Ferulic determination

Note The chromatogram zones exhibit a broad spectrum of colors [3, 12] that is very dependent on the duration and temperature of heating. Therefore the optimum reaction conditions must be determined empirically. With a few exceptions (ferulic, 4-amino-benzoic and cumarinic acids) aromatic carboxylic acids do not react [3]. The reagent in 80 ethanolic sulfuric acid is reported to be most sensitive for steroids [25]. 

Portions (50 mU MCA-hydrolsing activity) of purified CinnAE were incubated at 37°C with SBP (10 mg), both in the presence and absence of other carbohydrases, in 100 mM MOPS (pH 6.0) in a final volume of 1 mL. Incubations containing boiled enzyme were performed as controls. Reactions were terminated by boiling (3 min) and the amount of free ferulic acid determined using a method described previously for de-starched wheat bran [18]. The total amount of alkali-extractable ferulic acid present in the SBP was 0.87% [5]. 

Bioassay for Toxicity of Inhibitory Compound(s). Since the identity of the inhibitory compound was determined to be ferulic acid (4-hydroxy-3-methoxycinnamic acid), ferulic acid obtained from Sigma Chemical Company was used in germination bioassays. 

Fig. 2 The effect of three phenolic acids on the Chi content of 2-week-old rice seedling. A. o-Hydroxyphenyl acetic acid B. ferulic acid and C. p-Coumaric acid. Kimura s culture solution contains 0, 25, 50, or 100 ppm of either o-hydroxyphenyl acetic, ferulic or p-coumaric acids. Extraction was done on liquid-nitrogen frozen leaves with 80% acetone. The data is mean of three determinations and the bars indicate the standard deviation (Yang et al. 2002, 2004).

We designed experiments to determine if residual concentrations of atrazine and near-threshold levels of phenolic acids have a cooperative action (51). Procedures in these studies were similar to the ones used in investigations described earlier for determining moisture-allelochemical interference, except oat (Avena sativa L.) seedlings were utilized and these were treated 9 days after germination. Ferulic acid was chosen as a representative allelochemical. Treatments of atrazine and ferulic acid were made as amendments to the nutrient solution in which the oat plants were grown. 

ABL contents, expressed in ferulic acid equivalents, were of the same order of magnitude as Klason and acid-insoluble lignin contents. However, this agreement was fortuitous as the ABL determination provided only... 

Two main anionic groups were present in the xylem and their activity towards ferulic salts and their fluorinated analogues was determined. Whether the two isozymes represent enzymes specifically involved in lignin biosynthesis is discussed. 

Rouseff RL, Dettweiler GR, Swaine RM, Naim M, Zehavi U. Solid-phase extraction and HPLC determination of 4-vinyl guaiacol and its precursor, ferulic acid, in orange juice. J Chromatogr Sci 1992 30(10) 383-387. 

V Pussayanawin, DL Wetzel. High-performance liquid chromatographic determination of ferulic acid in wheat milling fractions as a measure of bran contamination. J Chromatogr 391 243-255, 1987. 

Synthesis of podophyllotoxin (3.86) in cell culture of Linum album results in yields comparable to those of the most efficient tissue cultures of Podophyllum hexandrum. In order to further improve L. album cultures, Seidel et al. (2002) investigated the biosynthesis of podophyllotoxin (3.86). They fed a number of labeled compounds that to L. album cell cultures to identify which of these compounds could be used as precursors to podophyllotoxin. They determined that the substitution pattern on the benzene ring is critical. The substitution has to be either 3-methoxy, 4-hydroxy, as in ferulic acid (3.33), or, alternatively, 3,4-methylenedioxycinnamic acid (3.90) can serve as precursor. The precursor of podophyllotoxin in L. album appears to be deoxypodophyllotoxin (3.83), based on the higher level of isotope incorporation in the latter compound. This means that 7-hydroxymatairesinol, the precursors of 5-methoxypodophyllotoxin in L. flavum (Xia et al., 2000), is not a precursor of podophyllotoxin in L. album. 

Most compounds were studied as liquids or solids, depending on their state at ambient conditions. However, a few that were either available in very small quantities or difficult to study were analyzed in solutions. Others were studied both as solids and in solution to determine if any changes occurred in their spectral features upon dissolution. Coniferaldehyde and trans-ferulic acid (samples 17 and 18, respectively) were studied as solids and in solution in methanol. 3-methoxy-o-benzoquinone and 2-methoxy-p-benzoquinone (samples 23 and 24) were studied as solutions in benzene. 

Since the actual or potential phytotoxicity of a phenolic acid is determined by its physical and chemical properties and the susceptibility of the plant process involved, the actual or potential phytotoxicity of a given phenolic acid is best determined in nutrient culture in the absence of soil processes. The phytotoxicity observed in soil systems represents a realized or observed phytotoxicity, not the actual phytotoxicity, of a given phenolic acid. For example, the actual relative phytotoxicities (or potencies) for cucumber seedling leaf expansion were 1 for ferulic acid, 0.86 for p-coumaric acid, 0.74 for vanillic acid, 0.68 for sinapic acid, 0.67 for syringic acid, 0.65 for caffeic acid, 0.5 for p-hydroxybenzoic acid and 0.35 for protocatechuic acid in a pH 5.8 nutrient culture.5 In Portsmouth Bt-horizon soil (Typic Umbraquaalts, fine loamy, mixed, thermic pH 5.2), they were 1, 0.67, 0.67, 0.7, 0.59, 0.38, 0.35, and 0.13, respectively.19 The differences in phytotoxicity of the individual phenolic acids for nutrient culture and Portsmouth soil bioassays were due to various soil processes listed in the next paragraph and reduced contact (e.g., distribution and movement)36 of phenolic acids with roots in soils. 

Variyar and Bandyopadhyay (1995) determined the phenolic acid profile of nutmeg and mace. The chief phenolic acids in nutmeg were caffeic acid and vanillic acid, whereas ferulic acid and synapic acids predominated in mace. 

Determination of p-Hydroxycinnamic and Ferulic Acid Ester Units in Grass Lignins... 

It should be emphasized that a complex of substances is generally involved when allelopathic interferences occur, often with each below a threshold level for impact. This is illustrated by the combinations of phenolic acids found in decomposing crop residues (25-27) and from soils (28-34). In allelopathic situations which implicate phenolic acids, soil quantities of ferulic, p-coumaric, and caffeic acids have ranged from below 10 to above 1,000 ppm for each compound (11,35). The lower end of this spectrum is below a concentration required for an effect in current bioassays. However, additive and synergistic effects have been documented for combinations of cinnamic acids (35), benzoic acids (36), benzoic and cinnamic acids (37), and p-hydroxybenzaldehyde with coumarin (38). Each of the allelochemicals in these tests was not equally toxic, but they contributed incrementally to inhibition of germination and growth. Whereas combinations of many allelochemicals have not been determined, it appears that both additive and synergistic interactions are extremely important under field conditions. 

Anson, N.M. Berg, R.V.D. Flavenaar, R. Bast, A. Flaenen, G.R.M.M. 2008. Ferulic aeid from aleurone determines the antioxidant potency of wheat grain (Triticum aestivum L.). J. Agric. Food Chem. 56 5589-5594. 

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