QUALITATIVE AND QUANTITATIVE DETERMINATION OF THE WHEAT LEAF CARBOHYDRATES

1950 ◽  
Vol 28c (6) ◽  
pp. 754-779 ◽  
Author(s):  
D. W. A. Roberts

The nonreducing sugar in wheat leaves is probably entirely sucrose. It is the only abundant sugar. Free reducing sugars are absent, or almost absent from wheat leaves grown under the conditions described. The reducing power in the cleared alcoholic extracts of the leaves is, at least, partly due to degradation products of ascorbic acid. Other nonsugar reducing substances also are apparently present. The alcohol insoluble residue from wheat leaves contains little or no fructosan, dextrin, or starch at the two and one-half week old stage. Satisfactory methods for extracting and determining the sucrose are described. The following methods gave satisfactory results with wheat leaf extracts: the reducing power methods of Hanes and Somogyi after acid or preferably invertase hydrolysis, Ost's solution for fructose residues, the method of Neuberg and Strauss, the colorimetric resorcinol method. The latter method gives only approximate values for fructose residues unless the sugar concentration is high; the method is then fairly reliable. The following methods did not give satisfactory results: Hanes and Somogyi methods for free reducing sugars initially present in the extract, the hypoiodite titration for aldose sugars, and Sieben's method for fructose determination.

1956 ◽  
Vol 34 (6) ◽  
pp. 905-926 ◽  
Author(s):  
E. R. Waygood ◽  
Ann Oaks ◽  
G. A. Maclachlan

Dialyzed wheat leaf extracts, catalase, and horse-radish peroxidase catalyze the decarboxylation and oxidation of indoleacetic acid at pH 5.0–6.0 in the presence of critical concentrations of manganese and monohydric phenols or resorcinol. The equivalent of 1 mole of carbon dioxide is liberated and 1 mole of oxygen consumed per mole of substrate. Manganic ions formed by a phenol–peroxidase–peroxide system initiate the decarboxylation and oxidation. A naturally occurring ether soluble factor from wheat leaves, and maleic hydrazide, can substitute for the active phenols. Catechol, hydroquinone, pyrogallol, seopoletin, and riboflavin, etc. competitively inhibit the oxidation. The nature of the active peroxide is discussed and a reaction sequence involving an organic peroxide or radical rather than hydrogen peroxide is submitted as being a possibility.


1954 ◽  
Vol 32 (2) ◽  
pp. 186-194 ◽  
Author(s):  
G. A. Adams

Crude hemicellulose of mature wheat leaves has been prepared by alkaline extraction of leaf holocellulose. Purification by repeated complexing with Fehling′s solution yielded a polyuronide hemicellulose [Formula: see text] composed of D-xylose (88.5%), L-arabinose (6.90%), and uronic acid anhydride (5.27%). Methylation studies indicated a molecular structure comprising a main xylan chain of 30 an-hydro- D-xylose residues to which three L-arabinose residues and one D-glucuronic acid unit were attached as side chains by glycosidic linkages. Periodate oxidation data supported the proposed structure and the yield of formic acid indicated a molecule containing approximately 32 sugar residues. Estimations of the degree of polymerization of the molecule by measurements of viscosity and reducing power agreed with the foregoing values. The structure of the hemicellulose closely resembled that of one isolated previously from wheat straw.


1953 ◽  
Vol 31 (1) ◽  
pp. 75-80 ◽  
Author(s):  
G. M. Ward

Crystalline sucrose has been isolated from cleared alcoholic extracts of mature wheat leaves by precipitation as the barium salt. The crystals were positively identified by melting point, X-ray diffraction analysis, and glucose–fructose ratio as well as by conventional analytical techniques. The evidence for the presence of sucrose in the wheat leaf has been corroborated by chromatographic analysis of leaf extracts. It is concluded that sucrose forms the bulk of the soluble sugar reserve of this tissue.


1991 ◽  
Vol 273 (3) ◽  
pp. 733-738 ◽  
Author(s):  
C MacKintosh ◽  
J Coggins ◽  
P Cohen

Protein phosphatases 1 and 2A (PP1 and PP2A) were identified in a variety of plant cells and found to be particulate or soluble depending on the species. In extracts prepared from oilseed-rape seeds these enzymes were associated with microsomes and more rapidly sedimenting fractions, whereas in wheat leaf extracts they were largely microsomal, the remainder being present in the soluble fraction. In pea leaf and carrot cell extracts PP1 and PP2A were almost entirely soluble. No PP1 or PP2A activity was associated with the membranes or stroma of chloroplasts in oilseed-rape seeds, pea leaves and wheat leaves. An Mg2(+)-dependent okadaic acid-insensitive protein phosphatase that resembles protein phosphatase 2C (PP2C) was detected in carrot cells, pea leaves and wheat leaves, but not in oilseed-rape seeds. In wheat leaf extracts PP2C was mostly present in the soluble fraction, a different location from PP1 or PP2A. The rapid inactivation of the cytosolic enzyme quinate dehydrogenase (QDH) in a fraction prepared from light-grown carrot cells was completely blocked by either okadaic acid or microcystin (two potent and specific inhibitors of PP1 and PP2A), whereas inhibitor 2 (a specific inhibitor of PP1) inhibited inactivation by only about 10%. Addition of the purified PP2A catalytic subunit from mammalian skeletal muscle increased the rate of QDH inactivation, whereas addition of mammalian PP1 did not. It is concluded that PP2A is the major enzyme responsible for dephosphorylating (inactivating) QDH in carrot cells. These observations indicate that okadaic acid and microcystin may be useful for identifying other plant processes that are controlled by phosphorylation/dephosphorylation mechanisms. Okadaic acid did not prevent the rapid inactivation of phosphoribulokinase or activation of glucose-6-phosphate dehydrogenase in a fraction prepared from light-grown pea leaves, and addition of the purified catalytic subunits of PP1 and PP2A did not accelerate either process. These observations, in conjunction with the absence of PP1 and PP2A activity in chloroplasts, suggest that these phosphatases are not involved in the regulation of chloroplast metabolism.


2014 ◽  
Vol 81 (1) ◽  
pp. 432-440 ◽  
Author(s):  
T. Sotelo ◽  
M. Lema ◽  
P. Soengas ◽  
M. E. Cartea ◽  
P. Velasco

ABSTRACTGlucosinolates (GSLs) are secondary metabolites found inBrassicavegetables that confer on them resistance against pests and diseases. Both GSLs and glucosinolate hydrolysis products (GHPs) have shown positive effects in reducing soil pathogens. Information about theirin vitrobiocide effects is scarce, but previous studies have shown sinigrin GSLs and their associated allyl isothiocyanate (AITC) to be soil biocides. The objective of this work was to evaluate the biocide effects of 17 GSLs and GHPs and of leaf methanolic extracts of different GSL-enrichedBrassicacrops on suppressingin vitrogrowth of two bacterial (Xanthomonas campestrispv. campestris andPseudomonas syringaepv. maculicola) and two fungal (AlternariabrassicaeandSclerotiniascletoriorum)Brassicapathogens. GSLs, GHPs, and methanolic leaf extracts inhibited the development of the pathogens tested compared to the control, and the effect was dose dependent. Furthermore, the biocide effects of the different compounds studied were dependent on the species and race of the pathogen. These results indicate that GSLs and their GHPs, as well as extracts of differentBrassicaspecies, have potential to inhibit pathogen growth and offer new opportunities to study the use ofBrassicacrops in biofumigation for the control of multiple diseases.


1967 ◽  
Vol 45 (11) ◽  
pp. 2137-2153 ◽  
Author(s):  
A. Fuchs ◽  
R. Rohringer ◽  
D. J. Samborski

Wheat leaves infected with stem rust, especially those of susceptible plants, contained more phenylalanine and tyrosine than healthy leaves. The utilization of phenylalanine was increased in both the susceptible and resistant reaction, but the utilization of tyrosine was increased only in the susceptible reaction. No evidence of interconversion of these amino acids was obtained.In n-butanol extracts, which contained glycosides, many constituents were labelled after feeding of L-phenylalanine-U-14C. Most of the n-butanol extractives from resistant-reacting leaves contained more label than those from susceptible-reacting leaves or from healthy leaves. However, one of the n-butanol extractives from susceptible-reacting leaves was 5–10 times as active as that isolated from the other tissues.With L-phenylalanine-U-14C and ferulate-U-14C as precursors, more activity was recovered in insoluble than in soluble esters (of ferulate and p-coumarate). With L-tyrosine-U-14C as precursor, the reverse was observed. After infection, the proportion of label in insoluble esters increased more in resistant leaves than it did in susceptible leaves, regardless of the precursor used.A major portion of the activity from these precursors was recovered in the insoluble residue that contained protein and other polymers. In the experiment with L-phenylalanine-U-14C, this residue was fractionated into protein and non-hydrolyzable material. Susceptible-reacting leaves contained equal amounts of activity in these fractions, while resistant-reacting leaves incorporated 2.5 times as much activity into the non-hydrolyzable material as into protein.


Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1191
Author(s):  
Mahak Majeed ◽  
Tanveer Bilal Pirzadah ◽  
Manzoor Ahmad Mir ◽  
Khalid Rehman Hakeem ◽  
Hesham F. Alharby ◽  
...  

The study aimed at evaluating the antioxidant profile of a medicinal epiphyte Viscum album L. harvested from three tree species, namely, Populus ciliata L, Ulmus villosa L., and Juglans regia L. The crude extracts were obtained with ethanol, methanol, and water and were evaluated for the total phenol content (TPC), total flavonoid content (TFC), and antioxidant activities using total reducing power (TRP), ferric reducing antioxidant power (FRAP), 1, 1-diphenyl 1-2-picryl-hydrazyl (DPPH), superoxide radical scavenging (SOR), and hydroxyl radical scavenging (•OH) assays. Our results showed that crude leaf extracts of plants harvested from the host Juglans regia L. exhibited higher yields of phytochemical constituents and noticeable antioxidative properties. The ethanolic leaf samples reported the highest phenols (13.46 ± 0.87 mg/g), flavonoids (2.38 ± 0.04 mg/g), FRAP (500.63 ± 12.58 μM Fe II/g DW), and DPPH (87.26% ± 0.30 mg/mL). Moreover, the highest values for TRP (4.24 ± 0.26 μg/mL), SOR (89.79% ± 0.73 mg/mL), and OH (67.16% ± 1.15 mg/mL) were obtained from aqueous leaf extracts. Further, Pearson correlation was used for quantifying the relationship between TPC, TFC, and antioxidant (FRAP, DPPH, SOR, OH) activities in Viscum album L. compared to their hosts. It was revealed that the epiphyte showed variation with the type of host plant and extracting solvent.


2016 ◽  
Vol 40 (1) ◽  
pp. 87-90
Author(s):  
Shamim Shamsi ◽  
Mst Selina Momtaz

Pestalotiopsis guepinii (Desm.) Stay an anamorphic fungus belonging to the class Celomycetes was isolated from Bipolaris leaf blight (BpLB) infected wheat leaf of two wheat varieties namely, Balaka and Saurab during the period of February to March, 2011. Association of Pestalotiopsis guepinii with wheat is a new record.Journal of Bangladesh Academy of Sciences, Vol. 40, No. 1, 87-90, 2016


2018 ◽  
Vol 7 (2) ◽  
pp. 191-198
Author(s):  
Shruti Gupta ◽  
◽  
Kishori G Apte ◽  
◽  

Sesbania grandiflora Linn. is perennial branching, small erect quick-growing short-lived soft-wooded tree, mostly cultivated in southeast Asian countries including India and grows primarily in hot, humid environments. This study investigated on phytochemical values- total phenolic flavonoid, tannins and saponin contents for Sesbania grandiflora leaf extracts. The total antioxidant capacity, DPPH, reducing power, superoxide scavenging and Iron chelating effects were examined by established methods. In-vitro cytotoxicity by brine shrimp bioassay. Both the extracts of Sesbania grandiflora were found to possess moderate to high amounts of phytochemical contents. The total phenolic, flavonoid and saponin contents were found significantly higher in EQSG whereas tannins were more in AQSG. The EQSG and AQSG possessed low IC50 for H2O2 Scavenging (32.9, 27.3µg/ml), TAC (35.6, 41.8µg/ml) and moderate for DPPH (114.9, 113µg/ml) and reducing power (176.3, 181.6µg/ml) respectively. The Brine shrimp lethality bioassay showed a significantly high LC50 value with EQSG (10313µg/ml) and AQSG (12773µg/ml) compared to cyclophosphamide (110µg/ml) in cytotoxic assay. The results evidenced the potential of Sesbania grandiflora Linn. as potent drug with antioxidant and cytotoxic activity and could be useful for preparation of nutraceuticals for pharmaceutical use in the treatment of various human diseases and its complications


2020 ◽  
Vol 10 (1) ◽  
pp. 68-74
Author(s):  
Sabrina Sanvee ◽  
Oudjaniyobi Simalou ◽  
Gneiny Whad Tchani ◽  
Hèzouwè Kagnou ◽  
Batomayena Bakoma ◽  
...  

Introduction: Bridelia ferruginea is a plant known for its antidiabetic properties. However, few studies on leaf extracts have induced anti-hyperglycemic activity on normal mice subjected to carbohydrate overload. The current study was designed to assess the effect of the leaf extracts’ fraction on fructose-induced diabetic mice. Methods: The in vitro ferric-reducing antioxidant power (FRAP) assay were carried out and the condensed tannins quantified. The vanillin-HCl method was used to characterize the condensed tannins. The antidiabetic effect on fructose-induced diabetic mice was evaluated for 28 days using a fructose-enriched fat diet approach. Results: The fraction confirmed the antioxidant activity with a reducing power of 800 μg/mL comparable to ascorbic acid at 200 μg/mL. The condensed tannins were estimated at 79.6 ± 3.4 mg catechin equivalent per gram of sample. Significant decreases in blood sugar levels of 6.25% at the 7th day, 11.04% at the 14th day, 12.61% at the 21th day, and 11.35% at the 28th day were obtained in mice treated with the extract dose of 200 mg/kg of body weight, compared to the positive control group. The decreases of 37.11% of triglycerides and 40.16% of total cholesterol were also obtained. Conclusion: The investigated fraction showed notable antidiabetic activity and might be a good candidate in the treatment of diabetes.


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