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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Research » Publications at this Location » Publication #68016
Title: CELL-WALL-ESTERIFIED PHENOLIC MONOMERS AND DIMERS: IDENTIFICATION AND QUANTIFICATION BY REVERSE-PHASE HPLC AND DIODE-ARRAY DETECTION

Author
item WALDRON, K - INST FOOD RESEARCH - UK
item PARR, A - INST FOOD RESEARCH - UK
item NG, A - INST FOOD RESEARCH - UK
item Ralph, John

Submitted to: Phytochemical Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/16/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Although humans can't digest plant fibers, they are a major source of energy to ruminant animals. With the help of microbes, the fibers' complex carbohydrates are broken down to products that an animal can digest. However, rumen microbes cannot attack all of the fiber, and cannot break down all of the complex carbohydrates. In order to confer strength and other properties to the fiber, plants have developed a means of cross- linking complex carbohydrates to each other and to other (often indigestible) components of the fiber. These relatively minor cross-links effect significant property changes (in the same way that cross-linking rubber by vulcanizing changes it from a soft, easily worn material to a product that can survive 50,000 miles in contact with the road). They are substantially responsible for the indigestibility of complex carbohydrates. Grasses use a molecule that can link at two or more sites to produce this cross-linking. One site is attached to the complex carbohydrate in the fiber. At another site, these cross-linking molecules can attach to each other to produce so-called 'dimers' (two of the same molecules linked together) which effectively ties the two separate complex carbohydrates together. Measuring these dimers has become more important as an appreciation of their role in plant growth has developed. Here we report a new way that will enable researchers to readily identify and measure these compounds and assess their varied roles in plant development.

Technical Abstract: An optimized high-performance liquid chromatography (HPLC) procedure has been developed for the analysis and quantification of phenolic aldehydes, acids and ferulic acid dimers found in the cell walls of higher plants. The HPLC system uses an ODS-2 reversed-phase column (5 micron particle size) eluted with methanol, acetonitrile and water gradient with detection at 280 0nm. In addition to providing base-line resolution of most components, the method employs a spectrometric detector which facilitates the precise identification of eluted components through the analysis of their spectral properties. Analysis of the cell wall phenolics of wheat straw stem (Triticum vulgare) were carried out with this method which is more versatile and, for certain components, more sensitive than current GC-MS methodology.