Interaction of cinnamic acid derivatives with commercial hypoglycemic drugs on 2-deoxyglucose uptake in 3T3-L1 adipocytes

Hydroxycinnamic acid derivatives are naturally occurring substances found in fruits, vegetables, and flowers and are consumed as dietary phenolic compounds. The effect of cinnamic acid, ferulic acid, p-coumaric acid, eugenol, chlorogenic acid, and caffeic acid, alone and in combination with two commercial oral hypoglycemic drugs (OHD), namely, thiazolidinedione (THZ) and metformin, on the uptake of 2-deoxyglucose (2DG) by 3T3-L1 adipocytes is studied. All of the phytochemicals other than cinnamic acid show synergistic interaction in 2DG uptake with both of the OHDs. THZ (20 μM) in combination with ferulic acid (25 μM) or p-coumaric acid (25 μM) increases 2DG uptake by 7- or 6.34-fold, respectively, with respect to control, whereas metformin (20 μM), along with ferulic acid (25 μM) or cinnamic acid (25 μM), increases 2DG uptake by 6.45- or 5.87-fold, respectively, when compared to control. Chlorogenic and cinnamic acids increased the expression of PPARγ, whereas other hydroxycinnamic acids enhanced the expression of PI3K, indicating different mechanisms of action between these compounds. These phytochemicals were able to reduce the expressions of the fatty acid synthase and HMG CoA reductase genes, indicating that they may be able to reduce the secondary complications caused by the accumulation of lipids. These studies suggest that hydroxycinnamic acid derivatives may be beneficial for the treatment of diabetes mellitus. They may act as a supplement with commercial drugs and may reduce the secondary complications caused by OHDs.     

Characterization of the p-coumaric acid decarboxylase from Lactobacillus plantarum CECT 748(T)

It was previously reported that cell cultures from Lactobacillus plantarum CECT 748 (T) were able to decarboxylate phenolic acids, such as p-coumaric, m-coumaric, caffeic, ferulic, gallic, and protocatechuic acid. The p-coumaric acid decarboxylase (PDC) from this strain has been overexpressed and purified. This PDC differs at its C-terminal end when compared to the previously reported PDC from L. plantarum LPCHL2. Because the C-terminal region of PDC is involved in enzymatic activity, especially in substrate activity, it was decided to biochemically characterize the PDC from L. plantarum CECT 748 (T). Contrarily to L. plantarum LPCHL2 PDC, the recombinant PDC from L. plantarum CECT 748 (T) is a heat-labile enzyme, showing optimal activity at 22 degrees C. This PDC is able to decarboxylate exclusively the hydroxycinnamic acids p-coumaric, caffeic, and ferulic acids. Kinetic analysis showed that the enzyme has a 14-fold higher K(M) value for p-coumaric and caffeic acids than for ferulic acid. PDC catalyzes the formation of the corresponding 4-vinyl derivatives (vinylphenol and vinylguaiacol) from p-coumaric and ferulic acids, respectively, which are valuable food additives that have been approved as flavoring agents. The biochemical characteristics showed by L. plantarum PDC should be taken into account for its potential use in the food-processing industry.     

Variability in the release of free and bound hydroxycinnamic acids from diverse malted barley (Hordeum vulgare L.) cultivars during wort production

Volatile phenols have long been recognized as important flavor contributors to the aroma of various alcoholic beverages. The two main flavor-active volatile phenols in beer are 4-vinylguaiacol and 4-vinylphenol. They are the decarboxylation products of the precursors ferulic acid and p-coumaric acid, respectively, which are released during the brewing process, mainly from malt. In this study, the variability in the release of free and ester-bound hydroxycinnamic acids from nine malted barley ( Hordeum vulgare L.) varieties during wort production was investigated. A large variability between different barley malts and their corresponding worts was observed. Differences were also found between free ferulic acid levels from identical malt varieties originating from different malt houses. During mashing, free hydroxycinnamic acids in wort are both water-extracted and enzymatically released by cinnamoyl esterase activity. Esterase activities clearly differ between different barley malt varieties. Multiple linear regression analysis showed that the release of ferulic acid during mashing did not depend only on the barley malt esterase activity but also on the amount of ester-bound ferulic acid initially present in the wort and on its endoxylanase activity. The study demonstrates the importance of selecting a suitable malt variety as the first means of controlling the final volatile phenol levels in beer.     

Quantitative determination of hydroxycinnamic acids in wheat, rice, rye, and barley straws, maize stems, oil palm frond fiber, and fast-growing poplar wood.

A new method has been developed for the quantitative determination of hydroxycinnamic acids participating in ester or ether linkages to the cell wall polymers. The method is based on mild alkaline hydrolysis followed by acid hydrolysis or mild alkaline hydrolysis, which partially removed esterified phenolic acids, and high-temperature concentrated alkaline treatment, which cleaved both the ester and ether linkages. It was found that traditional mild alkaline hydrolysis and acid hydrolysis released only part of the ester- and ether-linked phenolic acids, respectively. Approximately half (44.0-47.9%) of the total ester-linked p-coumaric acid and 18.2-32.6% of the total esterified ferulic acid remained ester-linked to the mild alkali-soluble lignin polymers, and 55.0-72.0% of the total ether-linked p-coumaric acid and 37.5-53.8% of the total ether-linked ferulic acid remained ether-linked to the solubilized lignin molecules after the acid hydrolysis. To correct this, a second mild alkaline hydrolysis of the alkali-soluble lignin preparations and acid hydrolysis of the solubilized lignin fractions, obtained from the first acid hydrolysis of the cell wall materials, was investigated. On the basis of this new method, a majority of the cell wall p-coumaric acid (55.8-81.5%) was found to be ester-linked to cell wall components, mainly to lignin, and about half of the cell wall ferulic acid is etherified through its phenolic oxygen to the cell wall lignin component, whereas the remainder is esterified to the cell wall hemicelluloses and/or lignin in different plant materials.     

Antioxidant properties of ferulic acid and its related compounds

Antioxidant activity of 24 ferulic acid related compounds together with 6 gallic acid related compounds was evaluated using several different physical systems as well as their radical scavenging activity. The radical scavenging activity on 1,1-diphenyl-2-picrylhydrazyl (DPPH) decreased in the order caffeic acid > sinapic acid > ferulic acid > ferulic acid esters > p-coumaric acid. In bulk methyl linoleate, test hydroxycinnamic acids and ferulic acid esters showed antioxidant activity in parallel with their radical scavenging activity. In an ethanol-buffer solution of linoleic acid, the activity of test compounds was not always associated with their radical scavenging activity. Ferulic acid was most effective among the tested phenolic acids. Esterification of ferulic acid resulted in increasing activity. The activity of alkyl ferulates was somewhat influenced by the chain length of alcohol moiety. When the inhibitory effects of alkyl ferulates against oxidation of liposome induced by AAPH were tested, hexyl, octyl, and 2-ethyl-1-hexyl ferulates were more active than the other alkyl ferulates. Furthermore, lauryl gallate is most effective among the tested alkyl gallates. These results indicated that not only the radical scavenging activity of antioxidants, but also their affinity with lipid substrates, might be important factors in their activity.     

Free hydroxycinnamic acids, lycopene, and color parameters in tomato cultivars

Concentrations of antioxidant compounds (total phenolic compounds, free hydroxycinnamic acids, and lycopene) and color parameters ( a*, b*, and L*) were determined in 167 tomato samples belonging to five cultivars (Dorothy, Boludo, Dunkan, Dominique, and Thomas) produced on the island of Tenerife. Chlorogenic, caffeic, p-coumaric, and ferulic acids were identified and quantified in the tomato samples. Chlorogenic acid had the highest mean concentration, whereas the p-coumaric was not detected in almost half of the tomato samples. The cultivar, cultivation method, and production region had little influence on the concentration of analyzed parameters. Considerable seasonal variations in the levels of these parameters were observed. Many correlations were observed between the antioxidant compounds and color parameters. The tomato samples tended to be differentiated according to the sampling period when discriminant analysis was applied.     

Chitosan treatment of wheat seeds induces resistance to Fusarium graminearum and improves seed quality.

Chitosan treatment (2-8 mg/mL) of wheat seeds significantly improved seed germination to recommended seed certification standards (>85%) and vigor at concentrations >4 mg/mL, in two cultivars of spring wheat (Norseman and Max), by controlling seed-borne Fusarium graminearum infection. The germination was <80% in the control and >85% in benomyl- and chitosan-treated seeds. Seed-borne F. graminearum was reduced to >50% at higher chitosan treatments compared to the control. Synthesis of phenolic acids was stimulated in primary leaves following chitosan treatment, and levels of these phenolic acids, especially ferulic acid, increased significantly with increasing chitosan concentration. Lignin content of primary leaves also showed a similar pattern. The synthesis of precursors of lignin such as p-coumaric, ferulic, and sinapic acids and phenolic acids having antimicrobial activity such as benzoic, p-coumaric, caffeic, protocatechuic, chlorogenic, ferulic, and gallic acids was also stimulated by chitosan treatment. The induction of phenolic acids and lignin was significantly lower in cv. Max compared to Norseman. Chitosan also inhibited fungal transmission to the primary roots of germinating seedlings. Results suggest that chitosan controlled seed-borne F. graminearum infection and increased the resistance in seedlings by stimulating the accumulation of phenolics and lignin. Thus, chitosan has a potential for improvement of seed quality and enhancement of crop yields as well as increased value of stored grains for food and feed.     

Antioxidant activity of Centaurium erythraea infusion evidenced by its superoxide radical scavenging and xanthine oxidase inhibitory activity.

Centaurium erythraea Rafin. (Gentianaceae) has long been used in traditional medicine. This plant contains considerable amounts of polyphenolic compounds, namely, xanthones and phenolic acids as the main constituents. Because phenolic groups exhibit activity as radical scavengers and/or metal chelators, this study evaluated the superoxide radical scavenging properties of a lyophilized infusion obtained from C. erythraea flowering tops. Superoxide radical scavenging activity was assayed using enzymatic (xanthine/xanthine oxidase) and nonenzymatic (NADH/phenazine methosulfate) superoxide generating systems. This study provided evidence that C. erythraea exhibits interesting antioxidant properties, expressed either by the capacity to scavenge superoxide radical or to noncompetitively inhibit xanthine oxidase. The main phenolic compounds present in this extract were several esters of hydroxycinnamic acids, namely, p-coumaric, ferulic, and sinapic acids.     

Fermentative metabolism is induced by inhibiting different enzymes of the branched-chain amino acid biosynthesis pathway in pea plants

The inhibition of branched-chain amino acid (BCAA) biosynthesis was evaluated in pea plants in relation to the ability for induction of fermentative metabolism under aerobic conditions. Chlorsulfuron and imazethapyr (inhibitors of acetolactate synthase, ALS, EC 4.1.3.18) produced a strong induction of pyruvate decarboxylase (PDC, EC 4.1.1.1) and alcohol dehydrogenase (ADH, EC 1.1.1.1) activities and a lesser induction of lactate dehydrogenase (LDH, EC 1.1.1.27) and alanine aminotransferase (AlaAT, EC 2.6.1.2) activities in roots. Inhibition of the second enzyme of the BCAA biosynthesis (ketol-acid reductoisomerase, KARI, EC 1.1.1.86) by Hoe 704 (2-dimethylphosphinoyl-2-hydroxyacetic acid) and CPCA (1,1-cyclopropanedicarboxylic acid) enhanced fermentative enzyme activities including PDC, ADH, and AlaAT. Fermentative metabolism induction occurring with ALS- and KARI-inhibitors was related to a higher expression of PDC. In the case of KARI inhibition, it is proposed that fermentation induction is due to an inhibition of ALS activity resulted from an increase in acetolactate concentration. Fermentative metabolism induction in roots, or at least ethanolic fermentation, appeared to be a general physiological response to the BCAA biosynthesis inhibition.     

Inhibitory activities of soluble and bound millet seed phenolics on free radicals and reactive oxygen species

Oxidative stress, caused by reactive oxygen species (ROS), is responsible for modulating several pathological conditions and aging. Soluble and bound phenolic extracts of commonly consumed millets, namely, kodo, finger (Ravi), finger (local), foxtail, proso, little, and pearl, were investigated for their phenolic content and inhibition of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and ROS, namely, hydroxyl radical, peroxyl radical, hydrogen peroxide (H(2)O(2)), hypochlorous acid (HOCl), and singlet oxygen ((1)O(2)). Inhibition of DPPH and hydroxyl radicals was detrmined using electron paramagnetic resonance (EPR) spectroscopy. The peroxyl radical inhibitory activity was measured using the oxygen radical absorbance capacity (ORAC) assay. The scavenging of H(2)O(2), HOCl, and (1)O(2) was evaluated using colorimetric methods. The results were expressed as micromoles of ferulic acid equivalents (FAE) per gram of grain on a dry weight basis. In addition, major hydroxycinnamic acids were identified and quantified using high-performance liquid chromatography (HPLC) and HPLC-mass spectrometry (MS). All millet varieties displayed effective radical and ROS inhibition activities, which generally positively correlated with phenolic contents, except for hydroxyl radical. HPLC analysis revealed the presence of ferulic and p-coumaric acids as major hydroxycinnamic acids in phenolic extract and responsible for the observed effects. Bound extracts of millet contributed 38-99% to ROS scavenging, depending on the variety and the test system employed. Hence, bound phenolics must be included in the evaluation of the antioxidant activity of millets and other cereals.     

Phytotoxic effects of wheat extracts on a herbicide-resistant biotype of annual ryegrass (Lolium rigidum)

Thirty-nine wheat accessions were used to evaluate their extract phytotoxicity against annual ryegrass (Lolium rigidum Gaud.). Aqueous extracts of wheat shoot residues significantly inhibited the germination and root growth of a biotype of annual ryegrass resistant to herbicides of acetyl CoA carboxylase inhibitors (group A), acetolactate synthase inhibitors (B), photosystem II inhibitors (C), and tubulin formation inhibitors (D). The germination of the herbicide resistant (HR) biotype was inhibited by 3-100%, depending upon the wheat accession. The phytotoxic effects on ryegrass root growth ranged from 12% stimulation to 100% inhibition, compared to a control. The germination and root growth of a herbicide-susceptible (HS) biotype of annual ryegrass were also inhibited by the wheat extracts, with germination inhibited by 4-100%, and root growth by 19-100%. Bioassays with two known wheat allelochemicals showed that p-coumaric acid and propionic acid significantly inhibited the growth of both HR and HS biotypes of annual ryegrass. The two compounds completely inhibited the root growth of HR ryegrass at concentrations greater than 5.0 mM. In comparison with p-coumaric acid, propionic acid was more inhibitory to seed germination, shoot, and root growth of both ryegrass biotypes. The root growth of the HR biotype was more sensitive when exposed to wheat extracts, to p-coumaric acid, and to propionic acid. The results suggest that residues of certain wheat cultivars with strong allelopathic potential could provide a nonherbicidal alternative for the management of herbicide-resistant weed species.     

Esterase activity able to hydrolyze dietary antioxidant hydroxycinnamates is distributed along the intestine of mammals.

Hydroxycinnamic acids are effective antioxidants and are abundant components of plant cell walls, especially in cereal bran. For example, wheat and rye brans are rich sources of the hydroxycinnamates ferulic acid, sinapic acid, and p-coumaric acid. These phenolics are part of human and animal diets and may contribute to the beneficial effects derived from consumption of cereal bran. However, these compounds are ester linked to the main polymers in the plant cell wall and cannot be absorbed in this complex form. The present work shows that esterases with activity toward esters of the major dietary hydroxycinnamates are distributed throughout the intestinal tract of mammals. In rats, the cinnamoyl esterase activity in the small intestine is derived mainly from the mucosa, whereas in the large intestine the esterase activity was found predominantly in the luminal microflora. Mucosa cell-free extracts obtained from human duodenum, jejunum, and ileum efficiently hydrolyzed various hydroxycinnamoyl esters, providing the first evidence of human cinnamoyl esterase(s). This study first demonstrates the release by human colonic esterase(s) (mostly of microbial origin) of sinapic acid and p-coumaric acid from rye and wheat brans. Hydrolysis by intestinal esterase(s) is very likely the major route for release of antioxidant hydroxycinnamic acids in vivo.     

Absorption of hydroxycinnamates in humans after high-bran cereal consumption

Hydroxycinnamic acids are a group of phenolic compounds that exhibit a wide range of in vitro chemoprotective and antioxidant properties. Cereals containing a high proportion of the bran layers are rich in ester-linked hydroxycinnamic acids, such as ferulic and diferulic acids. The present work investigated the absorption in humans of hydroxycinnamic acids from high-bran breakfast cereal (wheat). Plasma and urine samples from six volunteers were collected before and after cereal consumption and analyzed for total hydroxycinnamic acids content after beta-glucuronidase/sulfatase treatment both by HPLC-DAD and by LC-MS (SIM monitoring). High-bran cereal administration resulted in increased plasma ferulic and sinapic acid concentrations (maximum levels detected of approximately 200 and approximately 40 nM, respectively) with absorption peaks between 1 and 3 h. Increases of approximately 4-fold in ferulic acid and approximately 5-fold in feruloylglycine were detected in 24-h urine after consumption of the cereal. Most of the ferulic acid detected in urine and plasma was present as conjugates (feruloylglycine and/or glucuronides). Diferulic acids were undetectable. The data show that ferulic and sinapic acids are taken up in humans from dietary high bran wheat but that absorption is limited and may originate only from the free and soluble portions present in the cereal.     

Effect of copigments and grape cultivar on the color of red wines fermented after the addition of copigments

The prefermentation addition of copigments led to significantly different red wines according to the copigment structure (flavonol or hydroxycinnamic acid) and the grape cultivar [Tempranillo (= Cencibel) or Cabernet Sauvignon]. The flavonol rutin enhanced copigmentation and anthocyanin extraction, improving the red color, but the hydroxycinnamic acids (especially caffeic acid) had converse results. The above effects were higher in Cabernet Sauvignon wines, particularly if rutin or p-coumaric acid was used. These wines showed the highest copigmentation as they contained more anthocyanins and flavonols, whereas the coumaroylated anthocyanins of Tempranillo wines could have prevented the action of the added copigments. After 21 months, the main pyranoanthocyanins found were the malvidin-3-glucoside 4-vinylphenol and the malvidin-3-glucoside 4-vinylcatechol (pinotin A) adducts. The results suggested that the former adduct was primarily generated following enzymatic decarboxylation of p-coumaric acid during fermentation, whereas pinotin A was formed through a pure chemical reaction, which depended on the concentration of free caffeic acid during aging.     

Evaluation of wheat (Triticum aestivum L.) phenolic acids during grain development and their contribution to Fusarium resistance

The phenolic acid profiles of six cultivars of wheat with known tolerance to Fusarium head blight were evaluated during plant development from anthesis through maturity. Analysis by HPLC of grain at anthesis revealed that p-coumaric and ferulic acid were the two principal phenolic compounds present. The effect of these two phenolic acids on Fusarium species was evaluated in vitro. Both phenolic acids demonstrated significant reductions (p < 0.05) of Fusarium species growth at all concentrations tested. Ferulic acid is the primary phenolic acid in grain at all stages of development, and its concentration increased steadily during grain development prior to a 50% decrease during grain ripening. The accumulation of ferulic acid synthesis from anthesis until approximately 20 days after anthesis appears related with cultivar resistance to Fusarium. Concentrations of ferulic acid in the grain were similar at maturity, implying that the end-use quality would be similar for both resistant and susceptible cultivars.     

HPLC-DAD-ESI-MS/MS characterization of pyranoanthocyanins pigments formed in model wine

Formation of wine pyranoanthocyanins in model wine was monitored by HPLC-DAD-ESI-MS/MS, using red grape skin extracts and wine fermentation metabolites (acetaldehyde, pyruvic and acetoacetic acids, and diacetyl) and also hydroxycinnamic acids (p-coumaric, caffeic, ferulic, and sinapic acids). Pyruvic acid and acetaldehyde reacted fast, the first reaching high product yield and the second inducing mainly pigment polymerization. In contrast, acetoacetic acid and diacetyl reacted slowly with poor product yields. Hydroxycinnamic acids progressively reacted without apparent formation of polymeric pigments, the reaction rate and yield increasing as the number of hydroxy/methoxy groups did. Substituent at C-10 strongly affected the visible maximum absorbance wavelength, whereas B-ring substitution pattern or sugar acylation exerted little effect. The 10-methylpyranoanthocyanins formed from acetoacetic acid were also found as side products in the formation of 10-carboxypyranoanthocyanins. Finally, we report for the first time on UV-vis and MS spectral data of 10-acetylpyranoanthocyanins formed from diacetyl, and their occurrence in commercial red wines is suggested.     

In vitro inhibitory effect on pancreatic lipase activity of subfractions from ethanol extracts of fermented Oats (Avena sativa L.) and synergistic effect of three phenolic acids

The purpose of the present work is to study the pancreatic lipase inhibitory effects of different subfractions (n-hexane, ethyl acetate (EA), n-butanol, and water) from ethanol extracts of nonfermented and fungi-fermented oats and to delineate the interactions of three primary phenolic acids in the EA subfractions. The EA subfraction showed the highest inhibitory effect on pancreatic lipase activity at 1.5 mg/mL compared to the other subfractions, regardless of whether the oats were fermented. Meanwhile, both of the EA subfractions of two fungi-fermented oats demonstrated more effective inhibitory activity than that of nonfermented oats. A positive correlation between the total phenolics content and inhibitory activity was found. The inhibitory ability of the EA subfraction from nonfermented or fermented oats also displayed a dose-dependent effect. The standards of caffeic, ferulic, and p-coumaric acids, mainly included in EA subfractions of fermented oats, also displayed a dose-dependent inhibitory effect. A synergistic effect of each binary combination of p-coumaric, ferulic, and caffeic acids was observed, especially at 150.0 μg/mL. Those results indicate that fungi-fermented oats have a more effective inhibitory ability on pancreatic lipase and polyphenols may be the most effective component and could be potentially used for dietary therapy of obesity.     

Separation,characterization, and quantitation of benzoic and phenolic antioxidants in American cranberry fruit by GC-MS

A GC-MS method is reported for separation and characterization of widely different amounts of benzoic and phenolic acids as their trimethylsilyl derivatives simultaneously in cranberry. Fifteen benzoic and phenolic acids (benzoic, o-hydroxybenzoic, cinnamic, m-hydroxybenzoic, p-hydroxybenzoic, p-hydroxyphenyl acetic, phthalic, 2,3-dihydroxybenzoic, vanillic, o-hydroxycinnamic, 2,4-dihydroxybenzoic, p-coumaric, ferulic, caffeic, and sinapic acid) were identified in cranberry fruit in their free and bound forms on the basis of GC retention times and simultaneously recorded mass spectra. Except for benzoic, p-coumaric, caffeic, ferulic, and sinapic acids, 10 other phenolic acids identified have not been reported in cranberry before. The quantitation of the identified components was based on total ion current (TIC). The experimental results indicated cranberry fruit contains a high content of benzoic and phenolic acids (5.7 g/kg fresh weight) with benzoic acid being the most abundant (4.7 g/kg fresh weight). The next most abundant are p-coumaric (0.25 g/kg fresh weight) and sinapic (0.21 g/kg fresh weight) acid. Benzoic and phenolic acids occur mainly in bound forms and only about 10% occurs as free acid.     

Microwave-assisted extraction of bound phenolic acids in bran and flour fractions from sorghum and maize cultivars varying in hardness

To release bound phenolic acids, a microwave-assisted extraction procedure was applied to bran and flour fractions obtained from eight sorghum and eight maize cultivars varying in hardness. The procedure was followed by HPLC analysis, and the identities of phenolic acids were confirmed by MS/MS spectra. The extraction of sorghum and maize bound phenolic acids was done for 90 s in 2 M NaOH to release ferulic acid and p-coumaric acid from bran and flour. Two diferulic acids, 8-O-4'- and 8-5'-benzofuran form, were identified and quantitated in sorghum bran, and only the former was found in maize bran. The contents of ferulic acid and diferulic acids in sorghum bran were 416-827 and 25-179 μg/g, respectively, compared to 2193-4779 and 271-819 μg/g in maize. Phenolic acid levels of sorghum were similar between hard and soft cultivars, whereas those of maize differed significantly (p < 0.05) except for ferulic acid in flour. Sorghum phenolic acids were not correlated with grain hardness as measured using a tangential abrasive decortication device. Maize ferulic acid (r = -0.601, p < 0.01), p-coumaric acid (r = -0.668, p < 0.01), and 8-O-4'-diferulic acid (r = -0.629, p < 0.01) were significantly correlated with hardness.     

Alteration of gymnosperm and angiosperm lignin during decomposition in forest humus layers

In the present investigation an attempt was made to characterize lignin decomposition in three forest humus profiles by the examination of their contents of simple lignin-derived phenolic compounds obtained from alkaline CuO oxidation. The total amounts of p-hydroxybenzoic, syringic, vanillic, p-coumaric and ferulic acids, p-hydroxybenzaldehyde, syringaldehyde and vanillin were determined. The acid to aldehyde weight ratios of the syringyl and vanillyl units, the weight ratio p-coumaric/ferulic acids and the weight ratios of syringyl and cinnamyl phenols, respectively, to vanillyl phenols were used for the characterization of the gymnosperm and angiosperm lignin in different stages of the decomposition process. The patterns of these parameters with depht point to a considerable decomposition and chemical alteration of the lignin molecule during biodegradation.