Showing papers on "Indole alkaloid published in 1992"
TL;DR: Results show that a first important regulatory step in the complex process leading to indole alkaloid accumulation in C. roseus suspension cells is transcription of the biosynthetic genes.
Abstract: Catharanthus roseus (periwinkle) produces a wide range of terpenoid indole alkaloids, including several pharmaceutically important compounds, from the intermediate strictosidine. The complete mRNA sequence for the enzyme strictosidine synthase (SSS) was determined. Comparison of the primary structure of the encoded protein with the amino-terminal sequence of purified SSS indicated the presence of a signal peptide of 31 amino acids in the putative primary translation product. SSS is encoded by a single-copy gene indicating that isoenzymes reported by others are formed post-translationally from a single precursor. The sss gene and the tryptophan decarboxylase gene (tdc), encoding another enzyme essential for indole alkaloid biosynthesis, are coordinately regulated. In plants steady-state mRNA levels are highest in roots. In cell suspension cultures the genes are rapidly down-regulated by auxin. In contrast, both genes are strongly induced by fungal elicitors such as Pythium aphanidermatum culture filtrate or yeast extract. Induction is a rapid, transcriptional event occurring independent of de novo protein synthesis. These results show that a first important regulatory step in the complex process leading to indole alkaloid accumulation in C. roseus suspension cells is transcription of the biosynthetic genes.
231 citations
TL;DR: A survey of the expression of str1 in the R. serpentina plant suggested that strictosidine synthase poly(A)+ RNA was present predominantly, but not exclusively, in theroot, and correlated well with the distribution of both enzyme activity and indole alkaloids which were also predominant in the root, but, in general, distributed throughout the shrub.
62 citations
TL;DR: The structure of a novel indole alkaloid, glyantrypine 2, a main secondary metabolite of Aspergillus clavatus has been elucidated by biosynthetic evidence, mass spectrometry and 1H and 13C NMR techniques.
Abstract: The structure of a novel indole alkaloid, glyantrypine 2, a main secondary metabolite of Aspergillus clavatus has been elucidated by biosynthetic evidence, mass spectrometry and 1H and 13C NMR techniques. The compound extends the variety of metabolites biosynthesised from anthranilic acid and tryptophan without forming a benzodiazepine.
39 citations
TL;DR: Cultivation of Catharanthus roseus hairy root cultures at different temperatures was found to have an effect on growth rate and indole alkaloid content as well as lipid composition, and the level of alkaloids accumulation showed a clear increase with lowering temperature.
Abstract: Cultivation of Catharanthus roseus hairy root cultures at different temperatures was found to have an effect on growth rate and indole alkaloid content as well as lipid composition. When lowering the temperature, the roots responded by increasing the degree of unsaturation of cellular lipids, which was mainly due to an increased proportion of linolenic acid in the main lipid classes. The modifications in lipid composition were obviously necessary for the roots to retain the proper cell membrane fluidity at each temperature. Despite of changes in membrane lipids, no effect on the distribution of indole alkaloids between the roots and the medium could be detected. Instead, the level of alkaloid accumulation showed a clear increase with lowering temperature.
35 citations
Journal Article•
TL;DR: Cell suspension cultures of Catharanthus roseus, Tabernaemontana divaricata, Taberellonia pandacaqui, Cinchona robusta, Rubia tinctorum and Euonymus europaeus, representing 3 different plant families, were compared with respect to indole alkaloid production and specific activities of the enzymes.
32 citations
TL;DR: In this article, the first synthesis of lyaloside from L-tryptophan and secologanin was reported, and full assignments of 1H and 13C-NMR spectra were performed on another natural glucoindole alkaloid of key importance, 5(S)-5-carboxystrictosidine, which was obtained during this synthesis.
Abstract: Lyaloside was synthesized, for the first time, from L-tryptophan and secologanin. This proved the stereochemistry of lyaloside unambiguously. Full assignments of 1H- and 13C-NMR spectra were performed on another natural glucoindole alkaloid of key importance, 5(S)-5-carboxystrictosidine, which was obtained during this synthesis.
25 citations
TL;DR: In this article, a new indole alkaloid 19- (S )-hydroxy N b -methylraumacline was isolated from the plant cell suspension cultures of Tauwolfia serpentina Benth.
13 citations
TL;DR: In this paper, the aerial parts of Ophiorrhiza major Ridl have been extracted from the C19 pentacyclic quaternary indole alkaloid, ophior rhizine.
Abstract: Extraction of the aerial parts of Ophiorrhiza major Ridl. has yielded a new C19 pentacyclic quaternary indole alkaloid, ophiorrhizine. The structure was established as 1 on the grounds of its spectral properties (optical rotation) and its X-ray molecular structure. Its biosynthetic relationship to the Cinchona alkaloids is discussed.
12 citations
TL;DR: The new indole alkaloid, 6alpha-hydroxyraumacline, was isolated from RAUWOLFIA SERPENTINA cells cultivated in the presence of ajmaline and a simple chemical synthesis was developed starting from aj maline.
Abstract: From RAUWOLFIA SERPENTINA cells cultivated in the presence of ajmaline ( 2) the new indole alkaloid, 6alpha-hydroxyraumacline ( 1), was isolated. This alkaloid also occurs in significant amounts in the nutrition medium. A simple chemical synthesis of 1 was developed starting from ajmaline ( 2).
9 citations
TL;DR: To produce economically important indole alkaloids by cell culture, protoclones ofCatharanthus roseus are selected for high yields of catharanthine and ajmalicine and qualitatively confirmed by LC-MS.
Abstract: To produce economically important indole alkaloids by cell culture, we have selected protoclones ofCatharanthus roseus for high yields of catharanthine and ajmalicine. Protoplasts were enzymatically isolated from suspension-cultured cells. Protoclone VPC-10 produced catharanthine at 5.9 μg/g fresh wt of cells after 10 days of culture, although the original cell line did not produce it at a level detectable by HPLC. Under the same conditions, protoclone VPC-15 produced ajmalicine at 133.6 μg/g, which was about 3 times the productivity of the original cell line. In addition, the indole alkaloids were qualitatively confirmed by LC-MS.
5 citations
Journal Article•
TL;DR: In this article, the aerial parts of Ophiorrhiza major Ridl have been extracted from the C19 pentacyclic quaternary indole alkaloid, ophior rhizine.
Abstract: Extraction of the aerial parts of Ophiorrhiza major Ridl. has yielded a new C19 pentacyclic quaternary indole alkaloid, ophiorrhizine. The structure was established as 1 on the grounds of its spectral properties (optical rotation) and its X-ray molecular structure. Its biosynthetic relationship to the Cinchona alkaloids is discussed.
TL;DR: The structure of a novel indole alkaloid, glyantrypine 2, a main secondary metabolite of Aspergillus clavatus has been elucidated by biosynthetic evidence, mass spectrometry and 1H and 13C NMR techniques as mentioned in this paper.
Abstract: The structure of a novel indole alkaloid, glyantrypine 2, a main secondary metabolite of Aspergillus clavatus has been elucidated by biosynthetic evidence, mass spectrometry and 1H and 13C NMR techniques. The compound extends the variety of metabolites biosynthesised from anthranilic acid and tryptophan without forming a benzodiazepine.