Grażyna Zgórka

VARIATION OF FREE PHENOLIC ACIDS IN MEDICINAL PLANTS BELONGING TO THE LAMIACEAE FAMILY

Ten species belonging to the family Lamiaceae and representing the most popular medicinal plants used in Polish phytotherapy were examined for the content of free phenolic acids (PhAs). Two depsides, rosmarinic and chlorogenic acids, as well as eight simple PhAs, protocatechuic, gentisic, p-hydroxybenzoic, caffeic, vanillic, syringic, p-coumaric and ferulic acids, in different qualitative and quantitative proportions depending on the plant examined were determined by the rapid, selective and accurate method combining solid-phase extraction and high-performance liquid chromatography.

Solid-phase extraction and reversed-phase high-performance liquid chromatography of free phenolic acids in some Echinacea species

Abstract A new method is described combining solid-phase extraction (SPE) and reversed-phase high-performance liquid chromatography (RP-HPLC) for the isolation, purification as well as qualitative and quantitative determination of free phenolic acids in six Echinacea species. Plant extracts were purified and phenolic acids isolated on octadecyl and quaternary amine Bakerbond SPE columns; final eluates were analysed by RP-HPLC. Significant differences in the composition and amount of phenolic acids within Echinacea genus have been shown. The method can be used for quick screening analysis of the content of phenolic acids in plant material.

Application of conventional UV, photodiode array (PDA) and fluorescence (FL) detection to analysis of phenolic acids in plant material and pharmaceutical preparations

Free phenolic acids (PhAs) contained in methanolic extracts of Eleutherococcus senticosus roots and pharmaceutical preparations, deriving from this plant, were isolated by solid-phase extraction (SPE) and identified by reversed-phase high-performance liquid chromatography (RP-HPLC). To obtain precise, accurate and validated results of qualitative and quantitative analysis, ultraviolet (at lambda=254 nm), photodiode array (at lambda=254 and 280 nm) and fluorescence (at lambda(Ex)=230 or 265 nm and lambda(Em)=350 nm) detection was used. Additionally, the HPLC separation of PhAs on two different octadecyl sorbents: Hypersil (Shandon, UK) and Symmetry (Waters, USA) was performed. Eight PhAs: chlorogenic, protocatechuic, p-hydroxybenzoic, caffeic, vanillic, syringic, p-coumaric and ferulic, in different quantitative proportions, were identified, both in the roots of E. senticosus and pharmaceutical formulations examined.

Pressurized liquid extraction versus other extraction techniques in micropreparative isolation of pharmacologically active isoflavones from Trifolium L. species

As a new sample preparation technique, pressurized liquid extraction (PLE), in combination with reversed-phase liquid chromatography (RP-LC) and photodiode-array (PDA) detection were used for the isolation and determination of phytoestrogenic isoflavones in hydrolyzed extracts obtained from aerial parts of five Trifolium L. (clover) species. To optimize the effectiveness of PLE procedure, variable extraction parameters: methanol and acetone (or their 75% aqueous solutions), as extraction solvents, temperatures (75, 100 and 125 degrees C) and the changeable number of static extraction cycles were tested. Additionally, two other micropreparative techniques: ultrasound-assisted extraction (UAE), and conventional solvent extraction (CSE), under optimized conditions, were also used and compared. Optimum extraction efficiency, expressed in the highest yield of biochanin A, formononetin, daidzein and genistein from plant material, with PLE, using methanol-water (75:25, v/v) as an extraction solvent, an oven temperature of 125 degrees C and three 5-min static extraction cycles, was obtained.

Sample preparation for taxol and cephalomannine determination in various organs of Taxus sp.

Solid-phase extraction and preparative thin-layer chromatography were applied as sample preparation techniques for the purification of crude extracts from twigs and needles of various Taxus species as well as for the isolation of taxol and cephalomannine for further reversed phase high performance liquid chromatography analysis. Significant differences in the contents of taxanes examined were found. The preparative chromatographic methods used were compared and evaluated as routine and reproducible procedures for the rapid isolation and determination of taxol and cephalomannine in plant extracts.

Effect of picloram and methyl jasmonate on growth and taxane accumulation in callus culture of Taxus × media var. Hatfieldii

We have analysed the effect of some culture conditions and media components on callus growth rate and production of taxanes in callus of Taxus × media var. Hatfieldii. For callus induction and maintenance a Gamborg B5 medium and a White - Rangaswamy medium (WR) with different modifications were used. On an improved WR medium (containing 10 μM picloram) the callus growth factor increased up to 5.8 fold (fresh weight). Picloram only enhanced the growth of callus, but not taxane production. On WR medium with (100 μM) methyl jasmonate the paclitaxel content increased from 2.37 μg g-1 to 90 μg g-1 and cephalomannine from 5.14 μg g-1 to 29.14 μg g-1 (dry weight), whereas growth of the cultures ceased. The presence of paclitaxel and cephalomannine was established by high performance liquid chromatography.

Determination of furanochromones and pyranocoumarins in drugs and Ammi visnaga fruits by combined solid-phase extraction–high-performance liquid chromatography and thin-layer chromatography–high-performance liquid chromatography

A new, simple and rapid solid-phase extraction method for the determination of furanochromones and pyranocoumarins in Ammi visnaga L. fruits and pharmaceuticals by reversed-phase high-performance liquid chromatography (RP-HPLC) was developed. The isolation of compounds examined was carried out on octadecyl BakerBond SPE columns using various concentrations of methanol, acetonitrile and tetrahydrofuran in water. High and reproducible recoveries were obtained. To compare the results of quantitative analysis a preparative TLC procedure was also elaborated and carried out.

Column chromatography and preparative TLC for isolation and purification of coumarins from Peucedanum verticillare L. Koch ex DC

Preparative separation and isolation of coumarins from petroleum ether and methanol extracts of the fruits and roots of Peucedanum verticillare L. Koch ex DC (Umbelliferae = Apiaceae) have been achieved by column chromatography and normal- and reversedphase TLC with gradient elution. Isolated coumarins were identified by comparison with standards in analytical TLC and in RP HPLC with gradient elution, by melting point (m.p.) measurement, by UV spectroscopy, by MS, and by 1H and 13C NMR spectroscopy. Esculin, umbeliferone, bergapten, xanthotoxin, isoimperatorin, imperatorin, psoralen, and cis-kellactone were isolated for the first time from P. verticillare L. Koch ex DC. Two angular-type pyranocoumarins isolated from the roots and fruits of Peucedanum verticillare L. Koch ex DC. were identified as pteryxin and epoxypteryxin by MS and 1H and 13C NMR.

Retention behavior of coumarin compounds on silica and florisil TLC layers

This paper describes the retention behavior on silica and Florisil layers of ten coumarin compounds identified and isolated from the fruits of Libanotis dolichostyla Schischkin (Umbelliferae). The variation of retention as a function of the solvent composition has been studied. The linear relationships between retention factors (RF and RM) of coumarins and log c of various polar organic modifiers in the non-polar mobile phase were established. The elaborated model of retention was used for further optimization of separation conditions for preparative isolation of some coumarins contained in crude fractions derived from a petroleum extract obtained from the fruits of L. dolichostyla.

Evaluation of the phytochemical composition and protective activities of methanolic extracts of Centaurea borysthenica and Centaurea daghestanica (Lipsky) Wagenitz on cardiomyocytes treated with doxorubicin

ABSTRACT Centaurea L. is a genus of the family Asteraceae that comprises over 600 taxa. Representatives of the Centaurea genus were used as natural medications for many diseases. Methanolic-aqueous extracts from aerial parts of two Centaurea species: C. borysthenica Gruner and C. daghestanica (Lipsky) Wagenitz were studied for their polyphenolic composition and potential protective effect on cardiomyocytes treated with doxorubicin. Effectiveness of doxorubicin in cancer therapy is limited by a dose-dependent cardiotoxicity. Oxidative stress is a widely recognized mechanism of this phenomenon. One of the most important strategies has been an application of drug together with antioxidant agents. A cardioprotective effect of selected extracts of Centaurea species was suspected in this study. Cell viability, oxidative stress, and mitochondrial membrane potential analyses showed protective activity of the methanolic extract of C. borysthenica and C. daghestanica on rat cardiomyocytes treated with doxorubicin. Although C. borysthenica is more effective as a cardiomyocyte protective agent, in higher concentrations it weakened the drug activity. C. daghestanica extract did not change the doxorubicin efficacy in the evaluated experiment. Interestingly, both tested extracts were cytotoxic for myeloma cells. The detected antioxidant activity of the studied extracts can be used in the prevention of doxorubicin-induced cardiotoxicity.