Showing papers on "Indole alkaloid published in 2002"
TL;DR: To obtain more insight into the regulation of terpenoid indole alkaloid (TIA) biosynthesis in Catharanthus roseus (L.) G. Don cell cultures, a transgenic cell line over-expressing tryptophan decarboxylase (Tdc), and thus having a high level of tryptamine, was fed with various amounts of precursors in different time schedules and analyzed for TIA production.
93 citations
TL;DR: Three novel quaternary indole alkaloids with an unprecedented 1-azoniatricyclo have been isolated from the barks of Aspidosperma subincanum Mart, and the structures of 1-6 and the stereochemistry of1-3 were elucidated by spectroscopic data and chemical means.
Abstract: Three novel quaternary indole alkaloids with an unprecedented 1-azoniatricyclo[4.3.3.0(1,5)]undecane moiety, subincanadines A-C (1-3), as well as two new indole alkaloids with a 1-azabicyclo[5.2.2]undecane moiety, subincanadines D (4) and E (5), and a new indole alkaloid with a 1-azabicyclo[4.3.1]decane moiety, subincanadine F (6), have been isolated from the barks of Aspidosperma subincanum Mart, and the structures of 1-6 and the stereochemistry of 1-3 were elucidated by spectroscopic data and chemical means.
74 citations
TL;DR: These compounds were obtained from the bark of Geissospermum sericeum together with the beta-carboline alkaloid flavopereirine and two new derivatives and their cytotoxicity was determined in a human (KB) cell line.
Abstract: The indole alkaloid geissoschizoline (1) and two new derivatives, geissoschizoline N(4)-oxide (2) and 1,2-dehydrogeissoschizoline (3), were obtained from the bark of Geissospermum sericeum together with the beta-carboline alkaloid flavopereirine (4). The in vitro antiplasmodial activity of these compounds was evaluated in chloroquine-resistant (K1) and chloroquine-sensitive (T9-96) Plasmodium falciparum. Their cytotoxicity was determined in a human (KB) cell line.
61 citations
TL;DR: Lotthanongine, a novel flavonoidal indole alkaloid, was isolated from the roots of Trigonostemon reidioides (Euphorbiaceae) together with afzelechin-(4α→8)-afzelechine as mentioned in this paper.
58 citations
TL;DR: The results suggest that high rates of tryptamines synthesis can still take place under conditions of low TDC activity and the flux towards tryptamine is induced by loganin feeding, however, accumulation oftryptamine seems to reduce the flux through feedback inhibition.
Abstract: The transgenic S1 cell line of Catharanthus roseus (L.) G. Don has been used to study possible rate limiting steps in the terpenoid indole alkaloid (TIA) biosynthesis. Line S1 carries a recombinant, over-expressed version of the endogenous Str gene which encodes strictosidine synthase (STR; EC 4.3.3.2). STR catalyzes the stereospecific condensation of tryptamine and secologanin to strictosidine. Various concentrations and combinations of biosynthetic indole precursors L-tryptophan, tryptamine, and iridoid precursors loganin and secologanin were added to the cell suspension cultures of line S1. The largest TIA accumulation occurred when the precursor was supplied at the time of inoculation of the cells into the production medium. Line S1 could supply tryptamine endogenously up to 0.8 mM loganin feeding. The enhancement of the accumulation of TIAs by addition of loganin indicates a limitation in the terpenoid pathway. Supplying tryptamine or tryptophan along with the iridoid precursors resulted in even further increase of alkaloid accumulation. Under optimal conditions, cultures of line S1 accumulated about 600 μmol l−1 of TIAs. Also, the conversion of strictosidine into other TIAs further down the pathway seems to be a limiting step. Considering the mass balance of the intermediates fed and TIAs recovered, several yet unknown pathways must be involved in channeling away intermediates from the TIA pathway and in the breakdown of the TIAs. Our results suggest that high rates of tryptamine synthesis can still take place under conditions of low TDC activity and the flux towards tryptamine is induced by loganin feeding. However, accumulation of tryptamine seems to reduce the flux through feedback inhibition.
56 citations
TL;DR: In this paper, three pentacyclic indole alkaloids, one novel named darcyribeirine (1), and the known isoreserpiline (2) and isore serpine (3), were isolated from the root bark of the Rauvolfia grandiflora Mart.
19 citations
TL;DR: This work has isolated a new monoterpenoid indole alkaloid from hairy root culture of Rauvolfia serpentina Benth and the structure was determined by 1D and 2D NMR analyses.
Abstract: A new monoterpenoid indole alkaloid, 10-hydroxy- N(alpha)-demethyl-19,20-dehydroraumacline ( 1), was isolated as a mixture of E- and Z-isomers from hairy root culture of Rauvolfia serpentina Benth. ex Kurz (Apocynaceae) and the structure was determined by 1D and 2D NMR analyses. The new indole alkaloid represents the first naturally occurring alkaloid of the raumacline group and its putative biosynthetical pathway is discussed.
13 citations
TL;DR: In this article, the enantiomer 3En of macroline 3 was synthesized from l -tryptophan methyl ester 6 in an overall yield of 12.3% (11 isolated intermediates).
12 citations
TL;DR: A new indole alkaloid, picranitine, has been isolated from the seeds of Picralima nitida, along with five known indole alkaloids, namely, akuammine, pseudoakuammine and akuammicine, previously identified from the same source as discussed by the authors.
Abstract: A new indole alkaloid, picranitine, has been isolated from the seeds of Picralima nitida, along with five known indole alkaloids picratidine, akuammine, pseudoakuammine, akuammicine and akuammidine previously identified from the same source. Structures were elucidated through exhaustive spectral studies including 1D (1H and 13C NMR) and 2D-NMR (HMQC, HMBC and NOESY).
(Bulletin of The Chemical Society of Ethiopia: 2002 16 (2): 165-169)
9 citations
TL;DR: Two novel aplysinopsin-type indole alkaloids, 1 and 2, and three known indole alkaloids were isolated from the marine sponge Hyrtios erecta.
Abstract: Two novel aplysinopsin-type indole alkaloids, 1 and 2, and three known indole alkaloids were isolated from the marine sponge Hyrtios erecta. These compounds exhibited selective inhibitory activity against the neuronal isozyme of nitric oxide synthase (nNOS). Furthermore, new quinolone 7 was also isolated from the same marine sponge. The chemical structures of these new compounds were elucidated on the basis of spectroscopic analysis.
7 citations
TL;DR: In this article, three pentacyclic indole alkaloids, one novel named darcyribeirine (1), and the known isoreserpiline (2) and isore serpine (3), were isolated from the root bark of the Rauvolfia grandiflora Mart.
Abstract: Three pentacyclic indole alkaloids, one novel named darcyribeirine (1) and the known isoreserpiline (2) and isoreserpine (3), were isolated from the root bark of the Rauvolfia grandiflora Mart. The structures were established by spectroscopic data.
TL;DR: Lead tetraacetate oxidation of a Corynanthe-type indole alkaloid produced mainly 7-acetoxyindolenine derivative together with a dimeric compound as a minor product.
Abstract: Lead tetraacetate oxidation of a Corynanthe-type indole alkaloid, mitragynine, produced mainly 7-acetoxyindolenine derivative (2) together with a dimeric compound (4) as a minor product. The novel structure having a bridge between the C-11' and C-7 positions in the respective indolenine parts and its formation mechanism were studied.
TL;DR: A model able to well correlate the antitumor activity with the chemical structures of mono and bis(indole) alkaloids 1-18 has been developed which is potentially helpful in the design of novel and more potent antitUMor agents.
Journal Article•
TL;DR: A new indole alkaloid, 19-epialstonine, has been isolated from the ethyl acetate extract of the roots of Amphicome emodi.
Abstract: A new indole alkaloid, 19-epialstonine has been isolated from the ethyl acetate extract of the roots of Amphicome emodi. The structure of the alkaloid has been established on the basis of spectroscopic (including 2D NMR experiments) and chemical studies.
TL;DR: In this article, the indole alkaloid trinervine was synthesized in enantiospecific fashion in an overall yield of 20% (from the tetracyclic ketone 8) in 10 reaction vessels (12.5% from tryptophan methyl ester).
Abstract: [structure: see text] The total synthesis of the indole alkaloid trinervine 1 was accomplished in enantiospecific fashion in an overall yield of 20% (from the tetracyclic ketone 8) in 10 reaction vessels (12.5% from tryptophan methyl ester). The synthesis of the N(a)-H substituted macroline equivalent 2 was also completed in high yield via the same intermediate 13. The unique protection/hydroboration process developed here should provide a method to functionalize the C(19)-C(20) double bond in similar systems.
01 Jan 2002
TL;DR: In this article, the authors report on some novel reactions of various aglycones of this class of compounds, which is a continuation of their studies on iridoids1, 4.
Abstract: As a continuation of our studies on iridoids1–4, we now report on some novel reactions of various aglycones of this class of compounds.