Effects of bioregulators on indole alkaloid biosynthesis in Catharanthus roseus cell culture

Several carotenoid-inducers are effective in promoting indole alkaloid formation in Catharanthtus roseus cell culture. Among the five compounds tested, viz. 1,1-dimethylpiperidine, 2-diethylaminoethyl-3,4-dichlorophenylether, 2-diethylaminoethyl-2,4-dichlorophenylether, 2-diethylaminoethyl-β-naphthylether and 2-diethylaminoethyl-3,4-dimethylphenylether, 1,1-dimethylpiperidine, 2-diethylaminoethyl-2,4-dichlorophenylether and 2-diethylaminoethyl-β-naphthylether at 5 ppm concentration increased total alkaloid production by up to ca 20 % with concomitant increases in ajmalicine and catharanthine. Concentrations of 2-diethylaminoethyl-2,4-dichlorophenylether higher than 5 ppm caused growth inhibition and decrease in alkaloid synthesis.     

Characterization of a 5-methyltryptophan resistant strain of Catharanthus roseus cultured cells

Strains of Catharanthus roseus suspension cells resistant to growth inhibition by various tryptophan analogs were selected. Tryptophan synthetase and anthranilate synthetase from the resistant cells differed from the normal cell enzymes by being more resistant to feedback inhibition by tryptophan. Though these altered enzymes allowed the free tryptophan level of the resistant cells to be 3–40 times higher than that of normal cells, the accumulation of tryptamine or ajmalicine could not be detected in the resistant cells.     

Medium- and light-induced formation of serpentine and anthocyanins in cell suspension cultures of Catharanthus roseus

By irradiation with fluorescent light, medium-induced cell cultures of Catharanthus roseus accumulated anthocyanins and the indole alkaloid serpentine. The formation of both compounds was inhibited by phosphate and nitrogen-containing mineral salts and stimulated by high sucrose concentrations. The accumulation of serpentine was preceded by an increase and subsequent decrease of its biogenetic precursor ajmalicine, which was the predominant alkaloid of medium-induced cultures in the dark. High concentrations of serpentine or anthocyanins were observed only in a small proportion of all cells present in a medium-induced culture. The aglycones of the anthocyanins were identified as petunidin, malvidin and hirsutidin.     

Alkaloid distribution and catabolism in Cephalotaxus harringtonia

Cephalotaxus harringtonia produces a variety of antitumor alkaloids that are distributed throughout the tree. In a young plant grown in a controlled environment, the concentration of free alkaloids (homoerythrina alkaloids and cephalotaxine) did not increase with age, whereas the concentration of cephalotaxine esters (harringtonine, deoxyharringtonine, isoharringtonine and homoharringtonine) increased roughly 5-fold. Total alkaloid concentrations increased in the older leaves of the plant and decreased in the older stems. Physiological stress (pruning) causes hydrolysis of part of the stored alkaloid esters to free cephalotaxine within one week. In 4 out of 5 field-grown trees environmental factors caused complete ester hydrolysis and, in addition, the oxidation of cephalotaxine to 11-hydroxycephalotaxine and drupacine and of homoerythrina alkaloid to its epoxy derivative. This shows that the alkaloids in this perennial tree are not inert storage products, but are under metabolic control.     

16-epi-19-S-vindolinine,an indoline alkaloid from Catharanthus roseus

Studies on the alkaloids of Catharanthus roseus have resulted in the isolation of a new alkaloid, to which the structure of 16-epi-19-S-vindolinine has been assigned.     

Alkaloid biosynthesis in Croton flavens

The biosynthesis of the morphinandienone alkaloids norsinoacutine, sinoacutine and flavinantine has been studied using 1-³ H-sinoacutine, 1-³H-norsinoacutine, 1-³H-norsinoacutinols, l-[S-methyl-¹⁴C]-methionine, glycine-2-¹⁴C, 1-³H-8,14-dihydronorsalutaridine, 1-³ H-8,14-dihydrosalutaridine, 1-³H-sinomenine, 1-³H-isosinomenine, (±)-[2-¹⁴C]phenylalanine, (±)-[N-methyl-¹⁴C]orientaline and (±)-[N-methyl-¹⁴C]reticuline.     

Leaf alkaloids of Rauwolfia volkensii

Thirteen alkaloids were isolated and identified from the leaves of Rauwolfia volkensii. The alkaloids included E-seco heteroyohimbine, heteroyohimbine, sarpagan, dihydroindole, pleiocarpamine, picrinine and akuammicine types together with peraksine.     

Alkaloids of Hunteria zeylanica

Twenty alkaloids were isolated from the leaves and stem bark of Hunteria zeylanica, collected in Kenya. They were: 3-epi-dihydrocorymine 3-acetate, norisocorymine, corymine, 3-epi-dihydrocorymine 17-acetate, picralinal, picrinine, 3-epi-dihydrocorymine, isositsirikine, lanceomigine, geissoschizol, gentianine, kopsinine, eburnamine, norpleiomutine, pleiocarpamine, tubotaiwine, pleiomutinine, 19′-epi-pleiomutinine, yohimbol and 10-hydroxy-16-epi-affinine.     

Alkaloids of Pterotaberna inconspicua

Sixteen alkaloids were isolated from the seeds and root-bark of Pterotaberna inconspicua, collected in Zaïre. They were voacangine 3-carbonitrile, voacangine, voacristine, 3,6-oxido-voacangine, vobasine, 10-hydroxycoronaridine, 10-hydroxyheyneanine, methuenine, apparicine, tubotaiwine, 16-epi-isositsirikine, 16-epimethuenine, 3,14-dihydroellipticine, an isomer of corynantheol, 16-epimethuenine N-oxide and tetra-hydroellipticine.     

Effects of PEG-induced drought stress on regulation of indole alkaloid biosynthesis in Catharanthus roseus

Catharanthus roseus (C. roseus) plants were used to investigate the terpenoid indole alkaloids (TIAs) accumulation under the condition of PEG-induced drought stress. Multivariate analysis showed that 35% PEG6000 could induce more obvious and stable accumulation on proline (PRO) content and the relative water content (RWC). The results indicated that there were gradual increase and then decrease (p?<?.05) in the contents of vindoline (VIN) and catharanthine (CAT) under 35% PEG6000 stress, but the content of vinblastine (VBL) increased gradually. In addition, the expression levels of tryptophan decarboxylase (TDC), strictosidine synthase (STR) and deacetylvindoline-4-O-acetyltransferase (DAT) were upregulated in plants under 35% PEG6000 stress. Further correlation analysis indicated that CAT accumulation was significantly correlated with TDC gene expression, and VBL accumulation was significantly correlated with peroxidase (p?<?.05). Our results suggest that the cultivation of C. roseus in drought stress would serve as effective treatment for accumulating TIAs.     

Alkaloid chemotaxonomy of the genus Sophora

Cytisine and matrine alkaloids detected in Sophora species have been used to classify the genus chemotaxonomically.     

Alkaloid production in Catharanthus roseus cell cultures: Initial studies on cell lines and their alkaloid content

Several hundred serially cultured cell suspensions derived from three cultivars of periwinkle (Catharanthus roseus) were established in Gamborg's B5 medium and then transferred to Zenk's alkaloid production medium. Total alkaloid concentration ranged from 0.1 to 1.5% of dry weight. Alkaloids present were of the corynanthe, strychnos and aspidosperma types, with the greatest diversity arising during the third to the fifth week of subculturing. The alkaloid content appeared both specific for, and reproducible in, individual cell lines.     

La criocerine: Nouvel alcaloide isole des tiges de Crioceras dipladeniiflorus

Seven indolic alkaloids have been isolated from the stem bark of Crioceras dipladeniiflorus. One of them is new and has been called criocerine. Its structure, 7, has been established by use of physical data and chemical correlation with [Δ¹⁴]-vincamine.     

16-Epivenenatine and 16-epialstovenine,new stereomers from Alstonia venenata

16-Epivenenatine and 16-epialstovenine have been isolated from Alstonia venenata. The structures and stereochemistry of these two new bases have been determined from spectral analysis, chemical studies and correlation experiments with venenatine and alstovenine.     

The biosynthesis of long-chain hydrocarbons in the green alga Botryococcus braunii

The green colonial alga Botryococcus braunii has unusually high levels of hydrocarbons. Two distinct sites of hydrocarbon accumulation are present in the species: an internal pool present in cytoplasmic inclusions and an external pool in the trilaminar outer walls and associated globules. It is generally assumed that the hydrocarbons are produced within the cells and then excreted into the external pool to maintain the intracellular content at a normal value. Various feeding experiments showed, however, that the radioactivity of the external pool is much higher than the internal one. On the other hand, there was no decrease in the labelling of internal hydrocarbons in chase experiments. Therefore, an excretory process apparently does not take place in B. braunii. The outer wall, therefore, is the main site of hydrocarbon accumulation and also the place where the bulk of B. braunii hydrocarbons are produced. The outer wall also is involved in the matrix of colony formation and the above findings account for the sharp decrease of hydrocarbon production which is associated with the loss of colonial habit. The cultures were also shown to be unable, under usual growth conditions, to catabolize their own hydrocarbons. Such a feature, along with the extracellular location of the main site of production, may account for the abnormally high content of hydrocarbons typical of B. braunii.     

Alkaloids of stem and rootbark of Tabernaemontana dichotoma

During chemical investigation for compounds possessing biological activity in the stem and rootbark of Tabernaemontana dichotoma, 22 alkaloids were isolated. Ten monomeric alkaloids were identified, viz. (?)-apparicine, coronaridine, 3-oxocoronaridine, 3-ketopropylcoronaridine, 19R-heyneanine, 3-ketopropyl-19R-heyneanine, ibogamine, isomethuenine, perivine and vobasine. Two of the monomeric alkaloids isolated were new, one was identified as 3,19R-oxidocoronaridine and the other one is not yet identified. The other ten alkaloids isolated were dimeric compounds, three were identified as tabernamine, voacamine and 3′R/S-hydroxyvoacamine. Five of the dimers were new alkaloids related to tabernamine and ervahanine type structures and identified as 3′R/S-hydroxytabernamine, 3′R/S-hydroxy-N₄-demethyltabernamine, N₄-demethyltabernamine and 3′R/S-hydroxy-N₄-demethytervahanine A and B. The remaining two alkaloids are partially characterized.     

Biosynthesis of thalicarpine in Thalictrum minus

Feeding experiments with ¹⁴C-labelled reticuline, protosinomenine, orientaline, their N-nor-analogues and ³H-labelled isoboldine have shown reticuline and isoboldine to be the most efficient precursors of thalicarpine in Thalictrum minus. A biosynthetic pathway for thalicarpine with reticuline and isoboldine at the benzylisoquinoline and aporphine stages respectively has been suggested. Support for this proposal has been provided by the demonstration by radioisotopic dilution that reticuline and isoboldine are minor constituents of the plant.