Showing papers on "Amaryllidaceae Alkaloids published in 2004"
TL;DR: The 80% aqueous methanolic extract from the bulbs of Crinum yemense showed a potent inhibitory effect on nitric oxide production in lipopolysaccharide-activated macrophages, and several alkaloids, e.g. 1, (+)-bulbispermine (6), (+)-crinamine (7), (+-6-hydroxycrinamines (8), and (-)-lycorine (9), showed inhibitory effects on nit
Abstract: The 80% aqueous methanolic extract from the bulbs of Crinum yemense showed a potent inhibitory effect on nitric oxide production in lipopolysaccharide-activated macrophages. Three new crinine-type alkaloids, yemenines A (1), B (2), and C (3), were isolated from the herbal extract together with six known alkaloids. The absolute configurations of 1-3 were determined on the basis of chemical and physicochemical evidence. The effects of the isolated alkaloids on nitric oxide production in lipopolysaccharide-activated macrophages were examined, and several alkaloids, e.g. 1, (+)-bulbispermine (6), (+)-crinamine (7), (+)-6-hydroxycrinamine (8), and (-)-lycorine (9), showed inhibitory effects on nitric oxide production and induction of inducible nitric oxide synthase.
151 citations
TL;DR: Lycorine-type alkaloids were the most active alkaloid with 1- O-acetyllycorine exhibiting inhibitory effects two-fold more potent than that of galanthamine.
Abstract: Twenty-three Amaryllidaceae alkaloids having several different ring types were evaluated for their acetylcholinesterase enzyme (AChE) inhibitory activity. The alkaloid 1- O-acetyllycorine (IC50 : 0.96 +/- 0.04) showed significant AChE inhibitory activity. In addition, crinine (IC50 : 461 +/- 14), crinamidine (IC50 : 300 +/- 27), epivittatine (IC50 : 239 +/- 9), 6-hydroxycrinamine (IC50 : 490 +/- 7), N-desmethyl-8alpha-ethoxypretazettine (IC50 : 234 +/- 13) N-desmethyl-8beta-ethoxypretazettine (IC50 : 419 +/- 8), lycorine (IC50 : 213 +/- 1), and 1,2-di- O-acetyllycorine (IC50 : 211 +/- 10) had weak activity. Lycorine-type alkaloids were the most active alkaloids with 1- O-acetyllycorine exhibiting inhibitory effects two-fold more potent than that of galanthamine.
143 citations
TL;DR: Three alkaloids, lycorine, homolycorine and 2- O-acetylly Corine, were isolated from the bulbs of Leucojum vernum (Amaryllidaceae) and identified by means of NMR analysis and demonstrate that trisphaeridine, lyCorine, Homolycorines and haemanthamine possess high antiretroviral activities.
Abstract: Three alkaloids, lycorine, homolycorine and 2- O-acetyllycorine, were isolated from the bulbs of Leucojum vernum (Amaryllidaceae) and identified by means of NMR analysis The alkaloids obtained from L vernum and from other Amaryllidaceae species were studied in vitro for HIV-1 replication inhibitory activity on MT4 cells The cytotoxicity of the compounds in uninfected cells was evaluated by using the MTT assay and the [ (3)H]thymidine incorporation test The antiviral activities were determined by means of the p24 antigen assay and solid-phase reverse transcriptase testing The results demonstrate that trisphaeridine, lycorine, homolycorine, and haemanthamine possess high antiretroviral activities (IC (50) = 04 - 73 microg/mL), accompanied by low therapeutic indices (TI (50) = 13 - 19)
137 citations
TL;DR: The total synthesis of the Amaryllidaceae alkaloids dehydroanhydrolylycorine, hippadine, pratosine, assoanine and oxoassoanine was achieved from the appropriate N -benzylisatin precursors using an intramolecular, palladium catalyzed, dehydrohalogenation, biaryl synthesis reaction to establish the carbon skeleton of the natural products as discussed by the authors.
67 citations
TL;DR: A GC/MS analysis of alkaloids from leaves, bulbs and roots of Pancratium maritimum found Haemanthamine was main alkaloid in the leaves and bulbs whereas galanthane was found to be main alkAloid in roots.
Abstract: A GC/MS analysis of alkaloids from leaves, bulbs and roots of Pancratium maritimum was performed. From the identified 16 alkaloids, 5 alkaloids were reported for the first time for this plant. Several compounds with pharmacological activity were found. Haemanthamine was main alkaloid in the leaves and bulbs whereas galanthane was found to be main alkaloid in roots.
60 citations
TL;DR: 1,2-Diacetyllycorine and 3-O-acetylsanguinine showed activity against Trypanosoma brucci rhodesiense, the parasite associated with sleeping sickness.
53 citations
TL;DR: Alkaloid pattern of individuals from 16 Bulgarian Galanthus elwesii populations was investigated and data demonstrate that like the morphological features, the alkaloid metabolism of G. elWesii is also variable.
46 citations
TL;DR: This work has succeeded in the first asymmetric total syntheses of the crinane-type alkaloids (+)-crinamine, (-)-haemanthidine, and (+)-pretazettine, and the overall yield is 19%.
Abstract: Much interest has been shown in Amaryllidaceae alkaloids as synthetic targets due to their wide range of biological activities. Over 100 alkaloids have been isolated from members of the Amaryllidaceae family; most of them can be classified into eight skeletally homogeneous groups. We have succeeded in the first asymmetric total syntheses of the crinane-type alkaloids (+)-crinamine (1), (-)-haemanthidine (2), and (+)-pretazettine (3). The starting cyclohexenylamine 14 was obtained from allyl phosphonate 11c by palladium-catalyzed asymmetric amination in 82% yield and with 74% ee. The product was recrystallized from MeOH. Interestingly, (-)-14 with 99% ee was obtained from the mother liquor (74% recovery). Intramolecular carbonyl-ene reaction of (-)-10 proceeds in a highly stereoselective manner to give hexahydroindole derivative 9 as the sole product. In the Lewis-acid-catalyzed carbonyl-ene reaction, an interesting rearrangement product, 20, was isolated in high yield. From 9, (+)-crinamine was synthesized. Thus, the asymmetric total synthesis of (+)-crinamine was achieved in 10 steps from 11c, and the overall yield is 19%. The total synthesis of (-)-haemanthidine was also achieved from 9 by a short sequence of steps.
44 citations
TL;DR: The concise synthesis of Amaryllidaceae alkaloids, which have a pyrrolophenanthridine skeleton, was achieved in moderate yield using the Pd-mediated biaryl coupling reaction of 1-(2-halobenzyl)-2,3-dihydroindole.
43 citations
TL;DR: In this paper, three crinane type of alkaloids isolated from Amaryllidaceae family were synthesized by taking advantage of the PIFA-mediated intramolecular p-p′ diphenol coupling reaction of norbelladine derivatives.
40 citations
TL;DR: In this paper, the stereoselective and chiral synthesis of the Amaryllidaceae alkaloid (+)-vittatine 1 was described; the quaternary carbon in 1 was generated by Claisen rearrangement of a cyclohexenol derived from D-glucose by way of a Ferrier's carbocyclisation reaction.
TL;DR: Extracts from five species of Hymenocallis Salisbury (Amaryllidaceae) were examined by means of gas chromatography-mass spectrometry, for sources of bioactive alkaloids; especially of the isocarbostyril type such as the antitumor compound narciclasine.
Abstract: Extracts from five species of Hymenocallis Salisbury (Amaryllidaceae) were examined by means of gas chromatography-mass spectrometry (GC-EIMS), for sources of bioactive alkaloids; especially of the isocarbostyril type such as the antitumor compound narciclasine. Ten different alkaloids were identified, all of them exhibiting skeletons of the lycorine, galanthamine, and pyrrolophenanthridine types considered typical for the family. The detection of 1-O-acetyl-pseudolycorine and 4,5-dehydro-anhydrolycorine constitutes the first report of these alkaloids for the genus. In addition, the identification of anhydropseudolycorine and 4,5-dehydro-anhydropseudolycorine from several species constitutes the first report of these alkaloids as naturally occurring compounds. Neither of the species contains isocarbostyrils and, due to the low alkaloid concentrations observed, they show no promise as a source of Amaryllidaceae alkaloids.
01 Jan 2004
01 Jan 2004
TL;DR: In this paper, the dichloromethane (CH 2 Cl 2 ) extracts obtained from different parts of the Hippeastrum glaucescens (Martius) Herbert (bulbs, roots, leaves and flowers) and the isolated alkaloids lycorine, tazettine and pretazetine were analyzed by a chromatographic method (TLC) and tested for antiviral activity.
Abstract: Evaluation of antiviral activity and determination of the chromatographic profile of Hippeastrum glaucescens (Martius) Herbert (Amaryllidaceae). Plants of Amaryllidaceae are characterized by isoquinoline alkaloids. Since the first study with Amaryllidaceae alkaloids in 1877, a large number of these plants have been chemically investigated. These compounds have shown a wide range of biological activities such as: antiviral, cytotoxic, antitumoral and analgesic. In this work, the dichloromethane (CH 2 Cl 2 ) extracts obtained from different parts of the Hippeastrum glaucescens (Martius) Herbert (bulbs, roots, leaves and flowers) and the isolated alkaloids lycorine, tazettine and pretazettine were analyzed by a chromatographic method (TLC) and tested for antiviral activity. The
TL;DR: In this paper, the stereoselective and chiral synthesis of the Amaryllidaceae alkaloid (+)-vittatine 1 was described; the quaternary carbon in 1 was generated by Claisen rearrangement of a cyclohexenol derived from D-glucose by way of a Ferrier's carbocyclisation reaction.
Abstract: The stereoselective and chiral synthesis of the Amaryllidaceae alkaloid, (+)-vittatine 1, is described; the quaternary carbon in 1 was generated by Claisen rearrangement of a cyclohexenol derived from D-glucose by way of a Ferrier's carbocyclisation reaction and a hexahydroindole skeleton was effectively constructed by intramolecular aminomercuration–demercuration, followed by Chugaev reaction.