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PubMed2004

Lipoxygenase inhibiting and antioxidant oligostilbene and monoterpene galactoside from Paeonia emodi.

Paeoninol and paeonin C, oligostilbene and monoterpene galactoside, have been isolated from the methanolic extract of the fruits of Paeonia emodi. Their structures have been assigned on the basis of spectral analysis including 1D and 2D NMR techniques. In addition, 4-hydroxybenzoic acid 3, gallic acid 4 and methyl gallate 5 have also been reported for the first time from this species. Compounds 1 and 2 have displayed potent inhibitory potential against enzyme lipoxygenase in a concentration-dependent fashion with the IC(50) values 0.77 and 99.5 microM, along with ABTS(.+) radical quenching activity with IC(50) values of 147.5 and 498.2 microM, respectively.

Antioxidants↗
PubMed2000

Gas chromatographic-mass spectrometric analysis of acids and phenols in distilled alcohol beverages. Application of anion-exchange disk extraction combined with in-vial elution and silylation.

A GC-MS protocol for profiling spirits, based on 19 acids and phenolic compounds, has been proposed and evaluated. The method combined a simple preconcentration procedure based on solid-phase (anion-exchange) disk extraction, and in-vial elution and silylation of the analytes. The derivatized extract was directly injected into the GC-MS system. These analytes were: C6, C8, C10, C12 acids, pyruvic acid, 2-furoic acid, succinic acid, fumaric acid, glutaric acid, lactic acid, glycolic acid, malic acid, tartaric acid, citric acid, vanillin, syringaldehyde, coniferaldehyde, vanillic acid and gallic acid. The profiles of six different spirits were found reproducible from day-to-day with <20% RSD for measurements of most of the analytes at different concentrations. Recoveries of individual analytes appear to be affected by the level of tannins in the spirits, and they varied from sample to sample. The method of standard addition was used to quantify age-related analytes. Good linearity of response with correlation coefficients in the range of 0.992-0.999 was obtained. The results of the study indicate that for spirits of the same brand but of different ages, the amounts of these analytes appear to increase with the ageing period.

Acids↗
PubMed2003

Semiquinone and ascorbyl radicals in the gut fluids of caterpillars measured with EPR spectrometry.

The biological activity of phenolic compounds ingested by caterpillars is commonly believed to result from their oxidation, although the products of oxidation have been well-characterized in only a few cases. The initial oxidation products of phenols (semiquinone or phenoxyl radicals) can be measured with electron paramagnetic resonance (EPR) spectrometry. In this study semiquinone radicals formed from tannic acid and gallic acid in the gut fluids of two species of caterpillars were measured. In Orgyia leucostigma, in which ingested phenols are not oxidized, semiquinone radicals were absent or at very low intensities. By contrast, in Malacosoma disstria, in which ingested phenols are oxidized, high semiquinone radical intensities were measured. In the absence of detectable levels of semiquinone radicals, ascorbyl radicals were detected in the EPR spectra instead. High molar ratios of ascorbate to phenols in an artificial diet produced ascorbyl radicals in the midgut fluids of both species, while diets containing low molar ratios produced semiquinone radicals. Similar results were obtained in M. disstria fed the leaves of red oak or sugar maple. The results of this study provide further evidence that ascorbate is an essential antioxidant that prevents the oxidation of phenols in the gut fluids of caterpillars, and demonstrate that EPR spectrometry is a valuable method for determining the degree of oxidative activation of phenols ingested by herbivorous insects.

Animals↗
PubMedDate not supplied

Synthesis and evaluation of novel dendrimers with a hydrophilic interior as nanocarriers for drug delivery.

Novel polyester-co-polyether dendrimers consisting of a hydrophilic core were synthesized by a combination of convergent and divergent syntheses. The core was synthesized from biocompatible moieties, butanetetracarboxylic acid and aspartic acid, and the dendrons from PEO (poly(ethylene oxide)), dihydroxybenzoic acid or gallic acid, and PEG monomethacrylate. The dendrimers, Den-1-(G 2) (second generation dendrimer-1) and Den-2-(G 2) (second generation dendrimer-2) consisting of 16 and 24 allyl surface groups, respectively, were obtained by coupling the dendrons to the core. The dendrimer (Den-1-(G 2)-OH) with hydroxyl groups at the surface was synthesized by oxidation of the allyl functional groups of Den-1-(G 2), which was divergently coupled to the dendrons to obtain the third generation dendrimer Den-1-(G 3) consisting of 32 surface groups. The modifications in surface groups and generation of dendrimers were shown to influence the shape of dendrimers in the AFM studies. The aggregation as well as self-assembly of dendrimers was observed at high concentration in water by light scattering studies; however, it was reduced on dilution and in the presence of sodium chloride. Dendrimers demonstrated good ability to encapsulate the guest molecule, with loading of 15.80 and 6.47% w/w for rhodamine and beta-carotene, respectively. UV spectroscopy proved the absence of any pi-pi complexation between the dendrimer and encapsulated compounds. (1)H NMR and FTIR studies showed that the physical entrapment and/or hydrogen bonding by PEO in the interior and branch of the dendrimer are the mechanisms of encapsulation. The release of the encapsulated compounds was found to be slow and sustained, suggesting that these dendrimers can serve as potential drug delivery vehicles.

Butanes↗
PubMedDate not supplied

Modulation of phosphoenolpyruvate synthase expression increases shikimate pathway product yields in E. coli.

Product yields in microbial synthesis are ultimately limited by the mechanism utilized for glucose transport. Altered expression of phosphoenolpyruvate synthase was examined as a method for circumventing these limits. Escherichia coli KL3/pJY1.216A was cultured under fed-batch fermentor conditions where glucose was the only source of carbon for the formation of microbial biomass and the synthesis of product 3-dehydroshikimic acid. Shikimate pathway byproducts 3-deoxy-D-arabino-heptulosonic acid, 3-dehydroquinic acid, and gallic acid were also generated. An optimal expression level of phosphoenolpyruvate synthase was identified, which did not correspond to the highest expression levels of this enzyme, where the total yield of 3-dehydroshikimic acid and shikimate pathway byproducts synthesized from glucose was 51% (mol/mol). For comparison, the theoretical maximum yield is 43% (mol/mol) for synthesis of 3-dehydroshikimic acid and shikimate pathway byproducts from glucose in lieu of amplified expression of phosphoenolpyruvate synthase.

Escherichia coli↗
PubMedDate not supplied

Altered glucose transport and shikimate pathway product yields in E. coli.

Different glucose transport systems are examined for their impact on phosphoenolpyruvate availability as reflected by the yields of 3-dehydroshikimic acid and byproducts 3-deoxy-d-arabino-heptulosonic acid, 3-dehydroquinic acid, and gallic acid synthesized by Escherichia coli from glucose. 3-Dehydroshikimic acid is an advanced shikimate pathway intermediate in the syntheses of a spectrum of commodity, pseudocommodity, and fine chemicals. All constructs carried plasmid aroF(FBR) and tktA inserts encoding, respectively, a feedback-insensitive isozyme of 3-deoxy-d-arabino-heptulosonic acid 7-phosphate synthase and transketolase. Reliance on the native E. coli phosphoenolpyruvate:carbohydrate phosphotransferase system for glucose transport led in 48 h to the synthesis of 3-dehydroshikimic acid (49 g/L) and shikimate pathway byproducts in a total yield of 33% (mol/mol). Use of heterologously expressed Zymomonas mobilis glf-encoded glucose facilitator and glk-encoded glucokinase resulted in the synthesis in 48 h of 3-dehydroshikimic acid (60 g/L) and shikimate pathway byproducts in a total yield of 41% (mol/mol). Recruitment of native E. coli galP-encoded galactose permease for glucose transport required 60 h to synthesize 3-dehydroshikimic acid (60 g/L) and shikimate pathway byproducts in a total yield of 43% (mol/mol). Direct comparison of the impact of altered glucose transport on the yields of shikimate pathway products synthesized by E. coli has been previously hampered by different experimental designs and culturing conditions. In this study, the same product and byproduct mixture synthesized by E. coli constructs derived from the same progenitor strain is used to compare strategies for increasing phosphoenolpyruvate availability. Constructs are cultured under the same set of fermentor-controlled conditions.

3-Deoxy-7-Phosphoheptulonate Synthase↗
PubMed2006

Concentration and mean degree of polymerization of Rubus ellagitannins evaluated by optimized acid methanolysis.

Ellagitannins are a major class of phenolics largely responsible for the astringent and antioxidant properties of raspberries and blackberries. The Rubus ellagitannins constitute a complex mixture of monomeric and oligomeric tannins. Rubus oligomeric ellagitannins contain, beside the well-known ellagic acid and gallic acid moieties, the sanguisorboyl linking ester group. When exposed to acids or bases, ester bonds are hydrolyzed and the hexahydroxydiphenic acid spontaneously cyclizes into ellagic acid. This study describes a new, rapid procedure for the acid hydrolysis of Rubus ellagitannins in methanol, which results in maximal yield and enables the quantification of all the major reaction products. Additionally, the method provides the rationale for estimating the mean degree of polymerization of Rubus ellagitannins.

Hydrochloric Acid↗
PubMed1999

Assessment of the antioxidant potential of scotch whiskeys by electron spin resonance spectroscopy: relationship to hydroxyl-containing aromatic components.

Electron spin resonance (ESR) spectroscopy has been used to assess the antioxidant capacity of eight Scotch whiskeys by measuring the extent by which the original spirits, or pyridine solutions of their residues, reduced Fremy's radical or galvinoxyl radical. All whiskeys displayed antioxidant activity greater than that of a 0.2 mM solution of Trolox in the Fremy's assay and of a 0.1 mM solution of quercetin in the galvinoxyl assay. The relative antioxidant capacities determined according to the two assays were highly correlated and strongly related to the total phenol content as determined by using the Folin-Ciocalteu method. Activity was a consequence of maturation in oak casks with the "newmake" spirit showing no effect. Of 10 aromatic constituents analyzed, activity was most strongly correlated with ellagic acid and gallic acid in both assays. The reductive capacities of four major phenolics were determined, which, in summation, accounted for 31-53% of the total antioxidant activity of the whiskeys. There was no evidence for synergistic interaction between the phenols investigated.

Alcoholic Beverages↗
PubMed1999

Comparative study of polyphenol scavenging activities assessed by different methods.

The effect of procyanidin solutions on superoxide anion radicals was studied with an enzymatic method and their EC(50) values were determined. A comparative study of the results suggested that the free radical scavenger potential of these phenolic compounds closely depends on their chemical and stereochemical structures. Oligomeric procyanidins were isolated in different fractions from grapes and wines by low- and high-pressure liquid chromatography. These compounds were found to be efficient free radical scavengers even for the weak concentrations in wines. Their activity in grapes or wines was much stronger than that of other commercially available natural antioxidants (such as ascorbic acid and gallic acid). The effect of tannins isolated from grapes on different radicals was analyzed according to three distinct methods: an enzymatic method for superoxide anion radicals (O(2)(*)(-)), a chemical method for the stable 1,1-diphenyl-2-picrylhydrazyl radical (DPPH(*)), and an immunochemical method to study the scavenging activity of seed procyanidins on DNA lesions induced by the radical HO(*).

Bepridil↗
PubMed1999

Alkylperoxyl radical-scavenging activity of various flavonoids and other phenolic compounds: implications for the anti-tumor-promoter effect of vegetables.

We recently reported that alkylperoxyl radical (ROO(*)) enhanced carcinogenesis in rats treated with carcinogen (Sawa et al. Cancer Epidemiol. Biomarkers Prev. 1998, 7, 1007-1012), and the tumor promoting action of ROO(*) could be reduced by addition of hot-water extracts of vegetables (Maeda et al. Jpn. J. Cancer Res. 1992, 83, 923-928). Here we described the ROO(*)-scavenging activity of flavonoids and nonflavonoid phenolics and their role in anti-tumor-promoter effects. A model molecular species, ROO(*), was generated from tert-butyl hydroperoxide (t-BuOOH) and heme iron, and the scavenging of t-BuOO(*) was determined by (a) bioassay based on the bactericidal action of ROO(*), (b) luminol-enhanced chemiluminescence, and (c) electron spin resonance. Of 17 authentic plant phenolics tested, 9 compounds (including rutin, chlorogenic acid, vanillin, vanillic acid, neohesperidin, gallic acid, shikimic acid, rhamnetin, and kaempferol) showed remarkably high ROO(*)-scavenging activity. Some of them were detected and quantified in hot-water extracts of mung bean sprouts, used as the model vegetable, and their contents increased after germination, which paralleled very well to the ROO(*)-scavenging capacity of the vegetable extracts. Thus, a diet rich in these radical scavengers would reduce the cancer-promoting action of ROO(*). Consequently, the carcinogenic potentials of oxygen-related radicals may be suppressed.

Anticarcinogenic Agents↗
PubMed1999

Phenolic constituents, furans, and total antioxidant status of distilled spirits.

The concentrations of 11 phenols and 5 furans were measured in 12 categories of distilled spirits by HPLC methodology, together with the total antioxidant status (TAS) of the same beverages. Ellagic acid was the phenol present in highest concentration in all beverages. Moderate amounts of syringaldehyde, syringic acid, and gallic acid, as well as lesser amounts of vanillin and vanillic acid, were measurable in most samples of whiskey, brandy, and rum but were largely undetectable in gin, vodka, liqueurs, and miscellaneous spirits. 5-(Hydroxymethyl)furfural was the predominant furan in the former three beverages, notably cognac, with 2-furaldehyde the next highest, but these were undetectable in most of the latter beverages. Highest TAS values were given by armagnac, cognac, and bourbon whiskey, all three of which tended toward the highest concentrations of phenols. Negative TAS values were exhibited by rum, vodka, gin, and miscellaneous spirits in line with the low or undetectable phenol concentrations in these beverages. Wood aging is the most likely source of phenols and furans in distilled spirits. Those beverages exposed to this treatment contain significant antioxidant activity, which is between the ranges for white and red wines, with the potential to augment the antiatherosclerotic functions attributable to the ethanol that they contain.

Alcoholic Beverages↗
PubMed1992

Antitumor-promoting activities of hydrolyzable tannins in mouse skin.

Ellagic acid and gallic acid and its derivatives, applied topically to female CF-1 mice 20 min before each 12-O-tetradecanoylphorbol-13-acetate (TPA) treatment inhibit the inductions of epidermal ornithine decarboxylase activity, hydroperoxide production and DNA synthesis caused by this potent tumor promoter in relation with their abilities to inhibit the promotion of skin papillomas and carcinomas in the two-step initiation-promotion protocol. Because of its potency against TPA promotion, tannic acid, which is already known to inhibit tumor initiation, may inhibit the multistage process of carcinogenesis.

Animals↗
PubMed1993

Enhancing effect of concomitant L-ascorbic acid administration on BHA-induced forestomach carcinogenesis in rats.

The effects of the synthetic antioxidant butylated hydroxyanisole (BHA) and naturally occurring antioxidants such as L-ascorbic acid (AsA; vitamin C), citric acid, benzoic acid or gallic acid in combination, on the development of rat forestomach epithelial lesions were investigated. A dietary level of 2.0% was selected for all antioxidants and the experimental period was 1 year. As compared with BHA alone, treatment with AsA in combination with BHA increased the severity of the hyperplasia in the mid-region, but not in the prefundic region of the forestomach epithelium, as well as the multiplicity of forestomach tumors. Furthermore, incidences of squamous cell carcinomas (SCCs) in the forestomach were significantly elevated in this group, while papilloma development only showed a tendency to increase. In addition, SCC invasion into the muscle layer of the forestomach was observed only in the BHA + AsA group. Treatment with the other antioxidants did not affect BHA-induced forestomach lesion development. The present study demonstrated that AsA can clearly enhance BHA forestomach carcinogenesis.

Animals↗
PubMed1994

Responses of lipid membranes of taste sensor to astringent and pungent substances.

Astringent substances and pungent substances were studied using a multichannel taste sensor with lipid membranes. The electric-potential pattern constructed of eight outputs from the membranes has information of taste quality and intensity. Pungent substances, such as capsaicin, piperine and allyl isothiocyanate, had no effect on the membrane potentials of the lipid membranes. On the other hand, astringent substances such as tannic acid, catechin, gallic acid and chlorogenic acid changed the potentials remarkably. A principal component analysis of the patterns in electric potential changes caused by the taste substances revealed the astringency is located between bitterness and sourness.

Astringents↗
PubMed1994

Involvement of lipid peroxidation in necrosis of skin flaps and its suppression by ellagic acid.

To evaluate the pathogenesis of lipid peroxidation in skin-flap necrosis and to select a novel herbal antioxidant to suppress lipid peroxidation and salvage the flaps, in vitro and in vivo experiments were instituted. In vitro studies revealed (1) the potentiality of the cutaneous microsomal system (vesicular fragment of endoplasmic reticulum) to generate oxyradicals by FeCl3 (oxidative agent), since NADPH-dependent lipid peroxidation was elevated time-dependently, (2) suppression of microsomal lipid peroxidation by herbal antioxidants (dose- and time-dependently), further supporting the theory of oxyradical-induced lipid peroxidation in the skin, and (3) that ellagic acid showed the strongest response, with curcumin, chlorogenic acid, and alpha-tocopherol (tocopherol) being moderate, and ferulic acid and gallic acid remaining weakest. Thus ellagic acid, curcumin, chlorogenic acid, and tocopherol at doses of 10, 60, 80 and 100 microM (twice I50, the dose which could inhibit lipid peroxidation by 50 percent) were chosen for in vivo assessments, respectively. In vivo studies were performed using rat back skin random flaps (70 x 15 mm and based anteriorly) and circular island flaps (20 mm in diameter and raised on superficial epigastric vessels). Control flaps were painted with a Tris-ethanol solution, and test flaps were painted with either ellagic acid, curcumin, chlorogenic acid, or tocopherol (above-mentioned doses per 250 microliters of Tris-ethanol per 300 mm2 of flap surface 1 hour before the operation and once a day for 3 postoperative days). Doses, frequency, and period of drug application were based on in vitro and in vivo pilot experiments. The results were as follows: (1) a direct and time-dependent relation was noticed between lipid peroxide levels and the rate of necrosis in both types of flap; (2) time-dependent elevation of lipid peroxide levels of skin, subcutaneous fat, and exudate of island flaps during ischemia and those of skin and subdermal fat after reperfusion indicated pre- and post-reflow states of lipid peroxidation rather than the original conception of merely reperfusion state; and (3) in good agreement with the results of in vitro experiments, ellagic acid exerted the strongest effect to suppress lipid peroxide levels of skin and to augment the viability of random flaps more than that of island flaps.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed2005

Pomegranate flower extract diminishes cardiac fibrosis in Zucker diabetic fatty rats: modulation of cardiac endothelin-1 and nuclear factor-kappaB pathways.

The diabetic heart shows increased fibrosis, which impairs cardiac function. Endothelin (ET)-1 and nuclear factor-kappaB (NF-kappaB) interactively regulate fibroblast growth. We have recently demonstrated that Punica granatum flower (PGF), a Unani anti-diabetic medicine, is a dual activator of peroxisome proliferator-activated receptor (PPAR)-alpha and -gamma, and improves hyperglycemia, hyperlipidemia, and fatty heart in Zucker diabetic fatty (ZDF) rat, a genetic animal model of type 2 diabetes and obesity. Here, we demonstrated that six-week treatment with PGF extract (500 mg/kg, p.o.) in Zucker diabetic fatty rats reduced the ratios of van Gieson-stained interstitial collagen deposit area to total left ventricular area and perivascular collagen deposit areas to coronary artery media area in the heart. This was accompanied by suppression of overexpressed cardiac fibronectin and collagen I and III mRNAs. Punica granatum flower extract reduced the up-regulated cardiac mRNA expression of ET-1, ETA, inhibitor-kappaBbeta and c-jun, and normalized the down-regulated mRNA expression of inhibitor-kappaBalpha in Zucker diabetic fatty rats. In vitro, Punica granatum flower extract and its components oleanolic acid, ursolic acid, and gallic acid inhibited lipopolysaccharide-induced NF-kappaB activation in macrophages. Our findings indicate that Punica granatum flower extract diminishes cardiac fibrosis in Zucker diabetic fatty rats, at least in part, by modulating cardiac ET-1 and NF-kappaB signaling.

Animals↗
PubMedDate not supplied

Antimicrobial activity of fractions and compounds from Calophyllumbrasiliense (Clusiaceae/Guttiferae).

Calophyllum brasiliense (Clusiaceae/Guttiferae) is a native Brazilian medicinal plant traditionally used against several diseases, including infectious pathologies. Crude methanolic extracts (CME) and two fractions, denoted non-polar (soluble in chloroform) and polar (nonsoluble in chloroform), were prepared from different parts of the plant (roots, stems, leaves, flowers and fruits) and studied. The following compounds were isolated and tested against pathogenic bacteria and yeasts by determination of the minimal inhibitory concentration (MIC): brasiliensic acid (1), gallic acid (2), epicatechin (3), protocatechuic acid (4), friedelin (5) and 1,5-dihydroxyxanthone (6). The results indicated that all the parts of the plant exhibited antimicrobial activity against Gram-positive bacteria, which are selectively inhibited by components of C. brasiliense. No activity was observed against Gram-negative bacteria and yeasts tested. Regarding the isolated compounds, substance 4 showed antimicrobial activity against all the tested microorganisms, whereas compound 6 exhibited antimicrobial activity only against Gram-positive bacteria. The results from the current study confirm and justify the popular use of this plant to treat infectious processes.

Anti-Infective Agents↗
PubMed1988

Sodium-dependent L-lactate uptake by bovine intestinal brush border membrane vesicles.

In ruminants, intestinal digesta can contain considerable amounts of lactic acid derived from ingestion of lactic acid-containing feed and from production of lactic acid during ruminal digestion of readily fermentable carbohydrates. The aim of the present study was to investigate L-lactate transport across the bovine intestinal brush border membrane. The experiments were performed using isolated brush border membrane vesicles from the midjejunum of heifers. The results demonstrate the existence of Na+-stimulated L-lactate uptake by the brush border membrane vesicles. Acetate, propionate, and butyrate strongly inhibited Na+-dependent L-lactate transport. Acetate caused a 58% inhibition, whereas propionate and butyrate completely inhibited Na+-dependent uptake. Kinetic evaluation of L-lactate uptake in the presence or absence of extravesicular butyrate suggests a competitive inhibition by butyrate. Among the phenolic acids tested in this study only trans-cinnamic acid caused a significant reduction of L-lactate uptake, whereas cumaric acid, ferulic acid, and gallic acid only slightly reduced L-lactate transport. Thus, the L-lactate transporter appears to have some affinity for transcinnamic acid.

Animals↗