Apocynaceae Plants Research Articles

Molecular interrelations in the Melodinus alkaloids

Structural and chemotaxonomical data as well as consideration of standard organic reaction mechanisms provided a coherent picture about the probable formation of the small but characteristic group of Melodinus alkaloids in the plant family Apocynaceae. All 14 alkaloids could be classified into the melodan skeleton and its rearranged version and derived from 18,19- didehydrotabersonine as parent compound.

Reaction mechanism and chemotaxonomy in the formation of the type I indole alkaloids derived from secologanin

AbstractThe history of biomolecules is written into the structure of their educts and products. The group of indole alkaloids derived from secologanin and tryptamine has more than 2000 individual compounds isolated mainly from the Rubiaceae, Loganiaceae, and Apocynaceae plant families and having strictosidine as a common precursor. To detect their history in its main lines, the compounds isolated from the same or closely related species were ordered as intermediates into reaction sequences according to the principles of basic organic reaction mechanisms. The analysis is restricted to the main lines of the monomeric alkaloids having one un‐rearranged secologanin subunit (type I) closed to N‐4 atom and one tryptamine subunit in intact or cleaved form. Deglucosylation of strictosidine opens the way for different types of cyclizations. Subsequent key bond‐braking and bond‐making reactions involve bond C‐5C‐6 in the tryptamine subunit, bond C‐15C‐16 in the secologanin subunit, and bond C‐3C‐7 at the attachment of the two subunits, and indicate the crucial importance of a strong long‐range through‐bond interaction between the two nitrogen atoms. With a few principles it was possible to interpret such important biogenetic‐type steps, as the formation of the akuammidan and akuammilan bridges, the transition from the vincosan into the strychnan and further to the aspidospermatan skeleton, the breaking and transformation of the side‐chain of the triptamine subunit and the cleavage of the strategic bond C‐15C‐16 toward the formation of the formation of type II and type III alkaloids. The transformations are finely tuned by the stable chirality of C‐15, and activation of C‐7 and N‐4. Fragmentations and rearrangement are important reactions in these transformations, and abundantly supported by chemotaxonomic data based on the Dictionary of Natural Products Database (Version 14.1, 2006, Chapman and Hall/CRC, New York, London, 2005). Copyright © 2006 John Wiley & Sons, Ltd.

Eburnamine Derivatives and the Brain

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Eburnamine derivatives and the brain

The Apocynaceae plant family contains a great number of so called eburnamine-vincamine alkaloids. Quite a few of these alkaloids exert varied pharmacological activities on the cell multiplication, cardiovascular system, and brain functions. Many derivatives were also synthesized to find pharmacologically active compounds better characterized and safer to be administered than the natural plant alkaloids themselves. We concentrate on the eburnamine structures with cerebral activities in this review. Vincamine, vinburnine, vindeburnol, apovincaminate, and vinpocetine (cis-ethyl-apovincaminate) all share modulatory effects on brain circulation and neuronal homeostasis, bear antihypoxic and neuroprotective potencies to various degrees. The most eminent compound of this class of alkaloids is vinpocetine. Since its introduction to the market as a neuroprotective agent many non clinical and clinical studies proved vinpocetine's effects on calmodulin dependent phosphodiesterase E1, on sodium, calcium channels, peripheral benzodiazepine receptor, and glutamate receptors as well as its clinical usefulness in the treatment of post-ischaemic stroke disease states and various disorders of cerebrovascular origin. Lately, positron emission tomography studies proved that vinpocetine has a rapid uptake in the primate and human brain with a heterogeneous distribution pattern (preference areas: thalamus, basal ganglia, and visual cortex) both after intravenous and oral administration. Vinpocetine exerts beneficial effects in cerebral glucose metabolism and regional cerebral blood flow in chronic post-stroke patients.

The ajmaline group of indole alkaloids

Publisher Summary This chapter discusses an area of indole alkaloids, which has been neglected in the series for over 30 years—namely, the ajmaline group of alkaloids, where numerous advances in chemistry and biosynthesis have been made recently. The number of known ajmaline structures has grown markedly in recent years to a present count of 77. Some of these might be artefacts and a few structures have not been convincingly determined. In addition, seven bisindole alkaloids containing at least one monomeric ajmalan unit have been isolated, increasing the total number to 84. Ajmaline alkaloids contain the polycyclic ajmalan ring system. The “biogenetic numbering” of Le Men and Taylor is used throughout the chapter. The priority sequence for the C-17 substituents in the Cahn–Ingold–Prelog system is different in the absence and presence of the COOCH, substituent at C-16. All of the ajmaline alkaloids found thus far occur in the plant family Apocynaceae. They have been recognized in the following genera Alstonia , Aspidospenna , Cabucala , Melodinus , Rauvolfia , Tonduzia (Alstonia), and Vinca .

Is there a justification for differential a priori weighting in coding sequences? A case study from rbcL and Apocynaceae s.l.

Functional constraints are often assumed to influence the performance of nucleotide characters in phylogenetic analysis: First and second codon positions and sites of structural importance are considered to show less homoplasy. We investigate the performance of rbcL characters with differential functional constraints in a cladistic analysis of the plant family Apocynaceae s.l. (Sennblad and Bremer, in prep.). Performance is measured as rescaled consistency indices (rc). We show there is no significant difference in performance between parsimony-informative sites constrained by function in the enzyme, and sites that are not. Furthermore, the substitutions in third-codon position performed significantly better than those in first and second. The variation of rc within the different classes was high, however. Consequently, there is no support for routinely applied a priori differential weighting, neither of codon positions, nor of different functional classes from the present analysis of rbcL data in the Apocynaceae s.l.

Agrobacterium-mediated transformation of the terpenoid indole alkaloid-producing plant species Tabernaemontana pandacaqui.

Plants of the Apocynaceae family produce a wide range of terpenoid indole alkaloids (TIAs) which have important pharmaceutical applications. Studies of the molecular mechanisms controlling TIA biosynthesis may eventually provide possibilities to improve product yield by genetic modification of plants or cell cultures. However, these studies suffer from the lack of transformation/regeneration protocols for Apocynaceae plants. We chose to study the feasibility of Agrobacterium tumefaciens-mediated transformation of Tabernaemontana pandacaqui, because of the availability of an efficient regeneration procedure for this member of the Apocynaceae family. A procedure to produce transgenic T. pandacaqui plants was established, albeit with low efficiency. Transgenic expression was demonstrated of an intron-containing β-glucuronidase reporter gene and of a gene coding for the TIA biosynthetic enzyme strictosidine synthase from Catharanthus roseus, another Apocynaceae species.

Structure and Synthesis of a New Chiral .BETA.-Carboline Found in Cultured Cell Clumps of Rauwolfia serpentina and Rhazya stricta.

The structure of a new chiral β-carboline derivative, Compound D, which was found during the chemical investigation of metabolites formed by cultured hybrid cells of two Apocynaceae plants, Rauwolfia serpentina Benth. and Rhazya stricta Decaisne, was rigorously confirmed by chemical synthesis starting from tryptamine and D-glucose.

ChemInform Abstract: Chemical Studies of Indole Alkaloids

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Клеточная инженерия в биотехнологии растений-продуцентов из семейства кутровых (Apocynaceae)

Клеточная инженерия в биотехнологии растений-продуцентов из семейства кутровых (Apocynaceae)

キョウチクトウ科を特徴づけるカルデノライド, プレグナン及びイリドイドについて

The investigation on the constituents of five Apocynaceae plants including Nerium odorum (and N. oleander), Cerbera Manghas, Anodendron affine, Trachelospermum asiaticum, and Allamanda neriifolia were described. Novel cardenolide glycosides, pregnanes, and iridoids were isolated and their structures were determined. The distribution of the cardenolide glycosides in the wild and cultivated strains of Nerium were examined quantitatively. The biogenetic relationships of the new substances to the known components and chemotaxonomy of the plants were also discussed.

Studies on the constituents of apocynaceae plants. Gas chromatography-mass spectrometric determination of new flavonoid triglycosides from the leaves of Cerbera manghas L.

Two new flavonol triglycosides, named manghaslin (I) and clitorin (II), were isolated from the leaves of Cerbera manghas L. (Apocynaceae). The structures of I and II were elucidated as quercetin-3-O-L-rhamnosyl-(1→2)-O-[L-rhamnosyl-(1→6)] D-glucoside (I) and kaempferol-3-O-L-rhamnosyl-(1→2)-O-[L-rhamnosyl-(1→6)] D-glucoside (II), respectively, by chemical and gas chromatography-mass spectrometric studies.

Strictosidine synthase from cell cultures of apocynaceae plants

About 1000 monoterpenold indole alkaloids are known to occur in higher plants which include such unportant members as ajmaline, quinine, strychnine, vincrlstine and yohunbine. All these alkaloids are formed via the condensation of tryptamme with the monoterpenold irldold secologanin (renewed [ 1 ] ). Recently, the key enzyme catalysmg the stereospecific condensation of tryptamine with secologanm to give the glucosidal alkaloid strictosidme with 3-(w (S) configuration was discovered [2,3] . Tlus enzyme strictosldine synthase [3] , IS the starter enzyme in the pathway leadmg to the most diverse chemical structures found m the mdole alkaloid series. The product of catalysis, stnctosidme, is the universal precursor for the above-mentioned mdole alkaloids [3-61, The occurrence of strictosidme synthase m a number of cell cultures derived from Apocynaceue plants which are known to contain mdole alkaloids 1s now demonstrated and some of the properties of the enzyme obtamed from these origms are reported for the first time.

Chemical characters in plant taxonomy: some possibilities and limitations.

Abstract

The Alkaloids of Rauwolfia Serpentina Benth

Rauwolfia is an important genus of the plant family Apocynaceae. There are nearly one hundred and twenty‐five species of Rauwolfia which are distributed all over the tropical regions of the world (1‐8). The most important member of the genus is R. serpentina Benth; the crude drug was known to the ancient Indians as a useful febrifuge (8), a remedy for snake bite, and as a cure for dysentery. In more recent times it has been used for insomnia, hypochondria and insanity.The presence of alkaloidal principles in R. serpentina was first pointed out in 1890 by Greshoff (9). In 1933, Chopra, Gupta, and Mukherjee (10) reported the hypotensive activity of the material extracted from the plant and in 1931 Siddiqui and Siddiqui (11) isolated a series of crystalline alkaloids from R. serpentina. Active chemical and pharmacological interest in R. serpentina has resulted in the discovery of several new alkaloids (Table I). The isolation by Muller, Schlittler, and Bein (12) of reserpine, an alkaloid with pronounced hypotensive and sedative activity, has lent further impetus to the pharmacological and chemical study of the alkaloids of R. serpentha. A brief summary of the chemical aspects of R. serpentina will be presented in this review.