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PubMed1996

cDNA cloning and characterization of a 3'/5'-O-methyltransferase for partially methylated flavonols from Chrysosplenium americanum.

Enzymatic O-methylation of plant secondary metabolites is an important mechanism for the inactivation of reactive hydroxyl groups and for the modification of their solubility. A cDNA clone (pFOMT3') encoding the gene for the 3'/5'-O-methylation of partially methylated flavonols was isolated from Chrysosplenium americanum (Saxifragaceae). We used a PCR fragment obtained with degenerate oligonucleotides designed from conserved regions of various O-methyltransferases (OMTs). The pFOMT3' cDNA sequence shows about 67-85% similarity to other plant OMT sequences. The recombinant protein expresses strict specificity for positions 3'/5' (meta) of partially methylated flavonols, but does not accept quercetin or caffeic acid for further methylation. Southern blot analysis of the genomic DNA probed with an OMT sequence suggests the presence of a number of related genes in this species, consistent with the multiple enzymatic methylations involved in the biosynthesis of polymethylated flavonols in this plant.

Amino Acid Sequence↗
PubMed1993

Comparative cytotoxicities of selected minor dietary non-nutrients with chemopreventive properties.

The comparative acute cytotoxicities were determined for a varied spectrum of minor dietary non-nutrients that have been implicated as chemopreventive agents. Cytotoxicity was determined with the neutral red (NR) assay, using BALB/c mouse 3T3 fibroblasts as the bioindicators. Based on midpoint cytotoxicity (NR50) values, the range of cytotoxicity for the different chemicals varied by 1000 times. The sequence of potency was tannic acid, tamoxifen citrate, quercetin, benzyl and phenethyl isothiocyanate > glycyrrhetinic acid > indole-3-carbinol > caffeic acid > phytic acid > vanillin > ellagic acid > D-saccharic acid 1,4-lactone. Vanillin, at slight to moderately toxic concentrations, was the only test agent that induced multinucleation in the 3T3 fibroblasts.

3T3 Cells↗
PubMed2005

Determination of phenolics in cosmetic creams and similar emulsions.

A new method for the analysis of phenolics in cosmetic creams has been developed, based on a systematic study of the extractability of five phenolic compounds from such emulsions. A solid-liquid extraction using ultrasound was applied as a prior stage to the chromatographic determination of phenolics in the extracts. Three solvents, hexane, methanol and water, were used as extracting agents. These solvents permit both the de-emulsification of the creams and the extraction of phenolics. A factorial fractional experimental design was developed to analyse the influence in the extraction process of five different extraction variables: ultrasound horn, temperature, extracting volume, cycle and amplitude of ultrasounds. Graphic analysis of results revealed the variables with most influence in the extraction, as well as the interactions between the variables. Finally, the influence of the extraction time and the sample quantity were also studied. With this new method, phenolics can be extracted from silicone-based cosmetic creams in 10 min, using 50 degrees C as extraction temperature. RSDs (n=6) calculated ranged from 1.5% for ferulic acid to 6.5% for epicatechin. Recoveries of between 88.9% for gallic acid and 98.4% for caffeic acid were obtained.

Cosmetics↗
PubMed2004

Purification and cloning of a Chinese red radish peroxidase that metabolise pelargonidin and forms a gene family in Brassicaceae.

An anionic peroxidase RsPrx1 was purified (RZ=3.0) and characterized from roots of Chinese red radish (Raphanus sativus var. niger, Brassicaceae). The specific activity of RsPrx1 (micromol mg(-1) min(-1)) is 413.5 (ferulic acid); 258.7 (ABTS); 177.3 (caffeic acid) and 10.0 (guaiacol acid). The optimum pH is 4.0 (citrate buffer) using ABTS as substrate. RsPrx1 can utilise the red pigment present in the root, pelargonidin, as substrate and the specific activity is 93.6 micromol mg(-1) min(-1). The molecular mass of RsPrx1 is 45 kDa (denatured) and 46 kDa (native) as determined by SDS-PAGE and gel filtration, respectively. The isoelectric point (pI) determined by native IEF is 4.7 and by chromatofocusing (Mono P) is 5.1. Analysis of tryptic peptides by nanoscale liquid chromatography-tandem mass spectrometry (LC-MS/MS) covered 27% of the RsPrx1 sequence and confirmed its identity. The gene encoding RsPrx1 was cloned by PCR and the amino acid sequence showed the highest identity (82%) to peroxidase AtPrx22 and AtPrx23 from Arabidopsis thaliana and to HRPC3 and HRPE5 from horseradish, respectively. Activity-stained IEF gels show that RsPrx1 is primarily expressed in the roots in agreement with the expression profile of the orthologous genes. These five orthologous peroxidases have three introns of variable length and sequence at conserved locations between the distal and proximal histidine. The results suggest that RsPrx1 orthologs are widespread in the Brassicaceae plant family with a 15-residue-long C-terminal propeptide in common. Based on the results, we propose that RsPrx1 and orthologs are targeted to the vacuoles to modify stored anthocyanins like pelargonidin.

Amino Acid Sequence↗
PubMed2001

Properties of diphenolase from Vanilla planifolia (Andr.) shoot primordia cultured in vitro.

Properties of diphenolase (PPO, EC1.10.3.1) from vanilla (Vanilla planifolia Andr.) shoot primordia culture were investigated. Two pH optima of the enzyme extraction at pH 6 and 8 were found. Nevertheless, the enzymes shared the same optimum pH of activity-between pH 3 and 4. Sodium dodecyl sulfate slightly improved diphenolase extraction but caused a 3-fold increase in its specific activity. The extracts of pH 6 and 8.0 revealed three isozyme bands after polyacrylamide gel electrophoresis-two of them were similar in both extracts and two distinct. The enzyme showed high thermal stability-no loss was observed after 120 min at 50 degrees C. Diethyldithiocarbamic acid, ethylenediaminetetracetic acid disodium salt, ethylene glycol bis(beta-aminoethyl ether) N,N,N',N'-tetraacetic acid, L-ascorbic acid, dithiothreitol, glutathione (reduced), and beta-mercaptoethanol were found to be potent inhibitors of the diphenolase studied. The enzyme showed also monophenolase activity. Km and Vmax were calculated with monophenols [p-coumaric acid, 3-(p-hydroxyphenyl)propionic acid, 4-hydroxybenzyl alcohol, 4-hydroxybenzaldehyde, 4-hydroxybenzoic acid] and with diphenols (caffeic acid, hydrocaffeic acid, chlorogenic acid, 4-methylcatechol, protocatechuic aldehyde and acid, and 3,4-dihydroxyphenylalanine). The highest Vmax was found with 4-hydroxybenzyl alcohol and the greatest affinity to protocatechuic acid, respectively-the most abundant monophenol and one of the least abundant o-diphenols in the studied Vanilla tissue.

Catechol Oxidase↗
PubMed2007

High-amylose corn exhibits better antioxidant activity than typical and waxy genotypes.

The consumption of fruits, vegetables, and whole grains rich in antioxidative phytochemicals is associated with a reduced risk of chronic diseases such as cancer, coronary heart disease, diabetes, Alzheimer's disease, cataract, and aged-related functional decline. For example, phenolic acids are among the main antioxidative phytochemicals in grains that have been shown to be beneficial to human health. Corn (Zea mays L.) is a major staple food in several parts of the world; thus, the antioxidant activity of several corn types was evaluated. The 2,2-Diphenyl-1-picryhydrazyl free radical (DPPH*) scavenging activity, total phenolic content (TPC), antioxidant capacity of lipid-soluble substances (ACL), oxygen radical absorbance capacity (ORAC), and phenolic acid compositions of typical and mutant genotypes (typical-1, waxy, typical-2, and high-amylose) were investigated. The DPPH* scavenging activity at 60 min was 34.39-44.51% in methanol extracts and 60.41-67.26% in HCl/methanol (1/99, v/v) extracts of corn. The DPPH* scavenging activity of alkaline hydrolysates of corn ranged from 48.63 to 64.85%. The TPC ranged from 0.67 to 1.02 g and from 0.91 to 2.15 g of ferulic acid equiv/kg of corn in methanol and HCl/methanol extracts, respectively. The TPC of alkaline hydrolysates ranged from 2.74 to 6.27 g of ferulic acid equiv/kg of corn. The ACL values were 0.41-0.80 and 0.84-1.59 g of Trolox equiv/kg of corn in methanol and HCl/methanol extracts, respectively. The ORAC values were 10.57-12.47 and 18.76-24.92 g of Trolox equiv/kg of corn in methanol and HCl/methanol extracts, respectively. ORAC values of alkaline hydrolysates ranged from 42.85 to 68.31 g of Trolox equiv/kg of corn. The composition of phenolic acids in alkaline hydrolysates of corn was p-hydroxybenzoic acid (5.08-10.6 mg/kg), vanillic acid (3.25-14.71 mg/kg), caffeic acid (2.32-25.73 mg/kg), syringic acid (12.37-24.48 mg/kg), p-coumaric acid (97.87-211.03 mg/kg), ferulic acid (1552.48-2969.10 mg/kg), and o-coumaric acid (126.53-575.87 mg/kg). Levels of DPPH* scavenging activity, TPC, ACL, and ORAC in HCl/methanol extracts were obviously higher than those present in methanol extracts. There was no significant loss of antioxidant capacity when corn was dried at relatively high temperatures (65 and 93 degrees C) postharvest as compared to drying at ambient temperatures (27 degrees C). Alkaline hydrolysates showed very high TPC, ACL, and ORAC values when compared to methanol and HCl/methanol extracts. High-amylose corn had a better antioxidant capacity than did typical (nonmutant) corn genotypes.

Amylose↗
PubMed2005

Inhibition of activator protein-1, NF-kappaB, and MAPKs and induction of phase 2 detoxifying enzyme activity by chlorogenic acid.

Chlorogenic acid, the ester of caffeic acid with quinic acid, is one of the most abundant polyphenols in the human diet. The antioxidant and anticarcinogenic properties of chlorogenic acid have been established in animal studies. However, little is known about the molecular mechanisms through which chlorogenic acid inhibits carcinogenesis. In this study, we found that chlorogenic acid inhibited the proliferation of A549 human cancer cells in vitro. The results of the soft agar assay indicated that chlorogenic acid suppressed 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced neoplastic transformation of JB6 P+ cells in a dose-dependent manner. Pretreatment of JB6 cells with chlorogenic acid blocked UVB- or TPA-induced transactivation of AP-1 and NF-kappaB over the same dose range. At low concentrations, chlorogenic acid decreased the phosphorylation of c-Jun NH2-terminal kinases, p38 kinase, and MAPK kinase 4 induced by UVB/12-O-tetradecanoylphorbol-13-acetate, yet higher doses were required to inhibit extracellular signal-regulated kinases. Chlorogenic acid also increased the enzymatic activities of glutathione S-transferases (GST) and NAD(P)H: quinone oxidoreductase. Further studies indicated that chlorogenic acid could stimulate the nuclear translocation of Nrf2 (NF-E2-related factor) as well as subsequent induction of GSTA1 antioxidant response element (ARE)-mediated GST activity. The phosphatidylinositol 3-kinase pathway might be involved in the activation of Nrf2 translocation. These results provide the first evidence that chlorogenic acid could protect against environmental carcinogen-induced carcinogenesis and suggest that the chemopreventive effects of chlorogenic acid may be through its up-regulation of cellular antioxidant enzymes and suppression of ROS-mediated NF-kappaB, AP-1, and MAPK activation.

Agar↗
PubMed1988

Modulatory role of eicosanoids in vascular changes during the preovulatory period in the rat.

Previous studies have demonstrated the involvement of eicosanoids (prostaglandins and hydroxyperoxides, including leukotrienes) in ovulation in several mammalian species. In this study, the role played by eicosanoids in the vascular changes that occur in the immediate preovulatory period after human chorionic gonadotropin (hCG) stimulation was examined in the rat. Changes in the ovarian uptake of two iodinated proteins were examined 30 minutes after i.v. injection of 125I-bovine serum albumin (BSA, Mr = 68,000) and 125I-alpha 2-macroglobulin (alpha 2M, Mr = 750,000). Uptake was measured during 30 min, 0, 3, 6, and 9 h after induction of ovulation by an i.p. injection of human chorionic gonadotropin (hCG, 10 IU). hCG enhanced the uptake of both iodinated proteins, with peak uptake values at 6 and 9 h. Intra-bursal injections of an ovulation inhibiting dose (0.5 mg/bursa) of indomethacin-a cycooxygenase inhibitor-and nordihydroguaiaretic acid (NDGA), esculetin, or caffeic acid--inhibitors of lipoxygenase--concomitantly with hCG attenuated the action of the hormone on 125I-BSA uptake. Indomethacin and esculetin were without effect on the uptake of alpha 2M. Ovarian and follicular blood flow was measured using 113Sn-microspheres. hCG increased ovarian and follicular blood flow with the most pronounced effect at the early time of 1.5 h. Indomethacin and NDGA did not attenuate this action of hCG. Accordingly, ovarian vascular resistance was reduced by hCG at 1.5, 6, and 9 h post-hCG, respectively, and indomethacin and NDGA had no significant effects. We suggest that one way in which eicosanoids are involved in follicular rupture is by their modulation of vascular permeability as revealed by uptake of the protein marker albumin.

Animals↗
PubMed2002

Isolation from a shea cake digester of a tannin-degrading Streptococcus gallolyticus strain that decarboxylates protocatechuic and hydroxycinnamic acids, and emendation of the species.

A facultatively anaerobic, mesophilic, non-motile, non-sporulating bacterium, designated strain B7, was isolated from an anaerobic digester fed with shea cake rich in tannins and aromatic compounds, after enrichment on tannic acid. The coccoid cells (less than 2 microm in diameter) occurred in pairs or short chains and stained gram-positive. Strain B7 fermented a wide range of carbohydrates (cellobiose, fructose, galactose, glucose, lactose, maltose, mannitol, melibiose, raffinose and trehalose), grew optimally at pH 7.0 and had a G+C content of 40.4+/-0.3 mol%. Strain B7 was closely related to Streptococcus gallolyticus ACM 3611T, a member of the Streptococcus bovis rRNA cluster, with a sequence similarity of 98% and a DNA hybridization value of 86 mol%. Isolate B7 hydrolysed tannic acid and decarboxylated gallic acid to pyrogallol, traits also observed in S. gallolyticus ACM 3611T. In addition, both strains decarboxylated protocatechuic acid to catechol, p-coumaric acid to 4-vinylphenol, caffeic acid to 4-vinylcatechol and ferulic acid to 4-vinylguaiacol. An unsubstituted para-hydroxyl group on the benzene ring was required for decarboxylation. Glucose addition markedly increased the conversion rate. As these traits were not described previously, emendation of the description of the species Streptococcus gallolyticus is proposed.

Anaerobiosis↗
PubMed2003

Pseudomonas aeruginosa-plant root interactions. Pathogenicity, biofilm formation, and root exudation.

Pseudomonas aeruginosa is an opportunistic human pathogen capable of forming a biofilm under physiological conditions that contributes to its persistence despite long-term treatment with antibiotics. Here, we report that pathogenic P. aeruginosa strains PAO1 and PA14 are capable of infecting the roots of Arabidopsis and sweet basil (Ocimum basilicum), in vitro and in the soil, and are capable of causing plant mortality 7 d postinoculation. Before plant mortality, PAO1 and PA14 colonize the roots of Arabidopsis and sweet basil and form a biofilm as observed by scanning electron microscopy, phase contrast microscopy, and confocal scanning laser microscopy. Upon P. aeruginosa infection, sweet basil roots secrete rosmarinic acid (RA), a multifunctional caffeic acid ester that exhibits in vitro antibacterial activity against planktonic cells of both P. aeruginosa strains with a minimum inhibitory concentration of 3 microg mL(-1). However, in our studies RA did not attain minimum inhibitory concentration levels in sweet basil's root exudates before P. aeruginosa formed a biofilm that resisted the microbicidal effects of RA and ultimately caused plant mortality. We further demonstrated that P. aeruginosa biofilms were resistant to RA treatment under in vivo and in vitro conditions. In contrast, induction of RA secretion by sweet basil roots and exogenous supplementation of Arabidopsis root exudates with RA before infection conferred resistance to P. aeruginosa. Under the latter conditions, confocal scanning laser microscopy revealed large clusters of dead P. aeruginosa on the root surface of Arabidopsis and sweet basil, and biofilm formation was not observed. Studies with quorum-sensing mutants PAO210 (DeltarhlI), PAO214 (DeltalasI), and PAO216 (DeltalasI DeltarhlI) demonstrated that all of the strains were pathogenic to Arabidopsis, which does not naturally secrete RA as a root exudate. However, PAO214 was the only pathogenic strain toward sweet basil, and PAO214 biofilm appeared comparable with biofilms formed by wild-type strains of P. aeruginosa. Our results collectively suggest that upon root colonization, P. aeruginosa forms a biofilm that confers resistance against root-secreted antibiotics.

Anti-Bacterial Agents↗
PubMed2005

Characterization of a new tyrosinase from Pycnoporus species with high potential for food technological applications.

AIMS: Tyrosinase production by Pycnoporus cinnabarinus and Pycnoporus sanguineus was screened among 20 strains originating from various geographical areas, particularly from tropical environments. The tyrosinase from the most efficient strain was purified and characterized and tested for food additive applications. METHODS AND RESULTS: Monophenolase and diphenolase activities of tyrosinase were measured from cell lysate from the 20 Pycnoporus strains, for 8-10 days of cultivation. The strain P. sanguineus CBS 614.73 showed the highest productivity (45.4 and 163.6 U g(-1) protein per day for monophenolase and diphenolase respectively). P. sanguineus CBS 614.73 tyrosinase was purified from concentrated cell lysate, anion-exchange, size-exclusion and hydroxyapatite chromatography, with a final yield of 2% and a purification factor of 35-38. The pure enzyme was a monomere with a molecular mass of 45 kDa and it showed four isoforms or isoenzymes with pI between 4.5-5. No N-glycosylation was found. The N-terminal amino acid sequence was IVTGPVGGQTEGAPAPNR. The enzyme was shown to be almost fully active in a pH range of 6-7, in a large temperature range (30-70 degrees C), and was stable below 60 degrees C. The main kinetic constants were determined. The tyrosinase was able to convert p-tyrosol and p-coumaric acid into hydroxytyrosol and caffeic acid, respectively, and it could also catalyse the cross-linking formation of a model protein. CONCLUSIONS: Among the genus Pycnoporus, known for the production of laccase, the strain P. sanguineus CBS 614.73 was shown to produce one other phenoloxidase, a new monomeric tyrosinase with a specific activity of 30 and 84 U mg(-1) protein for monophenolase and diphenolase respectively. SIGNIFICANCE AND IMPACT OF THE STUDY: This study identified P. sanguineus CBS 614.73 as a potential producer of a tyrosinase which demonstrated effectiveness in the synthesis of antioxidant molecules and in protein cross-linking.

Base Sequence↗
PubMed1997

Characterization of a cytotoxic factor induced in murine serum after the intravenous administration of dehydrogenation polymers of phenylpropenoids (a class of synthetic lignins).

A cytotoxic factor (CF) appeared in murine serum after the intravenous injection of the dehydrogenation polymers (DHPs) of p-coumaric acid (DHP-pCA), caffeic acid (DHP-CA), and ferulic acid (DHP-FA), which are categorized as a class of synthetic lignins. The highest CF activity was observed 15 min after the i.v. injection of DHP-pCA. CF is likely to be cytocidal through an apoptotic mechanism accompanied by nucleosome-sized DNA fragmentation. CF is extractable with aqueous ethanol and highly stable against heat, proteases, and acid/alkali treatments. The ethanol extract showed cytotoxicity toward various cultured cell lines and also ascites carcinoma cells in vivo. The parent molecules DHPs did not show any appreciable cytotoxicity. After the induction of CF activity, the activity quickly diminished and completely disappeared from the blood stream within an hour or so. The cytotoxicity was observed only when the target cells were exposed to CF for longer than 10 h.

Animals↗
PubMed2003

[Phenolic compounds isolated from rhizoma of Aster tataricus].

OBJECTIVE: To study the chemical constituents in root and rhizome of Aster tataricus. METHODS: Compounds were isolated and purified by silica gel and sephadex LH-20 column chromatography. Their structures were identified by physicochemical properties and spectral analysis. RESULT: Nine compounds were isolated and identified as quercetin (I), kaemferol (II), emodin (III), chrysophanol (IV), physcion (V), benzoic acid (VI), p-hydroxy-bezoic acid (VII), E-caffeic acid (VIII), E-ferulic acid hexacosyl ester (IX). CONCLUSION: Compounds IV, V, VI, VII, VIII, IX were isolated from A. tataricus for the first time.

Anthraquinones↗
PubMed2004

Characterization of phenolic compounds in some Indian mango cultivars.

Mangoes (Mangifera indica) are rich in phenolic acids as detected by high-performance liquid chromatography. The phenolics have prominent medicinal properties. Among six important commercial mango cultivars (Deshi, Langra, Chausa, Mallika, Dashahari and Amrapali) tannic acid was maximal in Mallika, while gallic acid was maximal in Chausa and all other varieties. Caffeic acid was maximal in Langra followed by Chausa and Amrapali. Many of the pharmacological properties attributed to mango might be due to the presence of phenolic acids in fairly significant amounts.

Caffeic Acids↗
PubMed2001

Identification and quantification of caffeic and rosmarinic acid in complex plant extracts by the use of variable-temperature two-dimensional nuclear magnetic resonance spectroscopy.

A combination of advanced nuclear magnetic resonance (NMR) methodologies for the analysis of complex phenolic mixtures that occur in natural products is described, with particular emphasis on caffeic acid and its ester derivative, rosmarinic acid. The combination of variable-temperature two-dimensional proton-proton double quantum filter correlation spectroscopy (1H-1H DQF COSY) and proton-carbon heteronuclear multiple quantum coherence (1H-13C HMQC) gradient NMR spectroscopy allows the identification and tentative quantification of caffeic and rosmarinic acids at 243 K in extracts from plants of the Lamiaceae family, without resorting to previous chromatographic separation of the components. The use of proton-carbon heteronuclear multiple bond correlation (1H-13C HMBC) gradient NMR spectroscopy leads to the complete assignment of the correlations of the spins of H2a and H3a with the ester and carboxyl carbons of rosmarinic and caffeic acid, even at room temperature, and confirms the results of the above methodology Quantitative results are in reasonable agreement with reverse phase HPLC measurements.

Antioxidants↗
PubMed2005

Purification and characterization of a chlorogenic acid hydrolase from Aspergillus niger catalysing the hydrolysis of chlorogenic acid.

Among 15 Aspergillus strains, Aspergillus niger BRFM 131 was selected for its high chlorogenic acid hydrolase activity. The enzyme was purified and characterized with respect to its physico-chemical and kinetic properties. Four chromatographic steps were necessary to purify the protein to homogeneity with a recovery of 2%. Km of the chlorogenic acid hydrolase was estimated to be 10 microM against chlorogenic acid as substrate. Under native conditions, the protein presented a molecular mass of 170 kDa, and SDS-PAGE analysis suggested the presence of two identical 80 kDa subunits. Isoelectric point was 6.0; pH optimum for activity was determined to be 6.0 and temperature optima to be 55 degrees C. The N-terminal sequence did not present any homology with other cinnamoyl ester hydrolases previously described suggesting the purification of a new protein. The chlorogenic acid hydrolase was used successfully for the production of caffeic acid, which possesses strong antioxidant properties, from natural substrates specially rich in chlorogenic acid like apple marc and coffee pulp.

Aspergillus niger↗