1,721,125 research outputs found
Fast high-performance liquid chromatography analysis of phenethylamine alkaloids in Citrus natural products on a pentafluorophenylpropyl stationary phase
No full textIn this study, the chromatographic performance of a pentafluorophenylpropyl (PFPP) stationary phase was evaluated for the rapid separation of phenethylamine alkaloids (i.e. (±)-octopamine, (±)-synephrine, tyramine, N-methyltyramine and hordenine) in Citrus aurantium plant material (fruits and peel), various Citrus species, extracts and dietary supplements claiming to contain C. aurantium. The problems of phenethylaminealkaloid separation, such as peak tailing, low retention and low resolution, were successfully solved with this stationary phase. The parameters used for the method optimization included the mobile phase counter ion concentration and column temperature. A Discovery HS F5 column (150mm×4.6mm i.d., 5m) was used, with an isocratic mobile phase composed of 10mM ammonium acetate in 90:10 ACN–H2O (v/v), at a flow rate of 1.0 mL/min. The column temperature was set at 20 ◦C. The photodiode array detector monitored the eluent at 225 nm. The total analysis time was 10 min. The validation parameters, such as linearity, sensitivity, accuracy, precision and specificity, were found to be highly satisfactory. With a simple sample preparation procedure, different matrices were successfully analyzed for their alkaloid content. The results indicated that the products on sale, labeled as dietary supplements, vary widely in the quantitative composition of the active constituents: the amount of (±)-synephrine, the major alkaloid, in such products ranged from 0.65 to 27.41 mg/g. The other compounds were either not detected or were present at low levels. The developed method can be considered suitable for the quality control of Citrus plant material and commercial products
Determination of ephedrine alkaloids in Ephedra natural products using HPLC on a pentafluorophenylpropyl stationary phase
No full textIn this study a pentafluorophenylpropyl (PFPP) stationary phase was applied to the fast and reliable qualitative and quantitative analysis of ephedrine alkaloids in Ephedra plant material and derivatives. A Discovery HS F5 column (150 mm × 4.6 mm i.d., 5 um) was used, with an isocratic mobile phase composed of ammonium acetate (7 mM) in acetonitrile–water (90:10, v/v), at a flow rate of 1.0 ml/min. The column temperature was set at 45 °C. UV detection was set at 215 and 225 nm. The total analysis time was 16 min. The validation parameters, such as linearity, sensitivity, accuracy, precision and specificity, were found to be highly satisfactory. Sonication and microwave extractions were compared in order to optimize the yield of the target analytes. Under the optimized extraction conditions (based on two cycles of sonication with methanol at 40 °C for 15 min), different matrices containing Ephedra were successfully analyzed for their alkaloid content. The method was applied to the analysis of standard reference materials (SRMs) containing Ephedra. Furthermore, the developed technique allowed the simultaneous determinationof ephedrine alkaloids and synephrine, the main phenethylamine alkaloid of Citrus aurantium, that has replaced Ephedra in dietary supplements used in the treatment of obesity. The results indicated that this procedure is suitable for the phytochemical analysis of Ephedra plant material and extracts, and can be applied to demonstrate the label claims for product content, including the absence of ephedrine alkaloids in Ephedra-freeproducts
Attivité antifongique in vitro de l’huille essentielle de chemotypes de lavandin
No full textAttivité antifongique in vitro de l’huille essentielle de chemotypes de lavandi
SEPARATION OF 18-ALPHA-GLYCYRRHETINIC AND 18-BETA-GLYCYRRHETINIC ACID BY HIGH-PERFORMANCE THIN-LAYER CHROMATOGRAPHIC DENSITOMETRY
No full textA high-performance thin-layer chromatographic method with scanning densitometry was developed for the simultaneous separation and determination of 18-alpha- and 18-beta-glycyrrhetinic acid
Olio essenziale di Katrafay (Cedrelopsis grevei H. Baillon): profilo fitochimico e attività biologica
No full textCedrelopsis grevei H. Baillon, noto anche come Katrafay, è una pianta aromatica appartenente alla famiglia delle Ptaeroxylaceae, originaria del Madagascar. L’olio essenziale ottenuto dalla corteccia del fusto è largamente utilizzato nella medicina popolare per curare reumatismi, dolori muscolari, come agente antibatterico ed antimicotico; altri estratti sono stati utilizzati per il trattamento della malaria, della febbre e dello stato di affaticamento. Tuttavia, in letteratura non è stata riportata una descrizione approfondita della composizione dell’olio essenziale di C. grevei, probabilmente per la notevole variabilità fra le diverse zone di produzione. Questo studio è pertanto finalizzato alla caratterizzazione chimica completa dell’olio essenziale proveniente dal Madagascar, insieme alla valutazione delle sue attività citotossiche e antimicrobiche verso batteri fitopatogeni. I campioni di olio essenziale, forniti dalla ditta Ophera srl, sono stati caratterizzati e quantificati rispettivamente mediante tecniche GC-MS e GC-FID. Utilizzando i dati di ritenzione e gli spettri di massa sono stati identificati 35 composti, che rappresentano l’80% della composizione totale dell’olio essenziale. I componenti principali determinati nei campioni analizzati in questo studio sono rappresentati da ishwarane, β-elemene, α-copaene, calamenene, β-selinene, γ-muurolene, α-muurolene e β-pinene. L'olio essenziale di C. grevei è stato poi testato per la sua attività citotossica nei confronti di linee cellulari Caco 2, Hep-2, WKD e antimicrobica nei confronti di batteri fitopatogeni di interesse per l'agricoltura biologica, quali Agrobacterium tumefaciens, Agrobacterium vitis, Clavibacter michiganensis sub. michiganensis e Pseudomonas syringae pv syringae. I risultati ottenuti permettono di giungere ad alcune considerazioni in merito sia alla composizione di un o.e. ottenuto da un’insolita droga, quale la corteccia, al suo significato metabolico e sia sull’attività biologica dei sesquiterpeni, componenti maggiormente rappresentati nell’olio essenziale di C. grevei
Caratterizzazione fitochimica, proprietà biologiche e nuove prospettive di utilizzo di ribes, lamponi e mirtilli
No full textCaratterizzazione fitochimica, proprietà biologiche e nuove prospettive di utilizzo di ribes, lamponi e mirtill
Variability of the active compounds in phytotherapic products with antidepressant activity: the case of Hypericum perforatum L.
No full textIn this presentation, the variability of the active compounds in phytotherapic products containing Hypericum perforatum L. was discussed
Nuove metodiche HPLC per la separazione enantiomerica di agonisti adrenergici di Citrus aurantium L. var. amara
No full textIn questa presentazione vengono descritte tecniche HPLC per la determinazione di agonisti adrenergici in Citrus aurantium L. var. amara
Recent advances in the chromatographic analysis of phenethylamine alkaloids in natural products
No full textPhenethylamine alkaloids are a group of non-heterocyclic compounds widely distributed in plants. The main representative molecules of this class are ephedrine (isolated from Ephedra species) and synephrine (isolated from Citrus species). Products containing E. sinica or C. aurantium have been widely used for the treatment of obesity or for increasing performance in body-building. However, these products have shown side-effects on the cardiovascular system by means of adrenergic stimulation.
Considering the variability in the quality composition of the secondary metabolites of Ephedra and Citrus natural products, continued research effort is desired toward the application of fully validated methods to monitor the quality of crude drugs, extracts and dietary supplements.
There have been many reports on the HPLC determination of phenethylamine alkaloids in plant material and natural products. RP-HPLC with UV detection is usually employed for the determination of these analytes and most separations are based on ion-pairing. In recent years, RP-HPLC stationary phases that contain polar groups as part of their structure often succeed in retaining and resolving compounds that C18 phases do not, because they can interact with analytes by mechanisms that are not possible with C18 alkyl chains. Of many such phases currently available, the pentafluorophenylpropyl (PFPP) stationary phase has shown wide applicability.
In this study, the chromatographic performance of the fluorinated stationary phase was investigated to develop reliable HPLC methods for the separation and quantitative determination of phenethylamine alkaloids in Ephedra and Citrus natural products. The proposed methods were carefully optimised and fully validated in agreement with ICH guidelines. The practical applicability of the developed techniques was demonstrated by the analysis of Ephedra and Citrus natural products.
Furthermore, due to the difference in the pharmacological effect between the two enantiomeric forms of synephrine, an efficient method for the enantioselective separation and determination of this compound in Citrus natural products was optimized and validated
Study on the racemization of synephrine by off-column chiral high-performance liquid chromatography
No full textIn this study, the racemization kinetic parameters of R-(-)-synephrine, the active phenethylamine alkaloid of Citrus aurantium L., were determined by means of an off-column HPLC method. Enantioseparation was carried out in different buffer solutions and solvents on a chiral stationary phase (CSP) with cellobiohydrolase as the chiral selector (Chiral-CBH, 100 mm x 4.0 mm i.d., 5 microm). The mobile phase was 10 mM sodium phosphate buffer (pH 6.0)-2-propanol (95:5, w/w), with 50 microM disodium EDTA, at 0.8 mL/min. The column was thermostatted at 20 degrees C and detection was set at 225 nm. The influence of pH value, ionic strength, temperature and addition of organic modifier on the rate constant, the half-life of racemization and the free energy barrier of racemization of R-(-)-synephrine were determined. Among the different chemical and physical parameters evaluated as affecting the racemization of naturally occurring R-(-)-synephrine, pH, temperature and addition of an organic co-solvent appear to have the strongest effect, while ionic strength does not exert a significant influence on the racemization rate. The results of the present study indicated that synephrine racemization is possible at high temperature at both acidic and basic pH values; therefore, the extraction procedure of R-(-)-synephrine from the plant material should be carried out under specific conditions to preserve the stereochemical integrity and the biological activity of this secondary metabolite
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