Total phenolics plants

MATTILA p and KUMPULAINEN J (2002) Determination of free and total phenolic acids in plant-derived foods by HPLC with diode-array detection, JAgric Food Chem, 50, 3660-67. 

Figure 6. Time course of effects of 10 ug chlorsulfuron per seedling on total phenolic content of sunflower hypocotyls expressed as -coumaric acid equivalents. Reproduced with permission from Ref. 75. Copyright 1983, J. Plant Growth Regul.

Total Phenolics and Phenolic Acids in Plants and Soils 155... 

EXTRACTION AND DETECTION OF TOTAL PHENOLICS AND PHENOLIC ACIDS IN PLANTS... 

The Folin-Denis assay is used as a procedure for the quantification of total phenolics in plant materials, food, and beverages. Reduction of phosphomolybdic-phosphotungstic acid (Folin-Denis reagent) to a blue-colored complex in an alkaline solution occurs in the presence of phenolic compounds (Folin and Denis 1912). 

Ontario-grown American ginseng extracts were shown to have low total phenolic content in comparison to some previously tested extracts. Ontario ginseng samples ranged from 0.67 to 6.98 p,g quercetin equivalents/mg extract whereas values were in the order of 60-269 p,g quercetin equivalents/mg extract for plants known to be rich in phenolic compounds (such as quercetin, catechin, and other flavonoids) [21],... 

African elephants avoid plants with high contents of total phenols, steroidal saponins, and lignin (Jachmann, 1989). 

Ozone stimulates the synthesis of anthocyanins 2, caffeoyl derivatives ( ), and total phenols ( ) in plant foliage. It induces necrotic lesions and localized discolored areas of yellow, red or brown on foliage of plants of many species. The size and number of lesions and the intensity of color are related to plant cultivar, maturity of foliage, cultural conditions, concentration of ozone and duration of time after exposure. 

Plant susceptibility to ozone as determined by visible injury may be very closely related to quantities of o-diphenols associated with the chloroplasts and specific requirements for activation of polyphenol oxidase enzymes. There is a significant correlation between ozone injury and concentrations of total phenols expressed as percent caffeic acid equivalents in peanut cultivars. This concept is not intended to underestimate the importance of membranes that separate phenols and enzymes. Perhaps future research will demonstrate that membranes of resistant alfalfa, green bean and other species differ both qualitatively and quantitatively from those of susceptible plants of these species. 

It is unclear from the current data if the fungal bioremediation technology will be able to reduce all contaminant concentrations to below regulatory levels. In the PCP field test at the Montana Pole Plant, total detectable chlorinated phenolics (PCP and pentachloroanisole) decreased to 230 and 119 mg/kg (decreases of 78 and 84%, respectively) in the high and low plots. While... 

Harborne, J.B., General procedures and measurement of total phenolics, in Methods in Plant Biochemistry, Vol. 1, Plant Phenolics, Harborne, J.B., Ed., Academic Press, London, 1989, chap. 1. 

The chemical basis for the observed differences in leaf food quality is unknown. Little differences were found in Folin-Denis total phenolic or proanthocyanidin extinction coefficients of 85% aqueous methanol leaf extracts from the various plant groups throughout the experiment. There were no indications of changes in leaf quality of control willows 60 m distant from willows attacked by fall webworm. 

A third method relies on the precipitation of proanthocyanidins with formaldehyde. First, the total phenolic content is measured using the Folin-Ciocalteu reagent as described before. A 0.5 mole equivalent of phloroglucinol (1.3) is added for every gallic acid equivalent in the extract. To 2 mL of this plant extract and phloroglucinol is added 1 mL of a 2 5 HC1 /H20 solution and 1 mL of an aqueous solution of formaldehyde (13 mL of 37% formaldehyde diluted to 100 mL in water). After an overnight incubation at room temperature, the unprecipitated phenols are estimated in the supematent by the Folin-Ciocalteu method. The precipitate contains the proanthocyanidins and the known amount of phloroglucinol, which is always quantitatively precipitated. 

Harbome JB, General procedures and measurement of total phenolics. In Methods in plant biochemistry, vol. 1, Ed., Harbome JB, Academic Press, San Diego, CA, pp. 1-28 (1989). 

Phenolic compounds in plants play a role in disease resistance (Morandi, 1996). Mycorrhizal plants of maize accumulated more phenolic compounds p-hydrocinnamic acid and ferulic acid in roots than non-mycorrhizal plants (Huang, 2003). Mycorrhizal Ri T-DNA transformed carrot roots accumulated more phenolic compounds when challenged by Fusarium oxysporum (Benhamou et al., 1994). All cultivars of pea colonized with G. mosseae accumulated more phenolic acids, and total phenolic accumulation were closely correlated to disease intensity (Singh et al., 2004). 

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