Phytochemistry (v.58, #3)
Author Index (v).
Characterization of peroxidase-mediated chlorophyll bleaching in strawberry fruit by Gustavo A Martı́nez; Pedro M Civello; Alicia R Chaves; Marı́a C Añón (379-387).
Peroxidase (POX) from strawberry fruits was analyzed for its capacity to bleach chlorophyll. The partially purified enzyme preperation catalyzed the bleaching of chlorophylls and their derivatives in the presence of H2O2 and phenolic compounds. The optimal reaction conditions were 35 °C, pH 5.2 and ionic strength equal to 0.2. The maximum activity was observed at 1 mM of H2O2, while higher concentrations inhibited enzyme activity. Compounds with a high affinity to the heme group, radical scavengers and reducing agents, showed an inhibitory effect. Phenolic compounds such as umbelliferone, naringenin and p-substituted monophenols acted as cofactors. Instead, other phenolic compounds tested such as caffeic acid, catechin, ellagic acid, esculin and quercetin inhibited the activity of POX on chlorophylls. Phenolic compounds extracted from strawberry fruits showed an inhibitory effect on POX-chlorophyll bleaching activity, although this effect decreased markedly during ripening. POX showed higher affinity for compounds derived from chlorophyll a than from chlorophyll b , and the enzyme preferentially degraded chlorophyll derivatives with the Mg2+ ion present and the phytol group removed. The POX-chlorophyll bleaching activity was found in all ripening stages from small green to ripe, the highest activity corresponding to large green fruits.Peroxidase extracted from strawberry fruit catalyzed the bleaching of chlorophylls and their derivatives in the presence of H2O2 and p-coumaric acid. Phenolic compounds extracted from strawberry fruit inhibited this activity, although this effect decreased during ripening.
Keywords: Fragaria x ananassa; Rosaceae; Strawberry; Chlorophyll; Peroxidase; Phenolic compounds;
Altritol synthesis by Notheia anomala by John A Raven; John Beardall; J.A Chudek; Charles M Scrimgeour; Margaret N Clayton; Shona G McInroy (389-394).
The linear hexitol altritol has only been identified in six genera, all of them in the order Fucales of the brown algae. Five of these genera are closely related according to molecular phylogenetic and other data, while the sixth (Notheia) is an obligate epiphyte on two other altritol-containing genera with which it is symphanic. The possibility that Notheia obtains altritol from the algae on which it is epiphytic rather than by synthesizing altritol independently was investigated by supplying 13C-inorganic carbon in the light followed by mass spectrometric and nuclear magnetic resonance analysis. Notheia separated from the phorophyte Hormosira during exposure to 13C showed 13C enrichment in both altritol and mannitol, while the Hormosira only showed significant labelling of mannitol. These data show that altritol can be synthesized by Notheia, with implications for the number of gains and losses of the capacity to synthesize altritol in the evolution of the Fucales.The epiphytic alga Notheia anomala synthesises the unusual hexitol altritol independently of its phorophyte Hormosira banksii.
Keywords: Hormosira banksii; Hormosiraceae; Fucales; Phaeophyceae; Notheia anomala; Chemotaxonomy; Linear hexitols; Altritol; Mannitol; Epiphyte; Phorophyte;
Production of loline alkaloids by the grass endophyte, Neotyphodium uncinatum, in defined media by Jimmy D Blankenship; Martin J Spiering; Heather H Wilkinson; Franklin F Fannin; Lowell P Bush; Christopher L Schardl (395-401).
Lolines (saturated 1-aminopyrrolizidines with an oxygen bridge) are insecticidal alkaloids produced in symbioses of certain Epichloë (anamorph-Neotyphodium) species (fungal endophytes) with grasses, particularly of the genera Lolium and Festuca. Prior to the present study, it was unknown whether lolines were of plant or fungal origin. Neotyphodium uncinatum, the common endophyte of meadow fescue (Lolium pratense=Festuca pratensis) produced loline, N-acetylnorloline, and N-formylloline when grown in the defined minimal media at pH 5.0–7.5, with both organic and inorganic nitrogen sources and sugars as carbon sources. In contrast, lolines were not detected in complex medium cultures. GC–MS and 13C NMR spectroscopic analyses confirmed the identity of the alkaloids isolated from the defined medium cultures. Lolines accumulated to ca. 700 mg/l (4 mM) in cultures with 16.7 mM sucrose and 15–30 mM asparagine, ornithine or urea. Kinetics of loline production and fungal growth were assessed in defined medium with 16.7 mM sucrose and 30 mM ornithine. The alkaloid production rate peaked after the onset of stationary phase, as is common for secondary metabolism in other microbes. Neotyphodium uncinatum, a fungal endophyte of meadow fescue grass, produces loline alkaloids in culture. This is the first published account establishing that a fungus can produce 1-aminopyrrolizidines.
Keywords: Neotyphodium uncinatum; Clavicipitaceae; Epichloë endophyte; Lolium pratense; Festuca pratensis; Poaceae; Meadow fescue; Fungal fermentation; 1-Aminopyrrolizidines; Loline alkaloids;
Cytoplasmic accumulation of flavonoids in flower petals and its relevance to yellow flower colouration by Kenneth R. Markham; Kevin S. Gould; Ken G. Ryan (403-413).
It is widely accepted that the mix of flavonoids in the cell vacuole is the source of flavonoid based petal colour, and that analysis of the petal extract reveals the nature and relative levels of vacuolar flavonoid pigments. However, it has recently been established with lisianthus flowers that some petal flavonoids can be excluded from the vacuolar mix through deposition in the cell wall or through complexation with proteins inside the vacuole, and that these flavonoids are not readily extractable. The present work demonstrates that flavonoids can also be compartmented within the cell cytoplasm. Using adaxial epidermal peels from the petals of lisianthus (Eustoma grandiflorum), Lathyrus chrysanthus and Dianthus caryophyllus, light and laser scanning confocal microscopy studies revealed a significant concentration of petal flavonoids in the cell cytoplasm of some tissues. With lisianthus, flavonoid analyses of isolated protoplasts and vacuoles were used to establish that ca 14% of petal flavonoids are located in the cytoplasm (cf. 30% in the cell wall and 56% in the vacuole). The cytoplasmic flavonoids are predominantly acylated glycosides (cf. non-acylated in the cell wall). Flavonoid aggregation on a cytoplasmic protein substrate provides a rational mechanism to account for how colourless flavonoid glycosides can produce yellow colouration in petals, and perhaps also in other plant parts. High vacuolar concentrations of such flavonoids are shown to be insufficient.Flavonol glycosides have been found in the cell cytoplasm of lisianthus (Eustoma grandiflorum) and Lathyrus chrysanthus flower petals. Interactions within the cytoplasm are proposed to account for yellow petal colouration resulting from “colourless” flavonols.
Keywords: Compartmentation; Cytoplasm; Flavonoids; Petals; Eustoma grandiflorum; Lisianthus; Lathyrus chrysanthus; Yellow colouration; Flavonoid-protein binding;
Probing the role of calmodulin in Al toxicity in maize by Renato A Jorge; Marcelo Menossi; Paulo Arruda (415-422).
The role of calmodulin on Al toxicity was studied in two maize (Zea mays L.) inbred lines, Cat 100-6 (Al-tolerant) and S 1587-17 (Al-sensitive). Increasing levels of Al induced the release of malate at similar rate by roots of both genotypes, while the exudation of citrate, a stronger Al-binding compound, was 3.5 times higher in Cat 100-6 seedlings exposed to 16.2×10−6 Al3+ activity. The calmodulin inhibitor trifluoperazine significantly reduced the root growth in both genotypes, mimicking the main effect of Al. However, when Cat 100-6 and S 1587-17 seedlings were challenged with Al in conjunction with trifluoperazine, no further reduction in root growth or any other effect of Al toxicity was observed. The rate of Al-induced citrate exudation by both genotypes was not affected by treatment with trifluoperazine or calmidazolium, another calmodulin inhibitor. The Al3+ interaction with cytoplasmic CaM was estimated using models for the binding of Al3+ and Mg2+ with CaM and physiological concentrations of citrate, CaM, InsP3, ATP, ADP, Al3+ and Mg2+. In this simulation, Al3+ associated with citrate and InsP3, but not with CaM. We conclude that calmodulin is not relevant to the physiological processes leading to the Al tolerance in maize, nor is it a primary target for Al toxicity.The role of calmodulin (CaM) in Al toxicity was analyzed in two maize (Zea mays L.) inbred lines by measuring the Al-induced rate of citrate exudation of the intact roots and by using models for the binding of Al3+ and Mg2+ to CaM.
Keywords: Aluminum toxicity; Calmodulin; Maize; Zea mays; Gramineae; Organic acids; Tolerance;
Soybean sterol composition and utilization by Phytophthora sojae by Julie A. Marshall; Allen L. Dennis; Toshihiro Kumazawa; Ann M. Haynes; W.David Nes (423-428).
The sterol fraction of Glycine max (soybean) was found to contain a mixture of 13 major sterols which differed dramatically in composition between seeds and shoots. Typical C4-desmethyl Δ5-sterols, including sitosterol, predominate the sterol mixture of shoots, whereas C4-methyl sterol intermediates, cycloartenol and 24(28)-methylene cycloartanol, accumulate in seeds. The significance of modified sterol profile of shoot compared to seed was relevant to the physiology of Phytophthora sojae, a phytopathogen of soybean shown to be auxotrophic for sterol. Sterols native to the host plant containing a C4-methyl group, such as cycloartenol, were not utilized by the fungus. Alternatively, all Δ5-sterols added to the culture media of P. sojae supported normal growth and promoted viable oospore production. The results demonstrate the importance of sterols in plant–fungal interactions and offer the possibility of bioengineering the phytosterol pathway for resistance to phytopathogens which scavenge specific sterols of the host plant to complete the life cycle.The sterol composition of Glycine max (soybean) seeds and shoots have been determined. The physiological importance of these phytosterols, particularly cycloartenol (1) and sitosterol (8), in soybean-Phytophthora interactions are reported.
Keywords: Soybean; Glycine max; Leguminosae; Host-pathogen interactions; Oomycetes; Phytophthora sojae; Sitosterol; Sterol;
Fragrance chemistry and pollinator affinities in Nyctaginaceae by Rachel A. Levin; Robert A. Raguso; Lucinda A. McDade (429-440).
We present results of dynamic head-space collections and GC–MS analyses of floral and vegetative fragrances for 20 species in three genera of Nyctaginaceae: Acleisanthes, Mirabilis and Selinocarpus. Most of the species included in this study are either hawkmoth or noctuid moth-pollinated. A wide variety of compounds were observed, including mono- and sesquiterpenoids, aromatics (both benzenoids and phenylpropanoids), aliphatic compounds, lactones, and nitrogen-bearing compounds. Intraspecific variation in fragrance profiles was significantly lower than interspecific variation. Each species had a unique blend of volatiles, and the fragrance of many species contained species-specific compounds. The fragrance profiles presented here are generally consistent with previous studies of fragrance in a variety of moth-pollinated angiosperms.A wide variety of compounds including mono- and sesquiterpenoids, aromatics, aliphatic compounds, lactones, and nitrogen-bearing compounds were detected in the floral and vegetative fragrances of 20 Nyctaginaceae species.
Keywords: Acleisanthes; Mirabilis; Selinocarpus; Nyctaginaceae; Four o'clock; Floral fragrance; Pollination; Hawkmoths;
Isolation, characterization, and systematic significance of 2-pyrone-4,6-dicarboxylic acid in Rosaceae by Sonja Wilkes; Heinrich Glasl (441-449).
2-Pyrone-4,6-dicarboxylic acid was isolated from Potentilla anserina. Until now this substance was only found in bacteria and not in higher plants. By sterile cultivation it was verified that this compound is genuine also in plants. In addition the systematic relevance of 2-pyrone-4,6-dicarboxylic acid within the Rosaceae was tested. The compound seems to be a chemotaxonomic marker for the Rosoideae sensu stricto proposed by Morgan et al. (Morgan, D.R., Soltis, D.E., Robertson, K.R., 1994. Systematic and evolutionary implications of rbcL sequence variation in Rosaceae. American Journal of Botany 81, 890–903).The occurrence of 2-pyrone-4,6-dicarboxylic acid within the family Rosaceae is reported. The compound could be a chemotaxonomic marker for the Rosoideae sensu stricto proposed by Morgan et al. (Morgan, D.R., Soltis, D.E., Robertson, K.R., 1994. Systematic and evolutionary implications of rbcL sequence variation in Rosaceae. American Journal of Botany 81, 890–903).
Keywords: 2-Pyrone-4,6-dicarboxylic acid; Potentilla anserina L.; Potentilla recta L.; Rosaceae; Chemotaxonomy;
Betaine distribution in the Malvaceae by Gerald Blunden; Asmita V. Patel; Nigel J. Armstrong; John Gorham (451-454).
Aerial parts of 26 taxa, distributed in 18 genera and all 5 tribes of the Malvaceae have been examined for the presence of betaines. Glycinebetaine was obtained in high yield (0.5–4.6%, dry weight) from all the plants studied, except Abelmoschus moschatus, in extracts of which glycinebetaine was not detected. Trigonelline was recorded for 16 of the plants tested, but the yields were low (0.005–0.07%, dry weight). Roots and flowers of a few of the species were also examined for betaines. The same compounds as those found in the aerial parts were usually detected, but the glycinebetaine contents of the roots and flowers were considerably lower.Glycinebetaine (1) was isolated from 25 of the 26 taxa of Malvaceae examined and trigonelline (2) from 16. The species tested included examples from each of the 5 tribes of the family.
Keywords: Malvaceae; Betaines; Glycinebetaine; Trigonelline; Chemotaxonomy;
Calystegine distribution in some solanaceous species by Khalid Bekkouche; Youssef Daali; Samir Cherkaoui; Jean-Luc Veuthey; Philippe Christen (455-462).
The distribution of eight calystegines (A3, A5, B1, B2, B3, B4, C1 and N1) and their content was investigated by gas chromatography coupled to mass spectrometry (GC–MS) in Datura metel, Atropa belladonna, Hyoscyamus albus, Mandragora autumnalis, Solanum sodomaeum, Withania somnifera, Withania frutescens and Brunfelsia nitida. The most frequently encountered calystegines were A3, B1, B2 and B3, while distribution of N1 and C1 was more limited. In all the investigated samples, calystegines A5 and B4 were never detected. This report focuses for the first time on calystegines in Withania and Brunfelsia genera and in Mandragora autumnalis and Solanum sodomaeum species.Distribution and content of eight calystegines were studied in several solanaceous species by gas chromatography coupled to mass spectrometry.
Keywords: Atropa; Brunfelsia; Datura; Hyoscyamus; Mandragora; Solanum; Withania; Solanaceae; GC–MS; Calystegines;
Semisynthetic derivatives of ent-kauranes and their antifeedant activity by Maurizio Bruno; Sergio Rosselli; Ivana Pibiri; Franco Piozzi; Maria Luisa Bondı̀; Monique S.J Simmonds (463-474).
Chemical modification of functional groups on linearol yielded several ent-kaurane derivatives. These compounds were tested for their antifeedant activity against larvae of Spodoptera littoralis. Although linearol did not influence the feeding behaviour of larvae, some of its derivatives showed significant antifeedant activity.Synthetic modifications of linearol furnished several derivatives, which, in some cases, showed a significant antifeedant activity.
Keywords: Lamiaceae; ent-Kaurane; Diterpenoids; Linearol; Chemical modifications; Spodoptera littoralis; Antifeedant;
Dihydroagarofuran alkaloid and triterpenes from Maytenus heterophylla and Maytenus arbutifolia by Khaled Y. Orabi; Saleh I. Al-Qasoumi; Mahmoud M. El-Olemy; Jaber S. Mossa; Ilias Muhammad (475-480).
The antimicrobially active EtOH extracts of Maytenus heterophylla yielded a new dihydroagarofuran alkaloid,1β-acetoxy-9α-benzoyloxy-2β,6α-dinicotinoyloxy-β-dihydroagarofuran, together with the known compounds β-amyrin, maytenfolic acid, 3α-hydroxy-2-oxofriedelane-20α-carboxylic acid, lup-20(29)-ene-1β,3β-diol, (−)-4′-methylepigallocatechin, and (−)-epicatechin. In addition, β-amyrin, (−)-epicatechin and (−)-4′-methylepigallocatechin were isolated from Maytenus arbutifolia. The structure elucidation of the isolated compounds was based primarily on 1D and 2D NMR analyses, including HMQC, HMBC, and NOESY correlations. Maytenfolic acid showed moderate antimicrobial activity by inhibiting the growth of Candida albicans, Cryptococcus neoformans, Staphylococcus aureus and Pseudomonas aeruginosa.The aerial parts of the Saudi native plant Maytenus heterophylla afforded a dihydroagarofuran alkaloid (1). In addition, both M. heterophylla and M. arbutifolia yielded other known triterpenes.
Keywords: Maytenus heterophylla; Maytenus arbutifolia; Celastraceae; Alkaloid; Dihydroagarofuran; Heterophylline; Triterpenes; Antimicrobial;
Germacrenes from fresh costus roots by Jan-Willem de Kraker; Maurice C.R Franssen; Aede de Groot; Toshiro Shibata; Harro J Bouwmeester (481-487).
Four germacrenes, previously shown to be intermediates in sesquiterpene lactone biosynthesis, were isolated from fresh costus roots (Saussurea lappa). The structures of (+)-germacrene A, germacra-1(10),4,11(13)-trien-12-ol, germacra-1(10),4,11(13)-trien-12-al, and germacra-1(10),4,11(13)-trien-12-oic acid were deduced by a combination of spectral data and chemical transformations. Heating of these compounds yields (−)-β-elemene, (−)-elema-1,3,11(13)-trien-12-ol, (−)-elema-1,3,11(13)-trien-12-al, and elema-1,3,11(13)-trien-12-oic acid respectively, in addition to small amounts of their diastereomers. Acid induced cyclisation of the germacrenes yields selinene, costol, costal, and costic acid respectively. It is highly probable that the elemenes reported in literature for costus root oil are artefacts.Four germacrenes that were previously shown to be intermediates of sesquiterpene lactone biosynthesis were isolated from fresh costus roots. Heating of these compounds yields the corresponding elemenes; acid induced cyclisation yields the corresponding eudesmanes. It is highly probable that the elemenes present in costus root oil and dried costus roots are artefacts.
Keywords: Saussurea lappa; Asteraceae; Sesquiterpenes; Sesquiterpene lactone biosynthesis; Germacrenes; Elemenes; Eudesmanes;
Coexistence of chrysanthenone, filifolone and (Z)-isogeranic acid in hydrodistillates. Artefacts! by Nigist Asfaw; Hans J Storesund; Lars Skattebøl; Arne J Aasen (489-492).
Hydrodistilled oil from leaves of the Ethiopian plant Laggera tomentosa has been shown to contain (−)-chrysanthenone (5%), (−)/(+)-filifolone (92:8; 8%) and (Z)-isogeranic acid (8%)—all likely to be artefacts. The main constituent of the oil, (+)-chrysanthenone (53%), is believed to be the precursor undergoing thermal and solvolytic reactions during the hydrodistillation process.Hydrodistillation of (+)-chrysanthenone from the Ethiopian plant Laggera tomentosa has been shown to yield thermal and solvolytic products which shall not be confused with natural constituents.
Keywords: Laggera tomentosa; Asteraceae; Chrysanthenone; Filifolone; (Z)-Isogeranic acid; Hydrodistillation; Artefacts;
Acylated anthocyanidin 3-sophoroside-5-glucosides from Ajuga reptans flowers and the corresponding cell cultures by Norihiko Terahara; Alfons Callebaut; Riichiro Ohba; Tadahiro Nagata; Mayumi Ohnishi-Kameyama; Masahiro Suzuki (493-500).
Four anthocyanins from Ajuga reptans flowers and its cell cultures were isolated, and a fifth was also characterized by HPLC-mass spectrometry. By means of chemical and spectroscopic analyses, their structures were identified as delphinidin 3-(p-coumaroyl-feruloyl)sophoroside-5-malonylglucoside, delphinidin 3-(diferuloyl)sophoroside-5-malonylglucoside, and cyanidin 3-(di-p-coumaroyl)sophoroside-5-glucoside, respectively. The other two were tentatively identified as delphinidin 3-(diferuloyl)sophoroside-5-glucoside and cyanidin 3-(feruloyl-p-coumaroyl)sophoroside-5-malonylglucoside. In neutral aqueous solution, the crude extract from A. reptans flower cell cultures and the major anthocyanin cyanidin 3-(di-p-coumaroyl)sophoroside-5-malonylglucoside were more stable than cyanidin 3-glucoside, and also prevented more efficiently peroxidation than did the latter. A. reptans flower cell culture anthocyanins may have a potential as natural colorants for food utilities or other purposes.Three anthocyanins, delphinidin 3-(p-coumaroyl-feruloyl)sophoroside-5-malonylglucoside and delphinidin 3-(differuloyl)sophoroside-5-malonylglucoside from Ajuga reptans flowers, and cyanidin 3-(di-p-coumaroyl)sophoroside-5-glucoside from the cell cultures of Ajuga reptans flowers, were isolated.
Keywords: Ajuga reptans L.; Lamiaceae; Cell culture; Flavonoid; Anthocyanin; Acylated anthocyanidin 3-Sophoroside-5-glucosides; Stability; Antioxidative activity;
Isolation of solasodine and other steroidal alkaloids and sapogenins by direct hydrolysis-extraction of Solanum plants or glycosides therefrom by Martin Weissenberg (501-508).
Concomitant extraction and hydrolysis of Solanum steroidal glycoalkaloids in a two-phase system containing an aqueous mineral acid and an organic water immiscible solvent, and having a boiling point under 100oC, is described. It is essentially a “one-pot” process, combining direct acid hydrolysis of the glycosides in the plant material and in situ extraction of the released aglycones after alkali treatment, in a single step, the various ingredients being added simultaneously or sequentially, as required. Application of the process to fruits, leaves, and tissue cultures of Solanum khasianum Clarke plants, either fresh or in dried, finely ground form, using a two-phase aqueous hydrochloric acid-toluene system, proved to be very suitable for continuous production of pure solasodine which is a valuable raw steroid for the preparation of steroidal drugs. Pure Solanum glycoalkaloids were also prepared and hydrolysed accordingly. The process has analytical applications too, and could be extended in a general way to glycosides in other series for preparation of their related aglycones.A “one-pot” process combining concomitant hydrolysis and extraction of Solanum steroidal glycoalkaloids in a two-phase system which contains an aqueous mineral acid and an organic water-immiscible solvent, and its preparative and analytical applications, are described.
Keywords: Solanum spp; Solanaceae; Spirosolane and solanidane derivatives; Steroidal glycoalkaloids; Solamargine; Solasonine; β-Solamarine; Solaverbascine chacotrioside and solatrioside; Tomatine; Aglycones; Solasodine; Tomatidenol; Solaverbascine; Tomatidine; Solanidine; Plant glycosides; Two-phase acid hydrolysis;
Glycoside esters from lichens of central Asia by Tomáš Řezanka; Irene A Guschina (509-516).
Ten compounds isolated from the extract of the central Asian lichens comprised new glycosides and glycoside esters having 18R-hydroxy-dihydroalloprotolichesterinic, 18S-hydroxy-dihydroprotolichesterinic and 18S-hydroxy-neodihydroprotolichesterinic acids, as the aglycones and a saccharide moiety linked at C-18 and also at C-21 made by glucose, xylose or rhamnose. The structures were elucidated using extensive spectroscopic analysis (1D and 2D NMR, MS, IR, UV and ORD) and by biochemical methods.Ten compounds isolated from the central Asian lichens comprised glycoside esters having 18R-OH-dihydroalloprotolichesterinic, 18S-OH-dihydroprotolichesterinic and 18S-OH-neodihydroprotolichesterinic acids, as the aglycones and a saccharide moiety linked at C-18 and also at C-21 made by glucose, xylose or rhamnose. The structures were elucidated using spectroscopic analysis (1D and 2D NMR, MS, IR, UV and ORD) and by biochemical methods.
Keywords: Glycoside esters; Lichens of central Asia; NMR, MS, IR, ORD and UV spectra;
Halogenated metabolites with antibacterial activity from the Okinawan Laurencia species by Charles Santhanaraju Vairappan; Minoru Suzuki; Tsuyoshi Abe; Michio Masuda (517-523).
The chemical compositions of five species of the red algal genus Laurencia from coastal waters of Okinawa Prefecture, Japan, have been investigated. A halogenated C15 acetogenin, (12E)-lembyne-A, was isolated from L. mariannensis, and a halogenated sesquiterpene, (6R,9R,10S)-10-bromo-9-hydroxy-chamigra-2,7(14)-diene, was first found from L. majuscula as a naturally occurring compound. Laurencia nidifica yielded previously known laurinterol and isolaurinterol. Samples of L. cartilaginea and L. concreta afforded no halogenated metabolites. The structures of these halogenated metabolites as well as their antibacterial activity against some marine bacteria are reported.Halogenated C15 acetogenin, such as (12E)-lembyne-A was isolated from the red alga Laurencia mariannensis, and other species, all were analysed for their antibacterial properties.
Keywords: Laurencia; Rhodomelaceae; Red alga; Sesquiterpene; C15 acetogenin; Halogenated compound; Chemotaxonomy; Antibacterial activity;
Xyloglucan from the leaves of Hymenaea courbaril by Ana P Busato; Carem G Vargas-Rechia; Fany Reicher (525-531).
A fucosylated xyloglucan was isolated from the leaves of Hymenaea courbaril by alkaline extraction, followed by ethanol precipitation and ion-exchange chromatography. The isolated polysaccharide showed Glc:Xyl:Gal:Fuc in molar ratio of 8:5:2.5:1 and α D 25 +40.5°. Composition and linkage analyses, supported by NMR spectroscopic measurements, showed that the polysaccharide has a glucan backbone which is highly substituted at O-6 with d-xylopyranose residues, about a half of which are substituted at O-2 by d-galactopyranosyl units. Some of the galactose residues are further substituted by l-fucopyranose at O-2. The M r, as determined by HPSEC, was 49,500.A fucosylated xyloglucan was isolated from the leaves of Hymenaea courbaril. Its structure was determined by 13C NMR spectroscopic analysis and by chemical methods, and compared with that previously found in the seeds of the same species.
Keywords: Hymenaea courbaril; Caesalpiniaceae; Leaf polysaccharides; Cell wall; Hemicellulose; Fucosylated xyloglucan;
Basil. The genus Ocimum by Renée J Grayer (533).
Ginseng: The Genus Panax Medicinal and Aromatic Plants—Industrial Profiles by Geoffrey A Cordell (534).
Tea Tree—The Genus Melaleuca by Jürgen Reichling (534-535).