Mentha aquatica L. aerial parts: in vitro anti-proliferative evaluation on human tumour and non-tumour cell lines

Bearing in mind the several medicinal properties of Mentha genus, this work aimed to evaluate the anti-proliferative potential of the ethanolic extract (EE) and fractions from M. aquatica L aerial parts. Using the anti-proliferative protocol developed by the NCI/USA, four fractions (F2 - F4 and F6) obtained from EE showed promising anti-proliferative profile against a panel of human tumor and non-tumor cell lines. After 24-h exposure, F2 (0.25 µg/mL) showed potent and irreversible anti-proliferative effect without inducing cell cycle arrest in both NCI-H460 and MCF-7 cells, without (anti) estrogenic activity. These effects were lost after storage of F2 diluted in dimethyl sulfoxide at -80 °C during 2 weeks. Analysis by gas chromatography coupled to mass detection evidenced some chemical changes induced by F2 storage in solution. The present study demonstrated the anti-proliferative effect of M. aquatica. Further studies are necessary to determine better storage conditions to enhance F2 stability.

Gold nanoparticles for enhanced ionization and fragmentation of biomolecules using LDI-MS

New applications for gold nanoparticles (AuNPs) in laser desorption ionization mass spectrometry are presented here. This work expands on previous biomolecule studies and introduces carbohydrates, steroids, bile acids, and other small molecules as a focus. Broad trends in ionization are observed, and specifically of interest are new species that have not previously been reported from AuNPs (e.g., [M + Au]⁺ ). Interesting fragmentation effects have been observed for diphenhydramine, including similarity to electron impact mass spectra and possible radical driven reactions, providing insight into the mechanism of ionization when using AuNPs.

Tandem mass spectrometric characterization of acetylated polyhydroxy hellebosaponins, the principal steroid saponins in Helleborus niger L. roots(#)

RATIONALE

Isolation and extensive nuclear magnetic resonance (NMR) analyses revealed polyhydroxy steroid saponins to be characteristic constituents in Helleborus niger L. roots. A comprehensive study including various multi-stage mass spectrometry (MS(n) ) experiments provided first solid chromatographic and mass spectrometric information facilitating future analysis and structural assessment of polyhydroxy saponins by LC/MS(n) techniques without isolation and NMR analyses.

METHODS

The polyhydroxy saponins were analyzed by direct syringe injection or chromatographically separated on a capillary high-performance liquid chromatography (HPLC) system coupled to an electrospray ionization (ESI) source. MS(n) spectra were recorded on an ion trap mass spectrometer including up to four fragmentation stages (LC/ESI-MS/MS). Additionally, high-resolution mass spectra were recorded on an Orbitrap Fourier transform (FT) mass spectrometer equipped with a nanospray-ESI interface.

RESULTS

The polyhydroxy hellebosaponins A and D were discovered to be significant constituents from H. niger roots. Extensive study of their MS(n) data revealed that they readily fragmented in the positive ion mode providing diagnostic fragments for elucidation of the steroidal character and number of OH groups. The negative ion mode yielded valuable information on the [M-H](-) ion, number and location of acetyl groups and sugar units. Additionally, fragmentation pathways for positive and negative ion modes were proposed.

CONCLUSIONS

These results not only extend the knowledge about H. niger saponins, but also provide a facilitated approach to the analysis of polyhydroxy saponins by LC/MS(n) without prior isolation and extensive NMR identification. Additionally, proposed fragmentation pathways for positive and negative ionization modes provide a solid complementary database for further, more detailed MS(n) studies.

Application of self-ionization for enhancing stereochemical and positional effects from arylglycosides under electron ionization conditions in an ion trap mass spectrometer

Ion trap mass spectrometry has been used to structurally characterize and differentiate positional and stereo isomers of arylglycosides having potential antioxidant properties. The use of the self-ionization (SI) technique has allowed to evidence a strong reactivity of fragment ions produced from dissociations of the molecular ion towards the molecules introduced into the trap. Specific structural effects due to positional isomers and anomers have been also envisaged through the occurrence of bimolecular processes inside the ion trap analyzer. Under self-ionization conditions, even-electron ions are produced. The charge is retained on the sugar moiety, in agreement with its proton affinity higher than that of the substituted phenol moiety. Most of the fragmentation pathways involve elimination of acetic acid that protects the hydroxylic groups of the glycoside. SI also produces adduct ions, likely as covalent species, having higher m/z values than the molecular ion. The reaction site is mainly the double bond present in the pyranosidic ring. Even if some fragment ions have lost the initial stereochemistry, their formation can be related to the structure of the parent neutrals introduced into the cell. Collision-induced dissociation (CID) experiments, carried out on ions formed by ion-molecule reactions, have allowed to obtain further information on gas phase ion structures. The study of mass-selected ion-molecule reactions and their kinetics have evidenced a spectacularly different reactivity of the ion at m/z 111 towards the two anomers 2alpha and 2beta, with the latter showing a much more pronounced reactivity. The approach developed in this work revealed to be an useful tool in structural characterization, as well as in stereo and regiochemical differentiation of arylglycosides.

Unusual lipid composition of a Bacillus sp. isolated from Lake Pomorie in Bulgaria

The lipid composition of a Bacillus sp., isolated from Lake Pomorie in Bulgaria, was unusual and consisted of 26 different fatty acids between C12 and C26, with anteiso C15-C17 saturated fatty acids predominating. The furan fatty acid, 10,13-epoxy-11-methyloctadeca-10,12-dienoic acid, was also identified, a new finding for this genus. The hydrocarbons consisted of 30 different monounsaturated hydrocarbons, between C25 and C30, with the iso-iso, iso-anteiso, anteiso-anteiso, iso-normal, and anteiso-normal methyl branching for odd-numbered chains, and the iso-iso, iso-anteiso, iso-normal, and anteiso-normal methyl branching for even-numbered chains. The double bond positions in these hydrocarbons were determined by dimethyl disulfide derivatization followed by GC-MS, and the double-bond cis configuration was confirmed by infrared spectroscopy. Some previously unknown hydrocarbons in bacteria, such as (Z)-3,21-dimethyl-9-tricosene, (Z)-3,21-dimethyl-10-tricosene, (Z)-2,24-dimethyl-11-pentacosene, and (Z)-2,25-dimethyl-13-hexacosene were identified. Sterols were detected and were based on the sitosterol nucleus.

Characterization by gas chromatography/mass spectrometry of sterols in saccharomyces cerevisiae during autolysis

Yeast autolysis affects membrane stability and induces a release of vacuolar enzymes into the cell cytoplasm. Consecutively, it was important to study the evolution of sterol content in Saccharomycescerevisiae for a fourteen day period of accelerated autolysis. Unesterified and esterified sterols were analyzed both in the biomass and in the autolysis medium. Ten sterols were identified by gas chromatography/mass spectrometry. A second group of six sterols was separated and partially characterized. Among the first group of 10 sterols, a dehydroergosterol was identified as ergosta-5, 7,9(11),22-tetraen-3beta-ol, not yet charaterized in S. cerevisiae. Yeast autolysis induced a decrease of esterified sterol content, especially first intermediates in the sequence of the ergosterol biosynthesis, as zymosterol. In contrast, the yeast autolysis resulted in the release of a low quantity of sterols into the medium. At the end of the fourteenth day of autolysis, 0.015% of the total sterol content of the initial biomass was found in the medium.

Electrospray collision-induced dissociation of testosterone and testosterone hydroxy analogs

Complications with the gas chromatographic analysis of steroids prompted the use of alternative techniques for their identification. High-performance liquid chromatography/mass spectrometry with atmospheric pressure ionization allowed the collection of data for structural identification of these compounds. The objective of this study was to investigate the up-front collision-induced dissociation (UFCID) electrospray ionization (ESI) mass spectra of testosterone and monohydroxylated testosterones. The positive ion UFCID ESI mass spectrum of testosterone showed three significant ions at m/z 97, 109 and 123. The relative abundance of these ions in the UFCID ESI mass spectra of monohydroxylated testosterones varied with the position of the hydroxy group. Statistical data allowed the prediction of hydroxy group position on testosterone by evaluation of the relative abundance of the m/z 97, 109, 121 and 123 ions. Data from the ESI mass spectral analysis of testosterone in a deuterated solvent and from the analysis of cholestenone and 4-androstene-3 beta, 17 beta-diol indicated that the initial ionization of testosterone occurred at the 3-one position. CID parent ion monitoring analyses of the m/z 97, 109 and 123 ions indicated that each resulted from different fragmentation mechanisms and originated directly from the [M + H]+ parent ion. The elemental composition of these fragment ions is proposed based on evidence gathered from the CID analysis of the pseudo-molecular ions of [1,2-2H2]-, [2,2,4,6,6-2H5]-, [6,7-2H2]-, [7-2H]-, [19,19,19-2H3]- and [3,4-13C2]testosterone. The structure and a possible mechanism of formation of the m/z 109 and 123 ions is presented. The results of this study advance the understanding of the mechanisms of collision-induced fragmentation of ions.

Perturbation of sterol biosynthesis by itraconazole and ketoconazole in Leishmania mexicana mexicana infected macrophages

The azole antifungals ketoconazole and itraconazole possess in vitro antileishmanial activity against Leishmania mexicana mexicana amastigotes in macrophages (cell line J774G8). As in yeast and fungi, the activity is likely to be due to inhibition of the cytochrome P-450-dependent 14 alpha-demethylation of lanosterol and/or 24,25-dihydrolanosterol. Indeed, 50% inhibition of ergosterol synthesis was observed at 0.21 microM ketoconazole and 0.15 microM itraconazole. At 5 microM ketoconazole, traces of ergosterol could be found, whereas no ergosterol could be detected in cells treated with 5 microM itraconazole. The inhibition of ergosterol biosynthesis was concomitant with an accumulation of the 14 alpha-methylsterols lanosterol and 24,25-dihydrolanosterol. Fifty percent inhibition of cholesterol synthesis in uninfected macrophages was achieved at 0.95 microM and 1.5 microM itraconazole and ketoconazole, respectively. In infected macrophages all [14C]acetate was incorporated in ergosterol, suggesting an inhibition in cholesterol synthesis in the host cells. An inhibition of ergosterol synthesis coincided with increasing cholesterol synthesis. The latter synthesis was inhibited at concentrations greater than 1 microM. However, even at 5 microM cholesterol synthesis was higher than under control conditions.

Minor and trace sterols in marine invertebrates. 61. Isolation and structure elucidation of new A-nor sterols from the marine sponge Phakellia aruensis

An examination of the Australian sponge Phakellia aruensis led to the isolation and identification of sterols with six different nuclei. Eight new sterols were isolated which included three delta 15-A-nor sterols, three delta 7-A-nor sterols, and two saturated A-nor sterols. Their structures were established through mass spectrometry and 1H-NMR spectral studies.

The sterol composition of the marine sponge Aplysina (= Verongia) archeri: a comparative study of the Verongidae

1. The sterol composition of the marine sponge Aplysina archeri was studied revealing the presence, besides other common sterols, of considerable amounts (75%) of aplysterol (1), verongulasterol (3), and 25-dehydroaplysterol (4). 2. 24,28-Didehydroaplysterol (2) was not present in the sterol mixture as it was previously reported for the Verongidae. 3. A comparison between the characteristic sterols of the Verongidae was carried out.

Identification of 17 alpha,20 alpha-dihydroxyprogesterone in testicular extracts after incubation with ketoconazole

The antifungal ketoconazole affects testosterone synthesis in dispersed rat testicular cells. In the presence of ketoconazole an accumulation of 17 alpha,20 alpha-dihydroxyprogesterone has been observed. This steroid was isolated from the testis of Wistar rats after a [4-14C]progesterone incorporation in the presence of ketoconazole. Its identification was achieved from the gas chromatographic/mass spectrometric analysis of the isolated radioactive fraction. A chemical derivatization of the fraction with butylboronic acid followed by mass spectrometric analysis confirmed the presence of 17 alpha,20 alpha-dihydroxyprogesterone.

Metabolism of progesterone and testosterone by a Bacillus sp

Microbial transformations by a Bacillus sp. were employed as a means of preparing potentially important derivatives of progesterone and testosterone. Each microbial metabolite was subjected to structure elucidation employing 1H and 13C nmr, mass spectral and cd analysis. Hplc was used for the determination of the percentages of the metabolites formed. The progesterone metabolites were characterised as 14-hydroxy-4-pregnene-3,20-dione (II), 14-hydroxy-5 alpha -pregnane-3,6,20-trione (III), 11 alpha-hydroxy-5 alpha-pregnane-3, 6,20-trione (IV) and 11 alpha,14-dihydroxy-4-pregnene-3,20-dione (V). The testosterone analogs were identified as 4-androstene-3,17-dione (VII), 17 beta-hydroxy-5 alpha-androstane-3,6-dione (VIII), 14-hydroxy-4-androstene-3,17-dione (IX) and 14, 17 beta-dihydroxy-4-androsten-3-one (X). The availability of the metabolites enabled complete elucidation of their 13C nmr spectra.

The mass spectra of 13C labelled methylene derivatives of steroids--IV

The mass spectra of the 3-ethylene ketal of delta 5-pregnan[20-13C]methylene-3-one and 17 beta-acetoxyl[3-13C]methyleneandrost-1-ene have been examined. In both cases there are some fragments which show either relatively large retention or elimination of 13C label and these can be assigned to some fragmentation paths which generally follow those found for diterpenic and steroidal hydrocarbons, and are in good agreement with the empirical fragmentations rules in mass spectrometry.

Studies on anabolic steroids. The mass spectra of 17 alpha-methyl-17 beta-hydroxy-1,4-androstadien-3-one (Dianabol) and its metabolites

The metabolism of 17 alpha-methyl-17 beta-hydroxy-1,4-androstadien-3-one (dianabol) in human adults has been studied in detail by computer aided capillary gas chromatography mass spectrometry. After oral administration to man six metabolites were determined in the free fraction of the urine samples, the structures of which have been identified as 17-epidianabol, three isomers of 6-hydroxydianabol, 17 alpha-methyl-17 beta-hydroxy-1,4,6-androstatrien-3-one (delta 6-dianabol) and 18-nor-17,17-dimethyl-1,4,13(14)-androstatrien-3-one, respectively. In agreement with previous observations no measurable amounts of the administered drug itself could be detected in any of the urine samples investigated. The mass spectra of all metabolites and the main fragmentation processes are discussed in detail.