Free Phenolic Compounds Research Articles

Assessment of the Folin and Ciocalteu's Method for Determining Soil Phenolic Carbon

AbstractPrevious studies have shown that phenolic compounds are potentially allelopathic and present at low concentrations in soil solution. This study was conducted to evaluate the Folin and Ciocalteu's method for determining concentrations of phenolic C in aqueous and citrate extracts of soils containing 7.1 to 57.9 g kg−1 organic C. Soils were reacted for 18 h with a 0.3 mM phenolic acid mixture or DI‐H2O to serve as a control. Folin and Ciocalteu's reactive‐phenolic C content in the DI‐H2O control extracts suggested positive interference from dissolved organic matter rather than free phenolic compounds desorbed from the native soils. The absorptivity of the Folin and Ciocalteu's reduced complex was 1128 ± 25 L mol−1 cm−1 for the phenolic acid mixture and 45 ± 8 L mol−1 cm−1 for soluble organic matter ligands. Although the method has much higher sensitivity to phenolic acids than to organic matter, the higher concentration of organic matter results in substantial background positive interference. However, multiple regression equations of corrected Folin and Ciocalteu's absorbance (phenolic‐treated absorbance minus deionized water control absorbance) regressed with solution parameters had excellent fits (R2 > 0.97). This suggests that interference correction is possible in aqueous extracts. The Folin and Ciocalteu's reactive‐phenolic C concentration in the citrate extracts of the phenolic acid mixture‐amended soils were not significantly different from the DI‐H2O control soil extracts indicating that the Folin and Ciocalteu's method is not suitable for use with soil citrate extractions. The large quantity of organic matter extracted by citrate probably masks absorbance due to any extracted phenolic compounds.

Influence of wheat streak mosaic virus infection on phenylpropanoid metabolism and the accumulation of phenolics and lignin in wheat

Wheat plants infected with wheat streak mosaic virus were studied for their physiological response to infection. Previous histological data suggest that wheat streak mosaic virus-induced deposits of phenolic nature are present along the bundle sheath and mesophyll cell walls. In this study, we examined this phenomenon further by analysis of phenolic compounds and enzymes involved in their synthesis. In infected plants, the amounts of free and wall-bound phenolic compounds increased slightly, and chromatography showed that the type of free phenolic compounds present had changed. The amount of lignin did not change due to infection. Enzyme assays showed that while phenylalanine ammonia lyase and tyrosine ammonia lyase activities decreased as they do in healthy plants, cinnamyl alcohol dehydrogenase activity stayed high throughout infection. In addition, peroxidase activities in infected plants decreased around the time that the leaves ceased to expand. These results suggest that the general phenylpropanoid pathway is stimulated upon infection, but that lignification is not.

Evolution of Antioxidant Activity during Kilning: Role of Insoluble Bound Phenolic Acids of Barley and Malt

Phenolic acids, bound to the cellular walls of the germinated barley, are very interesting potential antioxidants of beer. Indeed, the antioxidant activity due to these bound compounds is about 2-fold higher than the activity due to the free phenolic compounds. Seven phenolic acids were separated by HPLC after alkaline hydrolysis of the cake resulting from a methanolic extraction of barley or malt. Three main compounds, trans-ferulic acid, trans-p-coumaric acid, and cis-ferulic acid, were quantified using an external standard method. They respectively represent 177.79, 78.50, and 47.15 μg/g of dry matter of germinated barley. Responsible for 20-40% of the antioxidant activity of the hydrolyzed cake, they probably have a real influence on the evolution of this activity during kilning.

Tissue-Specific Metabolism of Benzene in Zymbal Gland and Other Solid Tumor Target Tissues in Rats

In vitro studies were carried out to investigate whether target organ susceptibility to benzene-induced solid tumor formation is governed by tissue-specific differences in metabolism. The ability of several target and nontarget tissues to deconjugate and conjugate polar metabolites, to metabolize benzene to phenolic metabolites, to carry out peroxidative biotransformations, and to trap tissue glutathione was evaluated. The Zymbal gland, the organ most sensitive to benzene-induced tumorigenicity, showed extensive phenyl- and aryl-sulfatase activity but no phenol sulfoconjugating activity. Similarly, oral cavity tissue, mammary gland, and bone marrow showed sulfatase activity but lacked sulfotransferase activity. Sulfatase-mediated hydrolysis such as that observed in the Zymbal gland may represent an important pathway by which polar metabolites are shunted from urinary or biliary excretion as their sulfates to delivery to target tissues as phenolic or potentially reactive metabolite(s). Zymbal gland, nasal and oral cavity, and mammary gland tissue homogenates (10,000 g supernatant) all possess oxidative capability to metabolize benzene to phenol, hydroquinone, and catechol. Nasal cavity homogenates produced two-to eightfold higher levels of phenol, hydroquinone, and catechol from benzene than did liver homogenates. Zymbal gland, bone marrow, and oral cavity homogenates, when incubated with hydroquinone and glutathione, produced high levels of 2-(S-glutathionyl)hydroquinone, indirectly indicating the production of 1,4-benzoquinone, a reactive intermediate implicated in benzene toxicity. Peroxidases have been proposed to mediate the oxidation of p-hydroquinone to 1,4-benzoquinone. The Zymbal gland, nasal and oral cavities, mammary gland, and bone marrow all were found to possess greater peroxidase activity than contrasting nontarget tissues did. The metabolic capabilities of target tissues, including the ability to hydrolyze sulfate conjugates to free phenolic compounds, to oxidize benzene to phenolic metabolites, to bioactivate hydroquinone to a reactive intermediate, and to carry out peroxidative reactions may offer possible explanations for the greater susceptibility of these sites to benzene-induced tumorigenicity. Transport of sulfate conjugates and their release via hydrolysis (e.g., through sulfatase action) (“sulfate shunting”) and subsequent oxidation (e.g., through peroxidase action) may represent a novel mechanistic pathway by which potentially reactive benzene metabolites can gain access to target sites and initiate critical genotoxic events.

Toxicity in Relation To Structure of Substituted 2H-1-Benzopyran-2-Ones Against Root-Knot and Seed-Gall Nematodes

The toxicity of various hydroxy substituted 2H-1-benzopyran-2-ones (la-c, 2 and 3), ester (la-c, 5 and 6) and hydrazide (7a-c, 8 and 9) derivatives of 2H-l-benzopyranyloxyacetic acids and 2H-l-benzopyranyloxyacetylpiperidines (10a-c, 11 and 12) and corresponding morpholines (13a-c, 14 and 15) was determined against second stage juveniles of root-knot nematode (Meloidogyne javanica) and seed-gall nematode (Anguina tritici). Several of the compounds showed appreciable toxicity against both the tested nematodes. The activity results are discussed in relation to structure of the compounds. In general, the free phenolic compound and derived esters exhibited better toxicity.

Formation of Phenolic Compounds from the Callus of Bangah (Isodon japonicus, Hara)

The color of growting Bangah callus changed qnickly from white to dark brown in MS medium containing 2,4-D and kinetin at 1 ppm each. The callus produced a large amount of total polyphenols, about 1.45–2.98% dry weight. The amounts of bound phenolic compounds were larger than the free compounds. Among the free phenolic compounds, cinnamic acid was the most plentiful and major components of insoluble-bound phenolic compounds were ferulic, cinnamic, and sinapic acids.

Phenolic compounds in peanut seeds: Enhanced elicitation by chitosan and effects on growth and aflatoxin b1production byaspergillus flavus

Abstract Effects of chitosan and Aspergillus flavus to enhance elicitation of phenolic compounds in viable peanut seeds were conducted at two water activity levels. In vitro effects of phenolic acids on A. flavus growth and aflatoxin B1 production were also studied. Chitosan enhanced elicitation of free phenolic compounds (FPC) at Aw .85 and .95 levels. A. flavus treatment initially decreased and subsequently increased FPC content, but bound phenolic compounds (BPC) decreased during incubation. Chitosan + A. flavus treatments caused an increase in FPC that reached a plateau between 24–48 h at Aw .85 while BPC levels increased over the same time period at both Aw levels. The major free and bound phenolic acids detected were p‐coumaric and ferulic acids and an unknown phenol that eluted at a retention time of 22 min. Generally, chitosan treatment significantly enhanced elicitation of free ferulic and p‐coumaric acids and bound p‐coumaric acid at Aw .95. Free unknown phenolic and bound ferulic acids at Aw .8...

Preliminary Studies on Peptides in Wine by HPLC

Due to the importance of peptides and the absence of any analytical method for their study in wine using HPLC, an analytical method was developed which includes ultrafiltration for the separation of proteins and low pressure column chromatography using Sephadex LH-20 for separation of free amino acids and phenolic compounds. Peptide derivatives with <i>o</i>-phthalaldehyde were separated by reverse phase HPLC. Principal amino acids from peptides are: glutamic and aspartic acids, serine, glycine, alanine, and lysine.

Effects of phenolic smoke condensates and their components on hepatic drug metabolizing systems

Treatment of food with wood smoke is a long-established method of preservation and flavouring food. Recently, hardwood smoke condensates, purified of polycyclic hydrocarbons, have become of importance for direct flavouring of sausage-meat. The acute toxicity of the purified phenolic fraction in mice after intraperitoneal administration was therefore investigated. The LD 50 was found to be 940 mg/kg body weight, which is about three times the LD 50 of phenol (about 300 mg/kg). Only high concentrations of phenols or smoke condensate fractions are able to damage cytochrome P-450 by conversion to cytochrome P-420, whereas lower concentrations exhibit inhibitory effects on mono-oxygenase activity. Inductive properties of the phenolic fractions could not be demonstrated. Concentrations in vivo of free phenolic compounds do not reach inhibitory levels, since the hexobarbital-induced sleeping-time and 14CO 2-exhalation after administration of p-[methoxy- 14C] acetanilide are not altered. It is concluded that the phenolic compound intake with food regularly treated with smoke condensate fractions is below a toxicologically relevant level.

Effects of growth conditions on grain molding and phenols in sorghum caryopsis

Phenolic compounds (PC) and phenolic acids (PA) were quantified in mature caryopses of sorghum grown in wet or dry environments. Seventeen cultivars varying in pericarp color and presence of a pigmented testa exhibited different levels of resistance to molding in the wet environment. Sorghum caryopses with a white pericarp contained lower levels of free PC (14μg/caryopsis) than those with a red pericarp (41 μg/caryopsis) when grown in the dry environment. This difference diminished under humid conditions. Cultivars with a pigmented testa were more resistant to grain molding, contained higher levels of free PC (151 μg/caryopsis), and had a softer endosperm texture than cultivars without a pigmented testa. In cultivars without a pigmented testa, higher levels of free PC and free PA, especially free p-coumaric, ferulic, and caffeic acids, were observed in mold-susceptible cultivars. A scatter plot of free PC vs. free p-coumaric acid indicated that mold-susceptibility was related to higher levels of p-coumaric acid, regardless of environment.

Reproductive Function in the Mimosoid Legume Acacia retinodes: Ultrastructural and Cytochemical Characteristics of Stigma Receptivity

The stigma of Acacia retinodes is receptive from the moment the flower opens (female phase). Receptivity, assessed in terms of pod set, is highest at flower opening, and lowest the following day (male phase). Stigma receptivity is associated with the acquisition of a heterogeneous stigma exudate, the components of which are secreted sequentially during differentiation. Cytochemical probes have tentatively identified the principal components as unsaturated and saturated lipids, free fatty acids, flavonoid aglycones, carbohydrates, proteins and phenolic compounds. The onset of male phase in unpollinated stigmas is associated with a breakdown of the plasma membrane and organelle membranes of stigma cells, and subsequently a browning reaction.

Effect of methanol/acetone/water extraction and enzymatic hydrolysis on the nutritional value of unheated rapeseed proteins

The objective of this work was to study the effect of the extraction of phenols by methanol/acetone/water and proteolysis (pepsin 1 hour; trypsin 2 hours) on the nutritional characteristics of unheated rapeseed protein as measured by weight gain, protein intake, net protein ratio, apparent digestibility and absorbed protein. The effect of proteolysis of the methanol/acetone/water extracted rapeseed protein, and the effect of mixing the methanol/acetone/water extract back with the extracted rapeseed protein was also studied. Extraction of phenolic compounds from rapeseed flour significantly improved weight gain, protein intake, net protein ratio and absorbed protein value. However, the mixing of phenolic extract with the extracted rapeseed protein did not appear to have a significant effect. Enzymatic hydrolysis (1 hour with pepsin and 2 hours with trypsin) of the raw material significantly improved the weight gain and protein intake. The combined methanol/acetone/water extraction and protein hydrolysis treatments were beneficial on all nutritional quality parameters of rapeseed protein. These results suggest that the protein-bound phenolic compounds, rather than the free phenolic compounds contribute mainly to the decrease in the nutritional values of proteins associated with phenolic compounds in raw flour before extraction.

Phenolic compounds in different sorghum tissues during maturation

Sorghum bicolor (L.) Moench contains phenolic compounds which vary according to growth stage and plant tissue. Caryopses, glumes, stalks, and leaves of AT × 623 ∗ CS3541 were sampled from 0 do t0 days after anthesis (DAA) and analyzed for free phenolic compounds (FPC) using the Folin-Ciocalteu method and total phenolic acids (TPA) using high performance liquid chromatography. Average levels of FPC were 0·5 (caryopses), 2·2 (glumes), 0·9 (stalks), and 6·2 mg g −1 (leaves). Caryopses and glumes had higher FPC levels 15 DAA; FPC levels within stalks did not change during maturity; young, lower leaves had higher FPC levels. Average levels of TPA were 2·5 (caryopses), 10·6 (glumes), 4·8 (stalks), and 7·6 mg g −1 (leaves). Caryopses and stalks contained stable levels of TPA during maturation. Glumes contained maximum levels of TPA at physiological maturity of caryopsis (27 DAA) while young, upper leaves contained more TPA. The most abundant phenolic acids, p-coumaric, salicyclic, and ferulic acids, were present at 0·2–2·0 mg g −1. These levels of FPC and phenolic acids are inhibitory to many microbes and enzymes involved with digestion of biomass in the rumen of livestock and in biomass-fuel systems.

Inhibitors in Sorghum biomass during growth and processing into fuel

The presence and inhibitory activity of phenolic compounds in sorghum biomass were determined. Sorghum contains phenolic compounds at all stages of growth, with higher levels in leaves and glumes compared to stalks and caryopses. The phenolic compounds inhibited alpha- and gluco-amylase activity. Storage of sorghum resulted in increased levels of some phenolic acids. Levels of free phenolic compounds in ensiled sorghum leachate were sufficient to inhibit the hydrolysis of carbohydrates. The phenolic compounds from sorghum appeared to be detoxified during anaerobic digestion.

Enzymatic biotransformations of Peritan-Na by immobilized fungal mycelium fragments ofTrametes versicolor

The mycelium ofTrametes versicolor after 5 d growing in submerged cultures was homogenized and the pellets containing cell membranes were immobilized on alkylamine glass beads. The immobilized mycelial fragments were able to modify the molecular weight of Peritan-Na after only 4 h of incubation. Besides this phenomenon, the release of six free phenolic compounds was detected. Among these there were, for example, vanillin derivatives, syringic acid, andp-hydroxybenzaldehyde. This release was dependent upon pH, temperature, and the reaction time of the supposed enzymatic mechanism of the reaction. In short term (up to 6 h) experiments, the complex polymer of Peritan-Na might be transformed into molecules approximately closer to monomers of lignin as well as new lignin-like forms. According to our observations, the biotransformation of Peritan-Na follows a series of enzymatic reactions. It is supposed that enzymes necessary for these reactions are present in immobilized cell membrane fragments ofTrametes versicolor.

Preparation of colorless sunflower protein products: Effect of processing on physicochemical and nutritional properties

AbstractA comparison was made of the different technological treatments for the preparation of colorless sunflower protein products from the viewpoint of the effect of processing conditions on the extraction yield of nitrogen and lipid, chemical, physicochemical and nutritional properties of the processed products. The technological treatments comprised soaking dehulled seeds in dilute citric acid or sodium bisulfite solution and washing the defatted meal with the respective solution. The defatting process was carried out with hexane or azeotrope (hexane/ethanol). Nitrogen and lipid recovery was slightly greater for hexane defatted products than for azeotrope defatted products. About 21.4% of the phenolic compounds of the sunflower seeds were bound to the proteins of the seeds before processing and therefore could not be eliminated by the aqueous extraction. Aqueous extraction of phenolic compounds was limited for full fat seed. The free phenolic compounds were very stable in acid medium but sensitive to oxidation in alkaline medium and had no significant effect on in vitro enzymatic proteolysis and growth inhibition of rats. Lysine and the bound phenolic compounds were the critical factors responsible for inhibition of enzymatic proteolysis and reduced growth of rats. The diet containing whole seed meal presented a low protein efficiency ratio (PER) value. Citric acid, a chelating agent, proved to be an antioxidant as effective as sodium bisulfite; the products obtained by citric acid treatment had a visually whiter color than those processed by sodium bisulfite.

Hydrolysis of bis(p-hydroxyphenyl)pyridyl-2-methane disulfate. I. Presence of arylsulfatase and laxative activity.

The laxative action of bis (p-hydroxyphenyl) pyridyl-2-methane disulfate is considered to be dependent on the formation of the free phenolic compound, bis (p-hydroxyphenyl)-pyridyl-2-methane by hydrolysis. Therefore, the activity of the parent compound as a laxative must be governed by arylsulfatase activity in the human intestine. When examinations of human feces were made, arylsulfatase activity in the intestine was detected, and about 98% of the samples were shown to be positive. Validity of the fecal arylsulfatase test in the test population might be supported by the liquefaction test of rat feces with the injection of the parent compound into duodenum.

Characterization of New Glycosides from the Fermentation Broths of Streptomyces hygroscopicus

Abstract Four new glycosides, hygromycin C, and Compounds D, E, and F, isolated from the fermentation broths of Streptomyces hygroscopicus, have been partially characterized. Adsorption spectra in the infrared and ultraviolet regions and isolation of components after acid and basic hydrolysis indicated that the glycosides have a similar aglycon, composed of 3,4-dihydroxy-α-methylcinnamic acid or an isomer of this compound and neoinosamine-2, linked via an amide bond. An unusual feature was the dioxymethylene bridge previously reported to exist on the inosamine portion of hygromycin A, evidence for which was obtained for hygromycin C but not for Compounds D, E, or F. The carbohydrate component of Compound F was identified as D-glucose, and that of hygromycin C as L-fucose. The carbohydrate component of Compounds D and E was determined to be a 5-keto-6-deoxyarabohexose; it was not determined if this was the D or L form. A number of free phenolic compounds were found in the ether-soluble extract of acidified broths and two of these were identified as p-hydroxybenzoic acid and 3,4-dihydroxy-α-methylcinnamic acid.

DEACETYLATION AND ABSORPTION OF PHENOLATED LAXATIVES

The acetylated phenolic laxatives bisaeodyl and diphesatin become absorbable from the intestine and active, pharmacologically, after deacetylation. The cleavage of the acetyl groups is effeeted by an enzyme present in the intestinal lumen. Diphesatin which is hardly soluble in water, is cleaved only to a small proportion, probably about 10%. Accordingly, the free phenolic compound is ten times more active as a laxative than the original acetylated compound. Bisacodyl, having a slightly better water solubility than diphesatin is deacetylated completely and thus its deacetylated derivative is only as active as bisacodyl itself. The acetyl compounds as such are, probably, neither absorbed nor active. After absorption the compounds are re-excreted into the intestine partly, and partly eliminated by the kidney. Excretion of bisacodyl into the intestine is effeeted via the bile. Only after this does the compound become active in the colon. This is substantiated by the fact that ligating the bile duct or the ileum prevents the laxative effect regardless whether (deacetylated) bisacodyl has been given orally or intraperitoneally. As on the first passage through the intestine the deacetylated compound is absorbed, one has to conclude that after re-excretion it is present in the gut in another state which prevents enteral absorption. In this state it moves down the intestinal tract and reaches the colon by this way. Another explanation of the experimental findings would be to assume t h a t bile is necessary for the laxative effect and that the ligatures would only prevent bile from reaching the colon. This explanation is, however, less likely as even with simultaneous application of bovine bile is bisacodyl, given by mouth, ineffective when the bile duct is ligated. Further, bisaeodyl on rectal application is active in patients with biliary obstruction and stimulates the isolated perfused (bile-free) colon of cats (Goring and Schaumann).

Patent invention

Physical features, bioactive compounds and total antioxidant capacity (TAC) of coloured quinoa varieties (Chenopodium quinoa Willd.) from Peruvian Altiplano were studied. Quinoa seeds did not show a pure red colour, but a mixture which corresponded to different fractal colour values (51.0–71.8), and they varied from small to large size. Regarding bioactive compounds, total phenolic (1.23–3.24 mg gallic acid equivalents/g) and flavonol contents (0.47–2.55 mg quercetin equivalents/g) were highly correlated (r = 0.910). Betalains content (0.15–6.10 mg/100 g) was correlated with L colour parameter (r = −0.569), total phenolics (r = 0.703) and flavonols content (r = 0.718). Ratio of betaxanthins to betacyanins (0.0–1.41) was negatively correlated with L value (r = −0.744). Whereas, high TAC values (119.8–335.9 mmol Trolox equivalents/kg) were negatively correlated with L value (r = −0.779), but positively with betalains (r = 0.730), as well as with free (r = 0.639), bound (r = 0.558) and total phenolic compounds (r = 0.676). Unexploited coloured quinoa seeds are proposed as a valuable natural source of phenolics and betalains with high antioxidant capacity.