Constance Nozzolillo

Correlation of phenolic acid content of maize to resistance toSitophilus zeamais, the maize weevil, in CIMMYT'S collections.

The (E)-ferulic acid content of the grain of nine populations of land races of maize derived from CIMMYTs collections was found to be negatively correlated to susceptibility characteristics towards the maize weevilSitophilus zeamais. Correlation coefficients for six susceptibility parameters and (E)-ferulic acid content were significant and ranged from −0.58 to −0.79. A multiple regression analysis by the SAS forward procedure using the primary seed characteristics associated with susceptibility indicated that the ferulic acid content was the only significant factor in explaining variation in at least two susceptibility parameters: the Dobie index and adult preference. In 15 CIMMYT pools, correlations between four susceptibility parameters and (E)-ferulic acid content were also significant (−0.76 to −0.81). The results suggest that phenolic acid content is a leading indicator of grain resistance or susceptibility to insects and may represent a newly identified mechanism of resistance.

Anthocyanin and Anthocyanoplast Content of Cruciferous Seedlings Subjected to Mineral Nutrient Deficiencies

Summary Seedlings of red varieties of cabbage, cauliflower, kohl rabi, radish, and canola were grown hydroponically with complete nutrient, or with nutrient lacking nitrogen. (-N), phosphorus. (-P), or potassium. (-K). Generally anthocyanin content was increased and growth was reduced on -N and -P nutrients as compared to plants on complete or -K nutrients. Anthocyanoplasts were most prominent in April Red cabbage seedlings. Their numbers tended to increase under N starvation and to decrease under P and K starvation. This is a first report of the effect of environmental factors on anthocyanoplast numbers in intact plants.

Alfalfa Leaf Saponins and Insect Resistance

Dried alfalfa (Medicago sativa) leaf tissue incorporated in artificial diet to give a final concentration of 0.5 or 1.6 mg/g fresh weight of saponins significantly inhibited growth and development of larvae of the European corn borer (Ostrinia nubilalis). Saponin fractions isolated from root or shoot tissues of alfalfa also inhibited growth when incorporated at equivalent concentrations but had little effect on development. Root saponins were somewhat more harmful than shoot saponins.

Homology between rice glutelin and oat 12 S globulin

Abstract The rice glutelin fraction consists of a heterogeneous array of polypeptides wherein two subunit groups (19–22 kDa and 30–36 kDa) predominate. In the absence of a reducing agent, these subunit groups were found to be associated by disulfide linkage into molecules occurring between 50 and 62 kDa. The larger subunit group (30–36 kDa) was shown to display both molecular mass and charge heterogeneity and to possess relatively acidic p I values. The smaller subunit group (19–22 kDa) exhibited less heterogeneity and more basic p I values. All these characteristics are typical of oat 12 S globulin. Antibodies raised against purified oat 12 S globulin hybridized strongly to both subunit groups of rice glutelin upon Western blot analysis. The antibody also detected the glutelin subunits within the rice globulin fraction, indicating that they are partially soluble in saline solution. The low salt-solubility of rice glutelin is apparently related to extensive protein aggregation, bringing about the need for strong solvents for complete solubilization. Hence, rice glutelin, like oat 12 S globulin, is in fact a legumin-like protein.

High-Performance Liquid Chromatography Characterization and Identification of Antioxidant Polyphenols in Maple Syrup

Abstract Maple syrup of four grades (extra-light, light, medium, and dark) of the 2007 crop was provided by three local (St. Josephs Island, Ontario, Canada) producers. Twenty-four phenolic compounds were isolated from a medium-grade syrup and identified on the basis of spectral and chemical evidence. They were (a) benzoic acid and several hydroxylated and methoxylated derivatives (gallic acid, 1-O.-galloyl-β-d-glucose, γ-resorcylic acid); (b) cinnamic acid derivatives (p.-coumaric acid, 4-methoxycinnamic acid, caffeic acid, ferulic acid, sinapic acid, and the ester chlorogenic acid); (c) flavonoids, the flavanols catechin and epicatechin, and the flavonols kaempferol and its 3-O.-β-d-glucoside, 3-O.-β-d-galactoside, quercetin and its 3-O.-β-d-glucoside, 3-O.-β-L-rhamnoside and 3-O.-rhamnoglucoside (rutin). Traces obtained at 280 and 350 nm in HPLC runs of the ethyl acetate–soluble fractions of eight samples indicated the presence of many more phenolic substances, most at very low concentration with some varibilities in peak heights, but not in retention times, among the syrups. In view of the well-established antioxidant activity these substances possess, it is suggested that it is the complexity of the mixture rather than any one compound that may serve to counter the unhealthful presence of the high concentration of sugars in the syrup.

Total Solubilization of Groat Proteins in High Protein Oat (Avena sativa L. cv. Hinoat): Evidence that Glutelins are a Minor Component

Abstract The oat grain displays the protein of best nutritive value among the cereals. However, controversy still surrounds the basic delineation and quantification of its Osborne fractions. Water-soluble albumin, and alcohol-soluble prolamin levels are generally considered quite low in oat (approximately 10% each), but estimates for the salt-soluble globulin, and residual glutelin fractions vary considerably. Values ranging from 10% to 80% have previously been attributed to either of these two fractions. To clarify this situation, proteins from oat groats (cv. Hinoat) were extracted using eight solvents normally associated with cereal glutelin solubilization (i.e., acetic acid, pH 2.5 and 5.0; NaOH, pH 7.3, 9.2 and 12.1; 0.4% NaOH, 0.5% SDS, 0.5% borax; 7M urea, 1.0% 2-mercaptoethanol; 0.5% SDS, 0.6% 2-mercaptoethanol). Methods varied greatly in their efficiency to extract proteins from the oat flour (2-98%). The extracted proteins were compared to typical oat Osborne fractions by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The majority of extraction procedures displayed some capacity to solubilize the major globulin subunit polypeptides (molecular weights 20,000 to 25,000 and 33,000 to 43,000). Results indicated a low percentage of glutelins in oat and the possibility of globulins and prolamins being the only true seed storage protein fractions. The globulin fraction might actually contribute 70–80% of the total groat proteins.

Ethyl m-digallate from red maple, Acer rubrum L., as the major resistance factor to forest tent caterpillar, Malacosoma disstria Hbn.

An ethanolic extract of red maple (Acer rubrum L.) leaves (RME) applied to trembling aspen (Populus tremuloides Michx.) leaves reduced feeding in choice test assays with forest tent caterpillar larvae (Malacosoma disstria Hbn.) (FTC), whereas a trembling aspen foliage extract, similarly applied, stimulated feeding. Compounds isolated from the RME were gallic acid, methyl gallate, ethyl gallate, m-digallate, ethyl m-digallate, 1-O-galloyl-β-D-glucose, 1-O-galloyl-α-L-rhamnose, kaempferol 3-O-β-D-glucoside, kaempferol 3-O-β-D-galactoside, kaempferol 3-O-β-L-rhamnoside, kaempferol-3-O-rhamnoglucoside, quercetin 3-O-β-D-glucoside, quercetin 3-O-β-L-rhamnoside and quercetin 3-O-rhamnoglucoside, (−)-epicatechin, (+)-catechin and ellagic acid. All of the gallates, (−)-epicatechin, and kaempferol 3-O-β-L-rhamnoside deterred feeding on trembling aspen leaf disks when applied at 0.28 mg/cm2. The two digallates deterred feeding by 90% and were the most effective. HPLC analysis indicated that ethyl m-digallate is present in amounts 10–100 × higher in RME (∼2.5–250 mg/g) than any other compound. Thus, ethyl m-digallate appears to be the major compound protecting red maple from feeding by FTC, with a minor contribution from other gallates.

The effect of one flavone, two catechins and four flavonols on mortality and growth of the european corn borer (Ostrinia nubilalis Hubner)

Abstract Seven compounds incorporated into an artificial diet at concentrations of 1, 10 and 100 mg g −1 were evaluated for their effect on growth and mortality of the European corn borer Ostrinia nubilalis (Hubner). At all three concentrations the flavanone pinocembrin, two flavan-3-ols, catechin and epicatechin, and the flavonols, quercetin, rhamnetin, quercitrin and rutin significantly reduced the growth of larvae after only eight days of feeding. By day 18, only larvae fed pinocembrin had a survival rate in excess of 50% at all concentrations. Flavonols were the most toxic, ec 50 (effective concentration to reduce growth relative to controls by 50%) values evaluated on day 8 ranged from 0.17 to 7.4 mg g −1 ; estimated lc 50 (lethal concentration resulting in 50% larval mortality evaluated on day 18) values ranged from 0.16 to 12 mg g −1 . The results suggest the potential of flavonoids for reducing the growth and survivorship of the European corn borer.

Flavonoid variations in Avena species

Abstract Twenty-five Avena species were investigated for their flavonoids. The flavonoids identified were vitexin, isovitexin, vitexin 2″-rhamnoside, isovitexin 2″-arabinoside, isoswertisin 2″-rhamnoside, tricin 5-glucoside, tricin 7-glucoside and tricin 7-diglucoside. Chemosystematic relationships are discussed.

1-O-galloyl-α-l-rhamnose from Acer rubrum

Abstract Leaves of Acer rubrum L. afforded the novel 1-O-galloyl-α- l -rhamnose as well as 1-O-galloyl-β- d -glucose; gallic acid; methyl gallate; ethyl gallate; m-digallate and ethyl digallate. Their structures were established on the basis of spectral and chemical evidence.