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PubMed1978

[High-performance liquid chromatography in the determination of organic acids in wine].

We shall distinguish the case of non aromatic organic acids from that one of phenolic acids. In the first one, we have applied to wines a method used for fruit-juices by Palmer and List, 1973. After contact of the wine with a strong acid resin, its is injected on anion exchange resin Aminex A 25 precolumn (formiate form) which retains all the organic acids. The precolumn is washed with water to eliminate neutral components, then connected with the chromatographic column which contains the same resin. The different acids are eluted with a solution of natrium formiate at 70 degrees C. They are detected by differential refractometry (galacturonic, lactic, malic, succinic, tartric acids) and by ultraviolet at 254 nm (shikimic acid). Beside these compounds which are identified by their retention volumes, others not yet attributed peaks are detected. The limits of detection are 2 mg/l for shikimic acid, 30 mg/l for tartric acid and 15 mg/l for the others. Analysis time is about one hour. In the case of phenolic acids, we extract them from wine by diethyl ether after saturation with NaCl or by demixtion. The determination of phenolic acids is done on the ether extract or on the organic layer of the demixtion. Chromatography is obtained on octadecylsilanised column (RP 18) with solvent gradient (from 10% methanol in KH2PO4O,1 M pH 2,1 to 60% methanol in the same buffer) and detection in ultraviolet at 254 nm. The knowledge of recovery of acids by diethyl ether or by demixtion permits to obtain their concentrations in wine. The different so determinated phenolic acids are: gallic, 4 hydroxybenzoic, cafeic, vanillic, syringic and para coumaric acids. We have applied these methods to 32 wines for phenolic acids and 80 wines for non aromatic acids. Some results are presented in the case of 24 wines issued from Gamay and 8 wines from Pinot and it appears that tartric and shikimic acids have more important average concentrations in the former than in the latter.

Acetates↗
PubMed1979

Inhibition of rat liver mevalonate pyrophosphate decarboxylase and mevalonate phosphate kinase by phenyl and phenolic compounds.

1. Mevalonate pyrophosphate decarboxylase of rat liver is inhibited by various phenyl and phenolic acids. 2. Some of the phenyl and phenolic acids also inhibited mevalonate phosphate kinase. 3. Compounds with the phenyl-vinyl structure were more effective. 4. Kinetic studies showed that some of the phenolic acids compete with the substrates, mevalonate 5-phosphate and mevalonate 5-pyrophosphate, whereas others inhibit umcompetitively. 5. Dihydroxyphenyl and trihydroxyphenyl compounds and p-chlorophenoxyisobutyrate, a hypocholesterolaemic drug, had no effect on these enzymes. 6. Of the three mevalonate-metabolizing enzymes, mevalonate pyrophosphate decarboxylase has the lowest specific activity and is probably the rate-determining step in this part of the pathway.

Animals↗
PubMed1977

Screening for metabolic disorders among high risk infants and children.

In a screening program in Cincinnati urine specimens from over 20,000 infants and children were tested for inherited metabolic disorders involving amino acids, carbohydrates, phenolic acids, organic acids, keto acids, mucopolysaccharides, and imidazoles. The subjects were selected on the basis of symptoms such as vomiting, diarrhea, acidosis, seizures, failure to thrive, delayed development, mental retardation, and others. The tests were based primarily on paper chromatographic techniques. Patients with 21 different metabolic disorders were found. The patterns of abnormal excretion of amino acids and other metabolites are often useful in making a diagnosis.

Amino Acid Metabolism, Inborn Errors↗
PubMed1978

[Rapid technic for preparation of thyroid ribonucleic acids without phenol].

Thyroid tissue was homogenized in 2 M LiCl. The homogenate was alloued to stand 1 h 30 min at 2 degrees C and then centrifuged. The pellet was suspended in 5% triisopropylnaphthalene sulfonic acid (the sodium salt), 0.05 M Tris--HCl, and 0.1 M NaCl (pH 8). After stirring and centrifuging, the supernatant containing the crude RNA was purified by filtration on Ultrogel AcA 22 (LKB, Sweden). Before adding the sample of crude RNA to the column, pronase was placed on the column. When pronase had entered the gel, we added the sample. The first peak contained pure RNA plus some DNA. The former was precipitated with 2 M LiCl. The RNA species obtained by this technique were undegraded and the yield was 30% better than that of the phenol technique.

Animals↗
PubMed1976

Colorimetric assay for guaiacol O-methyltransferase.

A relatively simple colorimetric assay was developed for guaiacol O-methyltransferase. Monomethylated phenolic acid substrates are enzymatically methylated to their corresponding dimethoxyl compounds; S-adenosylmethionine serves as the methyl donor. Enzymatic activity is measured by colorimetric assay of the monomethylated (nonreacted) substrate by coupling of the phenolic acid with a diazotized sulfanilic acid. The methoxyl and hydroxyl groups may be in the 3,4- or 4,3-positions on the substrate molecules; however, a side chain (COOH) or a substituted side chain is necessary for enzyme action. The radioactive demonstration of guaiacol O-methyltransferase as a separate entity from catechol O-methyl-transferase was confirmed.

Colorimetry↗
PubMed1976

Dose-dependent pharmacokinetics of laevodopa and its metabolites in the rat.

1. Plasma levels of total radioactivity, unchanged laevodopa, dopamine, 3-O-methyldopa and non-amino phenolic acids were measured in rats treated orally with [3H]laevodopa at total laevodopa doses of 1, 10, 20 and 100mg/kg while the radioactive dose was maintained at 100muCi/kg for all animal groups. 2. Within the dosage range studied, non-linear pharmacokinetics were observed for unchanged laevodopa, non-amino phenolic acids and dopamine but not for 3-O-methyldopa. 3. The area under the plasma concentration-time curve for laevodopa increased exponentially with linear increments in the oral dose. This non-linear increase in laevodopa bioavailability is consistent with the hypothesis that high oral doses of laevodopa are required to saturate gastro-intestinal metabolism of the drug. 4. At the lower doses (1 and 20 mg/kg), only 2-3% of total radioactivity could be attributed to dopamine. At 100mg/kg, the dopamine metabolite fraction amounted to about 1/3 of total radioactivity in the plasma.

Animals↗
PubMed2026

Polyphenol-Rich Opuntia ficus-indica Cladodes: An Integrated Metabolomic, In Vivo and In Silico Study Supporting Their Hypolipidemic and Hepatoprotective Effects.

Background: Hyperlipidemia is a major risk factor for cardiometabolic disorders, including non-alcoholic fatty liver disease (NAFLD), and is closely associated with oxidative stress. Opuntia ficus-indica (OFI) cladodes are recognized as a rich source of bioactive phytochemicals; however, the molecular mechanisms underlying their metabolic benefits remain incompletely understood. Objectives: This study aimed to comprehensively evaluate the hypolipidemic and hepatoprotective potential of a polyphenol-rich O. ficus-indica cladode extract (OCE) using an integrated approach combining in vivo evaluation, untargeted metabolomics (UHPLC-Orbitrap-MS/MS), molecular docking, and ADMET prediction. Methods: Hyperlipidemic mice fed a high-fat diet (HFD) were treated with OCE, while molecular docking was performed on ten major annotated phytochemicals against twelve key proteins involved in lipid metabolism and cholesterol homeostasis, including HMGCR, FAS, PPARα, PCSK9, and NPC1L1, using simvastatin as the reference compound. Results: OCE treatment significantly improved plasma and hepatic lipid profiles, improved glucose homeostasis, and markedly reduced hepatic malondialdehyde (MDA) levels, indicating attenuation of oxidative stress. Histopathological analysis further supported a pronounced hepatoprotective effect, with a substantial reduction in hepatic steatosis. Untargeted metabolomics enabled the annotation of 102 metabolites, putatively identifying piscidic acid as the predominant phenolic constituent together with a diverse profile of flavonoids and phenolic acids. Molecular docking supported the potential contribution of these phytochemicals to the regulation of lipid metabolism through favorable interactions with multiple therapeutic targets, while ADMET prediction suggested an overall favorable pharmacokinetic and toxicity profile despite the lower intestinal permeability predicted for glycosylated derivatives. Conclusions: Overall, these findings support O. ficus-indica cladodes as a promising source of dietary bioactive compounds with potential applications in the nutritional management and prevention of hyperlipidemia and related cardiometabolic disorders.

Animals↗
PubMed1978

Extraction of skin test activity from Coccidioides immitis mycelia by water, perchloric acid, and aqueous phenol extraction.

Water, perchloric acid extracts, and fractions of partially defatted whole mycelia of Coccidioides immitis contained delayed skin test activity when tested in C. immitis-infected guinea pits. Aqueous phenol extraction of these fractions resulted in partitioning of activity between aqueous-soluble and phenol-soluble fractions; activity was found to be water soluble after removal of phenol by extensive dialysis. Highest specific activity skin test antigen was invariably found in the phenol-soluble phase, water-soluble fraction. Material of equivalent activity could also be extracted directly from the defatted mycelia. Skin test active fractions contained glucose, mannose, 3-O-methylmannose, glucosamine, and amino acids.

Animals↗
PubMed1976

Cocarcinogenic and tumor-promoting agents in tobacco carcinogenesis.

A series of 21 tobacco smoke components and related compounds werere applied to mouse skin (50 female ICR/Ha Swiss mice/group) three times weekly with a low dose (5 mug/application) of benzo[a]pyrene (B[a]P). The test compounds were of five classes: aliphatic hydrocarbons, aromatic hydrocarbons, phenols, and long-chain acids and alcohols. The following compounds enhanced remarkably the carcinogenicity of B[a]P: catechol, pyrogallol, decane, undecane, pyrene, benzo[e]pyrene, and fluoranthene. The following compounds inhibited B[a]P carcinogenicity completely: esculin, quercetin, squalene, and oleic acid. Phenol, eugenol, resorcinol, hydroquinone, hexadecane, and limonene partially inhibited B[a]P carcinogenicity. Six of the 21 compounds were also tested as tumor promoters im two-stage carcinogenesis. No direct correlation existed between tumor-promoting activity and cocarcinogenic activity. The cocarcinogens pyrogallol and catechol did not show tumor-promoting activity. Decane, tetradecane, anthralin, and phorbol myristate acetate showed both types of activity. Structure-activity relationships and possible modes of action were described.

Acids↗
PubMed1976

On the occurence of vanillic acid in human brain and cerebrospinal fluid.

3-methoxy-4-hydroxyphenylbenzoic (vanillic) acid was previously shown to be one of the endogenous metabolites of adrenaline and noradrenaline. Using thin-layer chromatographic methods for identification and quantification of phenolic acids and phenolic alcohols, the authors identified vanillic acid in different regions of the human brain. The concentration of vanillic acid in the cerebrospinal fluid was also determined and compared to the concentration of 3-methoxy-4-hydroxyphenylethylene glycol. The identification of VA in the human brain suggests that the vanillic acid of the cerebrospinal fluid originates, at least in part, from the catecholamines in the brain. The authors discuss other possible origins of vanillic acid besides the noradrenaline catabolism of dopamine. As the concentration of vanillic acid in the cerebrospinal fluid was found to be greater than the concentration of 3-methoxy-4-hydroxyphenylethylene glycol, it might be important for clinical biological studies to measure vanillic acid in the cerebrospinal fluid as well as the other alcoholic and acid catabolites of the catecholamines.

Brain Chemistry↗
PubMed1978

Arene oxides in styrene metabolism, a new perspective in styrene toxicity?

The metabolism of styrene was studied in the rat after intraperitoneal administration of the cold and the 14C-labeled compound. In addition to phenylethylene glycol, mandelic acid, benzoic acid and hippuric acid, phenolic metabolites, namely, 4-vinylphenol, p-hydroxymandelic acid, p-hydroxybenzoic acid, and p-hydroxyhippuric acid, were identified in the urine of the treated animals. These biotransformation products were characterized by mass spectrometry and by comparative thin layer chromatography with standard compounds. Results of covalent binding studies of 14C-phenylethylene glycol to rat liver microsomal proteins suggest that these phenolic compounds may be formed as a result of chemical rearrangements of unstable arene oxides, reactive intermediates possibly implicated in styrene toxicity.

Animals↗
PubMed2026

Bioactivity and developmental toxicity of Raphanus raphanistrum: integrating phytochemistry, in vitro assays, and zebrafish model.

Raphanus raphanistrum L. (wild radish), a member of the Brassicaceae family, is an edible herb widely utilized in traditional medicine for the treatment of various ailments. This study aimed to evaluate the chemical composition, antioxidant capacity, enzyme inhibitory potential, and cytotoxic activity of extracts derived from its aerial parts. Among the tested extracts, the 70% ethanol extract contained the highest total phenolic content. A total of 38 compounds, mainly phenolic acids and flavonoids, were identified by HPLC-ESI-MS/MS analysis. The aqueous extract contained the highest levels of individual phenolic compounds, particularly ferulic acid and p-coumaric acid. The 70% ethanol extract showed the strongest antioxidant activity in all assays. The ethyl acetate extract exhibited the highest acetylcholinesterase and α-amylase inhibitory activities. Cytotoxicity assays revealed that the 70% ethanol extract was active against A549 lung cancer cells with an IC50 value of 56.77 µg mL-1 and a selectivity index of 1.6. In vivo zebrafish developmental toxicity assays demonstrated dose-dependent embryotoxic effects. Early exposure (0 hpf) caused increased mortality, reduced hatching, and morphological abnormalities, such as axial curvature and pericardial edema, whereas exposure at 72 hpf showed markedly reduced sensitivity. Overall, the findings suggest that R. raphanistrum is a promising natural source of bioactive compounds that could be used in the nutraceutical, pharmaceutical and cosmeceutical industries.

Journal Article↗
PubMed1977

[Pathogenesis of hepatic encephalopathy (author's transl)].

This contribution presents data from the literature as well as our own results concerning the mechanisms of hepatic encephalopathy (HE). 1. Blood chemistry: In patients with liver cirrhosis, the plasma levels of ammonia, phenylalanine, tyrosine, phenolic acids, and octopamine correlated with the stages of HE. Methionine and free tryptophan concentrations were increased only in stages 2-4. Further, branched chain amino acids were below the normal range. Experimental findings in animals elucidated some mechanisms of these changes. 2. Effects of administered substances: With ammonia, methionine, methanethiol, tryptophan, phenolic substances, and fatty acids central nervous disturbances were observed. 3. Interactions: Anemia, methanethiol, and fatty acids favored ammonia toxicity. Alkalosis diminished cerebral symptoms. 4. Neurotransmitters: HE was accompanied by an enhanced turnover of serotonin and by increased amounts of false neurotransmitters (like octopamine) in the brain. 5. Oxydative brain metabolism: Disorders of cerebral oxygen and glucose utilization were mainly documented in cases of long term HE with EEG alterations. 6. Structural changes of the brain: Most of them are irreversible.

Alkalosis↗
PubMed1979

The selection and evaluation of new chelating agents for the treatment of iron overload.

A large-scale systematic evaluation of potential iron chelators for the treatment of hemosiderosis was conducted. The compounds were identified and evaluated using a hypertransfused mouse screen in which deferrioxamine B was a standard. This screen was designed to measure iron depletion in the tissues as well as iron excretion. Groups of 10 previously hypertransfused BDF1 male mice received a single daily i.p. injection of either vehicle, standard, or test compound for 7 days. Iron in daily urine pools and individual spleen and liver homogenates was determined by atomic absorption. More than 70 chelators were evaluated, including natural and synthetic hydroxamic acids, phenols, catechols and tropolones known to have a high affinity for iron (III) in vitro. Ethylenediamine-N,N'-bis(2-hydroxyphenylacetic acid) was shown to be considerably more effective than deferrioxamine B (i.p.) and, in addition, was orally active. Factors determining the efficacy of this and other chelating agents are discussed.

Animals↗