Search results for "ALKALOIDS"

Synthesis of alkaloids by Stevens rearrangement of nitrile-stabilized ammonium ylides: (±)-laudanosine, (±)-laudanidine, (±)-armepavine, (±)-7-methox…

2013

The Stevens rearrangement of nitrile-stabilized ammonium ylides in conjunction with the reductive removal of the nitrile function permits the facile construction of α-branched amines from α-aminonitriles. We employed this reaction sequence for the preparation of (±)-laudanosine, (±)-laudanidine and (±)-armepavine, (±)-7-methoxycryptopleurine, and (±)-xylopinine from two closely related and readily accessible bicyclic α-aminonitriles. The final products were obtained in high to almost quantitative yields (71–98%) from the quaternary ammonium salts obtained by N-alkylation of these starting materials.

Die direkte quantitative Auswertung von Dünnschichtchromatogrammen durch Remissions- und Fluoreszenzmessungen 3. Mitt.: Bestimmung von Morphin, Codei…

1971

Es wird ein Verfahren zur quantitativen Bestimmung verschiedener Opiumalkaloide nebeneinander beschrieben, das auf der direkten Auswertung von DC durch Remissionsmessung mit Hilfe eines Chromatogramm-Spektralphotometers beruht. Anstelle des bisher ublichen Messpaltes wurde fur die Auswertung eine Kreisblende benutzt. Hierbei ist vorteilhaft, das die Form der Absorptions-Orts-Kurven keinen Einflus auf die Mesgenauigkeit besitzt, da nur die Peakhohe ausgewertet wird. Quantitative Determination of Opium Alkaloids A method for the quantitative determination of a number of single alkaloids in opium alkaloid mixtures is described, which is based on the direct evaluation of TLC by reflectance with…

Cytotoxicity of a naturally occurring furoquinoline alkaloid and four acridone alkaloids towards multi-factorial drug-resistant cancer cells

2015

Abstract Introduction Chemotherapy is one of the preferred mode of treatment of malignancies, but is complicated by the expression of diverse resistance mechanisms of cancer cells. Methods In the present study, we investigated the cytotoxicity of five alkaloids including a furoquinoline montrofoline (1) and four acridones namely 1-hydroxy-4-methoxy-10-methylacridone (2), norevoxanthine (3), evoxanthine (4), 1,3-dimethoxy-10-methylacridone (5) against 9 drug-sensitive and multidrug-resistant (MDR) cancer cell lines. The resazurin reduction assay was used to evaluate the cytotoxicity of these compounds, whilst caspase-Glo assay was used to detect caspase activation. Cell cycle, mitochondrial …

Therapeutic potential of alkaloids in autoimmune diseases: Promising candidates for clinical trials.

2020

Clinical investigations have characterized numerous disorders like autoimmune diseases, affecting the population at a rate of approximately 8-10%. These disorders are characterized by T-cell and auto-antibodies responses to self-molecules by immune system reactivity. Several therapeutic options have been adopted in clinics to combat such diseases, however, most of them are recurring. Thus, the discovery of new effective agents for the treatment of autoimmune diseases is paramount. In this context, natural products might be a useful alternative to the current therapies. Plant alkaloids with their substantial therapeutic history can be particularly interesting candidates for the alleviation o…

Synthesis of Bioactive 2-Aza-Analogues of Ipecac and Alangium Alkaloids

2010

Mikrobiologische C-17-Oxidation von Clavinalkaloiden

1984

Chemistry and biology of new marine alkaloids from the indole and annelated indole series.

2003

Chemistry and biology of marine natural products from the indole and annelated indole series have become an attractive research field for development of new pharmacological lead substances. In the past years some of the isolated natural organic compounds were synthesized by chemists and evaluated with great enthusiasm to find new lead natural compounds against different diseases. In this review the latest results for new compounds including isolation, biological evaluation, synthetic pathways and some retrosynthetic analyses are summarized.

Left, Right, or Both? On the Configuration of the Phenanthroindolizidine Alkaloid Tylophorine from Tylophora indica

2013

The alkaloid (-)-tylophorine was isolated from a sample of Tylophora indica, and the crude extract was analyzed by HPLC/MS(n) and chiral HPLC/MS. While the literature states that the naturally occurring form of this alkaloid is the R-enantiomer and that its S-antipode is usually not found in nature, we confirmed the hypothesis of Govindachari and Nagarajan that natural levorotatory tylophorine is indeed a nearly racemic mixture with a slight excess of the R-enantiomer.

Metabolomics-assisted discovery of a new anticancer GLS-1 inhibitor chemotype from a nortopsentin-inspired library: From phenotype screening to targe…

2022

The enzyme glutaminase-1 (GLS-1) has shown a clear and coherent implication in the progression and exacerbation of different aggressive tumors such as glioblastoma, hepatocarcinoma, pancreas, bone, and triple-negative breast cancer. Few chemotypes are currently available as selective GLS-1 inhibitors, and still, fewer of them are at the clinical stage. In the present paper, starting from a naturally-inspired antitumor compound library, metabolomics has been used to putatively identify the molecular mechanism underlying biological activity. GLS-1 was identified as a potential target. Biochemical analysis confirmed the hypothesis leading to the identification of a new hit compound acting as a…

Fast analysis of polyphenols and alkaloids in cocoa-based products by ultra-high performance liquid chromatography and Orbitrap high resolution mass …

2018

The cocoa varieties Criollo, Forastero and Trinitario, which have different organoleptic properties, quite often are mixed together in cocoa-based products. The objective of this work was to develop a rapid method for the simultaneous determination of polyphenols (n = 35) and alkaloids (n = 2) in cocoa-based products by using the high throughput advantages provided by the Q Exactive Hybrid Quadrupole-Orbitrap Mass Spectrometer (FIRMS). The proposed procedure was optimized and validated in terms of selectivity and specificity (mass accuracy 0.990), accuracy (recovery range from 89.1 to 112.4%) and precision (relative standard deviation < 10%). The method was applied to 80 cocoa-based samples…