Michał Gleńsk

Anticonvulsant and acute neurotoxic effects of imperatorin, osthole and valproate in the maximal electroshock seizure and chimney tests in mice: A comparative study

The aim of this study was to determine and compare the anticonvulsant and acute adverse (neurotoxic) effects of imperatorin and osthole (two natural coumarin derivatives) with valproate (a classical antiepileptic drug) in the maximal electroshock seizure and chimney tests in mice. The anticonvulsant and acute adverse effects of imperatorin, osthole and valproate were determined at 15, 30, 60 and 120 min after their systemic (i.p.) administration. The evaluation of time-course and dose-response relationships for imperatorin, osthole and valproate in the maximal electroshock seizure test revealed that the compounds produced a clear-cut antielectroshock action in mice and the experimentally derived ED(50) values for imperatorin ranged between 167 and 290 mg/kg, those for osthole ranged from 253 to 639 mg/kg, whereas the ED(50) values for valproate ranged from 189 to 255 mg/kg. The evaluation of acute neurotoxic effects in the chimney test revealed that the TD(50) values for imperatorin ranged between 329 and 443 mg/kg, the TD(50) values for osthole ranged from 531 to 648 mg/kg, while the TD(50) values for valproate ranged from 363 to 512 mg/kg. The protective index (as a ratio of TD(50) and ED(50) values) for imperatorin ranged between 1.13 and 2.60, for osthole ranged from 0.83 to 2.44, and for valproate ranged between 1.72 and 2.00. In conclusion, both natural coumarin derivatives deserve more attention from a preclinical point of view as compounds possessing some potentially favorable activities in terms of suppression of seizures, quite similar to those reported for valproate.

Immunomodulatory and anti-inflammatory activity of selected osthole derivatives.

I From osthole [7-methoxy-8-(3-methyl-but-2-enyl)-chromen-2-one] (), obtained by selective extraction of Peucedanum ostruthium (L.) W. Koch roots, ostholic acid (II) was synthetized as a result of its oxidation with chromium trioxide. From ostholic acid, through its chloride, four amides were obtained: the morpholide 1, the p-chloro-benzylamide 2, the piperidine 3 and the N-methyl-piperazide 4. Except for 1, other compounds have not been described before. The amides 1 - 4 and their precursor osthole (I) were tested for their potential activities in selected immunological assays. The compounds showed moderate inhibitory activity in the humoral immune response to sheep erythrocytes in mice in vitro, and 4 was the most suppressive. The effects of 1 and 3 on concanavalin A- and pokeweed mitogen-induced mouse splenocyte proliferation were inhibitory and those of 4 stimulatory. The compounds were also tested for their activity on tumour necrosis factor α and interleukin 6 production, induced by lipopolysaccharide, in cultures of rat peritoneal cells and human peripheral blood mononuclear cells. Compounds 1, 3 and 4 inhibited tumour necrosis factor α (rat cells), whereas compound 2 stimulated the production of both cytokines. Compounds 1, 2 and 3 were also strongly inhibitory on tumour necrosis factor α production in human blood cells (73, 78 and 80% inhibition at 10 μg/ml, respectively). On the other hand, 2 and 4 stimulated the interleukin 6 production (2- to 3-fold stimulation). In addition, 2 and 4 suppressed the carrageenan-induced inflammation in mice (56.5% and 68.3% inhibition, respectively). In summary, the compounds predominantly displayed suppressive and anti inflammatory activities in the investigated models

Anticonvulsant effects of four linear furanocoumarins, bergapten, imperatorin, oxypeucedanin, and xanthotoxin, in the mouse maximal electroshock-induced seizure model: a comparative study

The aim of this study was to determine and compare the anticonvulsant activities of four natural furanocoumarins [bergapten (5-methoxypsoralen), imperatorin (8-isopentenyloxypsoralen), oxypeucedanin (5-epoxy-isopentenyloxypsoralen) and xanthotoxin (8-methoxypsoralen)] in the maximal electroshock-induced seizure test in mice. The anticonvulsant effects of bergapten, imperatorin, oxypeucedanin, and xanthotoxin were evaluated at 15, 30, 60 and 120 min after their systemic (intraperitoneal) administration. Tonic hind limb extension (seizure activity) was evoked in adult albino Swiss mice by a current (sine-wave, 25 mA, 500 V, 50 Hz, 0.2 s stimulus duration) delivered via auricular electrodes. The time courses of protection by bergapten, imperatorin, oxypeucedanin and xanthotoxin against maximal electroshock-induced seizures revealed that 300 mg/kg imperatorin and xanthotoxin (C-8 substituted derivatives of psoralen) exerted strong anticonvulsant activity, whereas 300 mg/kg bergapten and oxypeucedanin (C-5 substituted derivatives of psoralen) did not produce any anticonvulsant activity in this model. In conclusion, imperatorin and xanthotoxin protected the animals against maximal electroshock-induced seizures, whereas bergapten and oxypeucedanin, despite their chemical and structural similarities to xanthotoxin and imperatorin, exerted no anticonvulsant activity in this seizure test.

2D TLC - Graft Planar Chromatography in the Analysis of a Mixture of Phenolic Acids

Of the many chromatographic methods currently available, thin-layer chromatography (TLC) is widely used for the rapid analysis of plant extracts. Although, most practical planar chromatographic problems can be solved by use of a single TLC plate, the power of one-dimensional TLC is often inadequate for clean resolution of the compounds present in complex samples. A marked improvement of the separation for such samples can be achieved by multidimensional (MD) separation procedures. One possible form of multidimensional planar separation is the form of 2D TLC known as graft planar chromatography in which chromatographic plates are connected for capillary-controlled planar chromatography. In this variant of 2D TLC the first development can be performed on an RP-18W HPTLC plate and that in the perpendicular direction on a silica gel TLC plate.

Determination of Ursolic and Oleanolic Acid in Sambuci Fructus

Elderberries are used in the preparation of pie, jelly, punch, wine, or liqueur, as well as in many herbal remedies and food supplements. Elderberry products may provide diaphoretic, diuretic, antioxidant, and immunostimulant activities that offer protection against cold and flu. Herein, we report for the first time the qualitative and quantitative evaluation of two isomeric triterpenoids isolated from Sambuci fructus. The analysis revealed that ursolic acid and oleanolic acid are present in Sambuci fructus. The average concentration of ursolic acid was ca. three times higher than the concentration of oleanolic acid. The triterpenoids were detected and quantified using chromatographic methods such as TLC and HPLC. Spectroscopic techniques, including HR‐MS and 2D‐NMR, allowed unequivocal structure determination.

TLC as a rapid and convenient method for saponin investigation

At an early stage of investigation natural compounds in plants it is essential to have suitable analytical methods available for rapid detection and characterization of the constituents present. Identification of metabolites and their levels at this early stage is also important because it enables collection of the right plant material and acts as a guide to rational and selective isolation procedures.

Two-dimensional TLC with a sorbent gradient for the analysis of alfalfa root saponins

SummaryA mixture of saponin standards obtained from the roots of Medicago sativa (Fabaceae) was chromatographed by two-dimensional TLC with a sorbent gradient. In this variant of 2D-TLC (denoted as graft TLC) the first development was performed on a TLC RP-18 plate and in the perpendicular direction on a TLC Silica gel plate. Additionally, the results obtained were compared with those acquired by 2D-TLC on the same monolayer stationary phase. The total saponin mixture consisting of 18 components could be separated into 17 individual saponins with a sorbent gradient, but into only 15 saponins by conventional 2D-TLC. Moreover, when using sorbent gradient the spots were spread over a relatively larger surface area of the silica gel plate. The results obtained indicate that solid phase gradient TLC gave better separation of the saponin mixture investigated and was quite simple and easy to perform.

Assessment of the Combined Treatment with Umbelliferone and Four Classical Antiepileptic Drugs Against Maximal Electroshock-Induced Seizures in Mice

Background/Aims: The aim of this study was to determine the effects of umbelliferone (7-hydroxycoumarin; UMB) on the anticonvulsant potency of four classical antiepileptic drugs (carbamazepine (CBZ), phenytoin (PHT), phenobarbital (PB) and valproate (VPA)) in the mouse maximal electroshock-induced seizure (MES) model. Results: UMB administered systemically intraperitoneally (ip) in a dose of 150 mg/kg significantly elevated the threshold for maximal electroconvulsions (p < 0.05) in mice. Moreover, UMB (150 mg/kg) co-administered with PB and VPA significantly enhanced the anticonvulsant potency of these drugs by reducing their median effective doses (ED50 values) from 35.39 to 21.78 mg/kg (p < 0.01) for PB, and from 281.4 to 215.5 mg/kg (p < 0.01) for VPA. In contrast, UMB (150 mg/kg, ip) had no significant effect on the antiseizure activity of CBZ and PHT in the mouse MES model. Neither total brain PB, nor total brain VPA concentrations were altered after ip administration of UMB, indicating a pharmacodynamic nature of interactions between the tested drugs. Conclusions: The selective potentiation of the anticonvulsant potency of PB and VPA by UMB, and lack of any pharmacokinetic interactions between drugs, make the combinations of UMB with PB or VPA worthy of consideration for epileptic patients who are refractory to standard antiepileptic treatment.

In vitro evaluation of the antioxidant and antimicrobial activity of DIMBOA [2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one]

Abstract The aim of this study was to evaluate the in vitro antioxidant and antimicrobial properties of the natural cyclic hydroxamic acid: 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA). Antioxidant activity of the isolated DIMBOA was examined using DPPH, FRAP and ABTS tests. It was found that DIMBOA exhibits a potent free-radical scavenging activity and a weaker iron (III) ions reducing activity. Antimicrobial activity against selected G(+), G(–) bacterial strains and against yeasts-like reference strains of fungi was investigated using disk-diffusion method. It has been shown that DIMBOA possess growth inhibitory properties against many strains of studied bacteria and fungi, such as Staphylococcus aureus, Escherichia coli as well as against Saccharomyces cerevisiae. Graphical abstract

Effect of xanthotoxin (8-methoxypsoralen) on the anticonvulsant activity of classical antiepileptic drugs against maximal electroshock-induced seizures in mice.

The effects of xanthotoxin (8-methoxypsoralen) on the anticonvulsant activity of four classical antiepileptic drugs (carbamazepine, phenobarbital, phenytoin and valproate) were studied in the mouse maximal electroshock seizure model. Tonic hind limb extension (seizure activity) was evoked in adult male albino Swiss mice by a current (25 mA, 500 V, 50 Hz, 0.2 s stimulus duration) delivered via auricular electrodes. Total brain concentrations of antiepileptic drugs were measured by fluorescence polarization immunoassay to ascertain any pharmacokinetic contribution to the observed anticonvulsant effects. Results indicate that xanthotoxin (50 and 100 mg/kg, i.p.) significantly potentiated the anticonvulsant activity of carbamazepine against maximal electroshock-induced seizures (P<0.05 and P<0.001, respectively). Similarly, xanthotoxin (100 mg/kg, i.p.) markedly enhanced the anticonvulsant action of valproate in the maximal electroshock seizure test (P<0.001). In contrast, xanthotoxin (100 mg/kg, i.p.) did not affect the protective action of phenobarbital and phenytoin against maximal electroshock-induced seizures in mice. Moreover, xanthotoxin (100 mg/kg, i.p.) significantly increased total brain concentrations of carbamazepine (P<0.001) and valproate (P<0.05), but not those of phenytoin and phenobarbital, indicating pharmacokinetic nature of interactions between drugs. In conclusion, the combinations of xanthotoxin with carbamazepine and valproate, despite their beneficial effects in terms of seizure suppression in mice, were probably due to a pharmacokinetic increase in total brain concentrations of these antiepileptic drugs in experimental animals.