La borrerine: Nouvel alcaloïde isolé du Borreria verticillata

Borreria verticillata has been found to contain two new tetrahydro-β-carboline alkaloids borrerine and an apparent dimer, borreverine. The structure of the former has been determined.     

Three quinicine derived alkaloids from Guettarda trimera

Three alkaloids, isolated from the trunk bark of Guettarda trimera have been identified as derivatives of quinicine on the basis of mass spectrometry, ¹H and ¹³C NMR data.     

Anthraquinones in callus cultures of Cinchona ledgeriana

From callus cultures of Cinchona ledgeriana seven known anthraquinones, purpurin, anthragallol-1,2-dimethylether, anthragallol-1,3-dimethylether, rubiadin, 1-hydroxy-2-hydroxymethylanthraquinone, 1-hydroxy-2-methylanthraquinone and morindone-5-methylether (or 1,7-dihydroxy-8-methoxy-2-methylanthraquinone), and eight new anthraquinones, 5,6-dimethoxy-1-(or -4-)hydroxy-2-(or -3-)hydroxymethylanthraquinone, 5-methoxy-2-(or -3-)methyl-1,4,6-trihydroxyanthraquinone, 2-hydroxy-1,3,4-trimethoxyanthraquinone, 4-methoxy-1,3,5-trihydroxyanthraquinone, 1,4-dimethoxy-2,3-methylenedioxyanthraquinone, 1,3-dihydroxy-4-methoxyanthraquinone, 1,3-dihydroxy-2,5-dimethoxyanthraquinone and 2,5-(or 3,5-)dihydroxy-1,3,4-(or -1,2,4-)trimethoxyanthraquinone have been isolated.     

A novel tryptophan-derived alkaloid and other constituents from Guettarda speciosa (Rubiaceae: Cinchonoideae–Guettardeae)

Phytochemical examination of two Thai accessions of the widespread paleotropical Guettarda speciosa (Rubiaceae: Cinchonoideae–Guettardeae) led to the isolation of the hitherto undescribed tryptophan-derived alkaloid 5α-carboxystrictosidinic acid together with 5α-carboxystrictosidine, the iridoid glucoside loganic acid and 5-O-caffeoylquinic acid from the root bark extract. The leaf extract further yielded 3-O-caffeoylquinic acid and 4,5-di-O-caffeoylquinic acid. The structures of the isolated compounds were established by NMR and MS techniques and compared to other species of Guettarda. In addition, the structural differentiation of alkaloids within this genus is discussed with special emphasis on 5α-carboxy derivatives suggesting a pathway apart from the strictosidine biosynthetic route.     

Desoxycordifolinic acid from Nauclea diderrichii

The heartwood of the stems of Nauclea diderrichii yielded as its major alkaloid the parent diacid of desoxycordifoline, which has been named desoxycordifolinic acid.     

N-Oxides of the oxindole alkaloids,isorhynchophylline, rhynchophylline,rhynchociline and ciliaphylline

The N-oxides of isorhynchophylline, rhynchophylline, rhynchociline and ciliaphylline were prepared, for comparison with a new alkaloid from Mitragyna tubulosa.     

Oxindole alkaloids from Uncaria macrophylla

Four isomeric oxindole alkaloids, isorhynchophylline, rhynchophylline, corynoxine and corynoxine B, have been isolated from the leaves of Uncaria macrophylla Wall. Corynoxine B has not previously been reported as a natural product.     

Chemical investigations of herbarium material for alkaloids

The chemical and biological screening of plants is reviewed briefly as an introduction to the concept of the use of herbarium material for investigations into the chemical constituents of plants. Such materials have been examined for a wide range of chemicals, and in particular, examples of the extraction of alkaloids from species of Rubiaceae and Papaveraceae are discussed. The present state of the art of such physical techniques as mass and nuclear magnetic resonance spectrometry for these investigations is commented upon and the plea is made that, wherever possible, wider use be made of herbarium material for chemical studies.     

Orientalidine and isothebaine from cell cultures of Papaver bracteatum

Orientalidine, isothebaine and sanguinarine were isolated from callus cultures of Papaver bracteatum when grown on M & S medium with various horm     

Somatic embryogenesis and shoot proliferation of Mussaenda cultivars

Midrib sections of Mussaenda 'Queen Sirikit', 'Do?a Luz', and 'Do?a Hilaria' were cultured on Murashige and Skoog medium (MS) supplemented with 87.7 mM sucrose, 5 g agar l⁻¹, 0, 5, 10 or 20 μM indole-3-acetic acid (IAA) and 0, 0.5, 1, 2.5, 5, 10, 25 or 50 μM 6-benzyladenine (BA). In addition, aseptic 5 mm shoot tips from 'Do?a Luz' cultures were excised and cultured on MS basal salts, 0.6 mM myo-inositol, 1.2 μM thiamine-HCl, 87.7 mM sucrose, 7 g agar l⁻¹, 0, 2.5, 5, 10, 20, or 40 μM BA, 0 or 1 μM α-naphthaleneacetic acid (NAA) and 0 or 217 μM adenine sulfate at pH 5.8. Calluses began to develop after two weeks at the cut ends of midribs when cultured on a medium containing IAA. Somatic embryos first appeared at eight weeks but only on 'Queen Sirikit' callus. After 15 weeks, the average number of somatic embryos produced per tube decreased as the IAA concentration increased from 0 to 20 μM. BA concentrations between 5.0 and 10.0 μM resulted in the largest number of somatic embryos per tube. After six weeks, the total, axillary and adventitious number of 'Do?a Luz' shoots increased as the BA concentration in the culture medium increased from 0 to 20 μM. Average shoot length and fresh weight decreased from 0 to 40 μM BA. The addition of NAA to the culture medium reduced shoot number. Adenine sulfate in the presence of BA reduced the total number of shoots. An ideal medium for proliferating the largest number of 'Do?a Luz' shoots would be a MS medium supplemented with 10–20 μM BA. This revised version was published online in June 2006 with corrections to the Cover Date.     

The effect of light on the production of Heimia alkaloids

Alkaloid extracts obtained from light- and dark-grown shoot cultures of Heimia salicifolia were partially fractionated and semi-quantitatively analysed for phenyl- and biphenylquinolizidine alkaloids. The concentrations of the two structural types of alkaloids in extracts of shoots grown with illumination increase over a 4 week culture period. In extracts obtained from shoots grown in darkness for 4 weeks, however, we observed substantial decreases in the concentrations of both the phenyl- and biphenylquinolizidine alkaloids. We observed that growth in the dark for periods of up to 9 weeks resulted in a further reduction in the levels of biphenyl alkaloids relative to those of the phenylquinolizidinols.     

植物组织培养生产药物研究进展

植物是药物的天然宝库。本文综述了利用组织培养方法合成药物的优点和主要药物,探讨了植物组织生产药物的研究进展和前景。     

Alkaloids of Uncaria longiflora

Six isomers of the pentacyclic oxindoie alkaloid mitraphylline and five of their N-oxides have been identified as being present in the leaves of Uncaria longiflora (Poir.) Merr. Isomitraphylline and mitraphylline N-oxides have been prepared and characterized.