Related Phenolic Compounds Research Articles

Artifacts in Cell Culture: Rapid Generation of Hydrogen Peroxide on Addition of (−)-Epigallocatechin, (−)-Epigallocatechin Gallate, (+)-Catechin, and Quercetin to Commonly Used Cell Culture Media

There is considerable current interest in the possible beneficial health effects of quercetin, catechins, epigallocatechins, epigallocatechin gallates, and related phenolic compounds found in teas, wines, and other plant products. As a result, many laboratories are studying the effects of these compounds on cells in culture. The present paper shows that addition of these compounds to commonly used cell culture media leads to generation of substantial amounts of hydrogen peroxide (H2O2). Dulbecco's modified Eagle medium gives the highest H2O2 level for all the compounds tested, with levels reaching >400 μM within 2 h for addition of 1 mM concentrations of gallic acid, epigallocatechin gallate, and epigallocatechin. Catechin and quercetin produced lower, but still significant, levels of H2O2. McCoy's 5A and RPMI 1640 media also promoted H2O2 production from the above phenolic compounds. This rapid generation of H2O2 could account for some or all of the reported effects of phenolic compounds on cells in culture.

Oleuropein and related compounds

In this paper, oleuropein and some other related phenolic compounds are reviewed. Their occurrence, distribution, biosynthesis and transformation during maturation and during industrial processing (preparation of table olives and oil production) are described. Their role in human health is proposed based on current human, animal and in vitro studies as molecules with antioxidant and antimicrobial properties. © 2000 Society of Chemical Industry

Production of lithospermic acid B and rosmarinic acid in hairy root cultures of Salvia miltiorrhiza

Hairy root cultures of Salvia miltiorrhiza were established by infecting sterile plantlets with Agrobacterium rhizogenes ATCC 15834, and the transformation was proved by direct detection of the inserted T-DNA by the polymerase chain reaction. As determined by HPLC, these hairy root cultures had the ability to produce lithospermic acid B (LAB), rosmarinic acid (RA) and other related phenolic compounds, the water-soluble active components of the plant. The effect of five different basal media, MS, MS-NH<INF>4</INF> (MS without ammonium nitrate), B5, WPM and 6,7-V on the root growth and phenolic compound production was studied. It was found that MS-NH<INF>4</INF> and 6,7-V media were superior to MS, B5 and WPM media in terms of both root growth and phenolic compound production. The time course of biomass accumulation and phenolic compound formation was also examined in the culture using MS-NH<INF>4</INF>medium. During cultivation, the content of RA in the roots was stable being approximately 0.48% of dry weight while the content of LAB fluctuated between 0.73% and 1.61% of dry weight, and decreased gradually at the stationary phase of growth. The highest production of LAB and RA was about 64 mg L−1 and 23 mg L−1, respectively.

Anti-diarrhoeal effects of seirogan in the rat small intestine and colon examined in vitro.

Seirogan is a beechwood extract composed of guaiacol, creosol and other related phenolic compounds which is widely used as an anti-diarrhoeal agent in Asia. Abnormalities in water and electrolyte transport are often the cause of diarrhoea, but the mechanism of action of seirogan on small intestinal and colonic mucosal ion transport is unknown. To examine the effect of seirogan on electrogenic ion transport in vitro. Sheets of rat jejunum and colon were mounted in Ussing chambers, and transmural potential difference (PD) was used as an electrical marker of changes in mucosal ion transport. Hypersecretory conditions were induced by acetylcholine (ACh). Serosal or mucosal application of seirogan (0.1-100 microg/mL) decreased basal jejunal transmural PD. Pre-treatment of the tissue with the neurotoxin, tetrodotoxin, did not inhibit the seirogan-induced changes in basal electrical activity. Seirogan had no effect on basal transmural PD in the ileum and colon. Under ACh-induced hypersecretory conditions in the small intestine and colon, addition of serosal or mucosal seirogan produced antisecretory effects determined indirectly by measurement of transmural PD. The ability of seirogan to decrease basal transmural PD in the jejunum, and inhibit the ACh-induced electrical responses, may contribute to its anti-diarrhoeal action.

Antioxidant and pro-oxidant actions of flavonoids: effects on DNA damage induced by nitric oxide, peroxynitrite and nitroxyl anion

Antioxidant and pro-oxidant activities of flavonoids have been reported. We have studied the effects of 18 flavonoids and related phenolic compounds on DNA damage induced by nitric oxide (NO), peroxynitrite, and nitroxyl anion (NO −). Similarly to our previous findings with catecholamines and catechol-estrogens, DNA single-strand breakage was induced synergistically when pBR322 plasmid was incubated in the presence of an NO-releasing compound (diethylamine NONOate) and a flavonoid having an ortho-trihydroxyl group in either the B ring (e.g., epigallocatechin gallate) or the A ring (e.g., quercetagetin). Either NO or any of the above flavonoids alone did not induce strand breakage significantly. However, most of the tested flavonoids inhibited the peroxynitrite-mediated formation of 8-nitroguanine in calf-thymus DNA, measured by a new HPLC-electrochemical detection method, as well as the peroxynitrite-induced strand breakage. NO − generated from Angeli’s salt caused DNA strand breakage, which was also inhibited by flavonoids but at only high concentrations. On the basis of these findings, we propose that NO − and/or peroxynitrite could be responsible for DNA strand breakage induced by NO and a flavonoid having an ortho-trihydroxyl group. Our results indicate that flavonoids have antioxidant properties, but some act as pro-oxidants in the presence of NO.

The phenolic recognition profiles of the Agrobacterium tumefaciens VirA protein are broadened by a high level of the sugar binding protein ChvE.

The formation of crown gall tumors by Agrobacterium tumefaciens requires that the virulence (vir) genes be induced by chemical signals which consist of specific phenolic compounds and monosaccharides, synthesized at plant wound sites. Signal transduction in the activation of these genes is mediated by the VirA-VirG two-component regulatory system, together with ChvE, a glucose-galactose binding protein which interacts with VirA. We have previously presented genetic evidence that virA senses phenolic compounds directly (Y.-W. Lee, S. Jin, W.-S. Sim, and E. W. Nester, Proc. Natl. Acad. Sci. USA 92:12245-12249, 1995). The vir genes of strain KU12 can be induced by 4-hydroxyacetophenone, p-coumaric acid, and phenol, whereas these same phenolic compounds are weak inducers of the vir genes of strain A6. In this report, we show that a specific inducing sugar can broaden the specificity of the phenolic compound which VirA senses. 4-Hydroxyacetophenone and other related phenolic compounds function as inducing phenolic compounds with the virA gene of A6 if arabinose replaces glucose as the inducing sugar. We further demonstrate that this broadened specificity for phenolic inducers results from the increased level of ChvE through induction by arabinose via the regulatory protein GbpR. If high levels of ChvE are present, then poorly inducing phenolic compounds can induce the vir genes to high levels in combination with glucose. Comparing the induction response of the wild type and that of a VirA mutant with a mutation in its receiver domain revealed that the activity of the receiver domain is controlled by the periplasmic domain. We discuss these observations in terms of how VirA senses and transduces signals elicited by the two classes of plant signal molecules.

HPLC with fluorescence detection of urinary phenol, cresols and xylenols using 4-(4,5-diphenyl-1H-imidazol-2-yl)benzoyl chloride as a fluorescence labeling reagent.

A simple and sensitive HPLC method for the determination of phenolic compounds, i.e., phenol (Phe), cresols (Cres) and xylenols (Xyls), was developed. After a pre-column fluorescence derivatization of these compounds with 4-(4,5-diphenyl-1H-imidazol-2-yl)benzoyl chloride (DIB-Cl) at 60 degrees C for 30 min, 11 DIB derivatives were successfully separated within 50 min with an ODS column using CH3CN-H2O-CH3OH (25 + 22 + 53, v/v) as the eluent. The detection limits of DIB derivatives at a signal-to-noise ratio of 3 ranged from 0.15 to 1.09 microM (0.2-1.6 pmol per 20 microliters). The precision of the proposed method for both within- and between-day assays of free and total phenol related compounds was satisfactory (RSD < 9.5%). By the proposed method, Phe and p-Cre could be detected in normal urine samples, and the calculated concentrations of free Phe and p-Cre in unhydrolysed urine samples were 1.5 +/- 1.3 and 23.9 +/- 24.3 microM and those of total Phe and p-Cre in hydrolysed urine samples were 87.3 +/- 81.2 and 200.7 +/- 195.4 microM (n = 21), respectively.

Effects of pectolytic enzymes on selected phenolic compounds in strawberry and raspberry juices

To evaluate the effect of commercial pectolytic enzymes on the content of phenolic compounds (anthocyanins, flavonols and ellagic acids), strawberry and raspberry juices under enzymatic pectinase treatment were analyzed using High Performance Liquid Chromatography (HPLC) with Spectral Array Detection (SAD). Each fruit had a distinctive phenolic pattern which enabled identification and characterization. The stability of phenolic compounds during processing was monitored at 2, 4 and 6 h. The use of commercial pectinases modified the composition of phenolic compounds in relation of the fruits and the time considered. At 6 h, a loss of anthocyanins (−20%) present in raspberry juice was observed when Pectinex® BE 3-L, Rohapect® B1L, Rohament® MAX and Pectinex™ 3XL were used. This result confirmed the hypothesis of a β-glycosidase activity present into commercial pectinase. On the other hand, in strawberry treated samples the ellagic acids concentration always increased (up to 19 mg l −1 with Pectinase™ LM, at 6 h) while flavonols content decreased (−35% with Pectinase™ LM, at 6 h). Rohapect® MB was the only enzyme able to considerably increase the content of total quercetin derivatives in raspberry (36 mg l −1).

Effects of the antioxidant turmeric on lipoprotein peroxides: Implications for the prevention of atherosclerosis

Extracts from the rhyzome of Curcuma longa are widely used as food additives in India and other Asiatic and Central American countries. It has been shown that these extracts ("turmeric"), as well as "curcumin" and related phenolic compounds isolated from Curcuma, have a powerful antioxidant action when tested in in vitro systems. Moreover, previous research from our laboratories has shown significant decreases in the levels of lipid peroxides in the blood of both mice and human subjects administered "turmeric." Our present research complements the previous data, showing that a daily intake of turmeric equivalent to 20 mg of the phenolic antioxidant curcumin for 60 days decreases the high levels of peroxidation of both the HDL and the LDL, in vivo, in 30 healthy volunteers ranging in age from 40 to 90 years. The effect was quite striking in the persons with high baseline values of peroxidized compounds in these lipoproteins, while no apparent change took place in the persons having low baseline values. In view of current concepts on the atherogenic role played by peroxidized HDL, and especially by peroxidized LDL, as inducers of foam and smooth cell proliferation in the arterial wall, this preliminary experiment suggests that the Curcuma phenolic antioxidants, because of their high antioxidant activity and lack of toxicity, might be a useful complement to standard hypo-lipidemic drugs in the prevention and treatment of atherosclerosis.

Antioxidant activity of Magnolol, honokiol, and related phenolic compounds

AbstractThe antioxidant activity of 10 Japanese and Chinese crude drugs (Kampo drugs) was determined in vitro. Extract of Magnolia cortex, which had the highest antioxidant activity, contained phenolic compounds magnolol and honokiol. However, inhibitory effects of these compounds on lipid oxidation were weaker than that of α‐tocopherol as measured by thiobarbituric acid assay. The structure‐activity relationship of phenolic compounds showed that antioxidant activities were in the order 4‐allyl‐2,6‐dimethoxyphenol ≥ p,p′‐biphenol &gt; eugenol &gt; 2‐allyl‐6‐methylphenol &gt; honokiol &gt; magnolol &gt; caffeic acid &gt; p‐ethylphenol &gt; guaiacol. As expected, these results showed that an electron donor and/or bulky groups at the ortho‐ or para‐position of the phenol were required for inhibition of lipid oxidation. Electron spin resonance spin trapping experiments showed that phenol compounds with an allyl substituent on their aromatic rings directly scavenged superoxide (O2−), and that only eugenol trapped hydroxyl radicals. These findings suggest that phenolic compounds that contain allyl groups may be effective antioxidants because of the scavenging ability of O2− or hydroxyl radical, whereas other phenols, without an allyl moiety such as α‐tocopherol, may play a role in the termination of free radical chain reactions.

Inhibition of arachidonate lipoxygenase activities by 2-(3,4-dihydroxyphenyl)ethanol, a phenolic compound from olives.

The effects of olive fruit extract on arachidonic acid lipoxygenase activities were investigated using rat platelets and rat polymorphonuclear leukocytes (PMNL). Olive extract strongly inhibited both 12-lipoxygenase (12-LO) and 5-lipoxygenase (5-LO) activities. One of the compounds responsible for this inhibition was purified and identified as 2-(3,4-dihydroxyphenyl)ethanol (DPE). DPE inhibited platelet 12-LO activity (IC50, 4.2 microM) and PMNL 5-LO activity (IC50, 13 microM) but not cyclooxygenase activity in cell-free conditions. It also inhibited 12-LO activity in intact platelets (IC50, 50 microM) and reduced leukotriene B4 production in intact PMNL stimulated by A23187 (IC50, 26 microM). The inhibition by DPE of both lipoxygenase activities was stronger than that by oleuropein, caffeic acid, or 7 other related phenolic compounds, especially in intact cells. These results suggest that DPE is a potent specific inhibitor of lipoxygenase activities.

Mass Spectrometric Behavior of 5-S-Cysteinyldopa and Structurally Related Phenolic Compounds. Fragmentation Susceptibility of the Alkylthioether Bond Under Electron Impact and Fast Atom Bombardment Conditions

The marked proclivity of 5-S-cysteinyldopa (1) and related phenolic alkylthioethers to undergo UV-induced desulfurization via primary photohomolytic cleavage of the CH 2 -S bond prompted an investigation of the mass spectrometric behavior of these compounds with a view to obtaining information on the intrinsic susceptibility to dissociation of the alkylthioether bond under non-irradiative conditions. Dealkylative fission of the carbon-sulfur bond was found to be an important dissociative channel in the fragmentation patterns of 1 and related compounds, including cysteinylhydroquinone (2), 4-S-cysteaminylphenol (3) and 4-S-cysteaminylcatechol (4) under electron impact conditions. The mode of fission and relative susceptibility of the CH 2 -S bond were, however, profoundly different in cysteaminyl vs. cysteinyl compounds. In particular, the former showed a marked tendency to undergo simple homolytic fission, whereas in the latter dealkylative C-S bond cleavage occurred largely via an intramolecular rearrangement mechanism, and proved highly sensitive to protonation-induced effects, as evidenced in fast atom bombardment experiments. Desulfurization processes with neat loss of the alkylthio residue, like those occurring upon UV irradiation, were virtually absent in the fragmentation patterns of 3 and 4, and provided only a minor contribution to those of 1 and 2. These and other data reported open fresh prospects for future studies on the chemistry and mass spectrometric behavior of 1 and structurally related phenolic compounds of biological relevance.

Antioxidant Curcuma extracts decrease the blood lipid peroxide levels of human subjects

Extracts of the rhyzome of Curcuma longa are widely used as food additives in India and other Asiatic and Central American countries. Moreover, it has been recently shown that these extracts (“turmeric”), as well as “curcumin” and related phenolic compounds isolated from Curcuma, have a powerful lipid anti-oxidant action, when tested in in vitro systems. This justifies the present attempt to find out whether hydroalcoholic extracts of Curcuma longa also exert an antioxidant effect in human subjects. Our data show that a 45-day intake (by healthy individuals ranging in age from 27 to 67 years) of Curcuma hydroalcoholic extract (at a daily dose equivalent to 20 mg of curcumine) results in a significant decrease in the levels of serum lipid peroxides. These peroxides probably play an important pathogenic role in normal senescence and age-related diseases such as atherosclerosis. Therefore, hydroalcoholic extracts of Curcuma longa (that have very low toxicity and have been cleared as food additives in the above countries) may find use in future preventive geriatrics after further clinical studies.

Carcinogenicity, mutagenicity and cancer preventing activities of flavonoids: a structure-system-activity relationship (SSAR) analysis.

Flavonoids and related phenolic compounds are widely distributed among vascular plants and are found in numerous fruits, grains vegetables and other parts of higher plants [1–3]. Isolation and structural determination of flavonoids have been employed in plant taxonomy [1, 2]. Because of the wide range of chemical structures of flavonoids, coupled with a variety of test systems and different dose levels used, sometimes conflicting reports have been published in the literature regarding their numerous pharmacological and toxicological activities. This prompted us to conduct a literature survey and a structure-system-activity-relationship (SSAR) analysis of existing data, with particular emphasis on the carcinogenicity/mutagenicity and cancer preventive aspects of the flavonoids.KeywordsMutagenic ActivityGenic DerivativeFlavonol GlycosideNational Toxicology ProgramSwiss Male MouseThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Sensing characteristics of an immobilized apple powder enzymic sensor

A polyphenol oxidase sensor has been fabricated by covering a dissolved oxygen probe with a polycarbonate membrane on which fine apple powder, which has been thoroughly washed and vacuum dried, is immobilized. The sensor shows good response and baseline recovery time, and good sensitivity, reproducibility and service life towards dopamine and other phenolic-related compounds. The natural environment of the polyphenol oxidase has a significant effect on its sensitivity and selectivity to various organic solutes. The pretreated apple powder used for the present sensor shows preferential sensitivity to dopamine. Major interfering solutes include l-DOPA, l-cysteine, tyrosine, DOPAC, catechols and l-histidine.

Improved extraction and reversed phase‐high performance liquid chromatographic separation of flavonoids and the identification of Rosa cultivars

AbstractOptimal extraction methods and Reversed‐Phase High Performance Liquid Chromatographic (RP‐HPLC) procedures were developed for the isolation and resolution of naturally occurring flavonoids and related phenolic compounds in Rosa petals. The following flavonoids and related phenolics were identified or partly identified: cyanidin 3, 5‐di‐O‐glucoside; cyanidin 3, 5‐di‐O‐glycoside (sugar moieties, glucose and arabinose); pelargonidin 3, 5‐di‐O‐glycoside; pelargonidin 3‐O‐glycoside; quercetin 3‐O‐glucoside; ellagic acid; quercetin 3‐O‐arabinoside; quercetin 4′‐O‐glucoside; kaempferol 4′‐O‐glucoside; kaempferol 3‐O‐rutinoside; kaempferol 3‐O‐glycoside; kaempferol 3‐O‐arabinoside; kaempferol 3‐O‐rhamnoside and kaempferol 3‐O‐glycoside. Significant qualitative and quantitative differences between the above flavonoid markers allowed an objective distinction between 44 cultivars examined. The production of ‘Flower Flavonoid RP‐HPLC Fingerprints’, which have been converted in the corresponding ‘Computer Flower Flavonoid Identity Cards’ via a suitable computer program, has proven to be of great value for Rosa cultivar recognition.

Improved determination of vanillin and related phenolic components in vanilla (Vanilla fragrans (Salisb.) Ames) by high‐performance liquid chromatography

AbstractThis paper describes a reverse‐phase high‐performance liquid chromatographic (HPLC) method for the separation, identification and quantification of vanillin and related phenolic compounds in ethanolic extracts of cured vanilla. The compounds were separated on a silica column, bonded with pentafluorophenyl, using a mobile phase gradient of methanol–citric acid with diode‐array detection at 275 nm. Vanillin, vanillic acid, p‐hydroxybenzoic acid and p‐hydroxybenzaldehyde were identified by the spectral data and retention times given by reference compounds. Retention times and spectral data for a further 36 compounds are presented. The new HPLC technique allows a more accurate means of determining the vanillin content of vanilla than the ISO spectrophotometric assay.

Performance evaluation of full scale wastewater treatment facility for finished leather industry

Abstract Medium strength finished leather wastewater has been successfully treated using anaerobic and aerobic systems in laboratory scale. Encouraged with the results, a full scale wastewater treatment facility was commissioned in one of the modern leather finishing industry in India. It has been possible to achieve an effluent BOD level of about 135 mg/L with an influent BOD of about 1260 mg/L. It is worthwhile to mention that wastewater contains some toxic materials which are very difficult to degrade. However, other parameters like phenol related compounds have been reduced to 0.3 mg/L in the effluent. Total dissolved solids could not be contained by biological methods. In addition a tannery equation has also been developed from an extensive survey carried out in India.

Analysis of phenolic compounds in relation to the prediction of digestibility and toxicity of ammonia-treated cereal straws

Thirty-five samples of cereal straws were collected from farms in southern Spain before and after treatment with ammonia (35 g NH 3 kg −1 straw) in sealed plastic-covered stacks. Seven of the treated straws produced symptoms of acute toxicity (hyperexcitability) when fed to sheep and cattle. Total phenolic content (TP), phenolic material solubilised by water extraction of straws at 70 °C (SP) and residual, water-insoluble phenolics (RP) were measured by the acetyl bromide method. No significant differences were found between the mean TP or RP content of untreated (136 ± 9 g kg −1 straw and 112 ± 9 g kg −1 straw, respectively) and treated straws (145 ± 21 g kg −1 straw and 107 ± 9 g kg −1 straw, respectively). Ammonia treatment did not significantly increase the water solubility of the phenolic fraction of the non-toxic straws examined. The mean SP content of toxic straws however, was found to be three to four times greater (91 g kg −1 straw) than non-toxic treated straws (24 g kg −1 straw), this difference being reflected in the TP values which were approximately 30% higher in the toxic samples. A significantly higher proportion of added nitrogen was fixed in the toxic straws compared with their non-toxic counterparts. Limited analysis of SP fractions from toxic straws by thinlayer chromatography and gas chromatography-mass spectroscopy failed to reveal any compound which co-chromatographed with reference imidazoles including 4- O-methyl imidazole. Thin-layer chromatography fractionation showed qualitative differences between SP fractions from toxic and non-toxic straws but the compounds involved were not identified. Results obtained suggest that soluble phenolics do not provide a means of predicting the digestibility of ammonia-treated straw but that a substantially elevated soluble phenolic content is indicative of potential toxicity.

Antioxidative activities of Olea europaea leaves and related phenolic compounds

Olea europaea leaves, oleuropein, hydroxytyrosol and tyrosol were compared with vitamin E and BHT, with regard to their antioxidative activities, by kinetic studies in model systems. The thermal initiated oxidation of methyl linoleate was performed in homogeneous solution at 60° or 40° with or without antioxidants. Olea europaea extracts, oleuropein and hydroxytyrosol were much more effective than BHT or vitamin E in extending the induction period. Assuming a stoichiometric factor f = 2 for BHT, this coefficient of inhibition reached 5 for hydroxytyrosol, 7 for oleuropein and 10 for O. europaea extracts. These extracts owe their antioxidative properties to their high oleuropein content (19% w/w) and also to a lesser amount of flavonoids (1.8% w/w with 0.8% of luteolin 7-glucoside). Tyrosol showed neither antioxidant nor prooxidant activity. No synergistic effect on the preservation of methyl linoleate was found when vitamin E was used together with tyrosol or O. europaea extracts.