Anticonvulsant and GABA Uptake Inhibition Properties of Venom Fractions from the Spiders Parawixia bistriata and Scaptocosa raptoria

In this article we describe an in vivo anticonvulsant effect from denatured crude venom and partially isolated fractions from two spiders: Parawixia bistriata and Scaptocosa raptoria. Intracerebroventricular injections of these venoms and fractions abolished rat convulsive tonic-clonic seizures induced by picrotoxin, bicuculline and pentylenetetrazole, and also, inhibited GABA uptake in synaptosomes of rat cerebral cortex. The venoms described in this work seems to be promising tools for the study of the GABAergic system, and may be a potential source for new anticonvulsant drugs.     

An approach to the inheritance of the sesquiterpene chemotypes within Petasites hybridus

Sesquiterpene esters are the active principle in the medicinal plant Petasites hybridus. Two chemotypes, the petasin chemotype and the furanopetasin chemotype, are known, but only the first one is suitable for pharmaceutical purposes. Experimental crossings were performed within and between plants of both chemotypes to study the genetic basis of the occurrence of these sesquiterpenes. The chemotype was determined by TLC in extracts of a small piece of rhizome in the parent plants and the progenies. A model including the combined action of two genes is proposed to explain the inheritance of the chemotypes where the furanopetasin chemotype is under recessive genetic control.     

Synthesis and evaluation of anticonvulsant activities of 7‐phenyl‐4,5,6,7‐tetrahydrothieno[3,2‐b ]pyridine derivatives

A series of 7‐phenyl‐4,5,6,7‐tetrahydrothieno[3,2‐b]pyridine derivatives containing triazole and other heterocycle substituents (methyltriazole, tetrazole, and triazolone) is described. Two experimental methods, maximal electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ), were used to evaluate the anticonvulsant activity of the target compounds. Moreover, the neurotoxicity (NT) was tested using the Rotarod test. 5‐(4‐Chlorophenyl)‐4,5‐dihydrothieno[2,3‐e][1,2,4]triazolo[4,3‐a]pyridine ( 6c ) showed the best anticonvulsant activity. In the MES and PTZ experiments, the 50% effective dose (ED₅₀) values of compound 6c were 9.5 and 20.5 mg/kg, respectively. From the therapeutic index (PI) values, 6c (MES and PTZ with PI values of 48.0 and 22.2, respectively) showed better safety than the clinical drugs carbamazepine (MES with PI value of 6.4) and ethosuximide (PTZ with PI value of 3.2). The biological activities of the compounds were verified by using molecular docking studies. Compound 6c showed significant interactions with residues at the benzodiazepine‐binding site on gamma‐aminobutyric acid A (GABA_A) receptors. The results of in vivo GABA estimation and bicuculline‐induced seizures showed that 6c may have an effect on the GABA system. The physicochemical and pharmacokinetic properties of the target compounds were predicted.     

Chemical composition and bioactivity of the volatile oil from leaves and stems of Eucalyptus cinerea

Context: Eucalyptus cinerea F. Muell. ex Benth. (Myrtaceae) is a medium-sized tree cultivated in Egypt.

Objective: First, to determine the chemical composition of the volatile oil of the juvenile leaves and stems of E. cinerea to identify its chemotype. Second, to study the in vivo antioxidant activity and in vitro antimicrobial activity of the studied volatile oils against selected Gram-positive, Gram-negative bacteria, yeast, and mycelia fungi.

Materials and methods: The volatile oil was prepared by hydrodistillation and then identified by GC/MS analysis. Broth microdilution and agar dilution methods were applied for determining the MIC. The antioxidant activity was studied by determination of glutathione level in blood of alloxan-induced diabetic rats.

Results: The yield of the volatile oil hydrodistilled from the juvenile leaves and stems of E. cinerea was 4.5 and 0.5%, respectively. 1,8-Cineole was the major identified oxygenated monoterpenoid (84.55% and 60.15% in the juvenile leaves and stems, respectively). The antibacterial activity of the oil of the juvenile leaves was more potent against all the tested organisms than that of the stems. The (MIC) of volatile oil of the juvenile leaves against Escherichia coli, Pseudomonas aeruginosa, Streptococcus faecalis, Candida albicans, and Aspergillus flavus were 5.2, 5.6, 4, 4.8, and 12.8?μg/ml, respectively. Also, the juvenile leaves’ oil was more active as an antioxidant than that of the stems. They restored glutathione level by 33.7?±?1.1 and 29.6?±?0.7?mg/dl, respectively, compared with vitamin E (35.9?±?1.2?mg/dl) which was used as a reference.

Discussion and conclusion: Results suggest that the volatile oil is 1,8-cineole chemotype. Moreover, the oil of the juvenile leaves of E. cinerea might find usefulness as a therapeutic agent following further development.     

Effect of Eclipta alba on Acute Seizure Models: a GABAA-mediated Effect

In the present study, anticonvulsant activity of methanol extract of Eclipta alba (10-200 mg/kg) was studied using pentylenetetrazole- and picrotoxin-induced seizure models. Mechanism of effect of methanol extract of Eclipta alba was further elucidated by studying its GABA_A receptor modulatory activity and its effect on levels of GABA in mice brain. Methanol extract of Eclipta alba exhibited potent anticonvulsant activity but has saturation of its pharmacological activity at 50 mg/kg. At the concentration of 10 mg/ml, contractions induced in guinea pig ileum was blocked by picrotoxin, but it didn’t not show any increase in GABA levels in mice brain after treatment. Hence, it can be concluded that methanol extract of Eclipta alba possesses potent anticonvulsant activity because of its positive modulatory effect on GABA_A receptors.     

Anticonvulsant activity of 1,2,3,4,6-penta-O-galloyl-β-d-glucopyranose isolated from leaves of Mangifera indica

The present study was aimed to evaluate the anticonvulsant activity of 1,2,3,4,6-penta-O-galloyl-β-d-glucopyranose (PGG) isolated from methanolic leaf extracts of Mangifera indica in mice. Anticonvulsant activity of PGG was evaluated against pentylenetetrazole (PTZ)-induced and maximal electroshock (MES)-induced convulsions in mice. Additionally, locomotor activity and GABA levels in the brain were estimated to explore the possible CNS-depressant activity and mechanism behind the anticonvulsant activity, respectively. In these studies, PGG (2.5, 5, and 10 mg/kg, intraperitoneal (i.p.)) showed significant and dose-dependent inhibition of PTZ and MES-induced convulsions. Furthermore, PGG administration showed significant decrease in the locomotor activity as an indication of its CNS-depressant property; also, PGG has significantly increased the GABA levels in the cerebellum and whole brain other than the cerebellum. In conclusion, PGG isolated from M. indica showed potent anticonvulsant activity, and possible mechanism may be due to enhanced GABA levels in the brain.     

Neuropharmacological effects in mice of Lychnophora species (Vernonieae, Asteraceae) and anticonvulsant activity of 4,5-di-O-[E]-caffeoylquinic acid isolated from the stem of L. rupestris and L. staavioides

Aiming at contributing with the search for neuroactive substances from natural sources, we report for the first time antinociceptive and anticonvulsant effects of some Lychnophora species. We verify the protective effects of polar extracts (600 mg/kg, intraperitoneally), and methanolic fractions of L. staavioides and L. rupestris (100 mg/kg, intraperitoneally) in pentylenetetrazole-induced seizures on mice. Previously, a screening was accomplished, evaluating the antinociceptive central activity (hot plate test), with different extracts of L. rupestris, L. staavioides and L. diamantinana. It was possible to select the possible extracts of Lychnophora with central nervous system activity. Some of the active extracts were submitted to fractionation and purification process and the methanolic fractions of L. rupestris (stem) and L. staavioides (stem), with anticonvulsant properties (100 mg/kg, intraperitoneally), yielded 4,5-di-O-[E]-caffeoylquinic acid. This substance was injected intraperitoneally in mice and showed anticonvulsant effect against pentylenetetrazole-induced seizures at doses of 25 and 50 mg/kg. It has often been shown that seizures induced by pentylenetetrazole are involved in inhibition and/or attenuation of GABAergic neurotransmission. However, other systems of the central nervous system such as adenosinergic and glutamatergic could be involved in the caffeoylquinic acid effects. Further studies should be conducted to verify that the target receptor could be participating in this anticonvulsant property. Although other investigations have reported a series of biological activities from Lychnophora species, this is the first report of central analgesic and anticonvulsant activity in species of this genus.     

Chemical composition of the essential oil of creeping thyme (Thymus serpyllum s.l.) growing wild in Lithuania

The results on the chemical composition of the essential oils hydrodistilled from three forms of T. serpyllum growing wild in the Curonian Spit (west of Lithuania) are presented in this study. GC and GC/MS results of volatile oils show that the analysed plants can be defined as a specific chemotype within the Serpyllum section, which can be characterised by a high content of 1,8-cineole (16.3-19.0%) in the essential oil. In addition, one form of the plants with white-coloured blossoms was exceptionally rich in E-carvyl acetate (18.7%). Phenolic compounds, thymol and carvacol, were not detected in the T. serpyllum plants analysed, which is a characteristic feature of the Serpyllum species growing in the Northern European countries.     

Anticonvulsant activity of fraction isolated from ethanolic extract of heartwood of Cedrus deodara

The heartwood of Cedrus deodara is traditionally used for the treatment of neurological disorders in India. In this study, the compound 3,4-bis(3,4-dimethoxyphenyl)furan-2,5-dione (BDFD) isolated from the ethanolic extract of C. deodara was evaluated for its anticonvulsant activity. The experimental studies were carried out in albino mice (18–22 g) and rats (180–220 g), employing different models of convulsions. The N-methyl-d-aspartic acid (NMDA)-induced lethality test and estimation of brain gamma-aminobutyric acid (GABA) were carried out to investigate the mechanism of action of this compound. BDFD gave dose-dependent protection against pentylenetetrazole (PTZ)-, pilocarpine- and 6-Hz-induced convulsions but it could not inhibit NMDA-induced lethality. Motor incoordination was displayed when the BDFD dose exceeded 400 mg/kg, whereas the therapeutic dose was below 100 mg/kg in the PTZ, pilocarpine and 6-Hz models (39–90 mg/kg). Furthermore, brain GABA estimation revealed that this compound increases the GABA level. BDFD dose levels up to 150 mg/kg did not prevent NMDA-induced lethality, which proves its weak influence on the excitatory neurotransmitter glutamate. The findings of the experiments on various animal models clearly demonstrated that BDFD possesses anticonvulsant activity by enhancing inhibitory GABAminergic neurotransmission.     

Effects of anticonvulsants on the in vivo and in vitro release of gaba

The actions of various anticonvulsant compounds on GABA release in vivo and in vitro were studied. An in vivo, superfusion of sensorimotor cerebral cortex was employed and drugs were administered either by intraperitoneal injection, or in superfusion fluid and release of endogenous amino acids was measured. The in vitro method involved superfusion of synaptosomes, with drugs dissolved in superfusate, with monitoring of the release of pre-loaded [U¹⁴C]-GABA. Two alkyl-GABA analogues, γ-acetylenic GABA and γ-vinyl GABA caused enhanced release of GABA to superfusate both in vivo and in vitro. However, phenobarbitone, diphenyl hydantoin, sodium n-dipropyl acetate and carbamazepine were without effect on GABA release in either test system. Taurine caused no detectable GABA release in vivo, or from purified synaptosomes in vitro, but did stimulate release in vitro, from crude synaptosome preparations containing mitochondria in large quantities, though histidine and leucine were equally effective.     

Chemical volatile composition and phytotoxic potential of Daphne gnidium L. leaves

Daphne gnidium L. (Thymelaeaceae) is an evergreen shrub from the Mediterranean area traditionally used for its medicinal and non-medicinal properties. Several studies showed its adverse impact on different targets including malignant cells, microbes, radicals, insects. The negative interactions between D. gnidium and other plant species have been rather neglected so far, as well as its chemical volatile composition. Therefore, this work aimed to assess the phytotoxic activity of D. gnidium on filter paper and soil in pre-emergence conditions by testing both the aqueous extract (10–100%) and the powder (0.25–1 g) obtained from the leaves as bioagrochemicals. The results showed that D. gnidium was able to significantly decrease seed germination and growth parameters of the receiver plants with different effectiveness (p-values < 0.05). Overall, Sinapis alba L. (Brassicaceae) was the most susceptible species followed by Lolium multiflorum Lam. (Poaceae) and Trifolium incarnatum L. (Fabaceae) while aqueous extract was more active than the powder. Solid-Phase Microextraction (SPME) sampling technique and Gas Chromatograph/Mass spectrometer (GC/MS) analyses were used to characterize the volatile fraction highlighting considerable differences in the composition of the analyzed samples. Hexahydrofarnesyl acetone (29.7%) followed by 3,7,11,15-tetramethyl-2-hexadecen-1-ol (28.3%) and β-damascenone (32.0%) followed by eudesma-1,4(15), 11-triene (27.1%) were detected as main volatile compounds of the powder and the aqueous extract, respectively.     

Anticonvulsant activity of some 2-aminoethanesulphonic acid (taurine) derivatives

A number of aliphatic 2-aminoethanesulphonic acid (taurine) derivatives were tested for their anticonvulsant activity in maximal electroshock seizure and pentylenetetrazole seizure threshold tests in mice. Certain piperidino, benzamido, phthalimido and phenylsuccinylimido derivatives were effective. Phthalimidoethanesulphon-N-methylamide, which inhibited the binding of both taurine and GABA to isolated synaptic membranes, appeared the best anticonvulsant among the derivatives tested.     

In vivo saturation binding of GABA‐A receptor ligands to estimate receptor occupancy using liquid chromatography/tandem mass spectrometry

Typically, the dose‐occupancy curves for GABA‐A receptor ligands are determined using in vivo binding of [³H]flumazenil. This study describes in vivo binding experiments without the use of tracer ligands. Bound and free fractions were measured directly using a highly sensitive LC/MS/MS detection method after in vivo administration of the GABA‐A ligands zolpidem, (RS)‐zopiclone, L‐838417 and flumazenil, to demonstrate affinity and saturation of the filter‐retained, membrane‐bound fraction. The in vivo binding of flumazenil and L‐838417 both saturated around 200 nm , at a similar level to the specific binding of (S)‐zopiclone after doses of the racemic zopiclone, using (R)‐zopiclone to estimate non‐specific binding. This saturable component represented an estimate of benzodiazepine binding sites available on GABA‐A receptors in vivo (200 nm ). Dose‐occupancy curves were constructed to estimate the dose required to achieve 50% occupancy and matched estimates obtained with tracer methods. In contrast to tracer methods, this method is uniquely suitable to the demonstration of stereoselective binding of the (S)‐isomer in vivo after doses of racemic zopiclone. These results demonstrate that the LC/MS/MS measurements of total drug concentrations typically used in early drug development can be adapted to provide information about receptor occupancy in vivo. Copyright © 2009 John Wiley & Sons, Ltd.     

Design,synthesis, and evaluation of anticonvulsant activities of benzoxazole derivatives containing the 1,2,4‐triazolone moiety

A novel series of benzoxazole derivatives containing 1,2,4‐triazolone ( 5a‐m ) was designed. These compounds were synthesized in order to screen their anticonvulsant activities by the maximal electroshock seizure (MES) model and the subcutaneous pentylenetetrazole (sc‐PTZ) seizure model in mice. The rotarod test was used to evaluate their neurotoxicities. Most of the compounds showed anti‐MES activities at 100 and 300 mg/kg. Compound 5f , which showed potential anticonvulsant activity in the MES model with ED₅₀ values of 22.0 mg/kg, was considered as the most promising one in this study. It exhibited greater safety than that of carbamazepine and valproate regarding neurotoxicity. The efficacy of compound 5f in inhibiting the tonic seizures and death induced by the convulsants 3‐mercaptopropionic acid and BIC was also verified. In an enzyme‐linked immunosorbent assay, compound 5f and the positive drug phenytoin significantly increased the γ‐aminobutyric acid (GABA) level in the mouse brain. Further, pretreatment with an inhibitor of the GABA synthesizing enzyme dramatically raised the ED₅₀ value of 5f in the MES model. These results confirmed that the compound 5f plays its anticonvulsive action via regulating the GABA function in the brain. Also, a docking study of the compound 5f in the benzodiazepine (BZD) binding site of the GABA_A receptor confirmed possible binding of the compound 5f with BZD receptors.     

Central Properties and Chemical Composition of Ocimum basilicum. Essential Oil

Abstract

Ocimum basilicum. L. (Lamiaceae) is an Egyptian plant used as a folkloric remedy in Egyptian traditional medicine. In the current study, the aerial part of this plant was used, and its essential oil was obtained by hydrodistillation. The essential oil of Ocimum basilicum. (OB) was screened for its composition and some CNS activities (viz., sedative, hypnotic, anticonvulsant, local anesthetic). When tested in mice, OB essential oil had no effect on motor activity up to a dose of 1.2 mL kg^?1 at 90 min postadministration. However, higher doses produced motor impairment at all time intervals. Pentobarbitone sleeping time tested in mice was significantly increased by all doses of the essential oil higher than 0.2 mL kg^?1. Intraperitoneal administration of OB essential oil significantly increased in a dose-dependent manner the latency of convulsion and percent of animals exhibiting clonic seizures. Likewise, it reduced lethality in response to different convulsive stimulus used in this study. The ED₅₀ values of the essential oil of OB were 0.61 mL kg^?1, 0.43 mL kg^?1, and 1.27 mL kg^?1, against convulsions induced by pentylenetetrazole, picrotoxin, and strychnine, respectively. A study of the local anesthetic activity of the OB essential oil by using a nerve block model employing in frog revealed that it had no local anesthetic effect. The LD₅₀ of the essential oil was 3.64 mL kg^?1 [correlation coefficient r = 0.961 and linear regression y. = 147 ln(x.) ? 141.7]. Gas chromatography (GC)/mass spectrometry (MS) analysis of the essential oil revealed the presence of linalool (44.18%), 1,8-cineol (13.65%), eugenol (8.59%), methyl cinnamate (4.26%), iso. caryophyllene (3.10%), and α.-cubebene (4.97%) as the main components. The observed anticonvulsant and hypnotic activities in this study could be related to the presence of a variety of terpenes in the essential oil.     

Phytochemical and Antiplatelet Investigation of Gundelia tournifortii.

ABSTRACT

Five known compounds from the aerial parts of Gundelia tournifortii. L. (scopoletin, isoscopoletin, esculin, and a mixture of β.-sitosterol and stigmasterol) were isolated and identified on the basis of spectral evidence (¹H NMR, ¹³C NMR, MS, and IR). The volatile oil from aerial parts of G. tournifortii. was obtained by hydrodistillation, for the first time, and its composition was determined by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). alpha-Terpinyl acetate (36.21%), methyl eugenol (12.57%), eugenol (6.7%), β.-caryophellene (5.94%), and zingiberene (5.84%) were the major oil components. The antiplatelet activity of G. tournifortii. was studied in vitro. using adenosine-5′-diphosphate (ADP) and arachidonic acid (AA) as agonists. The chloroform extract of G. tournifortii. was found to have a mild inhibitory effect on platelet aggregation induced by ADP and AA. None of the pure isolated compounds or the volatile oil showed an inhibitory effect on platelet aggregation using ADP and AA as agonists.     

DNA profiling of Acorus calamus chemotypes differing in essential oil composition.

The phylogenetic relationship of Acorus gramineus and three types of Acorus calamus was analyzed by comparing the 700 bp sequence of a 5S-rRNA gene spacer region. Although there was no intra-specific variation in the essential oil profile of A. gramineus which contained a phenylpropanoid (Z-asarone) as a predominant constituent, A. calamus was classified into two chemotypes: chemotype A in which Z-asarone is a major essential oil constituent and chemotype B which contained sesquiterpenoids predominantly. An intermediate type (M) of these two chemotypes in various ratios was also observable. The NJ tree constructed based on the sequences revealed that A. gramineus was clearly distinguished from any of the chemotypes of A. calamus and that the phylogenetic relationship predicted by the spacer region data correlated well with the essential oil chemotype pattern of A. calamus.     

Design, synthesis and evaluation of anticonvulsant activity of pyridinyl-pyrrolidones: a pharmacophore hybrid approach

Various 1‐[6‐(4‐substituted phenyl)‐3‐cyano‐4‐(substituted phenyl)‐pyridin‐2‐yl]‐5‐oxopyrrolidine‐3‐carboxylic acids ( 3a–t ) were designed and synthesized by clubbing pyrrolidinones and pyridines, the two active anticonvulsant pharmacophores. All the synthesized compounds fulfilled the requirements of suggested pharmacophoric model for anticonvulsant activity. Their in vivo anticonvulsant evaluation was performed by maximal electroshock seizure (MES) and subcutaneous pentylenetetrazole (scPTZ) tests. The minimal motor impairment was assessed by rotorod test and the estimation of various liver enzymes was performed to check the magnitude of liver toxicity posed by the synthesized compounds. Compounds 3d and 3k displayed comparable anticonvulsant activity to the standard drugs with ED₅₀ values of 13.4 and 18.6 mg/kg in electroshock screen, repectively. The compounds 3d and 3k were also found to have encouraging anticonvulsant activity (ED₅₀ = 86.1 and 271.6 mg/kg, respectively) in scPTZ screen. Interestingly, they did not show any sign of motor impairment at the maximum dose administered and were not toxic to the liver.     

Effect of metabolites of valproic acid on the metabolism of GABA in brain and brain nerve endings

Seven metabolites of valproic acid (VPA), i.e. 2-en-VPA, 3-en-VPA, 4-en-VPA, 3-hydroxy-VPA, 4-hydroxy-VPA, 5-hydroxy-VPA and 3-keto-VPA and valproic acid itself were examined for their effects on the metabolism of γ-aminobutyric acid (GABA) in the brain and brain nerve endings (synaptosomes) in mice. Administered in anticonvulsant doses, valproic acid and its metabolites caused elevations of the synaptosomal GABA content which were correlated with their anticonvulsant potency. No relationship was observed between the relative anticonvulsant activity of the respective compounds and the increase of GABA in the whole brain. The synaptosomal activity of glutamate decarboxylase (GAD) was increased parallel to the elevation of GABA and the activity of GABA aminotransferase (GABA-T) was partly inhibited. The present results emphasise the usefulness of determining the in vivo effects of drugs on GABA metabolism in brain nerve terminals which is thought to be the critical factor controlling the functioning of the amino acid as a neurotransmitter.     

Beneficial effect of Citrus limon peel aqueous methanol extract on experimentally induced urolithic rats

Context: Citrus limon (L.) Burm.f. (Rutaceace) is a commonly available fruit variety with high medicinal and industrial values.

Objective: Lemon peel (LP) extract was studied as a potent preventive and curative agent for experimentally induced hyperoxaluric rats.

Materials and methods: Gas chromatography–mass spectrometry (GC–MS) analyses and toxicity study were performed for aqueous methanol LP extract. Twenty-four Wistar rats were segregated into four groups. Group 1: Control; Group 2: Urolithic (ethylene glycol (EG) – 0.75%); Group 3: Preventive study (EG?+?LP extract administration from 0th to 7th week); Group 4: Curative study (EG?+?LP extract administration from 4th to 7th week). Animals received LP extract daily by oral administration (100?mg/kg body weight) for 7 weeks.

Results and discussion: GC–MS analyses revealed that compound 6 was abundant in the LP extract (32%) followed by compound 1 (～21%). The LD₅₀ value of LP extract was found to be >5000?mg/kg of body weight. Urolithic rats showed significantly higher urinary calcium and oxalate (4.47?±?0.44 and 18.86?±?0.55?mg/24 h, respectively) excretion compared with control and experimental rats. Renal function parameters like urea (84?±?8.5 and 96.1?±?3.6?mg/dL), creatinine (1.92?±?0.27 and 1.52?±?0.22?mg/dL), and urinary protein (2.03?±?0.02 and 2.13?±?0.16?mg/24 h) were also reduced by LP extract (p?<?0.001) and corroborated with tissue analyses (SOD, catalase, and MDA levels) and histological studies in normal and experimental animals. Immunohistochemical staining of THP and NF-κB in urolithic animals showed elevated expression than the control, while LP extract suppressed the expression of these proteins.

Conclusion: In conclusion, lemon peel is effective in curing kidney stone disease and also can be used to prevent the disease and its recurrence.