Showing papers in "Phytochemistry in 1981"
TL;DR: In this paper, the authors present a mathematical model to predict the overall isotope discrimination in terms of diffusion, interconversion, incorporation, and respiration in C 3, C 4 and crassulacean acid metabolism (CAM) photosynthetic pathways.
Abstract: Plants with the C 3 , C 4 , and crassulacean acid metabolism (CAM) photosynthetic pathways show characteristically different discriminations against 13 C during photosynthesis. For each photosynthetic type, no more than slight variations are observed within or among species. CAM plants show large variations in isotope fractionation with temperature, but other plants do not. Different plant organs, subcellular fractions and metabolises can show widely varying isotopic compositions. The isotopic composition of respired carbon is often different from that of plant carbon, but it is not currently possible to describe this effect in detail. The principal components which will affect the overall isotope discrimination during photosynthesis are diffusion of CO 2 , interconversion of CO 2 and HCO − 3 , incorporation of CO 2 by phosphoenolpyruvate carboxylase or ribulose bisphosphate carboxylase, and respiration. Theisotope fractionations associated with these processes are summarized. Mathematical models are presented which permit prediction of the overall isotope discrimination in terms of these components. These models also permit a correlation of isotope fractionations with internal CO 2 concentrations. Analysis of existing data in terms of these models reveals that CO 2 incorporation in C 3 plants is limited principally by ribulose bisphosphate carboxylase, but CO 2 diffusion also contributes. In C 4 plants, carbon fixation is principally limited by the rate of CO 2 diffusion into the leaf. There is probably a small fractionation in C 4 plants due to ribulose bisphosphate carboxylase.
1,927 citations
TL;DR: A new type of higher plant alkaloid, 1,6,7,8-tetrahydroxyoctahydroindolizine, designated castanospermine, has been isolated from the toxic seeds of the Australian legume Castanospermum australe.
Abstract: A new type of higher plant alkaloid, 1,6,7,8-tetrahydroxyoctahydroindolizine, designated castanospermine, has been isolated from the toxic seeds of the Australian legume Castanospermum australe .
344 citations
TL;DR: Evaluation of data reveals a correlation in most cases between the occurrence of flavonoid aglycones, the presence of secretory structures and the production of other lipophilic plant products.
Abstract: Flavonoids are widely present in plants as water-soluble glycosides but the lipophilic free aglycones are far less abundant. The 462 flavonoids reported so far to be present in the free state and their plant sources are listed. Evaluation of these data reveals a correlation in most cases between the occurrence of flavonoid aglycones, the presence of secretory structures and the production of other lipophilic plant products. Their accumulation in some plant organs and in certain taxa is discussed. Special attention is given to their occurrence in materials deposited externally on leaves and buds.
316 citations
TL;DR: In this article, two phytoalexins were isolated as chromatographically homogeneous amorphous solids from UV-irradiated, dark-grown rice coleoptiles.
Abstract: Two phytoalexins were isolated as chromatographically homogeneous amorphous solids from UV-irradiated, dark-grown rice coleoptiles. From their mass and 1 H NMR spectra, the compounds were characterized as the known diterpenes, momilactones A and B. The same compounds were also produced in blast-infected, WL 28325-treated rice leaves. They appear to be the first clearly identified cereal phytoalexins.
175 citations
TL;DR: In this article, the chemical shift for C-9 in a range of substituted compounds is shown to be numerically related to the stereochemistry at C-8, which allows the determination of the configuration at this centre for most types of substitution patterns by calculation of the C- 9 shift using increments for each substituent.
Abstract: The 13 C NMR data of 51 iridoid glucosides or glucoside acetates are tabulated. The collection includes 20 pairs of C-6, C-7 or C-8 epimers. Three parameters in using the data for the configurational assignment of 6- O -substituents are given. The chemical shift for C-9 in a range of substituted compounds is shown to be numerically related to the stereochemistry at C-8. This allows the determination of the configuration at this centre for most types of substitution patterns by calculation of the C-9 shift using increments for each substituent. Such increments are given for 25 substituents in three different solvents. A method for simulation of spectra of unknown iridoid glucosides is presented. By this method, the structures of five novel iridoid glucosides have been elucidated, and that of tecomoside has been revised. The methods used to assign the configurations to C-6 and C-8 epimeric iridoid glucosides by 1 H NMR spectroscopy are discussed and a table with selected data is presented. It is suggested that the structures in the literature for ajugol and myoporoside should be interchanged. Consequently, Horeau's method has failed in these instances. Finally, the differences in the 13 C NMR spectra of pairs of C-6 and C-8 epimeric iridoid glucosides have been interpreted as originating from cis/trans -interactions.
172 citations
TL;DR: Most flavonoids, including a number of dihydrochalcones related to phloretin, showed strong deterrency at concentrations well within the range often found in plants, and flavanone and flavone glycosides showed weak feeding deterrency relative to their corresponding aglycones.
Abstract: A number of naturally occurring flavonoids have been tested for their feeding deterrent activity against two aphid species, Schizaphis graminum and Myzus persicae . Most flavonoids, including a number of dihydrochalcones related to phloretin, showed strong deterrency at concentrations well within the range often found in plants. Flavanone and flavone glycosides showed weak feeding deterrency relative to their corresponding aglycones. S. graminum and M. persicae responded similarly towards the compounds tested. The feeding deterrency of wheat extracts towards S. graminum was confined to the phenolic fraction, which included the flavone tricin. The more polar phenolic fraction showed the strongest feeding deterrency towards S. graminum.
148 citations
TL;DR: The mucilage isolated from Opuntia is shown to contain arabinose, galactose, Galacturonic acid, rhamnose and xylose It has a uronic acid content of ca 10% and a MW of 43 × 106.
Abstract: The mucilage isolated from Opuntia is shown to contain arabinose, galactose, galacturonic acid, rhamnose and xylose It has a uronic acid content of ca 10% and a MW of 43 × 106 It equilibrates to 175% of its dry wt at 100% relative humidity Its possible role in the physiology of the plant is discussed
136 citations
TL;DR: It is proposed that the distribution of aphids on leaves of different ages is regulated by the hydroxamic acid content, which is always higher in the younger leaves.
Abstract: The content of hydroxamic acids in wheat plants shows substantial variations between different species and cultivars (1.0–6.3 mmol/kg fr. wt). It also varies with the age of the plant and the organ assayed. The maximum concentration is reached by the fourth day in epicotyls and roots. The amount in leaves at different plant ages is always higher in the younger leaves. Based on feeding and infestation experiments, it is proposed that the distribution of aphids on leaves of different ages is regulated by the hydroxamic acid content.
128 citations
TL;DR: In this article, 14 depsipeptides have been isolated from the culture medium of a strain of Metarhizium anisopliae and five of them were identified as known destruxins A, B, C, D and desmethyldestruxin B.
Abstract: From the culture medium of a strain of Metarhizium anisopliae , 14 depsipeptides have been isolated. Five of them were identified as known destruxins A, B, C, D and desmethyldestruxin B. The structures of the new compounds, named destruxins E, A 1 , A 2 , B 1 , B 2 , C 2 , D 1 , D 2 and E 1 ,were established mainly from the mass spectral analysis of their corresponding open-chain derivatives.
127 citations
TL;DR: The evidence that light appears to be involved in ureide assimilation in green tissues suggests that different regulatory mechanisms may exist in plants compared with micro-organisms.
Abstract: The synthesis, transport and assimilation of the ureides, allantoin and allantoic acid, in higher plants is reviewed Evidence indicates that in nodulated legumes ureides are synthesized from products of N2-fixation via purine synthesis and degradation Their synthesis in other plants also appears to be via purine degradation but is dependent on the inorganic nitrogen source fed to the plant; greatest ureide production is associated with ammonium assimilation The use of ureides rather than amides for N-transport from the root to the shoot via the xylem stream results in an improved carbon economy of the plant Good evidence for the transport of ureides in the phloem is lacking for most species examined although it is assumed to be important, particularly in fruit and seed development Ureides are stored and assimilated mainly in the shoot The precise pathways, localization and regulation of ureide assimilation are poorly understood and require further investigation Similarities exist between the properties of the enzymes involved in ureide assimilation in higher plants and in micro-organisms However, the evidence that light appears to be involved in ureide assimilation in green tissues suggests that different regulatory mechanisms may exist in plants compared with micro-organisms The economically important legume crops such as soybeans, cowpeas and Phaseolus sp are all ureide producers To aid our understanding of the productivity of these plants knowledge of how ureide-N is converted into seed protein is essential
123 citations
TL;DR: This resistance to degradation shown by the cutin derived acids (α,ω-dibasic, ω-hydroxy and long-chain monobasic acids) relative to the cellular and wax derived lipids may allow these cutin components to be used as quantitative markers of A. marina in mangrove associated sediments.
Abstract: The component hydrocarbons, sterols, alcohols, monobasic, α,ω-dibasic and ω-hydroxy acids of the fresh hand decayed leaves and the pneumatophores of the mangrove Avicennia marina are reported in detail. From the quantitative comparisons which can be drawn, relative changes in the lipid classes occurring during leaf decay can be highlighted. These base-line data are important to our understanding of inputs to marine intertidal sediments. During leaf decay the only significant changes were a reduction in the total absolute concentrations of monobasic acids due largely to a decrease in concentration of the C 18 polyunsaturated fatty acids, and an enhancement of the concentrations of the long-chain monobasic acids, ω-hydroxy acids and α,ω-dibasic acids. This resistance to degradation shown by the cutin derived acids (α,ω-dibasic, ω-hydroxy and long-chain monobasic acids) relative to the cellular and wax derived lipids may allow these cutin components to be used as quantitative markers of A. marina in mangrove associated sediments.
TL;DR: The seed globulins of Lupinus albus were extracted and 12 ditterent proteins were separated: four of them correspond to vicilins and two to legumin.
Abstract: The seed globulins of Lupinus albus were extracted and 12 ditterent proteins were separated: four of them correspond to vicilins and two to legumin
TL;DR: Haematococcus pluvialis cultivated in a N-deficient medium produced astaxanthin (1 % of total carotenoids), the monoester (76 %) and diester (7 %) of astaxantin, β,β-carotene (1%)), an adonirubin ester (3 %), (3R,3′R,6′R)-lutein (7%), violaxanthins (2%), and neoxanthin(1%) as mentioned in this paper.
Abstract: Haematococcus pluvialis cultivated in a N-deficient medium produced astaxanthin (1 % of total carotenoids), the monoester (76 %) and diester (7 %) of astaxanthin, β,β-carotene (1 %), an adonirubin ester (3 %), (3R,3′R,6′R)-lutein (7 %), violaxanthin (2 %) and neoxanthin (1 %). The CD values of the mono- and diesters of astaxanthin, the HPLC properties of astaxanthin monoester further esterified with (−)-camphanic acid and the optical purity of astaxanthin [determined by HPLC analysis of the diester of(−)-camphanic acid] produced by saponification of the natural mono- and diesters of astaxanthin in the absence of oxygen showed that this green alga synthesizes pure (3S,3′S)-astaxanthin esters.
TL;DR: The exceptional colour stability near neutrality of the Zebrina anthocyanin is related both to a high value of the acidity constant and to the total absence of formation of the colourless pseudobase and chalcone.
Abstract: The exceptional colour stability near neutrality of the Zebrina anthocyanin is related both to a high value of the acidity constant and to the total absence of formation of the colourless pseudobase and chalcone. The aromatic residues of the acylated groups (caffeic and ferulic) probably interact with the positively charged pyrylium nucleus. This intramolecular effect prevents further addition of nucleophiles to the pyrylium ring; in particular, addition of water is largely disfavoured compared to ordinary anthocyanins.
TL;DR: Evidence of 3′: 5′-cyclic nucleotide phosphodiesterases in higher plants, together with adenylate cyclase, a specific cyclic AMP binding protein, and calmodulin means that plants possess all the necessary components for a functional cyclicAMP-regulated system.
Abstract: Despite the evidence in support, the extent of which is outlined in this review, the occurrence of cyclic AMP in tissues of higher plants has been doubted by a number of previous reviewers. Recent MS and other evidence vindicates earlier identification of an adenosine nucleotide from plant tissues as adenosine 3′:5′-cyclic monophosphate. The additional demonstration of 3′: 5′-cyclic nucleotide phosphodiesterases in higher plants, together with adenylate cyclase, a specific cyclic AMP binding protein, and calmodulin, means that plants possess all the necessary components for a functional cyclic AMP-regulated system. Whether such a system does function in plants is considered as are also the reported physiological effects of exogenously supplied cyclic AMP on plant tissues.
TL;DR: In this paper, mass spectral data on 105 pentacyclic triterpenoids have been collated and analysed from which it has been possible to identify base peaks which are characteristic of specific stereoskeletons.
Abstract: Mass spectral data on 105 pentacyclic triterpenoids have been collated and analysedFrom this analysis, it has been possible to identify base peaks which are characteristic of specific stereoskeletons
TL;DR: In this paper, the authors show that the presence of a 3-hydroxyl group in the flavonoid molecule has little effect on the complex-forming ability and the nature of the sugar substituent has no influence on the reaction.
Abstract: The complex formation of flavonoids with anthocyanins, resulting in increase in both absorbance and in a bathochromic shift of the visible absorption maximum of the latter, is based mainly on hydrogen bond formation between the carbonyl group of the anthocyanin anhydrobase and aromatic hydroxyl groups of the complex-forming flavonoids. The larger the number of hydroxyl groups in the flavonoid molecule, the stronger the complex formation. The presence of a 3-hydroxyl group in the flavonoid molecule has little effect on the complex-forming ability. The nature of the sugar substituent of the complex-forming flavonoid compound has no influence on the reaction. The 5-hydroxyl group of flavonoids is strongly bound by intramolecular hydrogen bond to the 4-carbonyl and does not participate in the complex formation. The most important hydroxyl group in the flavonoid molecule is the one in the 7-position. Unsaturation at C2C3 in the heterocyclic ring is an important factor for complex formation. Aromatic hydroxyl groups in the flavonoid system alone cannot account for all the complex-forming ability, suggesting additional involvement by electrostatic forces and configurational or steric effects.
TL;DR: The polyamines spermidine and spermine inhibited ethylene production induced by the application of 1-aminocyclopropane-1-carboxylic acid and they also reduced the endogenous content of this amino acid in the treated tissues.
Abstract: The polyamines putrescine, cadaverine, spermidine and spermine reduced the amount of ethylene produced by senescing petals of Tradescantia but they did not prevent anthocyanin leakage from these same petals. These polyamines also inhibited auxin-mediated ethylene production by etiolated soybean hypocotyls to less than 7 % of the control. The basic amino acids lysine and histidine reduced the amount of auxin-induced ethylene produced by soybean hypocotyls by ca 50 %. In the hypocotyls, methionine was unable to overcome the inhibition caused by the polyamines. The polyamines spermidine and spermine inhibited ethylene production induced by the application of 1-aminocyclopropane-1-carboxylic acid and they also reduced the endogenous content of this amino acid in the treated tissues.
TL;DR: Pratorinine is a new phenanthridone alkaloid and anhydrolycorin-7-one was known before only as a synthetic compound and the physiological significance of hippadine is appraised.
Abstract: From the bulbs of Crinum pratense, collected at flowering, lycorine, 1,2-diacetyllycorine, ambelline, narcissidine, and three phenanthridone alkaloids, viz. hippadine, pratorinine and anhydrolycorin-7-one, were isolated and characterized on the basis of comprehensive spectral analyses (UV, IR, 1H NMR, 13C NMR, MS, [α]D) and chemical evidence. Among the phenanthridone alkaloids (1–3, only the natural occurrence of hippadine was previously known. Pratorinine is a new phenanthridone alkaloid and anhydrolycorin-7-one was known before only as a synthetic compound. The physiological significance of hippadine is appraised.
TL;DR: Evidence is presented which shows that NH 3 assimilation in Chlamydomonas occurs exclusively via the glutamate synthase cycle in illuminated and darkened cells and those in which the internal level of NH 3 is elevated, indicating that glutamate dehydrogenase probably plays a catabolic rather than anabolic role in the N nutrition of the alga.
Abstract: Evidence is presented which shows that NH 3 assimilation in Chlamydomonas occurs exclusively via the glutamate synthase cycle in illuminated and darkened cells and those in which the internal level of NH 3 is elevated. This result indicates that glutamate dehydrogenase probably plays a catabolic rather than anabolic role in the N nutrition of the alga. Glutamine synthetase and glutamate dehydrogenase were characterized and their kinetic properties shown to be consistent with these proposals. It is suggested that reversible activity modulations of glutamine synthetase regulate the operation of the glutamate synthase cycle in the light but the availability of reductant and ATP limits its activity in darkened cells. The possible involvement of the two glutamate synthase enzymes in both light and dark assimilation is discussed.
TL;DR: From the rhizomes of Alpinia speciosa, a new dihydrochalcone, diHydroflavokawin B, has been isolated together with six known phenolic compounds and the chemotaxonomic significance of these findings is discussed briefly.
Abstract: From the rhizomes of Alpinia speciosa, a new dihydrochalcone, dihydroflavokawin B, has been isolated together with six known phenolic compounds. The chemotaxonomic significance of these findings is discussed briefly.
TL;DR: The complete amino acid sequence of one of the major wheat protein iso-inhibitors of α-amylase was determined from analysis of fragments and peptides derived from the protein by cleavage with cyanogen bromide and by digestion with trypsin, chymotrypsin , thermolysin and the Staphylococcus aureus V8 protease.
Abstract: The complete amino acid sequence of one of the major wheat protein iso-inhibitors of α-amylase was determined. The sequence was deduced from analysis of fragments and peptides derived from the protein by cleavage with cyanogen bromide and by digestion with trypsin, chymotrypsin, thermolysin and the Staphylococcus aureus V8 protease. The molecule consists of a single polypeptide chain of 123 residues. Both serine and alanine were found in position 65, and further minor examples of microheterogeneity were observed in four other residues.
TL;DR: Several new 4α-methyl sterols with unusual unsaturation in the Δ 8(14) or Δ 14 -positions, such as 4α,24 S -dimethyl-5α-cholest-8 (14)-en-3β-ol, 4αmethyl-24ξ-ethyl-methyl-5 α-choline-8(14)-EN-3 β-ol and 14-dehydrodinosterol, have been isolated from extracts of the cultured marine dinoflagellates Amphidinium carterae
Abstract: Several new 4α-methyl sterols with unusual unsaturation in the Δ 8(14) -or Δ 14 -positions, 4α,24 S -dimethyl-5α-cholest-8 (14)-en-3β-ol, 4α-methyl-24ξ-ethyl-5α-cholest-8(14)-en-3β-ol, 4α-methyl-24( Z )-ethylidene-5α-cholest-8(14)- en-3β-ol, 4α,23 (or 22),24ξ-trimethyl-5α-cholesta-8(14),22-dien-3β-ol, 4α,24 S (or 23ξ)-dimethyl-5α-cholest-14-en-3β-ol and 14-dehydrodinosterol, have been isolated from extracts of the cultured marine dinoflagellates Amphidinium carterae, A. corpulentum and Glenodinium sp. 4α-Methyl-24ξ-ethyl-5α-cholestan-3β-ol was isolated from the steryl ester fraction of Glenodinium sp. The structures of these new sterols are based upon extensive 360 MHz 1 H NMR and MS analyses.
TL;DR: In this article, potato cells were fractionated by successive extractions with water at 80°, 0.2 M (NH 4 ) 2 C 2 O 4 at 80, 1 M and 4 M KOH, to leave a residue of α-cellulose.
Abstract: Cell-wall material from potatoes was fractionated by successive extractions with water at 80°, 0.2 M (NH 4 ) 2 C 2 O 4 at 80°, 1 M and 4 M KOH, to leave a residue of α-cellulose. The compositions of the isolated carbohydrate polymers were determined by sugar and methylation analysis. From the 4M KOH-soluble fraction an arabinogalactoxyloglucan was isolated and (partially) characterized by methylation analysis of the undegraded polymer and partially degraded methylated polymer. Methylation analysis of the oligosaccharides produced on treatment of the xyloglucan with cellulase threw additional light on the structural features of the polysaccharide. The results show that the xyloglucan has a cellulosic backbone which is highly substituted at position 6 with xylopyranose residues, some of which, in turn, carry either arabinofuranose or galactopyranose residues, as a substituent on position 2. The significance of these results is discussed.
TL;DR: This is the first report of 2-allosylglucose as a disaccharide unit of flavonoid, and the related isoscutellarein glycoside is also present.
Abstract: A novel flavone glycoside has been obtained from the whole plant of Veronica filiformis and identified by means of 13 C NMR spectroscopy as isoscutellarein 4′-methyl ether 7- O -β-(6‴- O -acetyl-2″- O -allosylglucoside). The related isoscutellarein glycoside is also present. This is the first report of 2-allosylglucose as a disaccharide unit of flavonoids. 13 `C NMR data on some A-ring trioxygenated flavonoids are also presented.
TL;DR: In this article, the IR studies of four proanthocyanidin dimers and all four 4-(2′,4′,6′-trihydroxyphenyl) derivatives of the flavan monomer units of ProanthOCYCLIDIN were carried out.
Abstract: IR studies of four proanthocyanidin dimers and all four 4-(2′,4′,6′-trihydroxyphenyl) derivatives of the flavan monomer units of proanthocyanidin
TL;DR: Bioassay directed fractionation of the waxy fractions derived from the fruit of Amorpha fruticosa resulted in the isolation of amorfrutin A and B, active new antimicrobial agents, which were found to be new bibenzyl metabolites.
Abstract: Bioassay directed fractionation of the waxy fractions derived from the fruit of Amorpha fruticosa resulted in the isolation of amorfrutin A and B, active new antimicrobial agents. Spectroscopic studies, chemical degradation and synthesis showed them to be new bibenzyl metabolites.
TL;DR: The wood of Alnus japonica has been shown to contain a number of biarylheptanoids as well as other phenolics, including secoisolariciresinol diferulate, which may have biosynthetic significance.
Abstract: The wood of Alnus japonica has been shown to contain a number of biarylheptanoids as well as other phenolics, including secoisolariciresinol diferulate. The co-occurrence of cyclized biarylheptanoids with their corresponding acyclic biarylheptanoids has been demonstrated and this fact may have biosynthetic significance. The possible chemotaxonomic importance of biarylheptanoids in members of the Betulaceae is discussed. The isolation and identification of several steroids and triterpenoids are also described.
TL;DR: Isoformononetin, glyceollins I, II and 2-isopentenyl-3,6a,9-trihydroxypterocarpan (glyceocarpin) accumulated in soybean leaves after treatment with aqueous sodium iodoacetate or a cell suspension of the bacterium, Pseudomonas pisi.
Abstract: Isoformononetin, glyceollins I, II and 2-isopentenyl-3,6a,9-trihydroxypterocarpan (glyceocarpin) accumulated in soybean ( Glycine max ) leaves after treatment with aqueous sodium iodoacetate or a cell suspension of the bacterium, Pseudomonas pisi . These compounds were also accompanied by two previously unreported pterocarpans, glyceofuran its 9- O -methyl derivative. Glyceocarpin is described for the first time as a plant product.
TL;DR: Three phytoalexins were isolated from groundnut seeds which had been sliced and incubated for 48 hours at 25† as mentioned in this paper, and two were novel isoprenylated stilbene derivatives.
Abstract: Three phytoalexins were isolated from groundnut seeds which had been sliced and incubated for 48 hr at 25†. Two were novel isoprenylated stilbene der