehicle-treated db/db and m/m (non-diabetic) mice. Serum and renal biochemical factors and protein expression related to lipid homeostasis and inflammation were measured.

Key findings

Morroniside produced significant dose-dependent reductions in serum triglyceride and renal glucose and lipid levels. Morroniside altered the abnormal protein expression of sterol regulatory element binding proteins (SREBP-1 and SREBP-2). In addition, the formation of reactive oxygen species and lipid peroxidation were inhibited in the morroniside-treated db/db mouse group, and the ratio of reduced glutathione to the oxidised form was significantly elevated. These results suggest that morroniside alleviated oxidative stress in the kidneys of db/db mice. Furthermore, 100 mg/kg morroniside down-regulated the expression of nuclear factor-κBp65, cyclooxygenase-2 and inducible nitric oxide synthase augmented in db/db mice.

Conclusions

Morroniside may inhibit abnormal lipid metabolism and inflammation due to reactive oxygen species in the kidneys in type 2 diabetes.
Gastroprotective activity of atractylenolide III from Atractylodes ovata on ethanol-induced gastric ulcer in vitro and in vivo
Authors: Wang Kun-Teng , Chen Lih-Geeng , Wu Chih-Hsiung , Chang Chun-Chao , Wang Ching-Chiung
Published: October 2010

Objectives

The rhizome of Atractylodes ovata De Candolle is popularly used in traditional Chinese medicine to treat gastrointestinal diseases. However, the major gastroprotective compounds of A. ovata have not been identified. This study reports on the principal gastro- protective component of A. ovata.

Methods

Five sesquiterpenoids (atractylon, atractylenolides I, II, III and biatractylolide) were isolated from the extracts of A. ovata rhizome via silica gel column chromatography. The gastroprotective effects of these five sesquiterpenoids were measured in in-vitro ethanol-induced primary culture rat gastric mucosal (PRGM) cell damage and in-vivo ethanol-induced acute rat gastric ulcer models.

Key findings

Atractylon, atractylenolide I and biatractylolide were strongly toxic in PRGM cells, whilst atractylenolides II and III were not. Atractylenolide II did not show cytoprotective effects, but oral administration of atractylenolide III dose-dependently prevented ethanol-induced PRGM cell death and cell membrane damage. The EC50 values were 0.27 and 0.34 mm, respectively. In the in-vivo assay, atractylenolide III 10 mg/kg significantly reduced 70% ethanol-induced Wistar rat gastric ulcer. Atractylenolide III could inhibit matrix metalloproteinase (MMP)-2 and MMP-9 expression through upregulation of tissue inhibitors of metalloproteinase from the gastric ulcerated tissues.

Conclusions

Atractylenolide III was the major gastroprotective component of A. ovata in ethanol-induced acute gastric ulcer. It is suggested that the gastroprotective mechanism of atractylenolide III was via inhibition of the MMP-2 and MMP-9 pathway.