Phytochemistry (v.55, #6)
Professor Otto Richard Gottlieb by Lucia Maria Xavier Lopes (Guest Editor); Norman G Lewis (Editor) (xiii-xiv).
Biodiversity and drug discovery — a symbiotic relationship by Geoffrey A Cordell (463-480).
The profound developments in natural products drug discovery in the past few years are discussed, and the importance of a global approach to biodiversity and drug discovery involving natural products for the early part of the 21st century is presented.
Keywords: Biodiversity; Drug discovery; Intellectual property rights; Future opportunities;
Advances in flavonoid research since 1992 by Jeffrey B Harborne; Christine A Williams (481-504).
Some of the recent advances in flavonoid research are reviewed. The role of anthocyanins and flavones in providing stable blue flower colours in the angiosperms is outlined. The contribution of leaf flavonoids to UV-B protection in plants is critically discussed. Advances in understanding the part played by flavonoids in warding off microbial infection and protecting plants from herbivory are described. The biological properties of flavonoids are considered in an evaluation of the medicinal and nutritional values of these compounds.
Keywords: Angiosperms; Flavonoids; Blue flower colour; UV-B protection; Medicinal properties;
Distribution of flavonoids in the Myristicaceae by Juan C. Martı́nez Valderrama (505-511).
During the past two decades the study of the Myristicaceae species has increased, and many flavonoids of different types have been isolated. This review discusses the flavonoids presently known in the Myristicaceae.
Keywords: Myristicaceae; Compsoneura; Dialyanthera; Iryanthera; Knema; Myristica; Osteophloeum; Otoba; Pycnanthus; Virola; Flavonoids;
Correlation of oxidative transformations of hydrolyzable tannins and plant evolution by Takuo Okuda; Takashi Yoshida; Tsutomu Hatano (513-529).
The progressive oxidative transformations in the biogenesis of hydrolyzable tannins, gallotannin (I) → ellagitannin (II) → dehydroellagitannin (III) → transformed dehydroellagitannin (IV), conform in several aspects to the evolutionary routes in the subclasses of Dicotyledonae, particularly in the Rosidae.
Keywords: Dicotyledonae; Subclass; Oxidation; Biosynthetic pathway; Evolution; Tannin; Hydrolyzable Tannin; Gallotannin; Ellagitannin; Dehydroellagitannin;
Light activation of vindoline biosynthesis does not require cytomorphogenesis in Catharanthus roseus seedlings by Felipe A Vázquez-Flota; Benoit St-Pierre; Vincenzo De Luca (531-536).
Upon illumination, the cotyledons of Catharanthus roseus seedlings readily synthesise vindoline from late biosynthetic intermediates, which accumulate in etiolated seedlings. The cellular localisation of tryptophan decarboxylase (TDC) and desacetoxyvindoline 4-hydroxylase (D4H), which catalyse the first and penultimate reactions of vindoline biosynthesis, was identified by immunocytochemistry in developing seedlings. The expression of TDC was restricted to the upper epidermis of cotyledons, whereas that of D4H was confined to laticifer cells. Light exposure of etiolated seedlings significantly induced D4H enzyme activity without changing the steady-state levels of D4H immunoreactive protein or modifying the cellular distribution of D4H expression in dark-grown seedlings. These results suggest that the early and late stages of vindoline biosynthesis occupy different cellular compartments, even in the early phases of etiolated seedling development. The role of light in activating the late stages of vindoline biosynthesis does not, therefore, seem to be related to the formation of the laticifer and idioblast cell types. It is concluded that light is not required for formation of these cell types, whereas regulatory factors, restricted to idioblasts and laticifers, may respond to light to activate localised expression of the late stages of vindoline biosynthesis.
Keywords: Catharanthus roseus; Apocynaceae; Development; Laticifer; Epidermis; Idioblast; Tryptophan decarboxylase; Deacetylvindoline-4-hydroxylase; Localisation;
Dirigent-mediated podophyllotoxin biosynthesis in Linum flavum and Podophyllum peltatum by Zhi-Qiang Xia; Michael A Costa; John Proctor; Laurence B Davin; Norman G Lewis (537-549).
Given the importance of the antitumor/antiviral lignans, podophyllotoxin and 5-methoxypodophyllotoxin, as biotechnological targets, their biosynthetic pathways were investigated in Podophyllum peltatum and Linum flavum. Entry into their pathways was established to occur via dirigent mediated coupling of E-coniferyl alcohol to afford (+)-pinoresinol; the encoding gene was cloned and the recombinant protein subsequently obtained. Radiolabeled substrate studies using partially purified enzyme preparations next revealed (+)-pinoresinol was enantiospecifically converted sequentially into (+)-lariciresinol and (−)-secoisolariciresinol via the action of an NADPH-dependent bifunctional pinoresinol/lariciresinol reductase. The resulting (−)-secoisolariciresinol was enantiospecifically dehydrogenated into (−)-matairesinol, as evidenced through the conversion of both radio- and stable isotopically labeled secoisolariciresinol into matairesinol, this being catalyzed by the NAD-dependent secoisolariciresinol dehydrogenase. (−)-Matairesinol was further hydroxylated to afford 7′-hydroxymatairesinol, this being efficiently metabolized into 5-methoxypodophyllotoxin. Thus much of the overall biosynthetic pathway to podophyllotoxin has been established, that is, from the dirigent mediated coupling of E-coniferyl alcohol to the subsequent conversions leading to 7′-hydroxymatairesinol.
Keywords: Podophyllum peltatum; Linum flavum; Berberidaceae; Linaceae; Dirigents; 7′-Hydroxymatairesinol; 5-Methoxypodophyllotoxin; Podophyllotoxin; Pinoresinol/lariciresinol reductase; Secoisolariciresinol dehydrogenase;
Floral scent compounds of Amazonian Annonaceae species pollinated by small beetles and thrips by Andreas Jürgens; Antonio C Webber; Gerhard Gottsberger (551-558).
Chemical analysis (GC–MS) yielded a total of 58 volatile compounds in the floral scents of six species of Annonaceae distributed in four genera (Xylopia, Anaxagorea, Duguetia, and Rollinia). Xylopia aromatica is pollinated principally by Thysanoptera and secondarily by small beetles (Nitidulidae and Staphylinidae), whereas the five other species were pollinated by Nitidulidae and Staphylinidae only. Although the six Annonaceae species attract a similar array of pollinator groups, the major constituents of their floral scents are of different biochemical origin. The fragrances of flowers of Anaxagorea brevipes and Anaxagorea dolichocarpa were dominated by esters of aliphatic acids (ethyl 2-methylbutanoate, ethyl 3-methylbutanoate), which were not detected in the other species. Monoterpenes (limonene, p-cymene, α-pinene) were the main scent compounds of Duguetia asterotricha, and naphthalene prevailed in the scent of Rollinia insignis flowers. The odors of X. aromatica and Xylopia benthamii flowers were dominated by high amounts of benzenoids (methylbenzoate, 2-phenylethyl alcohol).
Keywords: Anaxagorea; Duguetia; Rollinia; Xylopia; Annonaceae; Beetle pollination; Floral volatiles; Aliphatic esters; Benzenoids; Terpenes;
Biodiversity: modelling angiosperms as networks by Otto R Gottlieb; Maria Renata de M.B Borin (559-565).
In the neotropics, one of the last biological frontiers, the major ecological concern should not involve local strategies, but global effects often responsible for irreparable damage. For a holistic approach, angiosperms are ideal model systems dominating most land areas of the present world in an astonishing variety of form and function. Recognition of biogeographical patterns requires new methodologies and entails several questions, such as their nature, dynamics and mechanism. Demographical patterns of families, modelled via species dominance, reveal the existence of South American angiosperm networks converging at the central Brazilian plateau. Biodiversity of habitats, measured via taxonomic uniqueness, reveal higher creative power at this point of convergence than in more peripheral regions. Compositional affinities of habitats, measured via bioconnectivity, reveal the decisive role of ecotones in the exchange or redistribution of information, energy and organisms among the ecosystems. Forming dynamic boundaries, ecotones generate and relay evolutionary novelty, and integrate all neotropical ecosystems into a single vegetation net. Connectivity in such plant webs may depend on mycorrhizal links. If sufficiently general such means of metabolic transfer will require revision of the chemical composition of many plants.
Keywords: Angiosperms; Mycorrhizas; South American floristic inventories; Species dominance patterns; Habitat affinities; Taxonomic uniquenesses; Ecotones; Populational dynamics; Multicomponent networks; Plant web;
Foliar flavonoids of Annonaceae from Brazil: taxonomic significance by D.Y.A.C. Santos; M.L.F. Salatino (567-573).
Foliar flavonoids of 31 species of the Annonaceae native to Brazil, amounting to 76 compounds, were isolated and identified. All phenols found were glycosides of either flavones (apigenin, scutellarein, hispidulin and luteolin) or flavonols (kaempferol, rhamnocitrin, 6-hydroxyrhamnocitrin, quercetin, isorhamnetin and rhamnetin), with the latter predominating. Some members of the tribe Bocageeae are distinctive for accumulating 6-oxygenated flavones and flavonols, in addition to 7-O-methylated flavonols, a feature possibly linked to the assumed advanced condition of the tribe within the family. Members of Duguetia stand out for the apparent absence of quercetin glycosides. Anaxagorea dolichocharpa seemingly lacks flavones and flavonols entirely. A UPGMA analysis based on the distribution of flavonoids does not group the analyzed species according to the available tribal division of the Annonaceae. However, several taxonomically meaningful groupings emerged through the multivariate analysis.
Keywords: Annonaceae; Flavonoids; Flavones; Flavonols; UPGMA; Chemotaxonomy;
Phenylpropanoid derivatives and biflavones at different stages of differentiation and development of Araucaria angustifolia by Fabiana N Fonseca; Ari J.S Ferreira; Patricia Sartorelli; Norberto P Lopes; Eny I.S Floh; Walter Handro; Massuo J Kato (575-580).
Chemical investigations carried out with tissues at different developmental stages of Araucaria angustifolia established the presence of E and Z isomers of octadecyl p-coumarate and octadecyl ferulate in undifferentiated callus; in the seedling stems, the source of explants, three biflavones of the amentoflavone-type were isolated, whereas the diterpene, trans-communic acid, was obtained from the seedling roots. Adult stems accumulated the benzaldehydes, vanillin, p-hydroxybenzaldehyde and coniferaldehyde; the lignans, pinoresinol, eudesmin and lariciresinol; and the isoflavones, cabreuvine and irisolidone.
Keywords: Araucaria angustifolia; Araucariaceae; Cell culture; Long chain cinnamate esters; Biflavonoids; Lignans; Isoflavonoids; Benzaldehydes;
Monomer composition of polysaccharides of seed cell walls and the taxonomy of the Vochysiaceae by Marco A.S. Mayworm; Marcos S. Buckeridge; Antonio Salatino (581-587).
The distribution of polysaccharides from the seed cell walls of 57 samples of Vochysiaceae native to Brazil were studied, comprising 16 species distributed among the genera Callisthene, Qualea, Salvertia and Vochysia. The polysaccharides were extracted with hot water, then hydrolyzed with the resulting monomers analyzed by HPLC. All samples yielded arabinose, galactose, glucose, mannose and rhamnose, the relative amounts of each monomer, however, varying from one sample to another. Arabinose was always the predominant component, which implies that it might possibly be used as a marker of the Vochysiaceae. The quantitative distribution of monosaccharides was similar between the species of Qualea and Callisthene, characterized by the predominance of arabinose and mannose, and between the species of Salvertia and Vochysia, which contained higher amounts of arabinose and galactose. Such results are consistent with affinities inferred from floral morphology, wood anatomy and molecular data. Substantial intraspecific variation was observed for some species. UPGMA analysis based on the distribution of the monosaccharides reveals two main clusters, according to the links commented above. The resultant phenogram is not coherent with the current sectional classification of the Vochysiaceae, but the differences in the monosaccharides distribution between the two clusters are strongly supported by ANOVA.
Keywords: Callisthene; Qualea; Salvertia; Vochysia; Vochysiaceae; Seed cell wall polysaccharides; Chemotaxonomy;
Anti-leishmanial activity of neolignans from Virola species and synthetic analogues by Lauro E.S Barata; Lourivaldo S Santos; Pedro H Ferri; J.David Phillipson; Angela Paine; Simon L Croft (589-595).
Surinamensin, a neolignan isolated from Virola surinamensis, 3,4,5-trimethoxy-8-[2′,6′-dimethoxy-4′-(E)-propenylphenoxy]-phenylpropane, a neolignan isolated from Virola pavonis, and 25 of its synthetic analogues or correlated substances with ether linkages and their corresponding C-8 sulphur and nitrogen analogues, were tested for activity against Leishmania donovani amastigotes and promastigotes in vitro. Some were active against L. donovani promastigotes at 30 μM but inactive against intracellular amastigotes.The natural neolignan from V. pavonis was active against promastigotes at 100 μM. The highest selective activity was found in those compounds with sulphur bridges.The β-ketosulfide (3,4-dimethoxy)-8-(4′-methylthiophenoxy)-propiophenone produced 42% inhibition of L. donovani amastigotes in the liver of BALB/c mice at 100 mg/kg given once daily for five consecutive days (P>0.05).
Keywords: Virola surinamensis; Virola pavonis; Myristicaceae; Leishmania donovani; β-Ketoethers; β-Ketosulfides; β-Ketoamines; Neolignans; Anti-leishmanial activity;
nor-Lignans from the leaves of Styrax ferrugineus (Styracaceae) with antibacterial and antifungal activity by Patricia Mendonça Pauletti; Angela Regina Araújo; Maria Claudia Marx Young; Astréa M Giesbrecht; Vanderlan da Silva Bolzani (597-601).
Chemical examination of the leaves of Styrax ferrugineus yielded 5-[3″-(β-d-glucopyranosyloxy)propyl]-7-methoxy-2-(3′,4′-dimethoxyphenyl) benzofuran, along with the known nor-lignans 5-(3″-hydroxypropyl)-7-methoxy-2-(3′,4′-methylenedioxyphenyl)benzofuran, 5-(3″-hydroxypropyl)-7-methoxy-2-(3′,4′-dimethoxyphenyl)benzofuran, 5-[3″-(β-d-glucopyranosyloxy)propyl]-7-methoxy-2-(3′,4′-methylenedioxyphenyl)benzofuran and the lignan, dihydrodehydrodiconiferyl alcohol. All arylpropanoids isolated showed antibacterial and antifungal activities. The structures of the isolates were established by spectroscopic analysis.
Keywords: Styrax ferrugineus; Styracaceae; nor-Lignans; Antifungal activity; Antibacterial activity;
Molluscicidal saponins from Phytolacca icosandra by Virginie Treyvaud; Andrew Marston; Wahyo Dyatmiko; Kurt Hostettmann (603-609).
Five monodesmosidic serjanic acid saponins and a monodesmosidic spergulagenic acid saponin were isolated from an aqueous extract of the berries of Phytolacca icosandra. A methanol extract of the berries furnished three bidesmosidic serjanic acid glycosides. Their structures were established by spectroscopic (ES–MS, 1H NMR, COSY, HSQC, HMBC, 13C NMR) and chemical methods. The molluscicidal, spermicidal and haemolytic properties of the saponins were investigated.
Keywords: Phytolacca icosandra; Phytolaccaceae; Triterpene saponins; Molluscicidal activity; Haemolytic activity; Spermicidal activity;
Effects of lignoids on a hematophagous bug, Rhodnius prolixus: feeding, ecdysis and diuresis by Eloi S Garcia; Marise M.O Cabral; Günter A Schaub; Otto R Gottlieb; Patrı́cia Azambuja (611-616).
The effects of lignoids on feeding, ecdysis and diuresis in fourth-instar larvae of Rhodnius prolixus (Hemiptera) were investigated. Up to 100 μg/ml burchellin, podophyllotoxin, pinoresinol, sesamin, licarin A, or nordihydroguaiaretic acid (NDGA) in the diet did not induce antifeedant effects. Pinoresinol and NDGA significantly inhibited ecdysis. In experiments in vivo, burchellin and podophyllotoxin reduced the production of urine after feeding. 5-Hydroxytryptamine (5-HT), a diuretic hormone, partially counteracted this effect of burchellin. In experiments in vitro, using isolated Malpighian tubules, (i) burchellin reduced diuretic hormone levels in the hemolymph but not the amount of diuretic hormone stored in the thoracic ganglionic masses (including axons), (ii) burchellin decreased the volume of urine secreted by isolated Malpighian tubules, and (iii) 5-HT could not overcome the effect of burchellin upon the Malpighian tubules. We conclude that burchellin interfered with the release, but not with the production of diuretic hormone by the thoracic ganglionic mass or induced an antidiuretic hormone and directly affected the Malpighian tubules.
Keywords: Lignans; Neolignans; Lignoids; Rhodnius prolixus; Feeding; Ecdysis; Diuresis;
Diterpene from Baccharis trimera with a relaxant effect on rat vascular smooth muscle by Luce Maria Brandão Torres; Maria Thereza Gamberini; Nı́dia F. Roque; Maria Teresa Lima-Landman; Caden Souccar; Antonio José Lapa (617-619).
A bioassay monitored fractionation of a chloroform extract from the aerial parts of Baccharis trimera yielded a mixture that blocked the Ca2+-induced contractions of KCl- depolarized rat portal vein preparations. Pharmacological tests of two pure compounds isolated from the mixture revealed the dilactonic clerodane diterpene as the active compound.
Keywords: Baccharis trimera; Asteraceae; Portal vein; Dilactonic clerodane diterpene;
Antifungal amides from Piper hispidum and Piper tuberculatum by Hosana Maria D. Navickiene; Alberto Camilo Alécio; Massuo Jorge Kato; Vanderlan da S. Bolzani; Maria Claudia M. Young; Alberto José Cavalheiro; Maysa Furlan (621-626).
Piper hispidum and Piper tuberculatum accumulate amides bearing isobutyl, pyrrolidine, dihydropyridone and piperidine moieties. The isolation and characterization of several representatives including two hitherto unreported amides were performed by chromatographic techniques and by analysis of spectroscopic data. The antifungal activity of each amide was determined by direct bioautography against Cladosporium sphaerospermum.
Keywords: Piper hispidum; Piper tuberculatum; Piperaceae; Amides; Antifungal activity;
Plant natural products active against snake bite — the molecular approach by Walter B. Mors; Maria Célia do Nascimento; Bettina M. Ruppelt Pereira; Nuno Alvares Pereira (627-642).
The article surveys the substances identified in plants reputed to neutralize the effects of snake venoms. Protective activity of many of them against the lethal action of the venom of the jararaca (Bothrops jararaca) snake was confirmed by biological assays. It was shown that all belong to chemical classes capable of interacting with macromolecular targets — receptors and enzymes. In a few cases it has been shown that exogenous natural micromolecules can mimic the biological activity of endogenous macromolecules. From the evidence presented, it can be inferred that micromolecules which neutralize the action of snake venoms mechanistically replace endogenous antitoxic serum proteins with venom neutralizing capacity such as produced by some animals.
Keywords: Natural products against snake venom; Snake venom antidotes;
Pyrano chalcones and a flavone from Neoraputia magnifica and their Trypanosoma cruzi glycosomal glyceraldehyde-3-phosphate dehydrogenase-inhibitory activities by Daniela M Tomazela; Mônica T Pupo; Edna A.P Passador; M.Fátima das G.F da Silva; Paulo C Vieira; João B Fernandes; Edson Rodrigues Fo; Glaucius Oliva; José R Pirani (643-651).
The fruits of Neoraptua magnifica var. magnifica afforded three new flavonoids: 2′-hydroxy-4,4′,-dimethoxy-5′,6′-(2″,2″-dimethylpyrano)chalcone, 2′-hydroxy-3,4,4′-trimethoxy-5′,6′-(2″,2″-dimethylpyrano)chalcone, and 3′,4′-methylenedioxy-5,7-dimethoxyflavone which were identified on the basis of spectroscopic methods. The known flavonoids 2′-hydroxy-3,4,4′,5-tetramethoxy-5′,6′-(2″,2″-dimethylpyrano)chalcone, 2′-hydroxy-3,4,4′,5,6′-pentamethoxychalcone, 3′,4′-methylenedioxy-5,6,7-trimethoxyflavone, 3′,4′-methylenedioxy-5′,5,6,7-tetramethoxyflavone, 3′,4′,5′,5,7-pentamethoxyflavanone and 3′,4′,5′,5,7-pentamethoxyflavone were also identified. The latter flavone was the most active as glyceraldehyde-3-phosphate dehydrogenase-inhibitor
Keywords: Neoraputia magnifica; Rutaceae; Flavonoids; Biochemical systematics; Trypanosoma cruzi; Glycosomal glyceraldehyde-3-phosphate dehydrogenase-inhibitory activity;
Dibenzocyclooctadiene-type lignans from Magnolia pyramidata by Qi Song; Frank R. Fronczek; Nikolaus H. Fischer (653-661).
Eight dibenzocyclooctadiene-type lignans, pyramidatin A–H, were isolated from the leaves of Magnolia pyramidata. Their structures were established by spectral methods, mainly 2D NMR spectroscopic techniques, which involved combined applications of COSY, DEPT, 1H, 13C correlations, COLOC, INAPT and long-range inverse 1H, 13C NMR correlations. The molecular structures of pyramidatin A and B were determined by single crystal X-ray diffraction. The absolute configurations of all eight lignans were derived from CD spectral correlations with structurally related dibenzocyclooctadienes of known absolute configuration.
Keywords: Magnolia pyramidata; Magnoliaceae; Dibenzocyclooctadiene-type lignans; Pyramidatins A–H;
Atranones A–G, from the toxigenic mold Stachybotrys chartarum by Simon F. Hinkley; Eugene P. Mazzola; James C. Fettinger; Yiu-Fai Lam; Bruce B. Jarvis (663-673).
Atranones A–G have been isolated from the toxigenic fungus Stachybotrys chartarum. These compounds contain several unusual features including an enol-lactone as part of a 3,7-dioxabicyclo[3.3.0]octane-2-one ring system fused to an 11-membered ring. Two new dolabellane diterpenes, related in structure to the atranones were also isolated, which suggests a diterpenoid origin for the C24 atranones.
Keywords: Stachybotrys chartarum (S. atra); Diterpenoids; Dolabellanes; Enol lactones;
3,5-Dimethoxy-3-(1,1-dimethylprop-2-enyl)-3,4-dihydropsoralen-4-one: an unusual furanocoumarin derivative from Halfordia kendack by Nasim Sultana; Brian W Skelton; Peter G Waterman; Allan H White (675-678).
The aerial parts of Halfordia kendack (Rutaceae) have yielded a new furanocoumarin derivative which has been identified as 3,5-dimethoxy-3-(1,1-dimethylprop-2-enyl)-3,4-dihydropsoralen-4-one on the basis of spectroscopic and X-ray examination. This new compound, present in high concentration, is probably formed from a 4-O-prenylated precursor furanocoumarin via a Claisen re-arrangement. No trace of the putative precursor was found in this sample.
Keywords: Halfordia kendack; Rutaceae; Furanocoumarins; 3,5-Dimethoxy-3-(1,1-dimethylprop-2-enyl)-3,4-dihydropsoralen-4-one; NMR; X-ray diffraction;
Kaempferol glycosides from Siparuna apiosyce by Gilda G. Leitão; Simone S.V. Soares; M. Brito; Franco Delle Monache; Thelma de Barros (679-682).
The kaempferol derivative 3, 7-di-O-methyl-4′-O-β-[α rhamnosyl (1→6)]-glucopyranoside (siparunoside) was isolated from the leaves of Sparuna apiosyce. Its structure was established by extensive NMR studies. The alkaloids reticuline and liriodenine were also isolated from the leaves along with the kaempferol derivative tiliroside. Benzylisoquinoline alkaloids were isolated from the wood (liriodenine) and wood bark (liriodenine, laurotetanine, N-methyl-laurotetanine, reticuline), together with a mixture of cis and trans-N-feruloyltyramines. 3,7,4′-tri-O-methylkaempferol was isolated from all organs.
Keywords: Siparuna apiosyce De Candolle; Monimiaceae; Kaempferol-3,7-dimethylether-4′-O-β; -[α-rhamnosyl(1→6)]-glucopyranoside; Siparunoside; Kaempferol 3-O-β-(6″-p-coumaroyl) glucopyranoside; Tiliroside; 3,7,4′-tri-O-methylkaempferol;