Chemical Composition and Anti-Candida Activity of Mentha suaveolens Ehrh. Essential Oils Obtained by Different Distillation Processes

A comparative study on essential oils extracted from Mentha suaveolens Ehrh. from Italy is reported. Two extraction procedures were investigated: hydrodistillation and steam distillation, carried out as a continuous and fractionated procedure. Fresh and dried plant material from two harvests was used. The hydrodistillation method yielded a higher amount of essential oil. The dried plant was significantly richer in essential oil per kg of starting plant material. Gas chromatography-mass spectrometry analysis of 112 samples showed that the essential oils belong to the piperitenone oxide-rich chemotype. In addition, piperitenone, p-cymen-8-ol, and limonene were among the most abundant compounds in the different samples. A higher amount of piperitenone oxide was obtained by hydrodistillation, while steam distillation gave a higher percentage of piperitenone and limonene. The essential oils were characterized for their anti-Candida albicans activity; higher potency was observed for the samples rich in piperitenone oxide, with MIC values ranging from 0.39 to 0.78 mg·mL−1 (0.039% and 0.078% p/v). The results of this work provide a deep insight into the methodology of essential oil extraction and the associated chemical variability of M. suaveolens Ehrh. Some of the essential oils are potent against C. albicans and could be considered for potential use in therapy

Effect of different soil treatments on production and chemical composition of essential oils extracted from Foeniculum vulgare Mill., Origanum vulgare L. and Thymus vulgaris L

The aim of the present study was to investigate how essential oil production and associated chemical composition and related biological activity could be influenced by different cultivation treatments and distillation method. Foeniculum vulgare Mill. (fennel), Origanum vulgare L. (oregano), and Thymus vulgaris L. (thyme) were cultivated in absence of any fertilizer (control) and in presence of three different fertilizers: a chemical one with augmented of mineral phosphorus and potassium, a second added with hydrolysed organic substance and mineral phosphorus and potassium (organic-mineral) and a third one treated with high content of organic nitrogen of protein origin (organic). The plants were subjected to steam distillation using two modalities: recycled and continuous to obtain 32 essential oil samples. Chemical composition analysis was performed by gas chromatography-mass spectrometry; in vitro antimicrobial activity was evaluated by broth microdilution method. In general, the recycled distillation method appeared to have a slightly higher yield than the continuous method. The "mineral" and "organic-mineral" treatments resulted in the higher yield compared to the "organic" or "control" treatments, and this was particularly evident in the recycled method. The "control" plants had a lower yield of essential oils. Anethole (13.9-59.5%) and estragole (13.4-52.2%) were the main constituents of fennel oils, p-cymene and its derivatives carvacrol and thymol were the main constituents of oregano and thyme samples. The antimicrobial activity of thyme oils on Staphylococcus aureus ranged from 0.31 to 0.16% (v/v); a lower effect of oregano samples and no activity of fennel samples were observed. The essential oils failed to inhibit the growth of Pseudomonas aeruginosa strains

Chemico-biological characterization of Torpedino Di Fondi® tomato fruits. A comparison with San Marzano cultivar at two ripeness stages

Torpedino di Fondi (TF) is a hybrid tomato landrace developed in Sicily and recently introduced in the south Lazio area along with the classical San Marzano (SM) cultivar. The present study aimed at characterizing TF tomatoes at both pink and red ripening stages, and at comparing them with traditional SM tomatoes. A multidisciplinary approach consisting of morphological, chemical (FT‐ICR MS, NMR, HPLC, and spectrophotometric methods), and biological (antioxidant and antifungal in vitro activity) analyses was applied. Morphological analysis confirmed the mini‐ San Marzano nature and the peculiar crunchy and solid consistency of TF fruits. Pink TF tomatoes displayed the highest content of hydrophilic antioxidants, like total polyphenols (0.192 mg/g), tannins (0.013 mg/g), flavonoids (0.204 mg/g), and chlorophylls a (0.344 mg/g) and b (0.161 mg/g), whereas red TF fruits were characterized by the highest levels of fructose (3000 mg/100 g), glucose (2000 mg/100 g), tryptophan (2.7 mg/100 g), phenylalanine (13 mg/100 g), alanine (25 mg/100 g), and total tri‐unsaturated fatty acids (13% mol). Red SM fruits revealed the greatest content of lipophilic antioxidants, with 1234 mg/g of total carotenoids. In agreement with phenolics content, TF cultivar showed the greatest antioxidant activity. Lastly, red TF inhibited Candida species (albicans, glabrata and krusei) growth

Does a Chiral Alcohol Really Racemize when Its OH Group Is Protected with Boyer's Reaction?

Chiral reactants have been employed for assessing the real stereochemistry of the BiBr(3)-catalyzed synthesis of benzylic ethers, a very useful reaction for protecting alcoholic groups. The results of this investigation are in clear contrast with the conclusions of previous studies (Boyer et al., Tetrahedron 2001;57:1917-1921). Indeed, chiral GC-MS analysis of the ethereal products gives unequivocal evidence of the complete racemization of the benzylic moiety and the complete retention of configuration of the protected alcoholic substrate. Such findings make BiBr(3) a powerful and stereo-chemically preservative catalyst for benzylation of chiral alcohols, and a potential candidate for orthogonal protecting group strategies applicable to polyhydroxy compounds. Chirality 22:88-91, 2010. (C) 2009 Wiley-liss, Inc

Reaction diastereoselectivity of chiral aminoalcohols/[Co(II)NO3]+ complexes in evaporating ESI nanodroplets: new insights from a joint experimental and computational investigation.

The nature of the ionic species, formed by electrospray ionization (ESI) of Co(NO3)2/CH3OH solns. with a pair of aminoalcs. W and Y, has been investigated by mass spectrometric and computational methods. Collision induced dissocn. (CID) of ions, formally corresponding to the [WYCoNO3]+ structures, yields fragmentation patterns which reflect not only the expected [WYCoNO3]+ connectivity but also that of other isomeric structures. Formation of these latter species is obsd. only in the presence of a tertiary aminoalc., like N-methylpseudoephedrine. The CID patterns are found to be strongly dependent on the chem. form (whether the free aminoalc. or its hydrochloride), the configuration, and the relative concn. of the W and Y aminoalcs. This variability parallels the results of classical MD (mol. dynamics) simulations of the [WYCoNO3]+ adducts which show a drastic alteration of the mech.-dynamical features of the adducts by simply changing the charge state of W and/or Y, their abs. configuration, or by removing the solvent. The present exptl. and computational study confirms the observation of fast stereoselective reactions in ESI nanodroplets before their evapn. and warns against any automatic correlation between the ESI spectrum of an analyte and its structure in soln

Theoretical-computational modeling of gas-state thermodynamics in flexible molecular systems: ionic liquids in the gas phase as a case study

A theoretical-computational procedure based on the quasi-Gaussian entropy (QGE) theory and molecular dynamics (MD) simulations is proposed for the calculation of thermodynamic properties for molecular and supra-molecular species in the gas phase. The peculiarity of the methodology reported in this study is its ability to construct an analytical model of all the most relevant thermodynamic properties, even within a wide temperature range, based on a practically automatic sampling of the entire conformational repertoire of highly flexible systems, thereby bypassing the need for an explicit search for all possible conformers/rotamers deemed relevant. In this respect, the reliability of the presented method mainly depends on the quality of the force field used in the MD simulations and on the ability to discriminate in a physically coherent way between semi-classical and quantum degrees of freedom. The method was tested on six model systems (n-butane, n-butane, n-octanol, octadecane, 1-butyl-3-methylimidazolium hexafluorophosphate and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic pairs), which, being experimentally characterized and already addressed by other theoretical-computational methods, were considered as particularly suitable to allow us to evaluate the method's accuracy and efficiency, bringing out advantages and possible drawbacks. The results demonstrate that such a physically coherent yet relatively simple method can represent a further valid computational tool that is alternative and complementary to other extremely efficient computational methods, as it is particularly suited for addressing the thermodynamics of gaseous systems with a high conformational complexity over a large range of temperature

Isomerism of Cycloserine and Its Protonated Form

A comprehensive ab initio investigation has been performed on the structure and stability of the isomers of cycloserine and its protonated forms in the unsolvated state. Many conformers of cycloserine in the ketonic (K), enolic (E4 and E2), and zwitterionic (Z7 and Z2) forms have been characterized. Enols E2 are only a few kilocalories per mole less stable than the K isomers. Enols E4, as well as Z7 and Z2 zwitterions, are several tens of kilocalories per mole less stable than K. All the above isomeric structures exhibit pronounced isoxazolidine ring puckering, which generates very rich conformeric landscapes. The relative stability of the conformers of K, E2, and E4 responds essentially to a complex balance between the attractive and repulsive electrostatic interactions among their functional groups. The preferred site of protonation of cycloserine in the gas phase has been also investigated computationally and experimentally by IR multiphoton dissociation (IRMPD) spectroscopy. The most basic center of cycloserine is the N(7) nitrogen atom (proton affinity (PA)=215.3 kcal mol−1). Another important basic site is the O(6) oxygen atom (PA=213.0 kcal mol−1). Their most populated conformers have been identified by IRMPD spectroscopy. Their predominance responds to the electrostatic interactions among the functional groups of the protonated molecule