Passicoccin: a sulphated cyanogenic glycoside from Passiflora coccinea

A novel cyclopentenoid cyanogenic glycoside (1-(6-O-β-D-rhamnopyranosyl-β-D-glucopyranosyloxy)-cyclopent-2-en-1-nitrile-4-sulphate) has been isolated from Passiflora coccinea. The structure was determined by means of the ¹H and ¹³C NMR spectrum of the sulphate and its corresponding acetate derivative. Identification of the sugar constituents was made by HPLC and TLC. Passicoccin is so far unique to subgenus Distephana and its presence here is evidence for a phylogenetic relationship between Distephana and subgenera Granadilla and Tacsonia.     

Proacaciberin,A cyanogenic glycoside from Acacia sieberiana var. Woodii

A new cyanogenic glycoside isolated from pods of Acacia sieberiana var. woodii has been shown by chemical and spectroscopic methods to be (2S)-2-[(6-O-α-l-arabinopyranosyl-β-d-glucopyranosyl)oxy]-3-methylbut-3-enenitrileo. Acid-catalysed hydrolysis of the glycoside afforded arabinose and proacacipetalin, and base-catalysed double-bond migration gave 2- [(6-O-α-l-arabinopyranosyl-β- d-glucopyranosyl)oxy ]-3-methylbut-2-enenitrile.     

Two cyanogenic glucosides,tetraphyllin B and epi-tetraphyllin B,from Adenia volkensii

Tetraphyllin B and its previously unknown epimer have been isolated from the Kenyan plant Adenia volkensii. The structures were established by their NMR spectra and by GLC.     

The major cyanogenic glycoside in thalictrum aquilegifolium

The isolation and structure elucidation of the third and major cyanogenic glycoside of T. aquilegifolium as (II) is described.     

Passibiflorin,epipassibiflorin and passitrifasciatin: cyclopentenoid cyanogenic glycosides from Passiflora

An epimeric mixture of two novel cyclopentenoid cyanogenic glycosides, passibiflorin [1-(6-O-β-D-rhamnopyranosyl-β-D-glucopyranosyloxy)-4-hydroxycyclopent-2-en-1-nitrile] and its C-1 epimer, epipassibiflorin, has been isolated from Passiflora biflora and P. talamancensis. The structures were determined by means of ¹H NMR and ¹³C NMR. Another novel cyclopentenoid cyanogenic glycoside, passitrifasciatin [1-(4-O-β-D-rhamnopyranosyl-β-D-glucopyranosyloxy)-4-hydroxycyclopent-2-en-1-nitrile] is described from Passiflora trifasciata. The structure was determined by means of ¹H NMR. The identification of the sugar moieties was made by HPLC and TLC. The isolation of a β-1 → 4 and a β-1 → 6-rhamnoglucoside of cyclopentenoid cyanogens from three species of subgenus Plectostemma of Passiflora suggests that diglycosides of this type are taxonomically diagnostic for the section.     

Short Report : The cyanogenic glycoside barterin from Barteria fistulosa is epitetraphyllin B

Reisolation of the cyanogenic glycoside of Barteria fistulosa demonstrates that the structure of barterin, previously reported from this plant, is identical with that of epitetraphyllin B.     

Sitosterol biosynthesis in Hordeum vulgare

Excised barley embryos cultured on a nutrient medium containing methionine-[CD₃] incorporated deuterium into the newly biosynthesized sterols. Two deuterium atoms were present in 24-methylenecycloartanol, 24-methylenelophenol and campesterol and a maximum of four deuterium atoms were incorporated into 24-ethylidenelophenol, stigmasterol and sitosterol. Mevalonic acid-[2-¹⁴C(4R)4-³H₁] was utilized by the barley embryos to give 28-isofucosterol with a ³H-¹⁴C atomic ratio of 3:5 and stigmasterol and sitosterol with a ³H-¹⁴C atomic ratio of 2:5. 24-Methylenelophenol and 24-ethylidenelophenol were isolated from barley seed and 24-ethylidenelophenol-[2,4-³H₃] was incorporated into sitosterol by barley seedlings. These results show that in the production of sitosterol a 24-ethylidenesterol intermediate is produced and it is suggested that this is isomerized to give a Δ^24,(25) sterol prior to reduction to the saturated C₂₉ sterol side chain.     

Structural elucidation and partial synthesis of 3-hydroxyheterodendrin,a cyanogenic glucoside from Acacia sieberiana var. woodii

A new cyanogenic glucoside, isolated from pods of Acacia sieberiana var. woodii, was shown to be (2R)-2- (β-d-glucopyranosyloxy)-3-hydroxy-3-methylbutanenitrile by spectroscopic and chemical methods. The absolute configuration of this glucoside was correlated with that of proacacipetalin by oxymercuration of the latter, followed by borohydride reduction of the product.     

Amine levels in mineral-deficient Hordeum vulgare leaves

In potassium-deficient barley leaves, on the basis of fresh weight, putrescine was 13·3-fold greater and in magnesium deficiency 3-8-fold greater than controls. Putrescine was found to be reduced in phosphorus (× 0·6), sulphur (× 0·5) and nitrogen (× 0·2) deficiencies and on substituting nitrate for ammonium (× 0·2). Calcium deficiency and high salt (KCl) increased putrescine by 1·5-fold. High KCl reduced spermidine levels (× 0·2) without a corresponding reduction in spermine levels. The agmatine content was enhanced in magnesium- (× 2·5) and potassium- (× 5) deficient plants, while the arginine was increased × 1·4 and × 2·0 respectively on a fresh weight basis. Compounds tentatively identified as diaminopropane and 1-(3-aminopropyl)pyrroline were increased significantly with high KCl and low calcium. No homospermidine or diaminodipropylamine could be detected in any of the extracts, but traces of cadaverine may be present.     

Lysine-rich proteins in high-lysine Hordeum vulgare grain

The salt-soluble proteins in barley grain selected for high-lysine content (Hiproly, CI 7115 and the mutants 29 and 86) and of a control (Carlsberg II) with normal lysine content, contain identical major proteins as determined by MW and electrophoretic mobility. The concentration of a protein group with a high lysine content varies significantly among the barleys examined. One protein, present in large amounts in Hiproly, is assumed to be partially responsible for the high-lysine character of Hiproly, CI 7115 and the mutants 29 and 86.     

Polyamine oxidation by enzymes from Hordeum vulgare and Pisum sativum seedlings

The properties of the amine oxidases of barley leaves and pea seedling cotyledons have been compared using a colorimetric assay in which the hydrogen p     

Tetraphyllin B and epitetraphyillin B sulphates: Novel cyanogenic glucosides from Passiflora caerulea and P. alato-caerulea

An epimeric mixture of tetraphyllin B-4-sulphate and epitetraphyllin B-4-sulphate was isolated from Passiflora caerulea and P. alato-caerulea.     

Total hemicelluloses from Hordeum vulgare plants at different stages of maturity

The changes in the composition of the total hemicelluloses of leaf and stem tissues of field-grown barley plants have been examined at different stages of maturation. In each plant the proportion of xylose residues in the total hemicellulose increases with tissue maturity, that of galactose varies little, and the proportions of arabinose, glucose and uronic acid residues decrease. The ratio of β(1 → 3) to β(1 → 4) linkages in the β-glucans decreases with tissue maturity and there is a decrease in the $\text{DP}$_n of these β-glucans.     

Sarmentosin epoxide,a new cyanogenic compound from Sedum cepaea

A new cyanogenic compound, sarmentosin epoxide, was isolated from the aerial parts of Sedum cepaea. Its structure was established mainly by ¹H     

Coordination between plant and apex development in Hordeum vulgare ssp. distichum

Developmental scales for cereals describe apex and plant morphology separately. In order to link crucial steps of internal and external development, in three varieties of Hordeum vulgare spp. distichum L., sown in autumn and in spring, we recorded plant, leaf and apex stage, following the scales of Zadoks, Haun, and Banerjee and Wienhues, the number of primordia, culm and spike length, and the final number of leaves and spikelets. Primordia initiation was coordinated with leaf appearance and the relative rate was constant for the initiation of productive primordia. The maximum number of primordia was achieved just before the first node became detectable, but development was completed only by those initiated before floret differentiation and internode distension started. The first spikelet was initiated when the third leaf tip became visible, and the last one when plants were at the pseudo stem erection stage and five leaves had still to appear.     

Metabolism of gramine in Hordeum vulgare plants: A time course study

Intact Hordeum vulgare plants quantitatively degrade [α-¹⁴C] gramine to ¹⁴CO₂.     

Physiologically based pharmacokinetic modeling of hydrogen cyanide in humans following the oral administration of potassium cyanide and cyanogenic glycosides from food

Abstract

Cyanogenic glycosides (CGs) are commonly found in some edible plants and seeds. After ingestion, CGs can release toxic hydrogen cyanide (HCN) in humans. At present, unfortunately, there is no tool capable of predicting the cyanide concentration in human blood and organs following oral administration of CG-containing food. The aim of this study was to develop a physiologically based pharmacokinetic (PBPK) model of cyanide following the ingestion of CG-containing food in humans. To develop this model, pharmacokinetic data concerning cyanide concentration levels in humans exposed to potassium cyanide (KCN) and CG-containing foods (persipan paste, linseed, cassava, and bitter apricot kernels) were obtained from published data. This study created a model structure consisting of four organ compartments including the lungs, kidneys, liver, and slowly perfused tissues by employing Berkeley Madonna software to extract three unknown parameters including the maximum velocity of rhodanese, the absorption rate constant, and the bioavailability for oral administration of KCN and the four CG-containing foods (equivalent a 6.8?mg dose of cyanide). The model was then validated by comparing the simulated results for the concentration-time courses of cyanide levels in venous blood with data from two clinical studies covering the oral administration of KCN and linseed at three other doses.     

Detection and identification of cyanogenic glucosides in six species of Acacia

The presence of prunasin in Acacia deanei ssp. paucijuga, sambunigrin in Acacia cunninghamii, and acacipetalin in Acacia giraffae has been established by both chromatographic and NMR spectral evidence. Mandelonitrile glucosides of unknown configuration in Acacia parramattensis and Acacia pulchella and (an) as yet unidentified glycoside(s) in Acacia farnesiana are also reported.