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Udo Blum - One of the best experts on this subject based on the ideXlab platform.
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Interrelationships between p-Coumaric Acid, evapotranspiration, soil water content, and leaf expansion.
Journal of chemical ecology, 2006Co-Authors: Udo Blum, Thomas M. GerigAbstract:Increasing concentrations of p-Coumaric Acid applied to (cucumber seedling)–[Cecil Ap soil–sand mixture (or soil)] systems inhibited evapotranspiration (primarily transpiration) and leaf area expansion of cucumber seedlings and increased soil moisture. Higher soil moisture resulting from the inhibition of evapotranspiration lowered soil solution concentrations of p-Coumaric Acid by 14–40% but did not significantly influence the inhibitory effects of p-Coumaric Acid on seedlings. Inhibition of evapotranspiration and total leaf area and increases in lowest daily soil water were observed 1–3 d after the first p-Coumaric Acid treatment, whereas inhibition of absolute and relative rates of leaf expansion was observed within a 24-hr period. Development of the maximum effects of p-Coumaric Acid required several additional days. Recovery from effects, i.e., return to control levels, after p-Coumaric Acid depletion from soil solution was a gradual process requiring days for evapotranspiration, lowest daily soil water, and total leaf area, but was slightly faster for leaf area expansion. It appears, at least for short-term studies, that the initial input or treatment concentrations of p-Coumaric Acid represented a reasonable estimate of dose despite the dynamic nature of soil solution concentrations, and that the lowering of available p-Coumaric Acid concentrations, associated with the elevation of soil moisture, did not result in a concurrent detectable seedling response. However, increased soil moisture associated with p-Coumaric Acid treatments of sensitive species suggests a means by which the magnitude of some allelopathic interactions may be modified and resource competition and allelopathy could interact.
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Mechanism by which noninhibitory concentrations of glucose increase inhibitory activity ofp-Coumaric Acid on morning-glory seedling biomass accumulation.
Journal of chemical ecology, 1995Co-Authors: K. J. Pue, Udo Blum, T. M. Gerig, Steven R. ShaferAbstract:Noninhibitory levels of glucose-C [≤ 72 µg carbon (C)/g soil] increased the inhibitory activity ofp-Coumaric Acid on morning-glory seedling biomass accumulation in Cecil Bt-horizon soil. The amount ofp-Coumaric Acid required for a given level of inhibition of shoot and seedling biomass accumulation decreased as the concentration of glucose increased. Soil extractions with neutral EDTA (0.25 M, pH 7) after addition of combinations ofp-Coumaric Acid and glucose (concentrations ranging from 0 to 1.25 µmol/g soil) to the soil showed that utilization ofp-Coumaric Acid by microbes decreased linearly as the concentration of glucose increased. The increased inhibitory activity of a given concentration ofp-Coumaric Acid in the presence of glucose was not due to a reduction in soil sorption ofp-Coumaric Acid or effects of nitrogen-limited microbial growth. Noninhibitory levels of phenylalanine andp-hydroxybenzoic Acid slowed the utilization ofp-Coumaric Acid by microbes in a similar manner as glucose. The presence of methionine, however, did not affect the rate ofp-Coumaric Acid utilization by microbes. These observations suggest that differential utilization of individual molecules in organic mixtures by soil microbes can modify, and in this case increase, the effectiveness of a given concentration of an inhibitor such asp-Coumaric Acid on the inhibition of seedling growth such as morning-glory.
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Modification of allelopathic effects ofp-Coumaric Acid on morning-glory seedling biomass by glucose, methionine, and nitrate.
Journal of chemical ecology, 1993Co-Authors: Udo Blum, T. M. Gerig, A. D. Worsham, Larry D. KingAbstract:Studies of allelopathy have emphasized primarily the identification and quantification of phytotoxins in soils, with only limited attention directed toward how organic (carbon) and inorganic constituents (nutrients) in the soil may modify the action of such phytotoxins. In the present study, increasing carbon (C) levels (up to 108μg C/g soil) supplied as glucose, phenylalanine, orp-hydroxybenzoic Acid did not alter morning-glory biomass, but similar C levels supplied as leucine, methionine, orp-Coumaric Acid were inversely related to morning-glory biomass. Similar joint action and multiplicative analyses were used to describe morning-glory biomass response to various C sources and to generate dose isolines for combinations ofp-Coumaric Acid and methionine at two NO3-N levels and for combinations ofp-Coumaric Acid and glucose at one NO3-N level. Methionine, glucose, and NO3-N treatments influenced the inhibitory action ofp-Coumaric Acid on biomass production of morning-glory seedlings. For example, results from the multiplicative analysis indicated that a 10% inhibition of morning-glory biomass required 7.5μgp-Coumaric Acid/g soil, while the presence of 3.68μg methionine/g soil thep-Coumaric Acid concentration required for 10% inhibition was only 3.75μg/ g soil. Similar response trends were obtained forp-Coumaric Acid and glucose. The higher NO3-N (14 vs. 3.5μg/g) treatments lowered the methionine and increased thep-Coumaric Acid concentrations required for 10% inhibition of morning-glory biomass. These results suggested that allelopathic interactions in soil environments can be a function of interacting neutral substances (e.g., glucose), promoters (e.g., NO3-N), and/or inhibitors (e.g., methionine andp-Coumaric Acid) of plant growth.
Masahide Terazima - One of the best experts on this subject based on the ideXlab platform.
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Enthalpy changes and reaction volumes of photoisomerization reactions in solution: azobenzene and p-Coumaric Acid
Journal of Photochemistry and Photobiology A-chemistry, 2000Co-Authors: Kan Takeshita, Noboru Hirota, Masahide TerazimaAbstract:Abstract The photoisomerizations of azobenzene in ethanol and p-Coumaric Acid in water were studied by the transient grating and photoacoustic methods. The absorption spectrum of cis-p-Coumaric Acid and the quantum yield of the isomerization reaction in water were measured by a photostationary absorption method at two wavelengths (Φiso=0.46±0.05). The diffusion coefficient of p-Coumaric Acid in water at room temperature is 4.4×10−10 m2 s−1. This relatively small value suggests a hydrogen bonding between p-Coumaric Acid and water. Concomitant with the photoisomerization, the enthalpy changes (ΔH) and reaction volumes (ΔV) of azobenzene and p-Coumaric Acid were measured. The obtained values (ΔH=43±8 kJ/mol and ΔV=−3±5 cm3/mol for azobenzene, ΔH=49±7 kJ/mol and ΔV=−0.7±0.5 cm3/mol for p-Coumaric Acid) are discussed in terms of structural change in trans → cis isomerization.
M. Jackson - One of the best experts on this subject based on the ideXlab platform.
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Production of Coumaric Acid from sugarcane bagasse
Innovative Food Science & Emerging Technologies, 2009Co-Authors: Y.l. Luo, Caihuan Huang, M. JacksonAbstract:Abstract Phenolic Acids were released from sugarcane bagasse by alkaline hydrolysis at 30 °C for 4 h; The alkaline hydrolysates were ultrafiltrated, the permeates purified with anion exchange resin. The phenolic Acids bound by the resin were desorbed by a mixture of water–ethanol–HCl solution (36: 60: 4) after washing the resin with water, ethanol and dilute HCl respectively. The combined eluents were concentrated for crystalization, and the crystals filtered and washed using 1% (v/v) HCl. After this purification process, the purity of products reached 89.7% based on Coumaric Acid. Results of HPLC/MS, HPLC using standard Coumaric Acid and ferulic Acid showed that the main component of the purified bagasse hydrolysate was p-Coumaric Acid rather than ferulic Acid. The purified products showed the same antioxidant activity, reducing power and free radical scavenging capacity as the standard p-Coumaric Acid. The technology could be applied on industrial scale. Industrial relevance This research presents a technology to produce Coumaric Acids from sugarcane bagasse. The first step is to release Coumaric Acid by alkaline hydrolysis. The second step is to remove the viscous polysaccharides and protein by ultrafiltration. The third step is to purify Coumaric Acid from the permeate of ultrafiltration by anion chromatography, and the alkaline could be reused to hydrolyze the bagasse. The technology showed potential application on industrial scale.
Andrew G. Livingston - One of the best experts on this subject based on the ideXlab platform.
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Kinetics of Wet Oxidation of P-Coumaric Acid over a CuO.ZnO-Al2O3 Catalyst
Chemical Engineering Research and Design, 1997Co-Authors: Dionissios Mantzavinos, Rolf Hellenbrand, Andrew G. Livingston, Ian S. MetcalfeAbstract:The semi-batch wet oxidation of / p -Coumaric Acid, a biorecalcitrant polyphenolic compound typically found in olive processing and wine-distillery wastewaters, using a CuO.ZnO-Al 2 O 3 catalyst in slurry form at temperatures from 373 K to 403 K, oxygen partial pressures from 2.3 to 32.3 bar, catalyst concentrations from 0.088 to 4.4gl –1 and particle size from 38–250 /μm, has been investigated. The catalyst was found to be capable of increasing the rate of p -Coumaric Acid oxidation by as much as 20 times that of the uncatalysed reaction, at 403 K. The rate of p -Coumaric Acid oxidation was found to be first order with respect to its concentration and proportional to oxygen partial pressure to the power of 0.65 over the range of operating conditions where oxygen partial pressure exerts a significant effect (2.3 to 17.3 bar). With the particle sizes used, there were no intraparticle diffusional limitations.
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Partial wet oxidation of p-Coumaric Acid: Oxidation intermediates, reaction pathways and implications for wastewater treatment
Water Research, 1996Co-Authors: Dionissios Mantzavinos, Rolf Hellenbrand, Ian S. Metcalfe, Andrew G. LivingstonAbstract:p-Coumaric Acid is representative of the polyphenolic fraction typically found in olive oil processing and wine-distillery wastewaters. The batch oxidation of p-Coumaric Acid has been investigated using a high-pressure reactor at temperatures varying from 403 to 523 K and pressures from 3 to 7 MPa. Concentrations of reaction intermediates were determined as a function of oxidation time using High Performance Liquid Chromatography (HPLC) as the main analytical technique, and an oxidation mechanism for p-Coumaric Acid is suggested. The results are discussed with respect to developing an integrated chemical-biological treatment process for organic wastewater.
Ying Wang - One of the best experts on this subject based on the ideXlab platform.
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Effect of activated charcoal treatment of alkaline hydrolysates from sugarcane bagasse on purification of p-Coumaric Acid
Chemical Engineering Research and Design, 2011Co-Authors: Jian Zhao, Shenghua Ding, Yong Wang, Ying WangAbstract:Abstract The brown compounds in the ultrafiltration permeates resulting from the alkaline-hydrolysis of sugarcane bagasse were determined to be composed mainly of lignin monomers. These monomers significantly influence the separation and purification of p-Coumaric Acid. Addition of 3% of activated charcoal removed 78.10% of the compounds’ color value but adsorbed only 14.36% of the available Coumaric Acid in alkaline conditions. Decoloration by the application of activated charcoal before purification by anion exchange chromatography ensured the repeated use of the resins and crystallization of p-Coumaric Acid, thus significantly reducing preparation costs. A total of 8.56 g of crystal contained 95.2% of Coumaric Acid was obtained from 1 kg of sugarcane bagasse after decoloration and separation.
