Hygroline derivatives from Schizanthus tricolor and their anti-trypanosomatid and antiplasmodial activities.

Chemical investigation of the alkaloid extract of the aerial parts of Schizanthus tricolor led to the targeted isolation of 26 hygroline derivatives of which 20 were fully characterized. They have not yet been described in the literature and their structures were established by 1D and 2D NMR, UV and IR spectroscopy, and HRESIMS. The configuration was determined by Gauge-Independent Atomic Orbital NMR chemical shift calculations supported by the advanced statistical method DP4 plus, vibrational circular dichroism, and measurement of optical rotation.

Two New Hygroline and Tropane Alkaloids Isolated from Schizanthus hookeri and S. tricolor (Solanaceae).

Two new hygroline and tropane alkaloids, 4-hydroxybenzenepropanoylhygroline (1) and 3α,4β-dihydroxy-6β-angeloyoxytropane (2) have been isolated from the aerial parts of Schizanthus hookeri and S. tricolor, respectively, two plants indigenous from Chile. Their structures were elucidated by spectroscopic methods and high resolution mass spectrometry.

Inhibition of cholinergic contractions of rat ileum by tkopane-type alkaloids present in Schizanthus hookeri.

The relative lack of specificity of atropine as a competitive antagonist of muscarinic receptors is a frequent cause of undesirable parasympathetic side effects. Consequently, new tropane alkaloids with potentially greater selectivity are usually seen with real interest. The cholinergic antagonistic effects of a purified mixture of tropane alkaloids extracted from Schizanthus hookeri were evaluated in rat ileum.

Medicinal plants of Chile: evaluation of their anti-Trypanosoma cruzi activity.

The extracts of several plants of Central Chile exhibited anti-Trypanosoma cruzi trypomastigotes activity. Most active extracts were those obtained from Podanthus ovatifolius, Berberis microphylla, Kageneckia oblonga, and Drimys winteri. The active extract of Drimys winteri (IC50 51.

Grahamines A-E, cyclobutane-centered tropane alkaloids from the aerial parts of Schizanthus grahamii.

Schizanthus grahamii is an endemic Chilean plant that is known to contain tropane alkaloids. Five new alkaloids, grahamines A-E (1-5), were isolated and characterized by extensive spectroscopic analysis. Their structures were determined to be 2-{[(3α-hydroxytropo-6β-yl)oxy]carbonyl}-2-methyl-3-{[((6β-angeloyloxy)-3α-yl)oxy]carbonyl}-4-phenylcyclobutanecarboxylic acid (1), 2-{[(3α-hydroxytropo-6β-yl)oxy]carbonyl}-2-methyl-3-{[((6β-tigloyloxy)-3α-yl)oxy]carbonyl}-4-phenylcyclobutanecarboxylic acid (2), 1-methyl-2-{[(3α-hydroxytropo-6β-yl)oxy]carbonyl}-4-{[((6β-angeloyloxy)-3α-yl)oxy]carbonyl}-3-phenylcyclobutanecarboxylic acid (3), 1,2-bis{[(3α-hydroxytropo-6β-yl)oxy]carbonyl}-2-methyl-3-{[((6β-angeloyloxy)-3α-yl)oxy]carbonyl}-4-phenylcyclobutanecarboxylate (4), and 1-{[(3α-mesaconyloxytropo-6β-yl)oxy]carbonyl}-2-{[(3α-hydroxytropo-6β-yl)oxy]carbonyl}-2-methyl-3-{[((6β-angeloyloxy)-3α-yl)oxy]carbonyl}-4-phenylcyclobutanecarboxylate (5).

Chirality and numbering of substituted tropane alkaloids.

The strict application of IUPAC rules for the numbering of tropane alkaloids is not always applied by authors and there is hence a lot of confusion in the literature. In most cases, the notation of 3, 6/7-disubstituted derivatives has been chosen arbitrarily, based on NMR and MS data, without taking into account the absolute configuration of these two carbons. This paper discusses the problem and the relevance of CD and NMR to determine molecular configurations.

Comparison of the essential oils of leaves and stem bark from two different populations of Drimys winteri a Chilean herbal medicine.

The chemical composition of the essential oils obtained by hydrodistillation of stem bark and leaves of Drimys winteri J.R. et G.

Chemical study and anti-inflammatory, analgesic and antioxidant activities of the leaves of Aristotelia chilensis (Mol.) Stuntz, Elaeocarpaceae.

Objectives: Aristotelia chilensis leaves (Elaeocarpaceae) are used in Chilean folk medicine to treat pain and inflammation. A bioguided study was carried out on serial extracts (hexane, dichloromethane, methanol, aqueous extract (INFU) and a crude mixture of alkaloids (ALK-MIX). All extracts were evaluated for (1) topical administration against both arachidonic acid and 12-deoxyphorbol-13-decanoate (TPA)-induced inflammation in mice and (2) per-os administration against inflammation by λ-carrageenan-induced paw oedema in guinea-pigs and (3) topical analgesia in tail flick and formalin models and per-os writhing test in mice.

Schizanthines N, O, and P, tropane alkaloids from the aerial parts of Schizanthus tricolor.

Three tropane alkaloids, named schizanthines N, O, and P (1-3), have been isolated from the crude alkaloid extract of the endemic Chilean plant Schizanthus tricolor. On the basis of extensive NMR studies and MS fragmentation analysis, their structures were determined to be 3α-(E)-4-hydroxysenecioyloxy-6β-angeloyloxytropane (1), 3α-(E)-4-hydroxysenecioyloxy-6β-senecioyloxytropane (2), and 3α-mesaconyloxy-6β-senecioyloxytropane (3). Compounds 1 and 2 are the first isomeric alkaloids in the tropane series possessing a hydroxysenecioyl substituent as an esterifying moiety.

Isomeric tropane alkaloids from the aerial parts of Schizanthus tricolor.

Investigation of the aerial parts of Schizanthus tricolor yielded seven isomeric tropane alkaloids: 3alpha-(1-methylitaconyl)-6beta-senecioyloxytropane (1), 3alpha-(1-methylitaconyl)-6beta-angeloyloxytropane (2), 3alpha-(1-methylmesaconyl)-6beta-senecioyloxytropane (3), 3alpha-(1-methylmesaconyl)-6beta-angeloyloxytropane (4), 3alpha-(1-methylmesaconyl)-6beta-tigloyloxytropane (5), 3alpha-(1-methylcitraconyl)-6beta-senecioyloxytropane (6), and 3alpha-(1-methylcitraconyl)-6beta-angeloyloxytropane (7). Their structures were established by NMR including (1)H, (13)C NMR, HSQC, HMBC, COSY, and NOESY experiments, UV, IR, and mass spectrometry. Compounds 1, 6, and 7 are new to the literature.

Characterization of positional and configurational tropane alkaloid isomers by combining GC with NPD, MS and FTIR.

A purified stem bark extract from Schizanthus grahamii was analyzed by combining capillary gas chromatography with a selective nitrogen phosphorus detector, mass spectrometry and Fourier transform infrared spectroscopy. Several positional and configurational tropane isomers were detected and their structural elucidation was tentatively determined based on mass spectra and confirmed by vapor phase infrared spectra. Electron impact mass spectra of the isomeric alkaloids were virtually superimposable, whereas the corresponding infrared spectra differed markedly.

Absolute configuration determination and conformational analysis of (-)-(3S,6S)-3alpha,6beta-diacetoxytropane using vibrational circular dichroism and DFT techniques.

The absolute configuration of semisynthetic (-)-3alpha,6beta-acetoxytropane 1, prepared from (-)-6beta-hydroxyhyoscyamine 2, has been determined using vibrational circular dichroism (VCD) spectroscopy. The vibrational spectra (IR and VCD) were calculated using DFT at the B3LYP/DGDZVP level of theory for the eight more stable conformers which account for 99.97% of the total relative abundance in the first 10 kcal/mol range.

High-precision heteronuclear 2D NMR experiments using 10-ppm spectral window to resolve carbon overlap.

The acquisition of a complementary heteronuclear 2D NMR experiment with 10-ppm carbon window allows chemists to improve by a factor 20-25 the spectral resolution and determine carbon chemical shifts with five figures from 2D spectra.

Absolute configuration of tropane alkaloids bearing two alpha,beta-unsaturated ester functions using electronic CD spectroscopy: application to (R,R)-trans-3-hydroxysenecioyloxy-6-senecioyloxytropane.

The absolute configuration of heterocyclic natural products substituted with two mobile alpha,beta-unsaturated esters was studied using electronic circular dichroism (CD) spectroscopy. The conformational flexibility of the side chains imposed the use of density functional theory calculation to determine the set of the most probable conformations in solution. The electronic CD and UV spectra were calculated by Boltzmann-weighted average of the simulated spectra using the results of the excited states calculation of a set of simplified structures.

Absolute configuration of natural diastereoisomers of 6beta-hydroxyhyoscyamine by vibrational circular dichroism.

The absolute configuration of the two natural diastereoisomers of 6beta-hydroxyhyoscyamine has been determined using vibrational circular dichroism (VCD) spectroscopy. The predicted VCD and IR spectra of (3R,6R,2'S)-6beta-hydroxyhyoscyamine (1) and (3S,6S,2'S)-6beta-hydroxyhyoscyamine (2) were calculated using density functional theory (DFT) with the B3LYP functional and 6-31G(d) basis set and considering the eight lower energy conformations of each diastereoisomer. In both cases, the first four conformers showed the N-Me group in the syn orientation, permitting the formation of a hydrogen bond between the hydroxy group at the tropane ring and the tertiary nitrogen atom.

Identification of isomeric tropane alkaloids from Schizanthus grahamii by HPLC-NMR with loop storage and HPLC-UV-MS/SPE-NMR using a cryogenic flow probe.

Two fully automated HPLC-NMR methods are reported and compared for the structure elucidation of four isomeric tropane alkaloids from the stem-bark of an endemic Chilean plant, Schizanthus grahamii Gill. (Solanaceae). The first approach interfaced a conventional HPLC column to NMR by means of a loop storage unit.

Analysis of isomeric tropane alkaloids from Schizanthus grahamii by very fast gas chromatography.

This study presents a very fast GC analysis applied for the baseline separation of isomeric tropane alkaloids extracted from the stem-bark of Schizanthus grahamii (Solanaceae). The work provided a challenging application where isothermal analysis in conjunction with very short narrow bore columns (3 m x 100 microm ID and 1.5 m x 50 microm ID) was particularly suited for the speeding up.

Anthocyanins in berries of Maqui (Aristotelia chilensis (Mol.) Stuntz).

The anthocyanin composition of berries of Maqui [Aristotelia chilensis (Mol.) Stuntz] was determined by HPLC with photodiode array and MS detection. Eight pigments corresponding to the 3-glucosides, 3,5-diglucosides, 3-sambubiosides and 3-sambubioside-5-glucosides of delphinidin and cyanidin were identified, the principal anthocyanin being delphinidin 3-sambubioside-5-glucoside (34% of total anthocyanins).

In vitro shoot and root organogenesis, plant regeneration and production of tropane alkaloids in some species of Schizanthus.

A rapid in vitro propagation system leading to formation of shoots from callus, roots, and plantlets was developed for Schizanthus hookeri Gill. (Solanaceae), an endemic Chilean plant. The genus Schizanthus is of particular interest due to the presence of several tropane alkaloids.

Two new dammarane triterpenoids from Kageneckia angustifolia D. Don.

Two new dammarane triterpenoids, 20R,21-epoxydammar-24-ene-3,23-dione and 20R,21-epoxy-3beta-hydroxydammar-24-ene-23-one have been isolated from the aerial parts of Kageneckia angustifolia D. Don, Rosaceae, along with the previously reported triterpenoids oleanolic acid and 3beta-(beta-D-glucosyloxy)-16alpha,23alpha-epoxycucurbita-5,24-dien-11-one and the phenolic prunasin. The structures of these compounds were established by MS, 1D- and 2D-NMR experiments, and the structure of the new compounds were confirmed by X-ray diffraction analysis.

Use of porous graphitic carbon column for the separation of natural isomeric tropane alkaloids by capillary LC and mass spectrometry.

This study presents the outstanding chromatographic selectivity of a porous graphitic carbon support for the separation of four isomeric tropane alkaloids from the stem-bark of Schizanthus grahamii (Solanaceae). Capillary liquid chromatography coupled to mass spectrometry was studied after the appropriate selection of mobile phase composition, temperature, nature and concentration of the acidic modifier. Fragmentation behaviour by in-source collision-induced dissociation (CID) on a single quadrupole mass spectrometer, or MSn with an ion-trap, was investigated for structural identification.

Tropane alkaloids from Latua pubiflora.

Four known tropane alkaloids were isolated from the leaves of the endemic Chilean plant Latua pubiflora (Solanaceae). For the first time; 3alpha-cinnamoyloxitropane and apoatropine are reported in this plant. Scopolamine and hyoscyamine were previously reported.

Constituents and biological activities from Muehlenbeckia hastulata.

Muehlenbeckia hastulata (J. E.Sm.

Cucurbitacin F in seeds of Kageneckia angustifolia (Rosaceae).

Cucurbitacin F and the cyanogenetic compounds prunasin were isolated and identified from the seeds of Kageneckia angustifolia.

Pharmaco-toxicological study of Kageneckia oblonga, Rosaceae.

The probable antipyretic, antiinflammatory, analgesic and antioxidant properties of Kageneckia oblonga, Rosaceae, were investigated and the major compounds of its active extracts were isolated. The study comprised the acute toxicity of the extracts of global methanol, hexane, dichloromethane and methanol. The cytotoxicity of global methanol extract was studied in three tumoral cell lines.