Search

An NMR study of two known bis-indole alkaloids is described. In addition to conventional 1D NMRmethods, 2D shift-correlated NMR experiments [ 1 Hx 1 H-COSY, 1 Hx 13 C-HMQC- 1 J(C,H), 1 Hx 13 C-HMBC- n J(C,H)(nD2 and 3)] and 2D 1 Hx 1 H-NOESY were used for 1 Hand 13 C chemical shift assignments of these alkaloids.Copyright 1999 John Wiley & Sons, Ltd.KEYWORDS: bis-indole alkaloids; NMR; 1D NMR; 2D NMR; 1 HNMR; 13 C NMR; chemical shift assignments INTRODUCTION Alkaloids are secondary metabolites detected in plants andanimals, with great potential applications in taxonomy,ecology and medicine. 1;2 This paper reports the 1 Hand 13 C chemical shift assignments of two known bis-indolealkaloids, conodurine (1) and voacamine (2), isolatedfrom the Brazilian plant Tabernaemontana laeta Mart.(Apocynaceae).The results of the extensive application of 1D ( 1 HNMR, HBBD- 13 C NMR and DEPT- 13 C NMR) and 2D[ 1 Hx 1 H-COSY, 1 Hx 13 C-HMQC- 1 J(C,H), 1 Hx 13 C-HMBC- n J(C,H) (nD2 and 3)

A suspension culture of Cinchona robusta which under normal culture conditions does not produce anthraquinones, produces a range of these anthraquinones after elicitation. Eight new anthraquinones were identified, robustaquinones A–H, in addition to two known anthraquinones, 1,3,8-trihydroxy-2-methoxyanthraquinone and copareolatin 6-methyl ether. Their oxygenation pattern, characterized by a 6,7-disubstitution in the A-ring, is rare and raises questions about their biogenetic origin. They might be derived from phenylpropanoids and not from o -succinylbenzoic acid.

gilsane@farmacia.ufrgs.br; 2) PPG-Botanica, ICBS, 91509-900 Porto Alegre, RS, Brazil, fax (051) 33167670; 3) Grupo Metabolomica, LCQUI/CCT, Universidade Estadual do Norte Fluminense, 28015-620 Campos dos Goytacazes, RJ, Brazil; 4) Faculte de Pharmacie, Universite de Picardie Jules Verne, 80037 Amiens, France. Published in Khimiya Prirodnykh Soedinenii, No. 6, pp. 572-574, November-December, 2007. Original article submitted August 1, 2006.

Glandular and nonglandular trichomes are spread over the vegetative and reproductive organs of Plectranthus madagascariensis. Two morphologically distinct types of glandular trichomes (capitate and peltate) are described. Capitate trichomes have an ovoid unicellular head and a short stalk cell or an elongated two- to three-celled stalk slightly enlarged at the base. Peltate trichomes, which show in vivo a characteristic orange-to-reddish color, are large, flattened-to-depressed in the center, and often appear as a ring of minute gems. They are composed of a large head with eight glandular cells arranged in a single layer. An unusual kind of capitate trichomes, reported for the first time in Lamiaceae, occurs typically restricted to the calyx. These trichomes possess a two- or three-celled stalk and a long, unicellular conical, glandular head. The several types of trichomes differ in the secretion process The essential oils of P. madagascariensis, isolated by hydrodistillation and by distillation-extractio...

Sitosterol, stigmasterol, betulinic acid, lupeol, 3-O-beta-D-glucopiranosylsitosterol, 3-O-alpha-L-rhamnopiranosylchromone, 5,7-dihydroxy-4'-methoxyisoflavone, 3',5,7-trihydroxy-4'-methoxyisoflavone and a mixture of two rel-2R,3S-3-O-alpha-L-rhamnopiranosilflavanonols were isolated from the roots of Andira fraxinifolia. Their structures were established by spectral data analysis.

The 1H and 13C NMR spectra of 5-acetyl-7,4′-dimethoxyflavone-(6–8″)-5″-acetyl-7″,4‴-dimethoxyflavone, a new agathisflavone derivative, were completely assigned on the basis of 1D and 2D NMR techniques. Copyright © 2005 John Wiley & Sons, Ltd.

Aim Evaluation of the capability of Burkholderia sacchari to incorporate different monomers into polyhydroxyalkanoates (PHA). Methods and Results Thirty different carbon sources were evaluated as cosubstrates for B. sacchari growing on glucose with the intention to promote the incorporation of different monomers into the PHA produced by this species. With odd-numbered fatty acids, incorporation of the 3HV monomer was achieved, up to 65 mol% in the case of valerate. With 4-hydroxybutyrate, incorporation of 4HB was obtained, representing 9·1 mol%. With hexanoic acid, the production of P3HB-co-3HHx was achieved, containing up to 1·6 mol% of 3HHx. The molar fraction of 3HHx was found to be dependent on the ratio of glucose to hexanoic acid supplied. Metabolic flux analysis revealed a high efficiency of B. sacchari in converting carbon sources into P3HB-co-3HHx. Nevertheless, hexanoic acid was only poorly converted to 3HHx. Conclusions Burkholderia sacchari is able to incorporate 3HV, 4HB and 3HHx in PHA containing mainly 3HB. The 3HHx content of P3HB-co-3HHx can be controlled by varying the glucose to hexanoic acid ratio. Burkholderia sacchari is highly efficient in converting carbon sources into PHA; however, only 2% of the hexanoic acid supplied could be converted to 3HHx. Significance and Impact of the Study This is the first report describing an approach to modulate the composition of P3HB-co-3HHx produced by bacteria using mixtures of carbohydrate and hexanoic acid as carbon source.

In 9,10-anthraquinones the chemical shift of a peri-hydroxyl proton is affected by the substituents in the other benzenoid ring. These effects are additive. They are useful for the determination of substitution patterns and have been used to revise the structures of six previously reported anthraquinones containing methoxyl, hydroxyl, methylenedioxy and β-methyl substituents. Because the chemical shifts of the other protons are hardly affected by substitutions in the other ring, the characteristic chemical shifts for a wide variety of substitution patterns could be derived.

The possible limitation of the rate of biosynthesis of terpenoid indole alkaloids by low enzyme levels was investigated in two cell lines of Tabernaemontana divaricata with different terpenoid indole alkaloid biosynthetic capacities. The activities of tryptophan decarboxylase (TDC), strictosidine synthase (SSS), strictosidine glucosidase (SG), isopentenyl pyrophosphate isomerase (IPP isomerase) and geraniol 10-hydroxylase (G10H) of both cell lines were compared. The activities of TDC, SSS and IPP isomerase did not show a direct relationship with the biosynthetic capacity but SG and G10H might be limiting. In order to test whether the availability of the terpenoid precursor limits the biosynthesis of the terpenoid indole alkaloids, loganin was fed to the cultures. Loganin-feeding did not influence any of the measured enzyme activities but increased the terpenoid indole alkaloid accumulation of both cell lines to similar levels. A five-fold increase was observed for the accumulating line and a more than 100-fold increase for the low-accumulating one. Strictosidine accumulated mainly in the low-accumulating cell line which has high TDC and low SG activity; the amounts and types of the other terpenoid indole alkaloids which accumulated were similar in both lines. From this it can be concluded that the biosynthesis of terpenoid indole alkaloids in both cultures is limited by the availability of terpenoid precursors; this pathway is not saturated with substrates under normal culture conditions.

Ajmalicine degradation was investigated in a low alkaloid-accumulating Catharanthus roseus cell culture, and compared with the chemical degradation which occurred in medium without cells. Degradation was found to be faster in the presence of cells. By adding [Me- 2 H 3 ] ajmalicine to the cell culture the production and the degradation rates were estimated. Both were relatively high at the beginning of the growth phase while the degradation rate was also high in the stationary phase.

Two cell lines of Tabernaemontana divaricata derived from the same suspension culture were compared with respect to their biotransformation capacity. One is a high indole alkaloid-producing culture which accumulated mainly O-acetylvallesamine. The other cell line biosynthesizes terpenoid indole alkaloids in much lower amounts. Both cell lines were cultured in medium containing either conopharyngine, coronaridine, vobasine or tabersonine. Chemical breakdown was followed in fresh and used culture medium in the absence of cell culture. All the alkaloids investigated underwent chemical transformation. Most of the biotransformation products accumulated by the cultures have been reported to occur in intact plants. Since all the alkaloids added were transformed in the same way by both cultures, the two cell lines seem to have the same biotransformation potential.

A influência de diferentes adubos e disponibilidade de água no solo foi avaliada em relação ao teor e à composição química de óleos essenciais em folhas de alpínia. O experimento foi realizado em blocos casualizados, com três repetições, em esquema de parcelas subdivididas. As parcelas corresponderam a dois limites de disponibilidade de água no solo [LDA1 - redução de 75% da capacidade total de retenção de água (CTA) - e LDA2 - redução de 50% da CTA], e as subparcelas, aos adubos: esterco bovino, cama-de-galinha, torta-de-filtro, químico e o controle não-adubado. A disponibilidade de água no solo, assim como a adubação, não influenciou no teor e na composição química de óleos essenciais aos 12 meses após o plantio. Os principais constituintes químicos (teores) dos óleos essenciais em folhas de alpínia foram: α-thujeno (6,11%), α-pineno (2,69%), sabineno (16,69%), β-pineno (4,64%), β-mirceno (1,76%), 1,8-cineol (19,41%) e 1-terpinen-4-ol (14,32%). This study evaluated the influence of different fertilizers and soil water availability on the content and chemical composition of essential oil from alpinia leaves. The experiment was arranged in a randomized block design in a splitplot scheme, with three replicates. The plots corresponded to two limits of water availability at soil [LWD1 - reduction of 75% of the total water retention capacity (TWC) and LWD2 - reduction of 50% of TWC] and the subplots to the fertilizers: cattle manure, poultry bed, filter cake, chemical and the non-fertilized control. Water availability at soil, as well as, the fertilization did not affect either essential oils content or chemical composition at twelve months after planting. The major chemical constituents (contents) on leaves shell ginger essential oils were: α-thujene (6,11%), α-pinene (2,69%), sabinene (16,69%), β-pinene (4,64%), β-myrcene (1,76%), 1,8-cineole (19,41%) and 1-terpinen-4-ol (14,32%).

Calea serrata Less. (Asteraceae), an endemic species of south Brazil known as "quebra-tudo", is used in Afro-Brazilian religious rituals and in folk medicine for treating liver disorders. Phytochemical studies of the n-hexane extract of this plant demonstrated the presence of precocene II, a benzopyran derivative known for its insecticidal activity. The aim of this work was to isolate this benzopyran and determine the chemical composition of the essential oil of C. serrata and further to evaluate the acaricidal activity of the essential oil and precocene II against the larvae of Rhipicephalus (Boophilus) microplus. The LC(99.9) and LC(50) values obtained with the oil, which presents precocene II and sesquiterpenes, were 3.94 μL/mL and 0.28 μL/mL, respectively. For precocene II this values were 4.25mg/mL and 1.78 mg/mL, respectively. The results indicate a synergistic interaction between the components of the oil and precocene II.

The crude extracts of Hypericum species native to South Brazil showed analgesic and antidepressant-like effects in rodents. The chemical characterization of these species revealed that they are rich in flavonoids and phloroglucinol derivatives. In the present study a detailed investigation was performed on the activities of hyperoside (HYP), a common flavonoid in the genus Hypericum. Hyperoside was obtained from the aerial parts of H. caprifoliatum by chromatographic procedures. Mice treated with single doses (10, 20 and 40 mg/kg i.p.) did not present signs of toxicity or weight loss. At 20 and 40 mg/kg i.p. the mice exploratory behavior in the open field test was reduced. At 20 mg/kg i. p. the pentobarbital sleeping time increased, but not the sleeping latency. No activity was found on the hot-plate (10 and 20 mg/kg i.p.) or in the acetic acid-induced writhing test (20 and 40 mg/kg p.o.). Nevertheless, an antidepressant-like effect in the forced swimming test in mice and rats was observed (HYP 10 and 20 mg/kg i.p. in mice; HYP 1.8 mg/kg/day p.o. in rats). The antidepressant-like effect in rats was prevented by the administration of sulpiride (50 mg/kg i.p.) a D2 antagonist. In conclusion, hyperoside was found to present a depressor effect on the central nervous system as well as an antidepressant-like effect in rodents which is, at least in part, mediated by the dopaminergic system.

Baccharis ochracea contains a new diterpene in addition to the known compounds chlorogenic acid, isochlorogenic acid, α-spinasterol and isoquercitrin. The diterpene is a geranylgeraniol derivative with a butenolide ring.

From the aerial parts of Hypericum polyanthemum Klotzsch ex Reichardt (Guttiferae), three chromenes, 6-isobutyryl-5,7-dimethoxy-2,2-dimethyl-benzopyran; 7-hydroxy-6-isobutyryl-5-methoxy-2,2-dimethyl-benzopyran and 5-hydroxy-6-isobutyryl-7-methoxy-2,2-dimethyl-benzopyran were isolated. Their structures were determined by NMR spectroscopic analyses.

Three pentacyclic indole alkaloids, one novel named darcyribeirine (1) and the known isoreserpiline (2) and isoreserpine (3), were isolated from the root bark of the Rauvolfia grandiflora Mart. The structures were established by spectroscopic data.

The antioxidant activity of leaf extracts from Jacaranda puberula Cham., Bignoniaceae, was assayed by the DPPH (2,2-diphenyl-1-picryl-hydrazyl) free radical scavenging method. Three phytomedicines (F1, F2, and F3) used as blood depurative, were tested by the same method. The free radical scavenger potential was measured by the discoloration of the solution. The EC50 values from Gingko bilobaEGb 761® extract and rutin, used as antioxidant for medical purposes, were used as reference. The ethanol extract (EE), ethyl acetate (EA), butanol (EB), aqueous (EAq) and the sample A (obtained from extract EB), showed lower EC50 values than other extracts and phytomedicines. The antioxidant activity (AA) of the extracts was related with the presence of the polyphenol compounds such as verbascoside (1) and cis-caffeoyl aldehyde (2). These structures were determined by chemical and spectroscopic methods and comparison with literature data. Os extratos obtidos a partir das folhas de Jacaranda puberulaCham., Bignoniaceae, foram avaliados quanto à atividade antioxidante utilizando-se o método do radical livre DPPH (2,2-difenil-1-picril-hidrazila). Também foram incluídos na avaliação três medicamentos fitoterápicos comerciais (F1, F2 e F3) indicados como depurativos do sangue. Através da descoloração das soluções testadas, foi possível medir o potencial sequestrador do radical DPPH. Como referência, utilizou-se os dados da literatura de CE50 do extrato padronizado de Gingko bilobaEGb 761® e o flavonoide rutina, ambos empregados em medicamentos com atividade antioxidante. Entre os extratos testados, os que apresentaram valores baixos de CE50 foram os extratos etanólico bruto (EE), em acetato de etila (EA), em butanol (EB), aquoso (EAq) e da amostra A, obtida do extrato EB. Os fitoterápicos comerciais apresentaram altos valores de CE50. Com base nos resultados das análises feitas por de RMN de 13C e ¹H, CLAE-DAD e de acordo com os dados da literatura, a presença de substâncias fenólicas como o verbascosídeo (1) e o aldeído cis-caféico (2), contribuíram para a atividade antioxidante (AA) dos extratos ativos.

2-acetyl physcion (2-acetyl-1,8-dihydroxy-6-methoxy-3-methyl-9,10-anthraquinone, 2), a rare anthraquinone, was isolated from Senna macranthera var. nervosa (Vogel) H.S. Irwin & Barneby (Fabaceae). The chemical structure was elucidated and all ¹H and 13C NMR chemical shifts were assigned by NMR one- (¹HNMR, {¹H}-13CNMR, and APT-13CNMR) and two (COSY, NOESY, HMQC and HMBC) dimensional of this natural compound. Furthermore, the minor anthraquinones chrysophanol (3), chrysophanol-8-methyl ether (4) and physcion (5) were characterized by GC-MS analysis. The occurrence of the anthraquinones 3-5 confirms that S. macranthera is a typical representative of the genus Senna.2-acetil-fisciona (2-acetil-1, 8-di-hidróxi-6-metóxi-3-metil-9, 10-antraquinona, 2), uma antraquinona rara, foi isolada de Senna acranthera var. nervosa (Vogel) H.S. Irwin & Barneby (Fabaceae). estrutura química foi elucidada e todos os deslocamentos químicos de RMN ¹H e 13C foram atribuídos através de RMN uni- (RMN¹H, {¹H}-RMN-13C e APT-RMN13C) e bi- (COSY, NOESY, HMQC e HMBC) dimensional deste composto natural. Adicionalmente, as antraquinonas minoritárias crisofanol (3), crisofanol-8-metil éter (4) e fisciona (5) foram caraterizadas pela análise de CG-EM. A ocorrência das antraquinonas 3-5 confirma que S. macranthera é uma típica representante do gênero Senna.

Inoculation of Vicia sativa subsp. nigra (V. sativa) roots with Rhizobium leguminosarum biovar. viciae (R.l. viciae) bacteria substantially increases the ability of V. sativa to induce rhizobial nodulation (nod) genes. This increase is caused by the additional release of flavanones and chalcones which all induce the nod genes of R.l. viciae (K. Recourt et al., Plant Mol Biol 16: 841-852). In this paper, we describe the analyses of the flavonoids present in roots of V. sativa. Independent of inoculation with R.l. viciae, these roots contain four 3-O-glycosides of the flavonol kaempferol. These flavonoids appeared not capable of inducing the nod genes of R.l. viciae but instead are moderately active in inhibiting the activated state of those nod genes. Roots of 7-day-old V. sativa seedlings did not show any kaempferol-glycosidase activity consistent with the observation that kaempferol is not released upon inoculation with R.l. viciae. It is therefore most likely that inoculation with infective (nodulating) R.l. viciae bacteria results in de novo flavonoid biosynthesis and not in liberation of flavonoids from a pre-existing pool.

AUSTKACT.-A capillary gas chromatographic analysis is described by which non-dcrlvatizrd indolr alkaloids and indole-related compounds can br sepvrnted and identified whclr thr sysrem is coupled ro a mass spectrometer. By the USC of this analysis some phrnolics and stcrols could also be separuzd. The phenolics coniferyl alcohol and srnapyl alcohol and the stcrols campestrrol and stigmastem were identified in ‘~~&rr~~tvucln~rrrru Jwuril-utd cell suspcnsion cultures.

A method for the rapid phytochemical characterization of plant cell cultures, using proton nuclear magnetic resonance spectroscopy (1H NMR), is described. Aqueous extracts were prepared from a large number of plant cell suspension cultures. Following lyophilization, the extracts were redissolved in D2O containing an internal standard to enable quantification and 1H NMR spectra were measured. In the spectra, signals from sugars and amino acids were observed. The patterns obtained were characteristic of cell lines, with related lines typically showing similar characteristics, e.g., Tabernaemontana suspension cultures are characterized by their ability to accumulate large amounts of arginine, while Catharanthus cultures mainly accumulate glutamine. The amounts of amino acids accumulated were found to be determined mainly by the medium on which the cell cultures were growing. Murashige and Skoog medium supported nitrogen storage in amino acids, while Gamborg B5 medium did not. Reference spectra of some of the most common constituents are presented, together with data enabling a direct quantification of these compounds in aqueous extracts.

Summary The uptake and accumulation of the indole alkaloid cinchonamine and the quinoline alkaloid quinine in suspension cultured cells of Cinchona robusta and Catharanthus roseus were studied. Both alkaloids are endogenous to Cinchona and are not found in Catharanthus . Uptake in Cinchona appeared to be the resultant of two processes: rapid uptake with an equilibrium after 2 h, and slow and steady uptake with equilibrium after about 6 h. Occasionally, the cells of Cinchona lost their brownish-orange colour. During this physiological state of the cells only rapid uptake was observed. Steady uptake in these (white) cells could be induced by vanadate. The time course of rapid uptake in Cinchona was almost identical to the time course of uptake in Catharanthus , and had characteristics of free diffusion of non-protonated alkaloids in combination with ion-trapping of protonated alkaloids. Slow and steady uptake of quinine in Cinchona cells was determined and simultaneously the time course of the pH of the vacuoles was measured with in vivo 31 P-NMR. The slow and steady uptake appeared to be correlated with a steady decrease in vacuolar pH. The results demonstrate that a strong basic alkaloid, like quinine, can be accumulated by free diffusion of its neutral form in combination with ion-trapping of its charged form. Slow and steady uptake, which is often observed in alkaloid transport, is not caused by additional accumulation mechanisms or alkaloid carriers, but is the effect of slow acidification of the vacuoles.

Flavonoids released by roots of Vicia sativa subsp. nigra (V. sativa) activate nodulation genes of the homologous bacterium Rhizobium leguminosarum biovar viciae (R. l. viciae). Inoculation of V. sativa roots with infective R. l. viciae bacteria largely increases the nod gene-inducing ability of V. sativa root exudate (A.A.N. van Brussel et al., J Bact 172: 5394-5401). The present study showed that, in contrast to sterile roots and roots inoculated with R. l. viciae cured of its Sym plasmid, roots inoculated with R. l. viciae harboring its Sym plasmid released additional nod gene-inducing flavonoids. Using 1H-NMR, the structures of the major inducers released by inoculated roots, 6 flavanones and 2 chalcones, were elucidated. Roots extracts of (un)inoculated V. sativa contain 4 major non-inducing, most likely glycosylated, flavonoids. Therefore, the released flavonoids may either derive from the root flavonoids or inoculation with R. l. viciae activates de novo flavonoid biosynthesis.

A cell suspension culture from Tabernaemontana divaricata was fed with 15 N-labelled ammonium or nitrate. The incorporation of label in free amino acids, protein amino acids and indole alkaloids was determined. Ammonium was found to be used more extensively than nitrate in the biosynthesis of these compounds. For tryptamine considerably lower labelling percentages were found than for the indole alkaloid O -acetylvallesamine and the amino acids. This indicates a vacuolar pool of tryptamine, formed at the beginning of the culture-period and not available for further alkaloid biosynthesis.

Borreria verticillata contains the new iridoid aglycone borreriagenin (1), in addition to the known iridoids asperuloside (2) and daphylloside (3). The structure of borreriagenin (1) was elucidated by extensive NMR analysis.

The four stereoisomers of small bacteriocin, an autoinducer of the symbiotic nitrogen-fixing bacterium Rhizobium leguminosarum, were synthesized via a versatile methodology for 3′-hydroxyacyl homoserine lactones based on the Nagao asymmetric aldol reaction. The synthetic isomers were much less effective at inhibiting the growth of R. leguminosarum RBL5523 than the natural isomer, showing the importance of stereochemistry for activity.

Himatanthus sucuuba and Plumeria rubra are used in folk medicine in Brazil to treat various ailments. The isolation of the new iridoid 15-demethylisoplumieride from the bark of Plumeria rubra L. var. acutifolia (Ait) Woodson and latex of Himatanthus sucuuba (Spruce) Woodson is reported. Other iridoid glycosides were obtained from both plants. The structures of these substances were elucidated by spectral analysis and comparison with data already reported.

From the aerial parts of Pentas lanceolata, belonging to the family Rubiaceae, a series of iridoid glucosides was isolated by preparative HPLC. Seven iridoid glucosides were identified. Besides asperuloside and asperulosidic acid, characteristic iridoids for Rubiaceae, five new iridoids were isolated, namely, tudoside (1), 13R-epi-gaertneroside (2), 13R-epi-epoxygaertneroside (3), and a mixture of E-uenfoside (4) and Z-uenfoside (5). Further, it was shown that the compound reported as citrifolinin B (6) is in fact the same as tudoside and should be revised. Also, the configuration of the previously reported iridoids gaertneroside and epoxygaertneroside has been elucidated.

A new iridoid glucoside, 2′-apiosylgardoside together with the known compounds theviridoside, ipolamiide and verbascoside were isolated from leaves of Verbenoxylum reitzii. The structure of the new compound was determined mainly by NMR spectroscopy.

Callus and cell suspension cultures of Rauwolfia sellowii were established in Gamborg B5 medium supplemented with 1 mg l-1 2,4-dichlorophenoxyacetic acid, 0.2 mg l-1 kinetin and 30 g l-1 sucrose. The growth cycle of suspension cultures was completed in ca. 22 days and the maximum specific growth rate was 0.0098 h-1 with a doubling time of 71 h. The cultures accumulated the same major alkaloids as in the leaves of the parent plant, such as sellowiine, 19α,20α-epoxyakuammicine, vomilenine, picrinine and 12-demethoxytabernulosine. The alkaloid contents of leaves, callus and cell suspension cultures were quantitatively compared by HPLC.

Angelonia integerrima gave the known iridoid glucosides galiridoside, harpagide, ajugol, 6-hydroxyantirrhide, antirrhide, daunoside, aucubin and stegioside II, together with a new compound, named angeloside.

Eucnide bartonioides yielded morroniside as the main iridoid constituent. In addition, six minor iridoid glucosides were isolated namely the known glucosides; kingiside, sweroside, secologanol, 8-epi-loganin and loganin as well as a novel iridoid glucoside, which by spectroscopic methods was assigned to be 5-hydroxyloganin. The compound 8-epi-loganin has so far been reported only from Scrophulariaceae and related families and it is rather unexpected in Loasaceae. © 1997 Elsevier Science Ltd. All rights reserved

Baccharis ochracea contains a new diterpene in addition to the known compounds chlorogenic acid, isochlorogenic acid, α-spinasterol and isoquercitrin. The diterpene is a geranylgeraniol derivative with a butenolide ring.

Do extrato butanólico de Croton campestris St. Hill. (Euphorbiaceae) foram isolados quatro flavonóides, todos O-glicosídeos da quercetina. Estas substâncias foram identificadas como 3-O-b-D-apiofuranosil-(1®2)-galactopiranosil quercetina (1), 3-O-b-D-galactopiranosil quercetina (hiperina) (2), 3-O-a-L-arabinopiranosil quercetina (guaijaverina) (3) e 3-O-a-L-ramnopiranosil quercetina (quercitrina) (4).O presente trabalho relata a presença destas substâncias pela primeira vez para esta espécie de Croton, cuja elucidação estrutural deu-se por espectroscopia em UV, EM e RMN, incluindo as técnicas bidimensionais: ¹H-¹H (2D NOESY, 2D COSY), ¹H-13C (2D HETCOR) e 13C (APT), além de comparações com os dados da literatura. Four flavonoids were isolated from the butanolic extract of the aerial parts of Croton campestris St. Hill. (Euphorbiaceae). These compounds were identified as 3-O-b-D-apiofuranosyl-(1®2)-galactopyranoside quercetin (1), 3-O-b-D-galactopyranoside quercetin (hyperin) (2), 3-O-a-L-arabinopyranoside quercetin (guaijaverin) (3) and 3-O-a-L-ramnopyranoside quercetin (quercitrin) (4). They have been isolated for the first time from Croton campestris. Their structures were elucidated by UV, MS and NMR experiments including ¹H-¹H (2D NOESY, 2D COSY), ¹H-13C (2D HETCOR), 13C (APT) and by comparison of the spectral data with those reported in the literature.

Two new benzophenones were isolated from the leaves of Hypericum carinatum. Their structures were established on the basis of 2D NMR spectroscopic analyses and mass spectrometry as cariphenone A (6-benzoyl-5,7-dihydroxy-2,2,8-trimethyl-2H-chromene) (1) and cariphenone B (8-benzoyl-5,7-dihydroxy-2,2,6-trimethyl-2H-chromene) (2). Five known compounds, the phloroglucinol derivative uliginosin B (3), 1-eicosanol, sitosterol, stigmasterol, and campesterol, were also characterized. Compounds 1-3 were evaluated for their total antioxidant capacity through a total radical-trapping parameter assay. Only compound 1 showed moderate antioxidant activity, exhibiting inhibition of chemiluminescence similar to that of quercetin at the same concentration.

A complete procedure is described for the extraction, detection and quantification of anatoxin-a in biological samples. Anatoxin-a is extracted from biomass by a routine acid base extraction. The extract is analysed by GC–MS, without the need of derivatization, with a detection limit of 0.5 ng. A method was developed for the accurate quantification of anatoxin-a in the standard solution to be used for the calibration of the GC analysis. 1 H NMR allowed the accurate quantification of microgram quantities of anatoxin-a. The accurate quantification of compounds in standard solutions is rarely discussed, but for compounds like anatoxin-a (toxins with prices in the range of a million dollar a gram), of which generally only milligram quantities or less are available, this factor in the quantitative analysis is certainly not trivial. The method that was developed can easily be adapted for the accurate quantification of other toxins in very dilute solutions.

An isocratic HPLC system is described which allows the separation of the iridoid and indole precursors of terpenoid indole alkaloids, which are present in a single crude extract. The system consists of a column of LiChrospher 60 RP select B 5 μm, 250 x 4 mm (Merck) with an eluent of 1 % formic acid-acetonitrile-trichloroacetic acid (100 :10 :0.25, v :v :w) at a flow of 1.2 ml/min. In the suspension cultures of Catharanthus roseus secologanin and tryptophan were detected. In the cultures of Tabernaemontana divaricata loganin, tryptophan, and tryptamine accumulated.

An HPLC method with UV detection has been developed and validated in order to quantify quadranguloside, the main saponin of the leaves of Passiflora alata. The analysis was achieved by simple isocratic elution (with acetonitrile:aqueous phosphoric acid) using a Nova-Pak phenyl column. The amount of quadranguloside present in aqueous extracts from leaves of P. alata was estimated to be 22.2% (w/w), corresponding to 0.8% (w/w) in relation to dried leaves. The assay method described is simple, rapid, accurate and sensitive, and may form part of future drug authentication protocols.

From leaves of Psychotria leiocarpa, an indole alkaloid was isolated to which the structure N,beta-D-glucopyranosyl vincosamide (1) was assigned. This represents the first report of an N-glycosylated monoterpenoid indole alkaloid. In field-grown plants highest amounts of 1 were found in the leaves (2.5% of dry wt) and fruit pulp (1.5% dry wt). Lower amounts were found in the stems (0.2% dry wt) and the seeds (0.1% of dry wt), whereas the alkaloid was not detected in the roots. The accumulation of 1 in aseptic seedlings was also restricted to the shoots and increased with plant age and light exposure, independent of the supply of sucrose in the culture medium.

A mixture of the two new flavonols 8-hydroxy-3, 4', 5, 6, 7-pentamethoxyflavone (1) and 8-hydroxy-3, 3', 4', 5, 6, 7-hexamethoxyflavone (2) was isolated from a commercial sample of Citrus aurantifolia. An array of one- (1HNMR, {1H}-13C NMR, and APT-13C NMR) and two-dimensional NMR techniques (COSY, NOESY, HMQC and HMBC) was used to achieve the structural elucidation and the complete 1H and 13C chemical shift assignments of these natural compounds. In addition, the antifungal activity of these compounds against phytopathogenic and human pathogenic fungi was investigated.