2007 Publications

Consumers are increasingly aware of diet related health problems and therefore demanding natural ingredients which are expected to be safe and health-promoting. Recently, number of studies on health benefits associated with citrus phytochemicals have been demonstrated. In the present study, an attempt has been made to isolate antioxidant fractions from two different citrus species such as Citron (Citrus medica) and blood orange (C. sinensis). Antioxidant fractions were extracted from mature, ripe fruits using five different solvents using a Soxhlet extractor. The total phenolic content of the extracts was determined by Folin–Ciocalteu method. MeOH:water (80:20) extract of citron and acetone extract of blood orange was found to contain maximum phenolics. The dried fractions were screened for their antioxidant activity potential using in vitro model systems such as 1, 1-diphenyl-2-picryl hydrazyl (DPPH), phosphomolybdenum method and as well as by the nitroblue tetrazolium (NBT) reduction test at different concentrations. The MeOH:water (80:20) fraction of citron showed highest radical scavenging activity 42.5%, 77.8% and 92.1% at 250, 500 and 1000 ppm, respectively, while MeOH:water (80:20) fraction of blood orange showed lowest DPPH radical scavenging activity at all the tested concentrations. Furthermore, all the fractions showed remarkable antioxidant capacity by the formation of phosphomolybdenum complex. In addition, superoxide radical scavenging activity was assayed using non-enzymatic (NADH/phenaxine methosulfate) superoxide generating system. All the extracts showed variable radical scavenging activity. The data obtained in the in vitro models clearly establish the antioxidant potency of citrus fruit extracts. However, comprehensive studies need to be conducted to ascertain the in vivo safety of such extracts in experimental animal models. To the best of our knowledge, this is the first report on antioxidant activity of citron and blood orange varieties of citrus fruits.

Six pecan cultivars were analyzed for their antioxidant capacity (AC), total phenolics (TP), condensed tannin (CT), HPLC phenolic profile, tocopherol and fatty acid composition. Kernels which included the outer brown testa or pellicle, and shells which is the hard cover that surrounds the kernel, were evaluated for each cultivar. Strong correlations were found in kernels between AC and TP for both DPPH (r2 = 0.98) and ACORAC (r2 = 0.75) antioxidant assays. ACORAC values ranged from 372 to 817 μmol trolox equivalents/g defatted kernel, corresponding to Desirable and Kanza cultivars, respectively. CT ranged from 23 to 47 mg catechin equivalents/g defatted kernel and TP from 62 to 106 mg of chlorogenic acid equivalents/g defatted kernel. After a consecutive basic-acid hydrolysis, gallic acid, ellagic acid, catechin and epicatechin were identified by HPLC. The TP, AC and CT were 6, 4.5 and 18 times higher, respectively, for shells compared to kernels. The presence of phenolic compounds with high antioxidant capacity in kernels and shells indicates pecans can be considered an important dietary source of antioxidants.

Wounding of fresh produce may elicit an increase in antioxidant capacity associated with wound-induced phenolic compounds. However, there have been no reports on the wounding response of different types of fresh produce. Changes in antioxidant capacity, total soluble phenolics, ascorbic acid, total carotenoids and total anthocyanins were evaluated after wounding in zucchini, white and red cabbage, iceberg lettuce, celery, carrot, parsnips, red radish, sweetpotato and potatoes. Phenolic changes ranged from a 26% decrease to an increase up to 191%, while antioxidant capacity changes ranged from a 51% decrease to an increase up to 442%. Reduced ascorbic acid decreased up to 82%, whereas the changes in anthocyanins and carotenoids were less evident. In general, the wound response was dependent on the type of tissue and influenced by the initial levels of reduced ascorbic acid and phenolic compounds. Wounding may increase the antioxidant content towards the development of selected healthier fresh-cut produce.

The ability to selectively measure serine enantiomer concentrations in rat brain microdialysate is essential during drug discovery to study the interaction of d-serine with the N-methyl-d-aspartate (NMDA) subtype of the glutamate receptor. NMDA receptor-stimulating agents, such as d-serine, have been shown to reduce the negative symptoms and cognitive dysfunction in individuals with schizophrenia when added to conventional or atypical antipsychotic drug regimens. In the work presented here, an LC/MS/MS assay was developed and validated to simultaneously measure d-serine and l-serine concentrations in rat brain microdialysate. Reverse phase chromatographic resolution of the enantiomers was obtained through derivatization with 1-fluoro-2,4-dinitrophenyl-5-l-alanine amide (Marfey's reagent). The assay was validated to determine concentrations over the range of 10–7500 ng/mL using electrospray ionization and multiple reaction monitoring (MRM). Both intra- and inter-day precision and accuracy were less than 16.5% (RE) and 7% (CV) for both analytes, respectively, and assay throughput was increased significantly relative to existing methodologies. Keywords: d-Serine; l-Serine; Marfey's reagent; LC/MS/MS; Schizophrenia

Chronic inflammation and colorectal cancer are closely linked. Although the overall mechanisms of inflammation-associated gastrointestinal carcinogenesis are complex, it is clear that antiinflammatory therapy is efficacious against neoplastic progression and malignant conversion. From a dietary perspective, fish oil containing (n-3) polyunsaturated fatty acids (PUFAs) has antiinflammatory properties, but for years the mechanism has remained obscure. Of relevance to the immune system in the intestine, we showed that (n-3) PUFA feeding alters the balance between CD4+ T-helper (Th1 and Th2) subsets by directly suppressing Th1 cell development (i.e., clonal expansion). This is noteworthy because Th1 cells mediate inflammatory diseases and resistance to intracellular pathogens or allergic hypersensitivity, and Th2 cells mediate resistance to extracellular pathogens. Therefore, any changes induced by (n-3) PUFAs in T-cell subset balance and function are important because the outcome is expected to suppress the development of autoimmune diseases and possibly the occurrence of colon cancer. Precisely how the immunomodulatory effects of (n-3) PUFAs influence inflammation-associated colonic tumor development is the subject of an ongoing investigation.

Consumers are increasingly aware of diet related health problems and therefore demanding natural ingredients which are expected to be safe and health-promoting. Recently, number of studies on health benefits associated with citrus phytochemicals have been demonstrated. In the present study, an attempt has been made to isolate antioxidant fractions from two different citrus species such as Citron (Citrus medica) and blood orange (C. sinensis). Antioxidant fractions were extracted from mature, ripe fruits using five different solvents using a Soxhlet extractor. The total phenolic content of the extracts was determined by Folin-Ciocalteu method. MeOH:water (80:20) extract of citron and acetone extract of blood orange was found to contain maximum phenolics. The dried fractions were screened for their antioxidant activity potential using in vitro model systems such as 1, 1-diphenyl-2-picryl hydrazyl (DPPH), phosphomolybdenum method and as well as by the nitroblue tetrazolium (NBT) reduction test at different concentrations. The MeOH:water (80:20) fraction of citron showed highest radical scavenging activity 42.5%, 77.8% and 92.1% at 250, 500 and 1000 ppm, respectively, while MeOH:water (80:20) fraction of blood orange showed lowest DPPH radical scavenging activity at all the tested concentrations. Furthermore, all the fractions showed remarkable antioxidant capacity by the formation of phosphomolybdenum complex. In addition, superoxide radical scavenging activity was assayed using non-enzymatic (NADH/phenaxine methosulfate) superoxide generating system. All the extracts showed variable radical scavenging activity. The data obtained in the in vitro models clearly establish the antioxidant potency of citrus fruit extracts. However, comprehensive studies need to be conducted to ascertain the in vivo safety of such extracts in experimental animal models. To the best of our knowledge, this is the first report on antioxidant activity of citron and blood orange varieties of citrus fruits.

Chronic inflammation and colorectal cancer are closely linked. Although the overall mechanisms of inflammation-associated gastrointestinal carcinogenesis are complex, it is clear that antiinflammatory therapy is efficacious against neoplastic progression and malignant conversion. From a dietary perspective, fish oil containing (n-3) polyunsaturated fatty acids (PUFAs) has antiinflammatory properties, but for years the mechanism has remained obscure. Of relevance to the immune system in the intestine, we showed that (n-3) PUFA feeding alters the balance between CD4 + T-helper (Th1 and Th2) subsets by directly suppressing Th1 cell development (i.e., clonal expansion). This is noteworthy because Th1 cells mediate inflammatory diseases and resistance to intracellular pathogens or allergic hypersensitivity, and Th2 cells mediate resistance to extracellular pathogens. Therefore, any changes induced by (n-3) PUFAs in T-cell subset balance and function are important because the outcome is expected to suppress the development of autoimmune diseases and possibly the occurrence of colon cancer. Precisely how the immunomodulatory effects of (n-3) PUFAs influence inflammation-associated colonic tumor development is the subject of an ongoing investigation.

Recent studies demonstrated that citrus limonoids and flavonoids possess numerous health promoting properties. In the present study, glucosides of limonoids and flavonoids were purified from citrus molasses and Limonoid aglycones from citrus seeds. Glucosides were separated on styrene (divinylbenzene), Q-sepharose resins with increasing concentration of sodium chloride. A pH-dependent cold precipitation was carried out for the isolation of naringin in large quantity. Major aglycones such as limonin and nomilin were isolated from seeds by direct crystallization and minor limonoids were purified by vacuum liquid hromatography. The structures of the isolated compounds were confirmed by NMR spectra. Individual limonoids were tested for 0-dealkylase and hydroxylase activities of human cytochrome P450 (CYP) isoenzymes such as CYPlA2, CYPlB1, CYP3A4 and CYP19, using ethoxyresorufin, methoxyresorufin and dibenzylffuorescein as substrates. Partial to high inhibition of CYPs was observed in dose-dependent assays. Significant (P < 0.001) reductions in enzyme activities were observed with purified compounds above 2 pnol. Kinetic analyses indicated that limonin glucoside inhibited CYPl9 competitively (IC 50, 7.1 m mol L -1), whereas Nomilinic acid glucoside inhibited it noncompetitively (IC50, 9.4~m ol-I). Nomilinic acid glucoside was the most potent limonoid, with an overall IC 59.of < l0 m mol, for all the enzymes tested. The differential inhibition of CYPs can be ascribed to structural variations ofthe limonoid nucleus.Limonoid inhibition of key CYPs involved in carcinogenesis supports growing evidence that citrus limonoids act as anticancer agents. (c) 2007 Society of Chemical Industry

The applicability of commercially available remote sensing instrumentation was evaluated for site-specific management of abiotic and biotic stress on cotton (Gossypium birsutum L.) grown under a center pivot low energy precision application (LEPA) irrigation system. This study study was conducted in a field where three irrigation regimes (100%, 75%, and 50% ETc) were imposed on areas of Phymatorichum (root rot) with the specific objectives to (1) examine commercial remote sensing instrumentation for locating areas showing biotic and abiotic stress symptomology in a cotton field, (2) compare data obtained from commercial aerial infrared photography to the collected by infrared transducers (IRTs) mounted on a center pivot, (3) evaluate canopy temperature changes between irrigation regimes and their relationship to lint yield with IRTs and/or IR photography, and (4) explore the use of deficit irrigation and the use of crop coefficients for irrigation scheduling. Pivot-mounted IRTs and an IR camera were abale to differentiate water stress among irrigation regimes. The IR camera distinguished between biotic (root rot) and abiotic (drought) stress with the assistance of ground truthing. The 50% ETc regime had significantly higher canopy temperatures than the other two regimes, which was reflected in significantly lower lint yields when compared to the 75% and 100% ETc regimes. Deficit irrigation down to 75% ETc had no impact on lint yield, indicating that water savings were possible without reducing yield.

Six pecan cultivars were analyzed for their antioxidant capacity (AC), total phenolics (TP), condensed tannin (CT), HPLC phenolic profile, tocopherol and fatty acid composition. Kernels which included the outer brown testa or pellicle, and shells which is the hard cover that surrounds the kernel, were evaluated for each cultivar. Strong correlations were found in kernels between AC and TP for both DPPH (r 2 = 0.98) and AC ORAC (r 2 = 0.75) antioxidant assays. AC ORAC values ranged from 372 to 817 μmol trolox equivalents/g defatted kernel, corresponding to Desirable and Kanza cultivars, respectively. CT ranged from 23 to 47 mg catechin equivalents/g defatted kernel and TP from 62 to 106 mg of chlorogenic acid equivalents/g defatted kernel. After a consecutive basic-acid hydrolysis, gallic acid, ellagic acid, catechin and epicatechin were identified by HPLC. The TP, AC and CT were 6, 4.5 and 18 times higher, respectively, for shells compared to kernels. The presence of phenolic compounds with high antioxidant capacity in kernels and shells indicates pecans can be considered an important dietary source of antioxidants.

Wounding of fresh produce may elicit an increase in antioxidant capacity associated with wound-induced phenolic compounds. However, there have been no reports on the wounding response of different types of fresh produce. Changes in antioxidant capacity, total soluble phenolics, ascorbic acid, total carotenoids and total anthocyanins were evaluated after wounding in zucchini, white and red cabbage, iceberg lettuce, celery, carrot, parsnips, red radish, sweetpotato and potatoes. Phenolic changes ranged from a 26% decrease to an increase up to 191%, while antioxidant capacity changes ranged from a 51% decrease to an increase up to 442%. Reduced ascorbic acid decreased up to 82%, whereas the changes in anthocyanins and carotenoids were less evident. In general, the wound response was dependent on the type of tissue and influenced by the initial levels of reduced ascorbic acid and phenolic compounds. Wounding may increase the antioxidant content towards the development of selected healthier fresh-cut produce.

Bulb color in onions (Allium cepa) is an important trait whose complex inheritance mechanism involves epistatic interactions among major color-related loci. Recent studies revealed that inactivation of dihydroflavonol4-reductase (DFR) in the anthocyanin synthesis pathway was responsible for the color differences between yellow and red onions, and two recessive alleles of the anthocyanidin synthase (ANS) gene were responsible for a pink bulb color, Based on mntatious in the recessive alleles of these two genes, PCRbased markers for allelic selection were developed. In this study, genotype analysis of onions from segregating populations was carried out using these PCR based markers. Segregating populations were derived from the cross between yellow and red onions. Five yellow and thirteen pink bulbs from one segregating breeding line were genotyped for the two genes. Four pink bulbs were heterozygous for the DFR gene, which explains the continuous segregation of yellow and pink colors in this line. Most pink onions were homozygous recessive for the ANS gene, except for two heterozygotes. This finding indicated that the homozygous recessive ANS gene was primarily responsible for the pink color in this line. The two pink onions, heterozygous for the ANS gene, were also heterozygous for the DFR gene, which indicated that the pink color was produced by incomplete dominance of a red color gene over that of yellow. One pink line and six other segregating breeding lines were also analyzed. The genotyping results matched perfectly with phenotypic color segregation. 'present address. B~otech Appllcat~on Team, Dongbu Advanced Research Inst~tute, Dongbu Hannong Chemicals Co , Ltd , Daejeon 305-708, Korea * To whom correspondence should be addressed Tel: 1-979-845-4203, Fax:I-979-842-4522 E-mail: I-pike@tamu.edu

Bulb Color is an important trait in onion (Allium cepa) breeding, but the lack of a method to quantify and color intensity is a large number of samples have hindered assessment of essential breeding parameters such as heritability. We developed a new method on digital imagining that allows facile quantification of red color intensity in a large number of samples. The brightness of dry skin in digital images was measured using the histogram function of Adobe? Photoshop?and showed highly significant correlation with both visual rating of red haploid (DH) lines and location effects on red color development. Three red DH lines, four pink F, hybrids, and three red commercial cultivars were grown at two locations with three replications. DH lines showed less variation in combined analysis of variance from two locations.

The applicability of commercially available remote sensing instrumentation was evaluated for site-specific management of abiotic and biotic stress on cotton (Gossypium birsutum L.) grown under a center pivot low energy precision application (LEPA) irrigation system. This study study was conducted in a field where three irrigation regimes (100%, 75%, and 50% ETc) were imposed on areas of Phymatorichum (root rot) with the specific objectives to (1) examine commercial remote sensing instrumentation for locating areas showing biotic and abiotic stress symptomology in a cotton field, (2) compare data obtained from commercial aerial infrared photography to the collected by infrared transducers (IRTs) mounted on a center pivot, (3) evaluate canopy temperature changes between irrigation regimes and their relationship to lint yield with IRTs and/or IR photography, and (4) explore the use of deficit irrigation and the use of crop coefficients for irrigation scheduling. Pivot-mounted IRTs and an IR camera were abale to differentiate water stress among irrigation regimes. The IR camera distinguished between biotic (root rot) and abiotic (drought) stress with the assistance of ground truthing. The 50% ETc regime had significantly higher canopy temperatures than the other two regimes, which was reflected in significantly lower lint yields when compared to the 75% and 100% ETc regimes. Deficit irrigation down to 75% ETc had no impact on lint yield, indicating that water savings were possible without reducing yield.

Six pecan cultivars were analyzed for their antioxidant capacity (AC), total phenolics (TP), condensed tannin (CT), HPLC phenolic profile, tocopherol and fatty acid composition. Kernels which included the outer brown testa or pellicle, and shells which is the hard cover that surrounds the kernel, were evaluated for each cultivar. Strong correlations were found in kernels between AC and TP for both DPPH (r2 = 0.98) and ACORAC (r2 = 0.75) antioxidant assays. ACORAC values ranged from 372 to 817 µmol trolox equivalents/g defatted kernel, corresponding to Desirable and Kanza cultivars, respectively. CT ranged from 23 to 47 mg catechin equivalents/g defatted kernel and TP from 62 to 106 mg of chlorogenic acid equivalents/g defatted kernel. After a consecutive basic-acid hydrolysis, gallic acid, ellagic acid, catechin and epicatechin were identified by HPLC. The TP, AC and CT were 6, 4.5 and 18 times higher, respectively, for shells compared to kernels. The presence of phenolic compounds with high antioxidant capacity in kernels and shells indicates pecans can be considered an important dietary source of antioxidants.

Wounding of fresh produce may elicit an increase in antioxidant capacity associated with wound-induced phenolic compounds. However, there have been no reports on the wounding response of different types of fresh produce. Changes in antioxidant capacity, total soluble phenolics, ascorbic acid, total carotenoids and total anthocyanins were evaluated after wounding in zucchini, white and red cabbage, iceberg lettuce, celery, carrot, parsnips, red radish, sweetpotato and potatoes. Phenolic changes ranged from a 26% decrease to an increase up to 191%, while antioxidant capacity changes ranged from a 51% decrease to an increase up to 442%. Reduced ascorbic acid decreased up to 82%, whereas the changes in anthocyanins and carotenoids were less evident. In general, the wound response was dependent on the type of tissue and influenced by the initial levels of reduced ascorbic acid and phenolic compounds. Wounding may increase the antioxidant content towards the development of selected healthier fresh-cut produce.

Bulb Color is an important trait in onion (Allium cepa) breeding, but the lack of a method to quantify and color intensity is a large number of samples have hindered assessment of essential breeding parameters such as heritability. We developed a new method on digital imagining that allows facile quantification of red color intensity in a large number of samples. The brightness of dry skin in digital images was measured using the histogram function of Adobe? Photoshop?and showed highly significant correlation with both visual rating of red haploid (DH) lines and location effects on red color development. Three red DH lines, four pink F, hybrids, and three red commercial cultivars were grown at two locations with three replications. DH lines showed less variation in combined analysis of variance from two locations.

Doubled haploid lines in onion (Allilum cepa) are homozygous for all loci and can be used as valuable materials for inheritance studies of complex traits and pure line production for F1 hybrids were produced and their field performance was compared with commercial open-pollinated cultivars. Six doubled haploid lines were produced from haploid culture. Four F1, hybrids were produced by crossing doubled haploid lines with sterile breeding lines. Doubled haploid lines, F1, hybrids, and five commercial open-pollinated cultivars were grown at two locations. After harvesting the bulbs, equatorial diameter, polar diameter, shape index, weight, soluble solid content, and pungency were measured. Doubled haploid lines and F1, hybrids generally showed higher uniformity as compared with commercial cultivars for all traits. Hybrid vigor, a good response lo favorable growing conditions and high stability were observed in F1, hybrids. Overall, it was demonstrated that doubled haploid lines were more uniform than open-pollinated cultivars and could be utilized as parental lines for F1, hybrid production with high uniformity.

The cytochrome P450 enzyme family is the most abundant and responsible for the metabolism of more than 60% of currently marketed drugs and is considered central in many clinically important drug interactions. Seven different grapefruit and pummelo juices as well as 5 furocoumarins isolated from grapefruit juice were evaluated at different concentration on cytochrome P450 3A4 (CYP3A4), cytochrome P450 2C9 (CYP2C9), and cytochromeP450 2D6 (CYP2D6) isoenzyme activity.Grapefruit and pummelo juiceswere found to be potent inhibitors of cytochrome CYP3A4 and CYP2C9 isoenzymes at 25% concentration, while CYP2D6 is inhibited significantly low at all the tested concentration of juices (P < 0.05). Among the 5 furocoumarins tested, the inhibitory potency was in the order of paradisin A > dihydroxybergamottin > bergamottin > bergaptol > geranylcoumarin at 0.1 µMto 0.1 mMconcentrations. The IC50 valuewas lowest for paradisin A for CYP3A4 with 0.11 µMfollowed byDHBfor CYP2C9 with 1.58 µM.

Targeting multiple digestive proteases may be more effective in insect pest control than inhibition of a single enzyme class. We therefore explored possible interactions of three antimetabolic protease inhibitors fed to cowpea bruchids in artificial diets, using a recombinant soybean cysteine protease inhibitor scN, an aspartic protease inhibitor pepstatin A, and soybean Kunitz trypsin inhibitor KI. scN and pepstatin, inhibiting major digestive cysteine and aspartic proteases, respectively, significantly prolonged the developmental time of cowpea bruchids individually. When combined, the anti-insect effect was synergistic, i.e., the toxicity of the mixture was markedly greater than that of scN or pepstatin alone. KI alone did not impact insect development even at relatively high concentrations, but its anti-insect properties became apparent when acting jointly with scN or scN plus pepstatin. Incubating KI with bruchid midgut extract showed that it was partially degraded. This instability may explain its lack of anti-insect activity. However, this proteolytic degradation was inhibited by scN and/or pepstatin. Protection of KI from proteolysis in the insect digestive tract thus could be the basis for the synergistic effect. These observations support the concept that cowpea bruchid gut proteases play a dual role; digesting protein for nutrient needs and protecting insects by inactivating dietary proteins that may otherwise be toxic. Our results also suggest that transgenic resistance strategies that involve multigene products are likely to have enhanced efficacy and durability.

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