Search

Introduction The Annonaceae family is known as a promising abundant source of secondary metabolites, especially annonaceous acetogenins, terpenoids and isoquinoline-derived alkaloids. Although widely investigated from the phytochemical viewpoint, this family still presents some largely unexplored genera, e.g. the Bocageopsis. Objective To investigate the alkaloid content of Bocageopsis pleiosperma Maas using direct infusion electrospray ionisation ion trap tandem mass spectrometry (ESI-IT-MSn) analysis. Methodology Dichloromethane extracts of aerial parts were subjected to acid–base partitioning to yield the alkaloidal fractions. These fractions were analysed by direct infusion into a (+)ESI-IT-MSn system. The alkaloidal fraction from the leaves was also obtained on a large scale and subjected to chromatographic separation. Results The tentative MSn-based identification of alkaloids in leaves, twigs and trunk bark showed that aporphine alkaloids were restricted to the leaves and twigs, tetrahydroprotoberberine alkaloids were only found in the twigs and trunk bark while benzylisoquinoline alkaloids were found in the leaves, twigs and trunk bark. Chromatographic separation of the leaf alkaloidal fraction yielded the aporphine alkaloids nornuciferine, asimilobine and isoboldine, the β-carboline alkaloid tetrahydroharman and some mixtures containing benzylisoquinoline and aporphine alkaloids, all described for the first time in the Bocageopsis genus. Furthermore, tetrahydroharman has not previously been reported in the Magnoliales order. Conclusion Direct infusion ESI-IT-MSn analysis of alkaloids allowed fast recognition of alkaloidal classes previously reported in the Annonaceae family, aiding the chromatographic step and allowing a selective isolation of compounds previously not identified in the Bocageopsis genus. Copyright © 2015 John Wiley & Sons, Ltd.

A high performance liquid chromatographic method was developed to determine all types of β-carboline alkaloids in medicinal and edible plants. The alkaloids, including internal standards, were purified from plant homogenates by serial extractions after reacting with fluorescamine. The extracts were analysed twice using reversed-phase chromatography with fluorometric detection optimized for each individual analyte. β-Carbolines and tetrahydro-β-carbolines were analysed in the first run, while dihydro-β-carbolines were analysed in the second. The simultaneous separation of harmol, norharman, harman, harmine, harmalol, harmaline, tetrahydronorharman, tetrahydroharman and two internal standards was achieved within 17 min by an isocratic elution. β-Carbolines, dihydro-β-carbolines and tetrahydro-β-carbolines could be quantitatively determined in concentrations of 0.01–50.0 ng/mL. In replicate spiking experiments, the mean recovery was 71–110% and the relative standard deviation was 0.3–10.1% within and between assays. Application of the proposed method has revealed that medicinal plants and dried edible plants contain β-carboline alkaloids at ng/g to µg/g levels. Norharman and harman were distributed in all the tested plants, while harmol and harmalol were found only in some plant species. However, no significant amounts of tetrahydro-β-carbolines were detected in any plant materials tested, suggesting that the oxidation of tetrahydro-β-carbolines to β-carbolines occurs during the drying and/or the storing process. The β-carboline alkaloids may be responsible for the pharmacological effects of certain medicinal plants. Copyright © 1999 John Wiley & Sons, Ltd.

Helicobacter pylori contains alcohol dehydrogenase which oxidizes ethanol to acetaldehyde. In the present study, H . pylori cytosol was incubated in a buffered media at pH 6.0 and 7.4 in the presence of ethanol and tryptamine. Under these conditions, tetrahydroharman (1-methyl-tetrahydro-β-carboline) was produced as a condensation product of tryptamine and acetaldehyde. At pH 6.0, 20.60 ± 5.00% of the added tryptamine was converted to tetrahydroharman, while 27.00 ± 4.80% (mean ± SD) was converted at pH 7.4. Similar reactions between acetaldehyde and other dietary amines seem likely. Such biogenic alkaloids, if formed in vivo , might contribute to the dysphoric effects of alcohol.

The β-carboline alkaloid harman has been shown by a combination of feeding and trapping experiments to be formed in Passiflora edulis from N-acetyltryptamine via harmalan. N-acetyltryptamine was shown to be formed from tryptophan via tryptamine. Tetrahydroharman is dehydrogenated to harman presumably via harmalan. Radioactive harman obtained from 14C labelled N-acetyltryptamine, harmalan and tetrahydroharman was degraded to establish the position of the label and doubly labelled tryptophan was converted to N-acetyl tryptamine containing the same ration of 3H: 14C.

In vivo metabolism of 1-methyl-1,2,3,4-tetrahydro-beta-carboline-1-carboxylic acid (1-CTHH), a possible precursor of the endogenous beta-carbolines tetrahydro-harman (THH) and harman was investigated in rats. Following intraperitoneal injection of [4-14C]1-CTHH, a rapid distribution of the radioactivity in the tissues was observed. The highest radioactivity was measured in the kidney and the lowest in the brain as well as in the fat tissue. Approximately 55% of the administered dose was excreted in the urine within 90 min. The radioactivity in the urine consisted of unchanged 1-CTHH (greater than 90%) besides harmalan and trace amounts of harman. Harmalan represents the major degradation product of 1-CTHH; it could be identified in all tissues examined and in the urine. The concentration in the blood, however, was low at all time points investigated. The peak concentration of harmalan in most tissues was measured between 15-30 min after injection. A time-dependent formation of THH was found in the lung and spleen indicating an important role of these organs in the biosynthesis of THH. Furthermore, the metabolism of [4-14C]1-CTHH in the brain was studied following intracerebroventricular injection. The formation of harmalan in the brain was not affected by pretreatment with the aromatic amino acid decarboxylase inhibitor NSD 1015. Determination of the harmalan concentration in several brain regions revealed a high level in the hippocampus and hypothalamus and a small concentration in pons, corpus striatum, cerebellum and cerebral cortex 20 min after injection. The analyses of the