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PubMed2004

Phloroglucinol from phlorin hydrolysis for testing quality of commercial orange juices and beverages.

The European Association of Juices and Nectars Producers (AIJN) is evaluating the opportunity to introduce the content of phlorin (3,5-dihydroxyphenyl beta-D-glucopyranoside), a peel marker for oranges, as a parameter for testing the quality of orange juices. Because of the lack of a commercial standard of phlorin and its laborious isolation procedures, in this contribution is developed a simple and reliable method for measuring the phlorin level as the corresponding aglycon phloroglucinol, obtained after a total enzymatic hydrolysis of the sample. The method was applied to the quantification of phloroglucinol in several industrial and commercial blond and pigmented orange juices and beverages based on 12% orange juice. Under the same extraction procedure, the phloroglucinol content in the pigmented juices was higher than in the blond ones. No significant difference was obtained between not from concentrate juices and reconstituted from concentrate juices. The marker amount increases in the highly processed orange fruits and in the byproducts of citrus processing due to the contact of the juice with the albedo, which is the major source of phlorin. In orange-based beverages the phloroglucinol content revealed a large heterogeneity and a poor quality of the raw juices used.

Beverages↗

PubMed1976

Use of the Hungate anaerobic technique in the isolation of phloroglucinol-negative mutants of Coprococcus species.

The Hungate anaerobic technique was used with a standard procedure for bacterial mutagenesis employing N-methyl-N-nitro-N'-nitrosoguanidine to obtain mutants of an obligate anaerobe. Three mutant strains were derived from a Coprococcus sp., strain Pe15, a rumen anaerobe capable of growing on phloroglucinol. The mutants did not grow on phloroglucinol but did degrade the compound in anaerobic washed-cell suspensions, producing the same end products in approximately the same proportions as the wild type. It was concluded that the mutants were blocked in a unique step or steps necessary for carbon skeleton or energy synthesis from phloroglucinol and not in formation of an enzyme involved in the pathway of phloroglucinol degradation.

Anaerobiosis↗

PubMed1975

Isolation and identification of rumen bacteria capable of anaerobic phloroglucinol degradation.

Eight strains of rumen bacteria capable of degrading phloroglucinol (1,3,5-trihydroxybenzene) under anaerobic conditions were isolated from enrichment cultures of the bovine rumen microflora established in a prereduced medium containing 0.02 M phloroglucinol. Five of the strains were facultatively anaerobic Gram-positive streptococci which were identified as Streptococcus bovis. Three strains of obligately anaerobic Gram-positive cocci were assigned to the genus Coprococcus. Anaerobic cultures of the Streptococcus bovis strains in a 40% rumen fluid medium initially containing 0.02 M phloroglucinol degraded 50-80% of the substrate within 2 days, whereas cultures of the Coprococcus strains degraded more than 80% of the substrate under the same conditions. The Streptococcus bovis strains were incapable of degrading phloroglucinol in brain heart infusion or in the medium of de Man, Rogosa, and Sharpe (MRS broth) incubated aerobically.

Anaerobiosis↗

PubMedDate not supplied

[Bioavailability of phloroglucinol in man].

This work reports a bioavailability study between two oral dosage forms containing 125.2 mg active phloroglucinol. Twelve healthy volunteers subjects received a sublingual administration of both dosage forms, a flash liberation tablet and a freeze-dried reference tablet (lyoc), according to a randomized and cross-over design. An accurate, sensitive and specific high performance liquid chromatographic method was developed for the determination of free phloroglucinol as well as its conjugated metabolites, that allowed as to clarify phloroglucinol pharmacokinetic behaviour in man, specially its important metabolisation, its poor systemic bioavailability after oral administration and its total urinary elimination mainly under metabolized form. Total plasmatic phloroglucinol pharmacokinetic profiles led to pertinent parameters needed for statistical bioequivalence study, i.e. T1/2 alpha, T1/2 beta, AUC, Tmax, Cmax and MRT. The mean comparative values of these parameters showed the equivalent performances of both oral dosage forms studied and the statistical tests performed (ANOVA, Westlake and two one-sided t test) concluded to their bioequivalence.

Animals↗

PubMed2005

Phloroglucinol for acceleration of labour: double blind, randomized controlled trial.

OBJECTIVES: To determine the effects of Phloroglucinol in acceleration of labour and its adverse effects on mother and foetus. METHODS: A double blind randomized, placebo controlled trial was conducted on 100 patients in active phase of uncomplicated labour selected by convenient sampling. Patients were given Phloroglucinol or Placebo (distilled water) intravenously. Progress of labour was plotted on Partogram. Any adverse effects of the drug on mother and fetus were noted. Student's t-test was applied for statistical analysis. RESULTS: In patients receiving Phloroglucinol there was a mean 34% reduction in duration of 1st stage of labour and a mean 23% reduction in 2nd stage as compared to Placebo group respectively. Blood loss >500ml was observed in 2% patients. Otherwise there were no adverse effects on mother or foetus. CONCLUSION: Phloroglucinol shortens the duration of labour, is non toxic to both mother and fetus and does not cause primary post partum haemorrhage.

Female↗

PubMed2006

Phloroglucinol in irritable bowel syndrome.

OBJECTIVE: To determine the efficacy and tolerability of phloroglucinol, an antispasmodic agent in the treatment of Irritable Bowel Syndrome (IBS). METHODS: It was an open label (quasi interventional) study. One hundred patients coming to the gastroenterology clinics of Aga Khan University Hospital with IBS as defined by the Rome II criteria were enrolled between February 2004 and September 2004 to participate in the trial and were treated as outpatients. Phloroglucinol (Himont) 50mg orally three times daily was given for two months. Symptoms were assessed before and during treatment using a questionnaire. RESULTS: One hundred patients were enrolled in the study. Of them 61% (61/100) were males and 39% (39/100) were females. Their mean age was 41 +/- 14 years. Sixty-eight patients completed the study and 28 dropped out. On Phloroglucinol treatment there was an overall statistically significant improvement in abdominal pain (p<0.001), frequency of stools per day (p<0.001), urgency (p<0.001), passage of mucus per rectum (p<0.001), sense of incomplete defecation (p=0.001) and bloating (p=0.001). However, no response was seen in the feature of straining in both genders (p=0.676). The difference in response to treatment according to gender separately showed statistically significant improvement in the sense of incomplete defecation in females alone (p=0.003). CONCLUSION: Phloroglucinol in a dose of 50mg three times daily is effective and well tolerated by the IBS patients. It relieves most of the symptoms of IBS.

Administration, Oral↗

PubMed1998

Five phloroglucinol-monoterpene adducts from Eucalyptus grandis.

Five new euglobals possessing the phloroglucinol-monoterpene structure, euglobals G8-G12, together with a known euglobal-IIc were isolated from the hexane fraction of the methanol extract of the leaves of Eucalyptus grandis. Euglobal-G8 is an adduct of formyl-isovaleroyl-phloroglucinol and gamma-terpinene whereas -G9, -G10 and -G11 have the same phloroglucinol moiety fused with alpha-terpinene, while Euglobal-G12 has terpinolene fused with the same phloroglucinol moiety. The structures of these compounds were elucidated on the basis of spectral evidences. Biomimetic synthesis of euglobals suggests that these compounds are derived biogenetically by the Diels-Alder type cycloaddition of the corresponding terpenes with an ortho-quinone methide generated from grandinol.

Journal Article↗

PubMed1992

Sequential Transhydroxylations Converting Hydroxyhydroquinone to Phloroglucinol in the Strictly Anaerobic, Fermentative Bacterium Pelobacter massiliensis.

The recently isolated fermenting bacterium Pelobacter massiliensis is the only strict anaerobe known to grow on hydroxyhydroquinone (1,2,4-trihydroxybenzene) as the sole source of carbon and energy, converting it to stoichiometric amounts of acetate. In this paper, we report on the enzymatic reactions involved in the conversion of hydroxyhydroquinone and pyrogallol (1,2,3-trihydroxybenzene) to phloroglucinol (1,3,5-trihydroxybenzene). Cell extracts of P. massiliensis transhydroxylate pyrogallol to phloroglucinol after addition of 1,2,3,5-tetrahydroxybenzene (1,2,3,5-TTHB) as cosubstrate in a reaction identical to that found earlier with Pelobacter acidigallici (A. Brune and B. Schink, J. Bacteriol. 172:1070-1076, 1990). Hydroxyhydroquinone conversion to phloroglucinol is initiated in cell extracts without an external addition of cosubstrates. It involves a minimum of three consecutive transhydroxylation reactions characterized by the transient accumulation of two different TTHB isomers. Chemical synthesis of the TTHB intermediates allowed the resolution of the distinct transhydroxylation steps in this sequence. In an initial transhydroxylation, the hydroxyl group in the 1-position of a molecule of hydroxyhydroquinone is transferred to the 5-position of another molecule of hydroxyhydroquinone to give 1,2,4,5-TTHB and resorcinol (1,3-dihydroxybenzene) as products. Following this disproportionation of hydroxyhydroquinone, the 1,2,4,5-isomer is converted to 1,2,3,5-TTHB, an enzymatic activity present only in hydroxyhydroquinone-grown cells. Finally, phloroglucinol is formed from 1,2,3,5-TTHB by transfer of the 2-hydroxyl group to either hydroxyhydroquinone or resorcinol. The resulting coproducts are again cosubstrates in earlier reactions of this sequence. From the spectrum of hydroxybenzenes transhydroxylated by the cell extracts, the minimum structural prerequisites that render a hydroxybenzene a hydroxyl donor or acceptor are deduced.

Journal Article↗

PubMed1995

Antibacterial phloroglucinols and flavonoids from Hypericum brasiliense.

Three known phloroglucinols (japonicine A, uliginosin A and isouliginosin B) and a new phloroglucinol (hyperbrasiol A) have been isolated from a petrol extract of the leaves and flowers of Hypericum brasiliense. Their structures were established by spectroscopic methods (UV, DCI-MS, 1H and 13CNMR, including SINEPT, HMBC, HSQC, DQFCOSY experiments). The substitution pattern of hyperbrasilol A was confirmed by X-ray crystallography. All four phloroglucinols were antibacterial against Bacillus subtilis in a TLC bioautographic assay. The flavonoids, kaempferol, luteolin, quercetin, quercitrin, isoquercitrin, hyperoside and guaijaverin, were isolated from a methanol extract of the same organs.

Anti-Bacterial Agents↗

PubMed1994

Transhydroxylase of Pelobacter acidigallici: a molybdoenzyme catalyzing the conversion of pyrogallol to phloroglucinol.

Trihydroxybenzenes are degraded anaerobically through the phloroglucinol pathway. In Pelobacter acidigallici as well as in Pelobacter massiliensis, pyrogallol is converted to phloroglucinol in the presence of 1,2,3,5-tetrahydroxybenzene by intermolecular hydroxyl transfer. The enzyme catalyzing this reaction was purified to chromatographic and electrophoretic homogeneity. Gel filtration and electrophoresis revealed a heterodimer structure with an apparent molecular mass of 127 kDa for the native enzyme and 86 kDa and 38 kDa, respectively, for the subunits. The enzyme was not sensitive to oxygen. HgCl2, p-chloromercuribenzoic acid, and CuCl2 inhibited strongly the reaction indicating an essential function of SH-groups. Transhydroxylase had a pH-optimum of 7.0 and a pI of 4.1. The apparent temperature optimum was in the range of 53 degrees C to 58 degrees C. The activation energy for the conversion of pyrogallol and 1,2,3,5-tetrahydroxybenzene to phloroglucinol and tetrahydroxybenzene was 31.4 kJ per mol. Purified enzyme exhibited a specific activity of 3.1 mol min-1 mg-1 protein and an apparent Km for pyrogallol and 1,2,3,5-tetrahydroxybenzene of 0.70 mM and 0.71 mM, respectively. The enzyme was found to contain per mol heterodimer 1.1 mol molybdenum, 12.1 mol iron and 14.5 mol acid-labile sulfur. Requirement for molybdenum for transhydroxylating enzyme activity was proven also by cultivation experiments. No hints for the presence of flavins were obtained. The results presented here support the hypothesis that a redox reaction is involved in this intermolecular hydroxyl transfer.

Bacteria, Anaerobic↗

PubMed1993

Determination of phloroglucinol in human plasma by gas chromatography-mass spectrometry.

A specific and sensitive method has been developed for the determination of phloroglucinol in plasma; it involves an optimized procedure for blood sampling designed to minimize the in vitro oxidation of the molecule, and gas chromatography-mass spectrometry after silylation of the compound. The method allowed a reliable determination of phloroglucinol in plasma. The precision and accuracy of the assay, reported as coefficients of variation, were below 15%. Using a plasma sample of 0.25 ml, the limit of quantitation was 5 ng/ml with a precision of 17.4%, which is sensitive enough for pharmacokinetic studies. Stability studies under different conditions revealed that ascorbic acid limits the degradation of phloroglucinol in plasma during storage at freezer temperatures.

Drug Stability↗

PubMed1999

Towards the reaction mechanism of pyrogallol-phloroglucinol transhydroxylase of Pelobacter acidigallici.

Conversion of pyrogallol to phloroglucinol was studied with the molybdenum enzyme transhydroxylase of the strictly anaerobic fermenting bacterium Pelobacter acidigallici. Transhydroxylation experiments in H218O revealed that none of the hydroxyl groups of phloroglucinol was derived from water, confirming the concept that this enzyme transfers a hydroxyl group from the cosubstrate 1,2,3, 5-tetrahydroxybenzene (tetrahydroxybenzene) to the acceptor pyrogallol, and simultaneously regenerates the cosubstrate. This concept requires a reaction which synthesizes the cofactor de novo to maintain a sufficiently high intracellular pool during growth. Some sulfoxides and aromatic N-oxides were found to act as hydroxyl donors to convert pyrogallol to tetrahydroxybenzene. Again, water was not the source of the added hydroxyl groups; the oxides reacted as cosubstrates in a transhydroxylation reaction rather than as true oxidants in a net hydroxylation reaction. No oxidizing agent was found that supported a formation of tetrahydroxybenzene via a net hydroxylation of pyrogallol. However, conversion of pyrogallol to phloroglucinol in the absence of tetrahydroxybenzene was achieved if little pyrogallol and a high amount of enzyme preparation was used which had been pre-exposed to air. Obviously, the enzyme was oxidized by air to form sufficient amounts of tetrahydroxybenzene from pyrogallol to start the reaction. A reaction mechanism is proposed which combines an oxidative hydroxylation with a reductive dehydroxylation via the molybdenum cofactor, and allows the transfer of a hydroxyl group between tetrahydroxybenzene and pyrogallol without involvement of water. With this, the transhydroxylase differs basically from all other hydroxylating molybdenum enzymes which all use water as hydroxyl source.

Bacteria, Anaerobic↗

PubMed2003

Inhibition of lipopolysaccharide-induced pro-inflammatory cytokine expression via suppression of nuclear factor-kappaB activation by Mallotus japonicus phloroglucinol derivatives.

An aqueous acetone extract obtained from the pericarps of Mallotus japonicus (MJE) was observed to inhibit pro-inflammatory cytokine (tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) production in a lipopolysaccharide (LPS)-activated murine macrophage-like cell line, RAW 264.7, or human blood monocytes. Several phloroglucinol derivatives were isolated from the pericarps as active compounds. Among these compounds, isomallotochromanol and isomallotochromene were the most potent in inhibiting cytokine production. MJE and the phloroglucinol derivatives significantly reduced these cytokine mRNA expressions. Gel shift analysis revealed that stimulation of macrophages with LPS caused an increase in the DNA binding activity of nuclear factor-kappaB (NF-kappaB), which was inhibited by isomallotochromanol and isomallotochromene. Western blot analysis showed that LPS reduced the IkappaB-alpha level in macrophages, while 10 microM isomallotochromanol and 10 microM isomallotochromene attenuated the LPS-induced decrease in IkappaB-alpha protein. We conclude that these phloroglucinol derivatives inhibit pro-inflammatory cytokine production and mRNA expression via suppression of NF-kappaB activation in activated macrophages.

Animals↗

PubMed2001

Analysis of proanthocyanidin cleavage products following acid-catalysis in the presence of excess phloroglucinol.

The analysis of proanthocyanidin cleavage products after acid-catalysis in the presence of excess phloroglucinol was investigated. In the developed analytical method, a solution of 0.1 N HCl in methanol, containing 50 g/L phloroglucinol and 10 g/L ascorbic acid was prepared. The proanthocyanidin of interest was reacted in this solution (5 g/L) at 50 degrees C for 20 min, and afterward combined with 5 volumes of 40 mM aqueous sodium acetate before analysis by reversed-phase HPLC using an aqueous acetic acid and methanol gradient. This procedure was used to investigate the composition of proanthocyanidins isolated from the seed and skin tissue of Vitis vinifera L. berries. The results compared favorably to results obtained when benzyl mercaptan was used as the trapping nucleophile, indicating that phloroglucinol is an effective reagent for this analysis.

Anthocyanins↗

PubMed2004

The key role of phloroglucinol O-methyltransferase in the biosynthesis of Rosa chinensis volatile 1,3,5-trimethoxybenzene.

1,3,5-Trimethoxybenzene is a key component of the Chinese rose odor. This compound is synthesized in three successive methylation steps from phloroglucinol, the initial precursor. A novel, to our knowledge, phloroglucinol O-methyltransferase (POMT) characterized here methylates the first step to produce the intermediate 3,5-dihydroxyanisole, while two previously described orcinol O-methyltransferases catalyze the subsequent steps. We isolated POMT from rose petals and determined partial amino acid sequences of the purified enzyme. The full-length POMT cDNA was isolated and expressed in Escherichia coli. Both the native and recombinant POMT exhibited substrate specificity for phloroglucinol. POMT was expressed specifically in floral organs, in accordance with its role as a key enzyme in the synthesis of rose floral scent compounds.

Amino Acid Sequence↗

PubMed1992

Utilization of 1,3,5-trihydroxybenzene (phloroglucinol) by a soil isolate, Rhodococcus species BPG-8.

A Gram-positive bacterial strain was isolated from oil rich soil in Newfoundland and found to utilize various di- and trihydroxylated aromatic compounds as a source of carbon and energy. This bacterium exhibited rod/coccus dimorphism during its growth cycle. Chemical analysis of cell wall composition (amino acids, sugars, and fatty acids) was performed using gas chromatography-mass spectrophotometry and high pressure liquid chromatography. Comparison of both acid production and growth substrates showed complete homology with Rhodococcus erythropolis. Growth of the isolate on phloroglucinol (1,3,5 trihydroxybenzene) occurred in the pH range 5-8; with a substrate and temperature optima of 8.0 mM and 25 degrees C. The oxidation of PG was examined using whole cells as well as crude cell extracts. PG oxidation was shown to be due to an inducible enzyme system. Tentatively the isolate was identified as Rhodococcus species BPG-8 which is able to utilize phloroglucinol as the sole source of carbon and energy.

Acids↗

PubMed2002

Determination of naphthodianthrones and phloroglucinols from Hypericum perforatum extracts by liquid chromatography/tandem mass spectrometry.

Hypericum perforatum L. (St. John's Wort) has long been known as a medicinal plant, and has been used for the treatment of depression and neuralgic disorders. Its main active constituents are believed to be a naphthodianthrone, hypericin, and a phloroglucinol, hyperforin. A sensitive high performance liquid chromatography (HPLC)/electrospray tandem mass spectrometric method for fast simultaneous determination of six major naphthodianthrones and phloroglucinols of Hypericum perforatum extract has been developed. The method, based on multiple dissociation reaction monitoring (MRM), allows the analysis of hypericin, protohypericin, pseudohypericin, protopseudo-hypericin, hyperforin and adhyperforin from the extract in less than 5 min. Good linearity over the range 0.1-1000 ng/mL for hyperforin and 2-500 ng/mL for hypericin was observed. Intra-assay accuracy and precision varied from 2 to 19% within these ranges. Lower levels of quantitation for hyperforin were 0.5 ng/mL and 2 ng/mL for hypericin.

Anthraquinones↗

PubMed2000

An acylated phloroglucinol with antimicrobial properties from Helichrysum caespititium.

A new acylated form of a phloroglucinol with significant antimicrobial properties was isolated by bioactivity guided fractionation from Helichrysum caespititium (Asteraceae). The structure elucidation, and conformation of the new phloroglucinol, 2-methyl-4-[2',4',6'-trihydroxy-3'-(2-methylpropanoyl) phenyl]but-2-enyl acetate, was established by high field NMR spectroscopic and MS data. The compound inhibited growth of Bacillus cereus, B. pumilus, B. subtilis and Micrococcus kristinae at the very low concentration of 0.5 microg/ml and Staphylococcus aureus at 5.0 microg/ml. Six fungi tested were similarly inhibited at low MICs, Aspergillus flavus and A. niger (1.0 microg/ml), Cladosporium chladosporioides (5 microg/ml), C. cucumerinum and C. sphaerospermum (0.5 microg/ml) and Phylophthora capsici at 1.0 microg/ml.

Anti-Infective Agents↗