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PubMed1984

Kinetic study of beta-cyclodextrin-dye system by high-pressure temperature-jump method.

The pressure dependence of the formation and dissociation rate constants of the inclusion reaction between beta-cyclodextrin and phenolphthalein was investigated with a newly constructed high-pressure temperature-jump apparatus. The jump height of temperature was 2.8 degrees C within 1 microsecond under pressure up to 2,000 kg/cm2. The reaction was analyzed as a simple reversible bimolecular reaction. The activation volume was 1.78 +/- 0.85 cm3/mol for the forward reaction and 10.65 +/- 1.40 cm3/mol for the backward reaction. The values of activation volumes suggest that desolvation from the phenolphthalein molecule and release of hydrating water molecules from the beta-cyclodextrin cavity occur at the transition state.

Chemical Phenomena↗
PubMed1993

Laxative use not a risk for colorectal cancer: data from the Melbourne Colorectal Cancer Study.

Commercial laxative use as a risk factor in colorectal cancer was investigated as one part of a large population based epidemiological study of colorectal cancer incidence, aetiology and survival "The Melbourne Colorectal Cancer Study", conducted in Melbourne, Australia. Commercial laxative use was similar in 685 colorectal cancer patients and 723 age/sex matched community based controls. Also, when laxatives were subdivided into various groups containing anthraquinones, phenolphthalein, mineral salts and others, previous laxative intake was similar between cases and controls. Previous use of anthraquinone laxatives and of phenolphthalein containing laxatives was not associated with the risk of colorectal cancer.

Anthraquinones↗
PubMed1982

The effect of cathartics on prostaglandin synthesis by rat gastro-intestinal tract.

Rats were dosed with the cathartics cascara, phenolphthalein, senna or ricinoleic acid with or without a 3 day pretreatment with indomethacin. Jejunum, proximal and distal ileum and colon were assayed for prostaglandin E (PGE) content by RIA. While indomethacin significantly reduced the PGE content of all tissue in all treatment groups it did not completely prevent the increase in PGE content induced by phenolphthalein, senna and ricinoleic acid. It is concluded that the contact cathartics increase PGE synthesis by the gastro-intestinal tract and this could in part explain their action. Ricinoleic acid did not appear to act as a PG precursor.

Animals↗
PubMed1999

Poly(acrylic acid) microspheres containing beta-cyclodextrin: loading and in vitro release of two dyes.

Microspheres containing poly(acrylic acid) and beta-cyclodextrin or maltose were prepared by a w/o solvent evaporation technique. The dispersed aqueous phase contained poly(acrylic acid) (800 mg) and beta-cyclodextrin or maltose (0, 200 or 800 mg). Food-grade olive oil was the continuous phase. Microsphere particle size was consistently between 15 and 25 microm, and carbohydrate content was in good agreement with that added to the dispersed phase in all cases. Two dyes, phenolphthalein and rhodamine B, having different solubility characteristics and strengths of association with beta-cyclodextrin, were selected for loading and in vitro release studies. Microspheres were loaded by soaking in a saturated propan-2-ol solution of the appropriate dye (6 h). Microsphere dye content ranged between 2.8 and 4.8 mg/g microspheres for phenolphthalein and between 2.2 and 3.7 mg/g for rhodamine B. Release studies were performed in phosphate buffer (pH 7.4; 37 degrees C). No difference in the release profile of either dye was observed between microspheres. The failure of microspheres containing beta-cyclodextrin in particular, to alter the in vitro release kinetics of either dye may be due to a number of factors and include: (i) limited cross-linking giving rise to a the rapid hydration of the polymer matrix; (ii) perturbation of the dye-beta-cyclodextrin complex by oil and/or organic solvent residues; and (iii) conformational changes/steric hindrance of the beta-cyclodextrin cavity (due to its covalent binding with PAA) resulting in a reduction in its ability to form inclusion complexes.

Acrylic Resins↗
PubMed1999

Multiwavelength spectrophotometric determination of acid dissociation constants: Part II. First derivative vs. target factor analysis.

PURPOSE: Acid dissociation constants (pKa values) denote the extent of ionization of drug molecules at different pH values, which is important in understanding their penetration through biological membranes and their interaction with the receptors. However, many drug molecules are sparingly soluble in water or contain ionization centres with overlapping pKa values, making precise pKa determination difficult using conventional spectrophotometric titration. In this work, we investigate a multiwavelength spectrophotometric titration (WApH) method for the determination of pKa values. METHODS: Spectral changes which arise during pH-metric titrations of substances with concentration of about 10(-5) M were captured by means of an optical system developed in this study. All experiments were carried out in 0.15 M KCI solution at 25 +/- 0.5 degrees C. Mathematical treatments based on the first derivative spectrophotometry procedure and the target factor analysis method were applied to calculate the pKa values from the multiwavelength absorption titration data. RESULTS: pKa values were determined by the WApH technique for six ionizable substances, namely, benzoic acid, phenol, phthalic acid, nicotinic acid, p-aminosalicylic acid and phenolphthalein. CONCLUSIONS: The pKa values measured using the WApH technique are in excellent agreement with those measured pH-metrically. We have demonstrated that the first derivative spectrophometry procedure provides a relatively simple way to visualize the pKa values which are consistent with those determined using the target factor analysis method. However, for ionization systems with insufficient spectral data obtained around the sought pKa values or with closely overlapping pKa values, the target factor analysis method outperforms the first derivative procedure in terms of obtaining the results. Using the target factor analysis method, it has been shown that the two-step ionization of phenolphthalein involves a colorless anion intermediate and a red colored di-anion.

Benzoic Acid↗
PubMed1968

The submicrosomal distribution of hepatic uridine diphosphate glucuronyltransferases in the rabbit.

1. Rabbit liver microsomes were subfractionated into rough- and smooth-surfaced types, and glucuronyltransferase activity in each microsomal subfraction was determined with p-nitrophenol, o-aminophenol and phenolphthalein as substrates. The glucuronyltransferase activity measured with p-nitrophenol and o-aminophenol as substrates was localized predominantly in rough-surfaced microsomes. Glucuronyltransferase measured with phenolphthalein as substrate was equally present in rough- and smooth-surfaced microsomes. 2. Phenobarbital pretreatment of rabbits did not stimulate any of the glucuronyltransferase activities measured in either rough- or smooth-surfaced microsomes. 3. Preincubation of rabbit liver microsomes for 30-60min. at 37 degrees under oxygen did not cause any loss of glucuronyltransferase activity. Such preincubation caused either no change or increased enzyme activity in both submicrosomal fractions. The relative distribution of transferase activity in rough- and smooth-surfaced microsomes was not affected by preincubation.

Animals↗
PubMed1977

A rapid direct assay for the determination of the separate activities of the three arylsulphatases of Aspergillus oryzae.

1. The three arylsulphatases of Aspergillus oryzae exhibit pronounced kinetic differences and substrate specificities. Arylsulphatase I hydrolyses all substrates tested, whereas arylsulphatase III will not hydrolyse tyrosine O-sulphate or phenolphthalein disulphate. Arylsulphatase II does not hydrolyse p-nitrophenyl sulphate or phenolphthalein disulphate at appreciable rates in the absence of added phenolic compounds. Phenols such as tyramine increase the rate of hydrolysis of these substances by this enzyme 1000-fold. At pH 6.9 arylsulphatase I exhibits an apparent Km of 0.1 mM for p-nitrophenyl sulphate, whereas the Km of arylsulphatase III for this substrate is 1 mM. 2. These differences were utilized to develop an assay procedure which can be used to determine the separate activities of the three enzymes present in mixtures. This assay has potential use as a means of examining the relative activities of the three enzymes in investigations of the differences in the mechanisms regulating their synthesis.

Arylsulfatases↗
PubMed1996

Evidence for an UDP-glucuronic acid/phenol glucuronide antiport in rat liver microsomal vesicles.

The transport of glucuronides synthesized in the luminal compartment of the endoplasmic reticulum by UDP-glucuronosyltransferase isoenzymes was studied in rat liver microsomal vesicles. Microsomal vesicles were loaded with p-nitrophenol glucuronide (5 mM), phenolphthalein glucuronide or UDP-glucuronic acid, by a freeze-thawing method. In was shown that: (i) the loading procedure resulted in millimolar intravesicular concentrations of the different loading compounds; (ii) addition of UDP-glucuronic acid (5 mM) to the vesicles released both intravesicular glucuronides within 1 min; (iii) glucuronides stimulated the release of UDP-glucuronic acid from UDP acid-loaded microsomal vesicles; (iv) trans-stimulation of UDP-glucuronic acid entry by loading of microsomal vesicles with p-nitrophenol glucuronide, phenolphthalein glucuronide, UDP-glucuronic acid and UDP-N-acetyl-glucosamine almost completely abolished the latency of UDP-glucuronosyltransferase, although mannose 6-phosphatase latency remained unaltered; (v) the loading compounds by themselves did not stimulate UDP-glucuronosyltransferase activity. This study indicates that glucuronides synthesized in the lumen of endoplasmic reticulum can leave by an antiport, which concurrently transports USP-glucuronic acid into the lumen of the endoplasmic reticulum.

Animals↗
PubMed2001

Loss of heterozygosity frequency at the Trp53 locus in p53-deficient (+/-) mouse tumors is carcinogen-and tissue-dependent.

Mutagenic carcinogens rapidly induced tumors in the p53 haploinsufficient mouse. Heterozygous p53-deficient (+/-) mice were exposed to different mutagenic carcinogens to determine whether p53 loss of heterozygosity (LOH) was carcinogen-and tissue-dependent. For 26 weeks, C57BL/6 (N4) [corrected] p53-deficient (+/-) male or female mice were exposed to p-cresidine, benzene or phenolphthalein. Tumors were examined first for loss of the wild-type p53 allele. p-cresidine induced p53 LOH in three of 13 bladder tumors, whereas hepatocellular tumors showed p53 LOH in carcinomas (2/2), but not in adenomas (0/3). Benzene induced p53 LOH in 13 of 16 tumors examined. Finally, phenolphthalein induced p53 LOH in all tumors analyzed (21/21). Analysis of the p-cresidine-induced bladder tumors by cold single-strand conformation polymorphism (SSCP) analysis of exon 4-9 amplicons failed to demonstrate polymorphisms associated with mutations in tumors that retained the p53 wild-type allele. p-cresidine induced a dose-related increase in lacI mutations in bladder DNA. In summary, these data demonstrate that loss of the wild-type allele occurred frequently in thymic lymphomas and sarcomas, but less frequently in carcinomas of the urinary bladder. In the bladder carcinomas other mechanisms may be operational. These might include (i) other mechanisms of p53 inactivation, (ii) inactivating mutations occurring outside exons 4-9 or (iii) p53 haploinsufficiency creating a condition that favors other critical genetic events which drive bladder carcinogenesis, as evidenced by the significant decrease in tumor latency. Understanding the mechanisms of p53 LOH and chemical carcinogenesis in this genetically altered model could lead to better models for prospective identification and understanding of potential human carcinogens and the role of the p53 tumor suppressor gene in different pathways of chemical carcinogenesis.

Alleles↗
PubMed2007

Evaluation of six presumptive tests for blood, their specificity, sensitivity, and effect on high molecular-weight DNA.

Luminol, leuchomalachite green, phenolphthalein, Hemastix, Hemident, and Bluestar are all used as presumptive tests for blood. In this study, the tests were subjected to dilute blood (from 1:10,000 to 1:10,000,000), many common household substance, and chemicals. Samples were tested for DNA to determine whether the presumptive tests damaged or destroyed DNA. The DNA loci tested were D2S1338 and D19S433. Leuchomalachite green had a sensitivity of 1:10,000, while the remaining tests were able to detect blood to a dilution of 1:100,000. Substances tested include saliva, semen, potato, tomato, tomato sauce, tomato sauce with meat, red onion, red kidney bean, horseradish, 0.1 M ascorbic acid, 5% bleach, 10% cupric sulfate, 10% ferric sulfate, and 10% nickel chloride. Of all the substances tested, not one of the household items reacted with every test; however, the chemicals did. DNA was recovered and amplified from luminol, phenolphthalein, Hemastix, and Bluestar, but not from leuchomalachite green or Hemident.

Aniline Compounds↗
PubMed1982

Interaction between diphenolic laxatives and intestinal bacteria in vitro.

The ability of the laxative diphenols desacetylbisacodyl, oxyphenisatin, and phenolphthalein to inhibit growth and cause leakage of potassium ion from microbial cells in vitro was studied with 25 aerobic and 25 anaerobic bacterial strains. None of the aerobes, but some of the anaerobes showed growth inhibition. Potassium release assayed by flame photometry was observed in strains which showed growth inhibition, but also in other strains including anaerobes and aerobes. The highest antibacterial activity among the diphenols was observed with phenolphthalein and the least with desacetylbisacodyl; this relationship as noted for both growth inhibition and potassium release. Enzymatic hydrolysis of picosulphate to the free diphenol desacetylbisacodyl carried out by three strains of anaerobic bacteria was indicated by high pressure liquid chromatography.

Bacteria↗
PubMed2005

Tibolone metabolism in human liver is catalyzed by 3alpha/3beta-hydroxysteroid dehydrogenase activities of the four isoforms of the aldo-keto reductase (AKR)1C subfamily.

Tibolone [[7alpha,17alpha]-17-hydroxy-7-methyl-19-norpregn-5(10)-en-20-yn-3-one] is used to treat climacteric symptoms and prevent osteoporosis. It exerts tissue-selective effects via site-specific metabolism into 3alpha- and 3beta-hydroxymetabolites and a Delta4-isomer. Recombinant human cytosolic aldo-keto reductases 1C1 and 1C2 (AKR1C1 and AKR1C2) produce 3beta-hydroxytibolone, and the liver-specific AKR1C4 produces predominantly 3alpha-hydroxytibolone. These observations may account for the appearance of 3beta-hydroxytibolone in target tissues and 3alpha-hydroxytibolone in the circulation. Using liver autopsy samples (which express AKR1C1-AKR1C4), tibolone was reduced via 3alpha- and 3beta-hydroxysteroid dehydrogenase (HSD) activity. 3beta-Hydroxytibolone was exclusively formed in the cytosol and was inhibited by the AKR1C2-specific inhibitor 5beta-cholanic acid-3alpha, 7alpha-diol. The cytosolic formation of 3alpha-hydroxytibolone was inhibited by an AKR1C4-selective inhibitor, phenolphthalein. The ratio of these stereoisomers was 4:1 in favor of 3beta-hydroxytibolone. In HepG2 cell cytosol and intact cells (which do not express AKR1C4), tibolone was exclusively reduced to 3beta-hydroxytibolone and was blocked by the AKR1C1-AKR1C3 inhibitor flufenamic acid. In primary hepatocytes (which express AKR1C1-AKR1C4), time-dependent reduction of tibolone into 3beta- and 3alpha-hydroxytibolone was observed again in a 4:1 ratio. 3beta-HSD activity was inhibited by both 5beta-cholanic acid-3alpha,7alpha-diol and flufenamic acid, implicating a role for AKR1C2 and AKR1C1. By contrast, the formation of 3alpha-hydroxytibolone was exclusively inhibited by phenolphthalein implicating AKR1C4 in this reaction. 3beta- and 3alpha-Hydroxytibolone were rapidly metabolized into polar metabolites (>85%). The formation of minor amounts of tibolone was also observed followed by AKR1C-catalyzed epimerization. The low hepatic formation of 3alpha-hydroxytibolone suggests that AKR1C4 is not the primary source of this metabolite and instead it maybe formed by an intestinal or enterobacterial 3alpha-HSD.

17-Hydroxysteroid Dehydrogenases↗
PubMed1993

Structure-based discovery of inhibitors of thymidylate synthase.

A molecular docking computer program (DOCK) was used to screen the Fine Chemical Directory, a database of commercially available compounds, for molecules that are complementary to thymidylate synthase (TS), a chemotherapeutic target. Besides retrieving the substrate and several known inhibitors, DOCK proposed putative inhibitors previously unknown to bind to the enzyme. Three of these compounds inhibited Lactobacillus casei TS at submillimolar concentrations. One of these inhibitors, sulisobenzone, crystallized with TS in two configurations that differed from the DOCK-favored geometry: a counterion was bound in the substrate site, which resulted in a 6 to 9 angstrom displacement of the inhibitor. The structure of the complexes suggested another binding region in the active site that could be exploited. This region was probed with molecules sterically similar to sulisobenzone, which led to the identification of a family of phenolphthalein analogs that inhibit TS in the 1 to 30 micromolar range. These inhibitors do not resemble the substrates of the enzyme. A crystal structure of phenolphthalein with TS shows that it binds in the target site in a configuration that resembles the one suggested by DOCK.

Amino Acid Sequence↗
PubMed1999

Laxative drug products for over-the-counter human use. Food and Drug Administration, HHS. Final rule.

The Food and Drug Administration (FDA) is issuing a final rule establishing that the over-the-counter (OTC) stimulant laxative ingredients danthron and phenolphthalein are not generally recognized as safe and effective and are misbranded. FDA is issuing this final rule as part of its ongoing review of OTC drug products after considering data and information on the safety of danthron and phenolphthalein.

Anthraquinones↗
PubMedDate not supplied

[Beta-cyclodextrin inclusion complexes: effect of the host substitution on molecular recognition].

The stability of inclusion complexes (i.e. the measure of molecular recognition between a guest and beta-cyclodextrin) is highly influenced by the fit of the guest into the cavity of the host and by the secondary bonds among the functional groups getting in close connection. The strength of these interactions depend on the size, shape and functional groups of the guests as well as on the facts that both the size of the cavity and the reactivity of beta-cyclodextrins are altered when the hydroxy groups are substituted. As best models, the interactions among hydroxypropylated cyclodextrins of different average degree (and pattern) of substitution and phenolphthalein (as a model for "large" guests) and p-nitrophenol-p-nitrophenolate couple (as for "small" ones) have been studied. The formation constants of phenolphthalein hydroxypropyl-beta-cyclodextrin complexes are continuously decreasing, while those of p-nitrophenol/phenolate ones show a maximum with increasing degree of substitution. The pattern of substitution has also a significant effect on the quality of the interactions: the substitution on O(6) position alters the type of the interactions most, and a series of different findings prove that this change is the basis in the chiral selectivity of different cyclodextrin derivatives, too.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMed1977

Myocardial infarct imaging agents. III. Synthesis and evaluation of [203Hg] hydroxymercuriphthaleins.

Four Hg-203-mercurated phthaleins were prepared, purified, and compared with [203Hg] mercuric nitrate, [3H] phenolphthalein [203Hg] hydroxymercurifluorescein and Tc-99m-pyrophosphate in a rat model of myocardial necrosis to determine their specificities for damaged myocardium. The ratios of damaged myocardium to normal myocardium, and to blood, for the [203Hg] hydroxymercuriphthaleins (20.7-34.1 and 12.1-20.1, respectively) were somewhat lower than those reported previously for [203Hg] hydroxymercurifluorescein, but were higher than those found with [203Hg] mercuric nitrate, [3H] phenolphthalein, and Tc-99m pyrophosphate. Both the hydroxymercuri- functional group and the phthalein moiety are required for selectivity. The removal of the oxygen bridge present in fluorescein, and the replacement of carboxylic acid by sulfonic acid, had no significant effects on the sequestration process in damaged tissue.

Animals↗
PubMed1977

Rapid determination of alkaline phosphatase activity in cheese.

A visual screening method specifying phenolphthalein monophosphate as the substrate was applied to cheese by analyzing the extract obtained with 7.5% butanol. In the extraction step, all of the alcohol was added at one time, and the mixture was filtered after mixing. Analysis of 10 samples of various types of cheese resulted in data identical to that obtained by the Scharer rapid method. Quantitative data obtained by dialysis of the butanol filtrate and spectrophotometric measurement of the phenolphthalein compared favorably (r = 0.96) with data obtained by the Scharer spectrophotometric method on 13 samples of cheese.

Alkaline Phosphatase↗
PubMed1986

Dicoumarol-sensitive glucuronidation of benzo(a)pyrene metabolites in rat liver microsomes.

The effect of dicoumarol on glucuronidation of 3-OH-benzo(a)pyrene (BP) appears to be due to inhibition of UDPglucuronosyltransferase (UDPGT) and not to an inhibited DT-diaphorase (NAD(P)H:quinone oxidoreductase); to date the only enzyme known to be inhibited by dicoumarol. This dicoumarol-sensitive form of UDPGT does not seem to be identical to the major form catalyzing the glucuronidation of p-nitrophenol or methylumbelliferone, nor to the isozyme involved in the formation of phenolphthalein glucuronides. These conclusions are based on the following observations: In solubilized microsomes, devoid of DT-diaphorase, a 3-OH-BP glucuronidation activity is found which is very similar to that observed in microsomes before passing through an azodicoumarol Sepharose 6B column that binds more than 98% of DT-diaphorase; in the eluate from this column the inhibition by dicoumarol of 3-OH-BP glucuronidation is the same as in microsomes containing DT-diaphorase; other coumarin derivatives, which are either modified or substituted in the methylene bridge between the two coumarin entities in dicoumarol, are potent inhibitors of DT-diaphorase but not of UDPGT; a concentration of 10(-6) M dicoumarol is sufficient to inhibit 3-OH-BP glucuronidation 50%. In contrast, to inhibit glucuronidation of p-nitrophenol or methylumbelliferone the concentration of dicoumarol must be raised to the substrate level: i.e., 10(-4) M. Phenolphthalein glucuronidation is almost unaffected even by this high concentration of dicoumarol. The present investigation also reveals that DT-diaphorase and NADPH-cytochrome P-450 reductase can both catalyze the reduction of BP-3,6-quinone for the formation of BP-3,6-quinol glucuronides. In the eluate from the azodicoumarol Sepharose 6B column, no NADH-supported glucuronidation of BP-3,6-quinone can be detected unless DT-diaphorase is added. However, NADPH-supported formation of BP-3,6-quinol glucuronides can still be observed. The rate of the latter reaction is sufficient enough to allow studies on the effect of dicoumarol on BP-3,6-quinone glucuronidation. These results show that glucuronidation of BP-3,6-quinols is also catalyzed by a dicoumarol-sensitive UDPGT. However, not only is the formation of BP-3,6-quinol monoglucuronides inhibited by dicoumarol, but the conversion of monoglucuronides to diglucuronides is inhibited as well. The former reaction is inhibited 50% by 3.5 X 10(-6) M dicoumarol (close to the I50 for 3-OH-BP glucuronidation), whereas 10 times less dicoumarol (2 X 10(-7) M) is sufficient for 50% inhibition of the latter reaction.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗