F. F. Vincieri

New uses for old drugs. Auranofin, a clinically established antiarthritic metallodrug, exhibits potent antimalarial effects in vitro: Mechanistic and pharmacological implications

The clinically established gold‐based antiarthritic drug auranofin (AF) manifests a pronounced reactivity toward thiol and selenol groups of proteins. In particular, AF behaves as a potent inhibitor of mammalian thioredoxin reductases causing severe intracellular oxidative stress. Given the high sensitivity of Plasmodium falciparum to oxidative stress, we thought that auranofin might act as an effective antimalarial agent. Thus, we report here new experimental results showing that auranofin and a few related gold complexes strongly inhibit P. falciparum growth in vitro. The observed antiplasmodial effects probably arise from direct inhibition of P. falciparum thioredoxin reductase. The above findings and the safe toxicity profile of auranofin warrant rapid evaluation of AF for malaria treatment in animal models.

GC–MS analysis of essential oil of some commercial Fennel teas

Abstract Fennel teas were prepared by classical infusion or microwave decoction of unbroken and crushed fruits, three pre-packaged teabags and two instant teas. Their volatile constituents were obtained by extraction with n-hexane and analysed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC–MS), using two columns with stationary phases of different polarity. Of the constituents 85–95% were identified on the basis of their GC retention times and their mass spectra in relation to authentic compounds. No volatile constituents were detected in one sample of instant tea. Conventional teas from crushed fruits and teas prepared from the other instant tea showed the highest levels of volatile constituents. Anethole (30–90%) and/or anisaldehyde (0.7–51%) were the main constituents of all the samples. Methychavicol (0.8–4.1%), eugenol (1.5–11.3%) and fenchone (0.5–47%) were detected in most samples. Carvone (2.1–6.1%) was presenting only some teabags and camphor (2.3–2.6%) in others. The volatile constituents of only one instant tea included limonene (1.4%) and α-terpineol (0.4%).

HPLC-DAD and TLC-Densitometry for quantification of hypericin inHypericum perforatum L. Extracts

SummaryHypericum perforatum L. is a spontaneous perennial herbaceous plant, widely distributed in Europe, Asia, Northern Africa, and North America. The dried flowers or dried aerial parts are used to prepare the drug Hyperici Herba or St. Johns Wort. Nowadays this drug is largely used as a natural antidepressant; hypericin and hypericin-like substances are considered the main active ingredients. In this work the hypericin and pseudohypericin content of hydroalcoholic extracts both of Hyperici Herba and ofHypericum perforatum L. dried flowers were measured by two techniques, TLC-densitometry with fluorescence detection and reversed-phase HPLC-DAD (diode-array detection). The quantitative data obtained by applying these techniques were compared and the identification of the main flavonoid constituents was performed by HPLC-DAD for characterization of the extracts.The quantitative data obtained by use of the two techniques were in good agreement and statistical analysis of the findings was indicative of the equivalence of the techniques.

Extraction and identification procedures of polyphenolic compounds and carbohydrates in phillyrea (Phillyrea angustifolia L.) leaves

SummaryLiquid-liquid (LLE) and liquid-solid extraction (LSE) procedures were developed to identify polyphenols in phillyrea (Phillyrea angustifolia L.) leaves. The liquidsolid extraction, carried out by using two serial Bond-Elut® CH and Bond-Elut® SAX cartridges allowed the collection of both polyphenols and soluble carbohydrates during a single extraction of leaf. This method seems to be suitable for both phytochemical and physiological study of the species, allowing the identification of two classes of organic compounds which have a central role in the metabolism of phillyrea plants. A method of isolation and concentration of polyphenols for further molecular characterization, using centrifuge chromatography, was also developed. Molecular characterization, carried out by UV-Vis spectrophotometry and mass spectrometry, demonstrated the presence of compounds with interesting biological activity, i.e. flavonoids and oleuropein derivatives. The soluble carbohydrate composition of phillyrea leaves did not substantially differ from that ofOlea europaea L. leaves, except for a higher mannitol/glucose ratio. This carbohydrate distribution may be linked to the evolution pattern of this species which usually grows in severely stressed environments.

Optimization of the chromatographic determination of polyphenols in the aerial parts ofCichorium intybus L.

SummaryThe aim of this work was to contribute to the phytochemical characterization ofCichorium intybus L. var.silvestre, chicory. Semi-preparative HPLC analysis was applied to an extract of fresh wild chicory leaves to separate and collect the main polyphenolic compounds.HPLC-diode-array detection (DAD), HPLC-MS, and NMR were used for the complete chemical characterization of all the compounds isolated. The molecules characterized were monocaffeoyl tartaric acid, chicoric acid, monocaffeolyp-hydroxycinnamoyl tartaric acid, caffeoyl feruloyl tartaric acid, chlorogenic acid, quercetin-3-O-glucuronide, luteolin-7-O-glucuronide, and quercetin-3-O-glucoside.The chromatographic behaviour of the main components of the extract of the leaves has been compared on three different stationary phases-LiChrosorb RP18, Luna C18, and Luna Phenyl-Hexyl.

Food supplements ofTribulus terrestris L.: An HPLC-ESI-MS method for an estimation of the saponin content

SummaryAn HPLC-ESI-MS method in a positive mode is proposed to qualitatively analyse the saponin fractions from dietary supplements ofTribulus terrestris L. This method allows for theseparation of structural isomers, as highlighted for some terrestrosines. The MS fragmentation pattern resulted diagnostic to collect structural information and the characteristic loss of water from some furostanolic saponins was highlighted for the first time. Due to the wide number of glycosidic furostanolic and spirostanolic saponins extracted from tribulus, a complete reference “molecular weight map” was created. Finally, a seml-quantitative evaluation of the total saponin content was carried cut by HPLC-MS using protodioscin as external standard.

Capillary zone electrophoretic analysis of the main alkaloids fromEschscholtzia californica

SummaryCapillary zone electrophoresis (CZE) with multi-wavelength detection has been used for the separation of the main alkaloids fromEschscholtzia californica. Optimum separation has been achieved with a fused silica capillary tube and a running electrolyte at pH 2.8 prepared from a 40 mM solution of citric acid and a 80 mM solution of Na2HPO4. The applied voltage was 20 kV and the capillary thermostating temperature was kept constant at 10°C.

Analysis of flavonols ofSedum telephium L. leaves by capillary electrophoresis and HPLC-mass spectrometry

SummaryFlavonol glycosides ofSedum telephium L. were analysed by MEKC. Baseline separation was achieved within 14 min using a fused silica capillary and a borate/phosphate buffer solution (35 mM, pH 5.8) containing 35 mM SDS and 4% MeOH. The applied voltage was 25 kV and the thermostating temperature was kept constant at 40°C. Injection was performed via the pressure mode for 3 s, the detection wavelength was 205 nm. The optimized MEKC method was used for the quantitative determination of flavonol glycosides in extracts ofS. telephium leaves.Analysis was also performed by HPLC-MS using an electrospray ionization (ESI) interface. The good agreement between the quantitative CE results and those obtained by LC clearly demonstrated the applicability of the methods presented.