Search results for " alkaloids"
showing 10 items of 84 documents
Partialsynthese neuer Ergolinderivate aus Clavinalkaloiden, 2. Mitt.1) O-Acyl-8-hydroxymethyl-6-methylergol-8-ene und -ergol-9-ene
1983
Die Titelverbindungen sind durch Acylierung von Elymoclavin (1) bzw. Lysergol (2) mit Saurechloriden, im Fall der Ester von 2 auch durch Isomerisierung von O-Acyl-1 mit aktiviertem Al2O3 darstellbar. Umgekehrt fuhrt die Acylierung von 2 in bestimmten Fallen spontan zur Bildung eines Gemisches der O-Acylderivate von 1 und 2.. Partial Synthesis of New Ergoline Derivatives from Clavine Alkaloids, II: O-Acyl-8-(hydroxymethyl)-6-methylergol-8-enes and -ergol9-enes The title compounds can be prepared by acylation of elymoclavine (1) and lysergole (2), respectively, with acid chlorides or, in the case of the esters of 2, by isomerization of O-acyl-1 with activated Al2,O3. On the other hand, in cer…
Chemical Constituents and Biological Properties of Genus Doronicum (Asteraceae)
2021
The genus Doronicum, belonging to tribe Senecioneae (Fam. Asteraceae), is found mainly in the Asia, Europe and North Africa. This genus of plant has always been used in traditional medicinal treatments due to the many biological properties shown such as killing parasitic worms and for relieving constipation, as well as to improve heart health, to alleviate pain and inflammation, to treat insect bites, etc. According to the World Flora the genus Doronicum contains 39 subordinate taxa.[1-3] The purpose of this article, which covers data published from 1970 to 2021 with more than 110 articles, aims to carry out a complete and critical review of the Doronicum genus, examining traditional uses a…
Synthesis and antiproliferative activity of thiazolyl-bis-pyrrolo[2,3-b]pyridines and indolyl-thiazolyl-pyrrolo[2,3-c]pyridines, nortopsentin analogu…
2015
Two new series of nortopsentin analogues, in which the imidazole ring of the natural product was replaced by thiazole and indole units were both substituted by 7-azaindole moieties or one indole unit was replaced by a 6-azaindole portion, were efficiently synthesized. Compounds belonging to both series inhibited the growth of HCT-116 colorectal cancer cells at low micromolar concentrations, whereas they did not affect the viability of normal-like intestinal cells. A compound of the former series induced apoptosis, evident as externalization of plasma membrane phosphatidylserine (PS), and changes of mitochondrial trans-membrane potential, while blocking the cell cycle in G2/M phase. In contr…
The origin of the serpentine endemic Minuartia laricifolia subsp. ophiolitica by vicariance and competitive exclusion.
2013
Serpentine soils harbour a unique flora that is rich in endemics. We examined the evolution of serpentine endemism in Minuartia laricifolia, which has two ecologically distinct subspecies with disjunct distributions: subsp. laricifolia on siliceous rocks in the western Alps and eastern Pyrenees and subsp. ophiolitica on serpentine in the northern Apennines. We analysed AFLPs and chloroplast sequences from 30 populations to examine their relationships and how their current distributions and ecologies were influenced by Quaternary climatic changes. Minuartia laricifolia was divided into four groups with a BAPS cluster analysis of the AFLP data, one group consisted only of subsp. ophiolitica, …
Interactions between the yeast mitochondrial and nuclear genomes: isogenic suppressive and hypersuppressive petites differ in their resistance to the…
1990
In a previous paper we have shown that the alkaloid lycorine inhibits growth of rho+, mit- and rho-, strains of Saccharomyces cerevisiae, whereas strains devoid of mitochondrial DNA (rho degrees) are resistant to more than 200 micrograms/ml of the alkaloid. In this report we show that hypersuppressive petites are almost as resistant as rho degrees mutants, whereas isogenic rho- petites, which have retained longer segments of the genome, are sensitive to the drug.
Xylochemistry--Making Natural Products Entirely from Wood.
2015
The first total synthesis of the dimeric berberine alkaloid ilicifoline (ilicifoline B) is reported. Its carbon skeleton is constructed from ferulic acid, veratrole, and methanol. The synthesis reported herein employs starting materials solely derived from wood. The natural product is thus constructed entirely from renewable resources. The same strategy is applied to a formal total synthesis of morphinan alkaloids. The use of wood-derived building blocks (xylochemicals) instead of the conventional petrochemicals represents a sustainable alternative to classical synthetic approaches.
Ancistrocyclinones A and B, unprecedented pentacyclic N,C-coupled naphthylisoquinoline alkaloids, from the Chinese liana Ancistrocladus tectorius
2018
Two unique pentacyclic N,C-coupled naphthylisoquinolines, the ancistrocyclinones A (5) and B (6), were discovered in the Chinese liana Ancistrocladus tectorius. Furthermore, six known, likewise N,C-coupled alkaloids, viz., ancistrocladinium A (7a) and its mono- and bisphenolic analogs 8a and 9a were isolated, along with their atropo-diastereomers 7b, 8b, and 9b. The stereostructures of 5 and 6 were determined by HRESIMS, 1D and 2D NMR, oxidative degradation, and ECD calculations. The pentacyclic ancistrocyclinones A (5) and B (6) are structurally similar to berberine alkaloids - yet arising from a most different biosynthetic pathway: they are apparently formed by N,C-coupling of their polyk…
Development of an efficient system for the separation of indole alkaloids by high performance liquid chromatography and its applications
2001
An efficient system for the analysis of indole alkaloids by HPLC on a reversed-phase column using an ion pair technique is described. The optimised chromatographic conditions allowed the successful separation of 22 standard monoterpenoid indole alkaloids (including some isomers) and tryptamine. The described HPLC system was applied to the analysis of alkaloids in intergeneric somatic hybrid cell cultures of Rauvolfia serpentina x Rhazya stricta.
Novel indole alkaloids from cell suspension cultures of aspidosperma quebracho blanco schlecht
1991
Abstract Two novel monoterpenoid indole alkaloids, aspidochibine ( 1 ) and 3-oxo-14,15-dehydrorhazinilam ( 2 ), were isolated from cell suspension cultures of Aspidosperma quebracho blanco Schlecht. Aspidochibine ( 1 ) exhibits a new alkaloid skeleton. The structure of these alkaloids was elucidated by spectroscopic methods.
1,2,4-Oxadiazole topsentin analogs as staphylococcal biofilm inhibitors targeting the bacterial transpeptidase sortase A
2020
The inhibition or prevention of biofilm formation represents an emerging strategy in the war against antibiotic resistance, interfering with key players in bacterial virulence. This approach includes the inhibition of the catalytic activity of transpeptidase sortase A (Srt A), a membrane enzyme responsible for covalently attaching a wide variety of adhesive matrix molecules to the peptidoglycan cell wall in Gram-positive strains. A new series of seventeen 1,2,4-oxadiazole derivatives was efficiently synthesized and screened as potential new anti-virulence agents. The ability of inhibiting biofilm formation was evaluated against both Gram-positive and Gram-negative pathogens. Remarkably, all…