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A 34 year-old woman, working with pine wood treated with sodium hydroxide and pyrogallol, developed dermatitis on arms, face and neck. Patch testing showed allergic reaction to colophony and pine wood, but not to sodium hydroxide or pyrogallol. Pine wood contains colophony. Since avoiding pine wood, she has had no further attack of dermatitis.
Ganoderma lucidum was studied for its antioxidative activity by bioassay guided isolation in conjunction with in vitro tests. The powdered crude drug was treated with boiling water and the aqueous extract (Ex1) was further separated to obtain terpene and polysaccharide fractions. The two fractions and Ex1 were screened for their antioxidative effect against pyrogallol induced erythrocyte membrane oxidation and Fe (II)-ascorbic acid induced lipid peroxidation. All tested samples showed antioxidative activities in a dose dependent manner and the terpene fraction was found to possess the highest effect compared with the others. Chemical isolation of the terpene fraction resulted in the detection of ganoderic acids A, B, C and D, lucidenic acid B and ganodermanontriol as major ingredients.
Appropriate software settings and optimum procedures were determined for the measurement of the motion parameters of rabbit spermatozoa by the CellSoft (Cryo Resources Ltd., Montgomery, NY) computer-assisted digital image analysis system. The system was used to follow motion parameter changes occurring in spermatozoa incubated for 6 hr with or without exposure to chemicals. Mean amplitude of lateral head displacement (AALH) increased over the 6 hr period, while curvilinear velocity (Vc) first increased and then decreased. Values for linearity (Lin), or beat cross frequency (BCF), were unchanged. The majority of spermatozoa progressed linearly, with rapid rotation of the sperm head, but subpopulations of spermatozoa with different swimming patterns appeared after 1-3 hr of incubation. Percentage motile sperm and Vc were most sensitive to the action of the compounds (pyrogallol, hydroquinone, ammonium oxalate, triethyl phosphite, and pinocolyl alcohol), while BCF was least affected. The decline in percentage of motile sperm was dependent on duration of exposure and chemical concentration. Mean Vc of the sperm population decreased rapidly upon chemical exposure and remained at a low value until motility ceased. The initial decrease in Vc was dependent on the concentration of the added compound. Motion-based indices--motility concentration (MCI50), motility time (MTI50), and velocity (VI)--were defined and used as toxicological endpoints. The rank order of these indices, the end point of the neutral red in vitro assay for cytotoxicity, and LD50 values for the five compounds were the same, suggesting that chemical inhibition of sperm motility may be useful as a method for the in vitro assessment of chemical cytotoxicity.
The activities of catechol-O-methyl transferase (COMT), monoamine oxidase (MAO), and a methanol forming enzyme were studied in whole brain homogenates and in livers obtained from DBA/2J, C57B1/6J, and F1 hybrid mice. DBA/2J mice are extremely susceptible to audiogenic seizures, whereas C57B1/6J mice are resistant to sound-induced convulsions. C57B1/6J mice were found to have significantly higher brain levels of COMT, while MAO activities were not different in animals of these genotypes. No methanol forming activity was detected in animals of either strain. No differences were found in hepatic activities of either COMT or MAO. Pyrogallol was shown to protect DBA/2J animals against audiogenic seizures.
Free radicals generated by a partial reduction of O2 pose a serious threat to tissues and vital organs and cells. The major site of interaction between the lung and inhaled oxidants is the epithelium. We have examined the effect of pyrogallol, an O2- generator, on the ability of human epithelial cells to produce active DNA binding proteins and inducible nitric oxide synthase (iNOS) mRNA in cultured A549 epithelial cells. NF kappa B binding in the nuclei of these cells was determined by electrophoretic mobility shift assays. iNOS mRNA was measured using reverse transcription of PCR. There was a time- and concentration-dependent induction of NF kappa B binding, followed by a time and dose dependent increase in iNOS mRNA levels. These results suggest that in airways the initial response to oxidative stress may be to induce NF kappa B-responsive genes, such as iNOS, which may play an important role in defending the airway against oxidative stress.
CGP 28014 (N-(2-pyridone-6-yl)-N',N'-di-n-propylformamidine) or its methanesulfonate salt CGP 28014 A was suspected to be a catechol-O-methyl-transferase (COMT) inhibitor because it was found to reduce the levels of homovanillic acid (HVA) and to increase those of 3,4-dihydroxyphenylacetic acid (DOPAC) in the rat striatum, after oral or intraperitoneal administration. These effects were maintained after repeated administration. The compound was only weakly active as a COMT inhibitor in vitro. However, its effect on striatal HVA and DOPAC was not prevented by pretreatment with the inhibitor of microsomal drug metabolizing enzymes in the liver, proadifen, indicating that, if CGP 28014 acts as a prodrug, its conversion to the active compound is not by oxidative metabolism in the liver. Also, there was no evidence that conversion to 2-amino-6-hydroxypyridine could explain its effects. The in vivo effect of CGP 28014 was substantiated in two additional in vivo test systems. Thus, it inhibited the accumulation of 3-methoxytyramine in the rat striatum after MAO inhibition by clorgyline, and the formation of O-methyl-DOPA from exogenously administered DOPA. It proved to be equipotent or nearly so with tropolone, and also showed a similar duration of action. Similar to tropolone, it increased S-adenosylmethionine levels in the striatum. Pyrogallol, on the other hand, decreased them, because being a substrate of COMT, it consumes methyl groups. This suggests that CGP 28014 does not inhibit COMT because it is a substrate of the enzyme.(ABSTRACT TRUNCATED AT 250 WORDS)
The superoxide dismutase (SOD) activity of beef heart cytochrome oxidase, both in the resting (as isolated) and pulsed (reduced and reoxidized) states, has been investigated using their ability to inhibit the autoxidation rate of pyrogallol and epinephrine. Resting oxidase showed variable SOD activity, while in the pulsed state the SOD activity of cytochrome oxidase (CcO) increased by an order of magnitude. These results are discussed in terms of a physiological role for the pulsed oxidase.
A variety of arachidonic acid metabolites possess the ability to modulate immune cell function. Various inhibitors of arachidonic acid metabolism were compared with regard to their effects on T-suppressor (Ts) cell function. Using staphylococcal enterotoxin B (SEB) to activate Lyt-2+ Ts cells, it was shown that indomethacin and 5,8,11,14-eicosatetraynoic acid (ETYA) inhibit the induction phase, but not the expression phase, of suppressor cell activity. Agents which inhibit thromboxane synthetase or lipoxygenase activities (imidazole, nordihydroguaiaretic acid, and pyrogallol) were not found to affect Ts cell induction. Since inhibitors of prostaglandin synthesis are thought to induce lower levels of cyclic adenosine monophosphate, an attempt to overcome the indomethacin inhibition of Ts cell induction by modulating cyclic adenosine monophosphate levels was made. It was found that theophylline and isoproterenol are not able to overcome the inhibition by indomethacin of Ts cell activity. These results strongly suggest that induction of Ts cells by SEB is dependent on the synthesis of products of the prostaglandin synthetase pathway.
Autooxidation of polyphenolic metabolites of benzene, such as hydroquinone (HQ), catechol (CT), 1,2,4-benzenetriol (BT) and pyrogallol (PG), produced several kinds of active oxygen species (AOS). BT and PG induced DNA breaks in the absence of metal ions, especially when producing AOS such as H2O2, O2-, HO. or 1 delta gO2. HQ and CT did not result in double-strand DNA breaks, except when ferrous ion was added, indicating the participation of the Fenton reaction. Polyphenolic fractions isolated from green tea (GTP) exerted inhibitory effects on the autooxidation of BT and suppressive effects on H2O2 or HO. generated from phenolic metabolites of benzene in the presence of S9 or an in vivo system. Additionally, although the activities of antioxidant and phase II enzymes were elevated by both GTP and phenolic metabolites of benzene, GTP counteracted the lowering GSH caused by phenolic metabolites of benzene in rat liver. The above results suggest that GTP and phenolic metabolites of benzene are antagonistic in their response to AOS, especially hydroxyl radical.
The comparative pharmacology of endothelium-derived relaxing factor (EDRF) and nitric oxide (NO) was studied on isolated strips of rabbit aorta. Both compounds were equally unstable. The relaxations of the bioassay tissues induced by EDRF released by bradykinin (3-100 nM) and by NO (4-134 nM) were indistinguishable. The stability of both compounds was increased to a similar extent by infusions of superoxide dismutase (SOD; 15 U.ml-1) or of cytochrome c (40 microM). The relaxations induced by EDRF and NO were inhibited to similar extents by infusions of Fe2+, hydroquinone and pyrogallol, an effect attenuated by a concomitant infusion of SOD or cytochrome c. The relaxations induced by both compounds were also inhibited by haemoglobin, however, this effect was unaltered by concomitant infusion of SOD. These data indicate that EDRF and NO have identical biological activity, stability and susceptibility to inactivation by superoxide anions and haemoglobin, providing further confirmation that EDRF is NO.
It has been pointed out by several different groups of investigators in the past several years that ascorbic acid was a potent inhibitor of the binding of dopamine (DA) agonists including 3H-DA itself and 3H-ADTN, 3H-apomorphine and 3H-norpropylapomorphine to neostriatal membrane preparations. However, the significance of this effect of ascorbic acid has been controversial. For example, it has recently been claimed that the stereospecific binding of DA agonists is facilitated by ascorbic acid and can be measured only in its presence. In the present study in neostriatal membrane preparations in the absence of ascorbic acid, the binding of 3H-DA was very potently inhibited by potent DA agonists (DA, ADTN, apomorphine). Considerably weaker effects were obtained with norepinephrine, isoproterenol, serotonin, catechol and pyrogallol. Stereospecific effects were clearly observed in that the binding of 3H-DA was inhibited to a much greater extent by several biologically active enantiomers than by their less active counterparts. For example, (-)-2-hydroxyapomorphine and (-)-norpropylapomorphine were much more potent inhibitors than their corresponding (+) isomers. This binding of 3H-DA was also very strongly inhibited by sodium ascorbate and several other reducing agents. In control experiments in the neostriatal membrane preparation in the absence of ascorbic acid, there was no detectable decomposition of 3H-DA. The data suggest that 3H-DA can, in the absence of sodium ascorbate, bind stereospecifically to a site that has the properties of a DA receptor. Furthermore, sodium ascorbate is a potent inhibitor of this stereospecific binding.
Antioxidants were found to protect against the genotoxic effects of chemical and physical mutagenic and clastogenic agents. This study focused on the capacity of antioxidants to reduce an intrinsic and persistent chromosome instability. As a model system, strains of C127 cells, which were transformed by bovine papillomavirus (BPV) DNA and which carry BPV DNA varying from 20 to 160 copies, were used. Transformed cells of 10 different strains showed a persistently high incidence of mitotic irregularities detectable at anaphase and telophase (27.3-58.9%), an elevated frequency of cells with micronuclei (6.6-34.7%), and a broad spectrum of nuclear sizes, as measured by image analysis. A 3-day exposure to retinoic acid, retinol, beta-carotene, canthaxanthin, ascorbic acid and ellagic acid greatly reduced the degree of chromosome instability, whereas catechin, eugenol and pyrogallol showed a smaller inhibitory effect, and curcumin had no detectable effect on the frequency of mitotic irregularities. After withdrawal of retinoic acid treatment, the high levels of chromosome instability reappeared. The possibility that the protective effect of the retinoids and carotenoids examined in the model system points to their beneficial administration to human cells with an intrinsic or acquired chromosome instability is discussed.
On the premises of clinical studies, a possible contribution of oxygen radicals has been considered to the development of inflammatory pain and hyperalgesia. In a rat skin-saphenous nerve preparation using standard teased-fiber techniques (n = 57) hydrogen peroxide (1 mM, 10 mM and 50 mM) was applied in aqueous solution to cutaneous nerve endings of unmyelinated nociceptive afferents. Superoxide anion and hydroxyl radical were secondarily generated as reaction products from pyrogallol (1 and 10 mM) and from Fe-EDTA (1 mM) in hydrogen peroxide, respectively. None of these substances, except exceptionally, induced ongoing activity nor nociceptor sensitization to heat and mechanical stimuli. If occasionally there was a weak excitatory effect, the fibers were left with a profound desensitization to adequate stimulation. The addition of hydrogen peroxide did not enhance sustained responses to solutions of high proton concentration (pH 6.1). Responses to combined inflammatory mediators (bradykinin, serotonin, histamine and prostaglandin E2, 10 microM) were increased, on average, when hydrogen peroxide was added but this effect did just not reach significance. These findings suggest that oxygen radicals do not play a major and specific role in nociceptor sensitization.
Human epidermal keratinocytes which have been cultured were treated with the heavy metal ions of cadmium, mercury, copper and zinc. Cytotoxicity was measured either by protein estimation or by using the neutral red assay. Antioxidants were added in order to find out whether heavy metal-induced cytotoxicity is related to oxidative stress. All metals used showed considerable cytotoxic effects within 24 h in moderate concentrations. None of the antioxidants vitamin E (alpha-tocopherol), pyrogallol, propyl gallate, BHT or ebselen showed any protective or preventive effect. This indicates that oxidative stress may not be involved in the cytotoxicity induced by heavy metals in human epidermal keratinocytes. The cells used are, however, a valuable tool to study mechanisms of cytotoxicity.
1. Exogenous dopamine (DA), octopamine (OA), noradrenaline (NA), and the alpha 1-agonist methoxamine (MX), all induce tonic and rhythmic contractions in the rat vas deferens. 2. Tonic and rhythmic contractions can be separated by use of different concentrations of alpha 1-adrenoceptor antagonists, verapamil, pyrogallol (a COMT-inhibitor) and lowering bath temperature (greater than 20 degrees C). 3. The two types of contraction could not be distinguished by beta-adrenoceptor antagonists, cocaine (uptake 1 blocker) or metanephrine (uptake 2 blocker). 4. It is suggested that the tonic and rhythmic contractions induced by amines are mediated by different alpha-adrenoceptors.
The superoxide radical scavenging ability of centrophenoxine (CPH) and its components (dimethylaminoethanol = DMAE, p-chlorophenoxyacetic acid = PCPA) was studied in vitro using the method of pyrogallol autoxidation, cytochrome c reduction and photoxidation of o-dianisidine in salt-free assay media and in the presence of increasing NaCl or KCl concentrations. The CPH proved to be a superoxide radical scavenger in all three systems used, however, the rate constant for this reaction was rather low (1.7 X 10(2) M-1 s-1). This scavenging ability decreased linearly with increasing ionic strength. DMAE and PCPA behaved in a somewhat contradictory manner. The former proved to be a weak superoxide radical generating compound being partially sensitive to the ionic strength. The latter showed either superoxide radical scavenging or generating effects in various assays depending on the actual salt concentrations of the media. On the basis of the results one has to assume that the superoxide radical scavenger ability of CPH may hardly be responsible for the in vivo effects of this compound, therefore, its OH. radical scavenger reactions the rate constant of which is about 10(9) M-1 s-1 may be of much greater importance.
The inhibition of ribonucleotide reductase (RR) of intact Ehrlich ascites tumor cells by different antitumor agents was compared using EPR spectroscopy. The inactivation of M2 subunit was measured via quenching of the functionally essential tyrosine radical. Inhibitors of different classes, for example, hydroxyurea, pyrogallol, and thiosemicarbazones, differ in their efficiency by three orders of magnitude. Most effective inhibition was found for isoquinoline-1-aldehyde-thiosemicarbazone (IQ-1) with an IC50 value of 0.18 microM. Inhibition of RR inside tumor cells is comparable with that reported for isolated enzymes.
Chlorella vulgaris contained only one isoform of ascorbate peroxidase (AsAP) as the hydrogen peroxide (H2O2)-scavenging system except for catalase at a specific activity of 3.3 +/- 0.2 units/mg protein. The activity of glutathione peroxidase was not detected in the extracts from cells grown in the absence and presence of sodium selenite. We detected the activity of monodehydroascorbate reductase involved in the regeneration of ascorbate, but we failed to detect the dehydroascorbate reductase activity. AsAP has been purified to electrophoretic homogeneity from Chlorella cells. The enzyme was a monomer with a molecular mass of 32 kDa using gel filtration and SDS-polyacrylamide gel electrophoresis. The enzyme showed higher specificity with ascorbate than with pyrogallol. The K(m) values of the enzyme for ascorbate and H2O2 were 111 +/- 8.9 and 20 +/- 2.5 microM, respectively. When the enzyme was diluted with the ascorbate-deleted medium, the half inactivation time was approximately 15 min. The absorption spectra of the purified enzyme and the inhibition by cyanide and azide showed that it is a hemoprotein. The enzyme was markedly inhibited by 0.2 mM p-chloromercuribenzoate. The enzyme cross-reacted by immunoblotting with the monoclonal antibody raised against Euglena cytosolic AsAP. The amino acid sequences in the N-terminal region of Chlorella AsAP showed no significant similarity to any other AsAPs from higher plants and algae.