Craig S. Charron

The University of Tennessee Medical Center at Knoxville, Knoxville, Tennessee, United States

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Publications (12)12.4 Total impact

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    ABSTRACT: To study the efficacy of commercially available Echinacea supplements, solvent fractions from nine locally purchased supplements containing Echinacea were tested in a potato disc assay for their ability to suppress formation of crown-gall tumors, a process that resembles tumor formation in animal tissues. Acetone and ethanol fractions from two supplements inhibited tumor formation and water and ethanol fractions from a third supplement suppressed tumor formation. Comparison of the bio-assay results with the supplement ingredients, as listed on the supplement label, did not reveal any correlation between quantity and suppressive activity of the listed ingredients. These results are consistent with prior investigations that noted product labels were often inaccurate and that post-harvest handling practices can be deleterious to bioactive compounds contained in Echinacea.
    01/2007;
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    ABSTRACT: Dietary intake of certain carotenoids has been associated with reduced risks of specific cancers and chronic eye diseases. Kale (Brassica oleracea L. var. acephala D.C.) has been reported to contain the highest levels of the carotenoids lutein and -carotene among green leafy vegetable crops. Brassica vegetables also contain anti-carcinogenic glucosinolates (GS) and S-methyl-cysteine sulfoxide (MCSO) sulfur compounds responsible for flavor. In several experiments, we investigated the influence of S and Se fertility on: 1) elemental accumulation; 2) GS and MCSO production; and 3) the accumulation patterns of carotenoid pigments in the leaf tissues of kale. Plants were greenhouse grown using nutrient solution culture with a range of S and Se concentrations. Increasing S fertility increased S leaf content, but decreased Mg and Ca accumulation. Levels of GS and MSCO increased in response to increasing S in nutrient solution. However, accumulation of lutein and -carotene were unaffected by S treatment. Decreasing S and increasing Se fertility in kale production will decreases GS and MCSO compounds without affecting carotenoid pigments levels. Understanding the combined impact of fertility on flavor compounds and carotenoid pigments may help improve consumer acceptance of phytonutritionally-enhanced vegetable crops.
    01/2007;
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    ABSTRACT: Twelve isoflavones were detected by high-performance liquid chromatography in seeds of 17 soybean [Glycine max (L.) Merrill] cultivars grown at three locations. 6' '-O-Malonyldaidzin and 6' '-O-malonylgenistin together constituted 71-81% of total isoflavones, which ranged in concentration from 2038 to 9514 microg/g and averaged 5644 microg/g across locations and cultivars. The total as well as several individual isoflavones had a moderate negative correlation with oil across locations and cultivars. Six cultivars had a moderate or strong negative correlation of total isoflavones with oil. Five cultivars had a moderate or strong positive correlation of total isoflavones with protein. These results suggest that judicious selection of germplasm for soybean breeding may facilitate development of soybean lines with desirable isoflavone concentrations.
    Journal of Agricultural and Food Chemistry 10/2005; 53(18):7128-35. · 2.91 Impact Factor
  • Craig S Charron, Arnold M Saxton, Carl E Sams
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    ABSTRACT: Myrosinase catalyzes the hydrolysis of glucosinolates found in the Brassicaceae, generating a variety of bioactive reaction products that may aid in the prevention of some cancers and that are suppressive to soil-borne plant pathogens. Two cultivars each of broccoli (Brassica oleracea L var italica), Brussels sprouts (B oleracea var gemmifera), cabbage (B oleracea var capitata), cauliflower (B oleracea var botrytis), and kale (B oleracea var acephala) were grown during two fall seasons and two spring seasons to determine if myrosinase activity varied by season. Regression models that included mean temperature and photosynthetic photon flux (PPF) during the growing seasons showed that climatic variables explained seasonal differences for myrosinase activity. Activity-FW (FW = fresh weight; U g−1) and specific activity (U mg−1) were significantly (p ≤ 0.05) affected by season, botanical group and group × season. Activity-FW had a negative linear relationship with temperature, and a positive linear but negative quadratic relationship with PPF. Specific activity had a positive linear and a negative quadratic relationship with both temperature and PPF. Therefore the influence of climatic factors on myrosinase activity in Brassica species may affect the potential benefits of the glucosinolate–myrosinase system. Copyright © 2004 Society of Chemical Industry
    Journal of the Science of Food and Agriculture 02/2005; 85(4):682 - 690. · 1.76 Impact Factor
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    Craig S Charron, Arnold M Saxton, Carl E Sams
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    ABSTRACT: Two cultivars each of broccoli (Brassica oleracea L var italica), Brussels sprouts (B oleracea var gemmifera), cabbage (B oleracea var capitata), cauliflower (B oleracea var botrytis) and kale (B oleracea var acephala) were grown during two fall seasons and two spring seasons to determine whether significant seasonal effects on glucosinolate (GS) concentrations could be explained by mean temperature, photosynthetic photon flux (PPF) and daylength during the growing seasons. Concentrations of total GSs, indole GSs and glucoraphanin differed by genotype and season. Total GS concentrations at harvest had a negative linear but positive quadratic relationship with temperature and daylength over the 2 weeks preceding harvest and a positive linear but negative quadratic relationship with PPF over the same 2 weeks. The regression model for indole GS concentrations similarly varied with mean temperature, daylength and PPF over the 4 weeks prior to harvest. Glucoraphanin concentrations at harvest decreased linearly with mean PPF from transplanting to harvest and had a negative linear but positive quadratic relationship with daylength from transplanting to harvest. Because glucoraphanin and other GSs in cruciferous crops are important for cancer chemoprotection, climatic conditions should be considered when planning planting dates or when making breeding selections for GS concentration. Copyright © 2004 Society of Chemical Industry
    Journal of the Science of Food and Agriculture 02/2005; 85(4):671 - 681. · 1.76 Impact Factor
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    ABSTRACT: Selenium in soils can result in increased uptake of S and a reduction in glucosinolates in Brassica species. Rapid cycling B. oleracea plants were grown hydroponically in nutrient solution with Se treatments delivered as sodium selenate in concentrations of 0.0, 0.5, 0.75, 1.0 and 1.5 ppm. Elevated S treatments of 37 ppm sulfate and 37 ppm sulfate/ 0.75 ppm selenate were incorporated to compare with Se treatments. Se concentration in the nutrient solution was positively correlated with Se and S uptake in the plants. The S concentration of plants exposed to Se was equal to or greater than the S concentration of plants exposed to elevated S in the nutrient solution. In spite of higher S concentrations, there was a decrease in production of 5 of the 7 glucosinolates analyzed in Se enriched plants. Plants in elevated S treatments had higher glucosinolate production than Se treated plants. These results suggest that Se either up-regulates or prevents the down-regulation of S uptake in B. oleracea. In addition, Se's presence within the plant seems to have a negative impact on the production of certain glucosinolates despite adequate availability of S.
    01/2005;
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    ABSTRACT: ‘Golden Delicious’ apples (Malus×domestica Borkh.) were either untreated or pressure-infiltrated after harvest with 0, 1, 2, 3 or 4% CaCl2 solutions (w/v) and stored at 0 °C for up to 6 months. The chemical composition of the fruit cortical tissue and cell walls of the 2–4 mm layer under the epidermis was studied. Storage of untreated fruit resulted in a decrease in K, P, Mg, S and Suc content of the tissue, while Fru and Glc increased. In the cell wall, Ca, Mg and total polysaccharide content increased while S, P, total neutral sugar and protein content decreased. During storage, fruit infiltrated with 0% CaCl2 showed a decrease in total polysaccharide and uronic acid content while neutral sugar content increased. After 6 months, the 0% treated fruit had higher levels of total P, Na and S compared to the untreated fruit. These changes in the cell wall of both untreated and 0% treated fruit resulted in an overall decrease in cell wall content of the apple tissue during storage. Analyses of Ca-infiltrated tissue and cell wall characteristics showed an interaction between CaCl2 treatment and time in storage for total and cell wall-bound minerals, total neutral sugar (Glc, Ara, Gal and Rha), protein and cell wall content. CaCl2 infiltration resulted in an increase in both total and cell wall-bound Ca of the apple tissue during storage, with a maximum reached at 2% CaCl2 for fruit stored 4 or 6 months. Ca-infiltrated fruit had higher levels of total K and Na, cell wall-bound Mg, and reduced loss of Ara and Gal after 6 months storage compared to fruit treated with 0% CaCl2, resulting in reduced cell wall degradation of 2% CaCl2 treated fruit during storage. The major changes in the tissue and cell walls occurred after 6 months storage, indicating that this stage was critical for quality maintenance.
    Postharvest Biology and Technology 01/2003; · 2.45 Impact Factor
  • Craig S. Charron, Carl E. Sams, Craig H. Canaday
    Plant Disease - PLANT DIS. 01/2002; 86(6):629-632.
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    ABSTRACT: Glucosinolates (GSs) are S-containing compounds found in Brassica species and whose degradation products may provide protection against cancer. Sulphoraphane, a product of 4-methylsulphinylbutyl GS degradation, is a particularly potent inhibitor of anticarcinogenic detoxification enzymes. Selenium also has anticancer properties, and consumption of plants containing Se may be an effective way to increase dietary Se. Since plant uptake of Se and S is competitive, GS synthesis may be affected by Se fertilisation. The objective of this study was to determine how Se fertilisation of rapid-cycling B oleracea would affect Se and GS concentrations. Plants were grown in hydroponic solutions containing 0.0, 1.0, 2.0, 3.0, 6.0, 7.2 or 9.0 mg l-1 Na2SeO4. Mineral and glucosinolate concentrations were measured in shoots harvested just before anthesis. Total GSs decreased from 5.84 µmol g-1 (0.0 mg l-1 Na2SeO4) to 1.90 µmol g-1 (9.0 mg l-1Na2SeO4). Levels of 4-methylsulphinylbutyl GS decreased 90% when Na2SeO4 fertilisation was increased from 0 to 1 mg l-1, and remained low at higher Na2SeO4 concentrations. Shoot Se concentration was undetectable at 0.0 mg l-1 Na2SeO4 and increased significantly with Na2SeO4 fertilisation. Although B oleracea may not simultaneously deliver high levels of dietary 4-methylsulphinylbutyl GS and Se, levels of other GSs with anticarcinogenic benefits may be beneficial even with Se fertilisation.© 2001 Society of Chemical Industry
    Journal of the Science of Food and Agriculture 01/2001; 81(9). · 1.76 Impact Factor
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    ABSTRACT: Glucosinolates (GSs) are S-containing compounds found in Brassica species and whose degradation products may provide protection against cancer. Sulphoraphane, a product of 4-methylsulphinylbutyl GS degradation, is a particularly potent inhibitor of anticarcinogenic detoxification enzymes. Selenium also has anticancer properties, and consumption of plants containing Se may be an effective way to increase dietary Se. Since plant uptake of Se and S is competitive, GS synthesis may be affected by Se fertilisation. The objective of this study was to determine how Se fertilisation of rapid-cycling B oleracea would affect Se and GS concentrations. Plants were grown in hydroponic solutions containing 0.0, 1.0, 2.0, 3.0, 6.0, 7.2 or 9.0 mg l−1 Na2SeO4. Mineral and glucosinolate concentrations were measured in shoots harvested just before anthesis. Total GSs decreased from 5.84 µmol g−1 (0.0 mg l−1 Na2SeO4) to 1.90 µmol g−1 (9.0 mg l−1Na2SeO4). Levels of 4-methylsulphinylbutyl GS decreased 90% when Na2SeO4 fertilisation was increased from 0 to 1 mg l−1, and remained low at higher Na2SeO4 concentrations. Shoot Se concentration was undetectable at 0.0 mg l−1 Na2SeO4 and increased significantly with Na2SeO4 fertilisation. Although B oleracea may not simultaneously deliver high levels of dietary 4-methylsulphinylbutyl GS and Se, levels of other GSs with anticarcinogenic benefits may be beneficial even with Se fertilisation.
    Journal of the Science of Food and Agriculture 01/2001; · 1.76 Impact Factor
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    Andrew J. Price, Craig S. Charron, Arnold M. Saxton
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    ABSTRACT: A study was conducted to quantify volatiles generated from Indian mustard (Bras- sica juncea L. Czerniak) tissue incorporated into soils under controlled conditions. Mus- tard residues were incorporated into noncovered and covered soils that varied by texture, temperature, moisture, pH, or sterility (autoclaved or nonautoclaved). Sandy loam soil had 38% more allyl isothiocyanate (AITC) than clay loam soil. AITC concentration in 45 °C soil was 81% higher than in soil at 15 °C, and 56% higher in covered compared to noncovered treatments. The microbial catabolism of AITC was suggested by the result that AITC con- centration in autoclaved soils was over three times that measured in nonautoclaved soils. The highest AITC level detected (1.71 µmol·L -1 ) occurred in the autoclaved covered soil. Several factors also infl uenced CO2 evolution. At 30 or 45 °C, CO2 concentration was at least 64% higher than at 15°C. The covered soil had over twice the CO2 found in the noncovered soil, and the nonautoclaved soil treatment yielded twice the CO2 measured in the autoclaved soil. There were no main effect differences among soil moisture, soil pH, and soil texture treatments for CO2 concentrations. This information could be helpful in defi ning ideal soil conditions for fi eld scale experiments. Additionally, this study demonstrates a sampling technique for testing fumigation potential of biofumigation and solarization systems that may have the potential to replace methyl bromide.
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    Carl E. Sams, Craig S. Charron
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    ABSTRACT: One alternative approach to control of soilborne diseases is to exploit biotoxic chemicals present in plant tissue. The aldehydes (E)-2-hexenal, n-hexanal, and (Z)-3-hexenal, and the alcohol (Z)-3-hexenol suppressed the pathogens Botrytis cinerea, Rhizoctonia solani, Fusarium oxysporum, Didymella lycopersici, and Cladosporium fulvum (Urbasch, 1984). (E)-2-hexenal, hexanal, (Z)-3-hexenal, and (Z)-3-hexenol we commonly produced by crushed green plant material (Buttery, 1981). Other research has shown that macerated Brassica tissues release isothiocyanates (ITCs), particularly effective pesticidal plant chemicals. The incorporation of freshly chopped Brassica residues into soil is promising as a means of soilborne disease control. In our study, we tested several plant species for their biotoxicity to B. cinerea. Materials and Methods Experiment 1: A 5-mm diameter agar plug with B cinerea hyphae was transferred from a stock culture plate to the center of a petri dish containing fresh agar Ten g of freshly macerated leaf tissue was added to a 500-ml jar The agar plate with B cinerea hyphae was inverted, placed over the mouth of the jar, and scaled with Parafilm ®. This procedure was performed for 4 replications each of leaf material from Indian mustard, 'Florida Broadleaf mustard "Premium Crop' broccoli, 'Italian Green broccoli, 'Charmant' cabbage 'Florida Dutch' cabbage, 'Seven Top' turnip, 'Bin Scotch Curled' kale, upland cress, Michili Chinese cabbage, 'Long Island' Brussels sprouts, and a control treatment that contained no plant tissue. Plates were incubated for 4 days at 22 C in constant fight. After 4 days, the diameters of the B. cinerea colonies were measured, and calculated as a percentage of the colony diameters in the control jars. Experiment 2: The procedure for Experiment I was followed using leaf tissue from Indian mustard, 'Premium Crop' broccoli, Michili Chinese cabbage, 'Celebrity' tomato, and 'Chandler' strawberry. B. cinerea diameters were measured daily for 4 days.