Bruno Gabetta

Identification by high-performance liquid chromatography–diode array detection–mass spectrometry and quantification by high-performance liquid chromatography–UV absorbance detection of active constituents of Hypericum perforatum

Abstract Hypericum perforatum is a medicinal plant which has been known in traditional medicine as an anti-inflammatory and healing agent. Nowadays, the alcoholic extract of its aerial parts finds wide application for its antidepressant activity. A high-performance liquid chromatography (HPLC) method for the identification of its constituents using a wide pore RP-18 column and a water–methanol–acetonitrile–phosphoric acid mobile phase system was developed. The identification of its flavonoid, naphthodianthrone and phloroglucinol constituents was performed using combined HPLC–diode array detection (DAD) analysis, HPLC–thermospray and HPLC–electrospray mass spectrometry. Chlorogenic acid, quercetin, quercitrin, isoquercitrin, rutin, hyperoside, I3,II8-biapigenin, pseudohypericin, hypericin, hyperforin and adhyperforin were separated by an aqueous phosphoric acid–acetonitrile–methanol gradient within 50 min. The quantification of the above constituents was performed using rutin as an external standard.

Liquid chromatography–electrospray mass spectrometric identification of ginsenosides in Panax ginseng roots

A high-performance liquid chromatographic method was developed for electrospray mass spectrometric analysis of ginsenosides in Panax ginseng roots. The analyses were performed on a reversed-phase C18 column using a binary eluent (aqueous 8 mM NH4OAc, buffered to pH 7 with NH4OH-acetonitrile) under gradient conditions. Twenty-five ginsenosides could be separated and detected. The mass spectra obtained provided information on their molecular masses. A MS-MS experiment was undertaken in order to determine the sugar unit sequences and the aglycone moieties.

Characterization of proanthocyanidins from grape seeds

Leucoselect (grape seed selected proanthocyanidins) was analyzed. HPLC thermospray mass spectrometry (TSP-MS) allowed the detection of monomeric flavan-3-ols and dimeric proanthocyanidins. Fractionation over Sephadex LH-20 resin and analysis of the isolated fractions by gel permeation chromatography (GPC) and electrospray mass spectrometry (ESI-MS) led to the complete characterization of the proanthocyanidin constituents of Leucoselect. The analysis revealed the presence of approximately 15% of (+)-catechin (1) and (-)-epicatechin (2), 80% of (-)-epicatechin 3-O-gallate (3), dimers, trimers, tetramers and their gallates and 5% of pentamers, hexamers, heptamers and their gallates.

Qualitative and quantitative evaluation of vaccinium myrtillus anthocyanins by high-resolution gas chromatography and high-performance liquid chromatography

Abstract An analytical method for the separation and characterization of anthocyanins in Vaccinium myrtillus extracts has been developed based on capillary gas chromatography and mass spectrometry. In addition, a method involving reversed-phase high-performance liquid chromatography for the quantitative evaluation of anthocyanins in these pharmacologically important extracts is presented.

Taxanes from Taxus baccata

Abstract A winter collection of yew needles gave two pairs of taxicin-I and taxicin-II diesters, the structures of which were established by spectral data and chemical reactions. The mixture of these diesters might correspond to the so-called ‘desdimethylaminotaxine’ of the old literature on yew. A detailed NMR analysis of the diesters allowed an unambiguous assignment of all 1 H and 13 C NMR resonances of these and related taxane derivatives.

Triterpenoids of Terminalia sericea

Abstract The structures of sericic acid and sericoside, the major constituents of the roots of Terminalia sericea , have been determined. Sericic acid is 2α,3β,19α,24-tetrahydroxy-olean-12-en-28-oic acid and sericoside the corresponding C -28 D -glucosyl ester.

Taxanes from the needles of Taxus wallichiana

Abstract Besides known compounds, the needles of T. wallichiana gave five new taxanes, whose constitution, stereochemistry and conformation were established

Minor diterpenoids of Coleus forskohlii

The structures of four diterpenoids, isolated from the roots of Coleus forskohlii, have been elucidated as 7β-acetoxy-6β,9α-dihydroxy-8,13-epoxy-labd-14-en-11-one (7), 6β,7β,9α-trihydroxy-8,13-epoxy-labd-14-en-11-one (8), 6β-hydroxy-8,13-epoxy-labd-14-en-11-one (9), 8,13-epoxy-labd-14-en-11-one (10) by spectral analysis in comparison with forskolin (1) and its congeners.

Rearranged taxanes from Taxus baccata

Abstract The needles of Taxus baccata gave two rearranged taxanes of the 11 (15 → 1)- and 2 (3 → 20) abeo -type. A taxicin I triester was also isolated.

14β-Hydroxy-10-deacetylbaccatin III, a new taxane from Himalayan yew (Taxus wallichiana Zucc.)

The needles of T. wallichiana Zucc. gave a new taxane, whose structure was established as 14β-hydroxy-10-deacetylbaccatin III on the basis of chemical reactions, spectroscopic data and X-ray analysis.