Arturo A. Vitale

Highly sensitive method for the determination of melatonin by normal-phase high-performance liquid chromatography with fluorometric detection

In the present study a new chromatographic method was developed to quantify melatonin in rat pineal that can be extended to other tissues. Melatonin was extracted from an acid homogenate with ethyl acetate to avoid amine interference. HPLC was performed with silica normal-phase column and fluorescence detection. This method is sensitive enough for detecting melatonin in a single pineal gland with a detection limit of 3 pg/mg tissue.

Alkaloids of Datura ferox from Argentina

Chromatographic procedures (HPLC, GC-MS) are outlined in this paper for the analysis of alkaloids in poisonous Datura ferox seeds of Argentina, from which previously only quantitative analysis for scopolamine was known. Five additional tropane alkaloids are now identified as 3 alpha-tigloyloxytropane (tigloyltropeine), 3-phenylacetoxy-6 beta,7 beta-epoxytropane (3-phenylacetoxyscopine), aposcopolamine (apohyoscine), 7 beta-hydroxy-6 beta-propenyloxy-3 alpha-tropoyloxytropane, traces of 7 beta-hydroxy-6 beta-isovaleroyloxy-3 alpha-tigloyloxytropane and a pyrrolidine alkaloid, hygrine. Two new structures, 3-phenylacetoxy-6 beta,7 beta-epoxytropane (3-phenylacetoxyscopine) and 7 beta-hydroxy-6 beta-propenyloxy-3 alpha-tropolyoxytropane, are proposed on the basis of their spectra. Hyoscyamine, nicotine and tropane N-oxides were not detected in all samples studied.

Constituents of the root exudate of Avena fatua grown under far-infrared-enriched light.

The constituents of the root exudate of plantlets of wild oats (Avena fatua) grown in the greenhouse under far-IR-enriched radiation were analysed for the first time by HPTLC and capillary GC, and further separated by medium-pressure liquid chromatography (MPLC; monitored by TLC) and characterised by GC-EIMS and 1H-NMR. This combination of methodologies permitted the study of root exudates under controlled conditions and is appropriate for examining a variety of ecophysiological/environmental effects in a short time period. In this instance, the response compounds of the irradiated plantlets were identified as linear and branched alcohols, linear and branched alkanes, a bicyclic monoterpene, mono- and bicyclic sesquiterpenes, and free and esterified fatty acids. An ester, isopropyl myristate, was the main component present, although the unusual occurrence of branched compounds, sesquiterpenoids and related compounds of isoprenoid metabolism is noteworthy. The effect of far-IR-enriched light on the production of these compounds is discussed. Copyright

In Vivo Long-Term Kinetics of Radiolabeled N,N-Dimethyltryptamine and Tryptamine

N,N-dimethyltryptamine (DMT), a strong psychodysleptic drug, has been found in higher plants, shamanic hallucinogenic beverages, and the urine of schizophrenic patients. The aim of this work was to gain better knowledge on the relationship between this drug and hallucinogenic processes by studying DMT behavior in comparison with tryptamine. Methods: 131I-labeled DMT and tryptamine were injected into rabbits. γ-Camera and biodistribution studies were performed. Brain uptake, plasma clearance, and renal excretion were assessed for each indolealkylamine. Results: DMT and tryptamine showed different behavior when brain uptake, residence time, and excretion were compared. Labeled DMT entered the brain 10 s after injection, crossed the blood–brain barrier, and bound to receptors; then it was partially renally excreted. It was detected in urine within 24 h after injection and remained in the brain, even after urine excretion ceased; up to 0.1% of the injected dose was detected at 7 d after injection in the olfactory bulb. In contrast, tryptamine was rapidly taken up in the brain and fully excreted 10 min after injection. Conclusion: To our knowledge, this is the first demonstration that exogenous DMT remains in the brain for at least 7 d after injection. Although labeled DMT and tryptamine behave as agonists for at least 5-hydroxytryptamine 2A receptor, 5-hydroxytryptamine 2C receptor, trace amine-associated receptor, and σ-1 putative receptor targets, binding to the latter can explain the different behavior of labeled DMT and tryptamine in the brain. The persistence in the brain can be further explained on the basis that DMT and other N,N-dialkyltryptamines are transporter substrates for both the plasma membrane serotonin transporter and the vesicle monoamine transporter 2. Furthermore, storage in vesicles prevents DMT degradation by monoamine oxidase. At high concentrations, DMT is taken up by the serotonin transporter and further stored in vesicles by the vesicle monoamine transporter 2, to be released under appropriate stimuli. Moreover, the 131I-labeling proved to be a useful tool to perform long-term in vivo studies.

Synthesis of 131I derivatives of indolealkylamines for brain mapping

The synthesis and spectral properties of new radioiodinated indolealkylamines like 2-[131I]-iodo-N,N-dimethyltryptamine, 2-[131I]-iodo-N-methyltryptamine, 2-[131I]-iodo-5-methoxy-N,N-dimethyltryptamine, 2-[131I]-iodio-5-hydroxy-N,N-dimethyltryptamine (2-[131I]-iodo-bufotenine), and 2-[131I]-iodo-tryptamine and the known 2-[131I]-iodo-N-acetly-5-methoxy-tryptamine (2-[131I]-iodo-melatonine) are described herein. There were synthesized by a high-yield novel method, and their spectral properties are fully described. These compounds are of biological importance and can be used for brain mapping with SPECT technology.

Nonpolar lipid composition of Chenopodium album grown in continuously cultivated and nondisturbed soils

Chenopodium album L. plants grown in continuously cultivated and in nondisturbed soils were compared in terms of the compositions of nonpolar extracts of the corresponding aerial parts. Both light petroleum ether extracts of C. album L. were analyzed by high-performance thin-layer LC, capillary GC, and capillary GC-El-MS. Further percolation and medium-pressure LC, along with EI-MS analysis, permitted the separation and identification of the chemical constituents. Differences were observed between mean contents of the chemical constituents of C. album L., with respect to nonpolar extracts, obtained from continuously cultivated and from nondisturbed soils, in particular in linear and branched long-chain hydrocarbons, FA and their esters, and long-chain linear alcohols and aldehydes. The most remarkable features of the disturbed soils were a pronounced increase in the amounts of linear hydrocarbons and a decrease in the relative proportions of FA.

Semiempirical AM1 and ab initio parameters of the lethal cyclopeptides α-amanitin and its related thioether, S-sulphoxide, sulphone, and O-methyl derivative

Abstract The electronic structures and conformational analysis of the toxic cyclopeptides, α-amanitin ( I ), O -methyl-α-amanitin ( II ), S -deoxo-α-amanitin ( III ), α-amanitin-( S )-sulphoxide ( IV ) and α-amanitin sulphone ( V ) were obtained for the first time from molecular parameters on the basis of AM1 and ab initio methods. Stereochemical changes, total energy, MEPs, MO calculations and dipole moments were calculated. Both semiempirical and ab initio methods have been compared, showing to be in good agreement. Limitations of the methods are discussed in each case. Binding and toxicity can be thus satisfactorily explained by the results, showing that stereochemical as well as electronic factors are involved.

Relationship Between the Conformation of the Cyclopeptides Isolated from the Fungus Amanita Phalloides (Vaill. Ex Fr.) Secr. and Its Toxicity

The electronic structures and conformational studies of the cyclopeptides, Omethyl-α-amanitin, phalloidin and antamanide, were obtained from molecular parameters on the basis of semiempiric and ab initio methods.

Synthesis of derivatives of [I-131] phenylalkylamines for brain mapping

The synthesis and spectral properties of new radioiodinated phenylalkylamines like 2-[131I]-iodo-4,5-dimethoxyphenethylamine, 2-[131I]-iodo-4,5-dimethoxy-N,N-dimethyl-phenethylamine 2-[131I]-iodophenethylamine, 2-[131I]-iodo-N,N-dimethylphenethylamine, 2-[131I]-iodo-3,4,5-trimethoxy-phenethylamine (mescaline) are described for the first time. These compounds are of biological importance and can be used for brain mapping with SPECT technology.

New Insights of the Fenton Reaction Using Glycerol as the Experimental Model. Effect of O2, Inhibition by Mg2+, and Oxidation State of Fe

The use of iron ions as catalyst of oxidation with hydrogen peroxide, known as the Fenton reaction, is important for industry and biological systems. It has been widely studied since its discovery in the 19th century, but important aspects of the reaction as which is the oxidant, the role of oxygen, and the oxidation state of Fe still remain unclear. In this work new mechanistic insights of the oxidation of carbohydrates by the Fenton reaction using glycerol as experimental model are described. The reaction was studied by means of oxidation reduction potential (ORP) measures. The stoichiometry was measured, showing the important role of oxygen for lowering H2O2 consumption under aerobic conditions. Evidence is provided to demonstrate that in this system Fe(2+) generates a catalyst by reacting with a substrate to produce a complex, which gives rise to singlet oxygen after reacting with H2O2. This is the first time that the inhibitor effect of Mg(2+) is reported in this reaction, and its participation in the mechanism is described. A rational mechanism for the oxidation of glycerol using the Fenton reaction under these specific conditions is proposed. The role of oxygen, the participation of Fe(2+), and the inhibition by Mg(2+) are fully demonstrated experimentally.