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PubMed1985

Co-oxidation of luminol by hypochlorite and hydrogen peroxide implications for neutrophil chemiluminescence.

Stimulated neutrophils produce several potent oxidants including H2O2, O2- and HOCl. Previous studies have revealed all of these compounds to be capable of oxidizing luminol, a reagent often used to indicate, by its chemiluminescence, the oxidative burst of neutrophils. Data presented in this paper indicate that H2O2 and HOCl spontaneously react at physiologic pH to produce luminol-dependent chemiluminescence 100 times the sum of the chemiluminescence of either reagent alone. This enhancement is due to a co-oxidation by HOCl and H2O2, or to a novel oxidant generated by the interaction of HOCl and H2O2. The HOCl scavenger, taurine, inhibits the chemiluminescence. Evidence is presented against the participation of hydroxyl radical, O2- or singlet oxygen in the oxidation of luminol by HOCl and H2O2. These findings have implications for potential anti-inflammatory compounds.

Humans↗

PubMed1982

A sensitive method for determination of serum hemoglobin based on iso-luminol chemiluminescence.

A simple and rapid method for determination of serum hemoglobin is described. Hemoglobin may be determined in serum within the range of 0.02-400 mg/1 by the sensitive chemiluminescent iso-luminol reaction. The iso-luminol assay was considerably more sensitive than the conventional colorimetric procedure based on tetramethylbenzidine. Precision and accuracy were higher with the iso-luminol assay especially at low levels of hemoglobin. The correlation between the luminescent and colorimetric method was linear but the colorimetric determinations resulted in higher concentrations of hemoglobin. This discrepancy was probably caused by non-heme serum iron which interfered more strongly with the colorimetric method.

Benzidines↗

PubMed1990

Luminol enhanced chemiluminescence of the perfused rat heart during ischemia and reperfusion.

We show that the production of Luminol reactive oxygen radicals in the perfused rat heart under ischemia and reperfusion can be monitored continuously by measuring the chemiluminescence of Luminol-perfused hearts. Luminol did not affect the monitored physiological parameters of the hearts. Chemiluminescence increased during ischemia and reperfusion. Superoxide dismutase treatment of the heart before ischemia, but not catalase, abolished these increases.

Animals↗

PubMed1995

Chemiluminescent detection of artemisinin. Novel endoperoxide analysis using luminol without hydrogen peroxide.

A novel method for artemisinin quantitation employing high-performance liquid chromatography (HPLC) with chemiluminescence (CL) detection in the absence of hydrogen peroxide (H2O2), is reported. After elution from the HPLC column, artemisinin is combined with an alkaline solution of hematin and luminol. The resulting CL signal is detected by use of a spectrofluorometer with the excitation lamp disabled, and is proportional to artemisinin concentration. The CL method was optimized and applied to the analysis of artemisinin in spiked human serum. CL in the absence of H2O2 or other known oxidizing species is remarkable since such oxidizers are usually required to produce CL from luminol under alkaline conditions. Artemisinin, a naturally occurring sesquiterpene, is one of several natural products that contain an endoperoxide functional group. Since H2O2 is not needed in the analysis, the endoperoxide moiety on artemisinin is implicated as a contributing source of superoxide radicals required for the light-producing reaction with luminol.

Antimalarials↗

PubMed1983

Luminol-dependent chemiluminescence analysis of the variables of the phagocytic response by canine granulocytes.

Variables which influence the oxygen-dependent chemiluminescence (CL) response of canine polymorphonuclear leukocytes (PMN) to zymosan were examined in a luminol-dependent CL assay system. Maximal CL responses were obtained when 5 x 10(6) canine PMN, isolated from heparinized blood, were assayed at 37 degrees C in a Luminometer. The response was enhanced by the addition of 0.05 mM Luminol and inhibited by the addition of 0.06 mM sodium azide and 60 micrograms superoxide dismutase. Repeatability on a given day was very good; however, day to day variations in CL activity prevented direct comparison of phagocytic activity between days. Opsonization of zymosan in equine serum significantly reduced the CL response by canine PMN as compared to opsonization of zymosan in autologous or homologous canine serum and bovine serum. The present results show that luminol-dependent CL analysis can be used to measure phagocytosis by canine granulocytes in a luminometer and has potential use in clinical situations.

Animals↗

PubMed1989

Comparison of the effects of superoxide dismutase and cytochrome c on luminol chemiluminescence produced by xanthine oxidase-catalyzed reactions.

Superoxide dismutase (superoxide: superoxide oxidoreductase, EC 1.15.1.1) (SOD) and ferricytochrome c are used to check the effects on luminol chemiluminescence induced by a xanthine or hypoxanthine/xanthine oxidase/oxygen system. Luminol chemiluminescence has been attributed to superoxide anion radical (O2.-) in this system. From kinetic studies on the light intensity vs. time curves it is demonstrated that addition of SOD into the system does not affect the mechanism of O2.- generation, whilst ferricytochrome c dramatically alters the time-course of the reaction. This is interpreted as the effect of cytochrome c redox cycling by reaction with H2O2, modifying oxy-radical generation in the reaction medium. Also, an alternative mechanism for luminol chemiexcitation is proposed under certain experimental conditions.

Catalysis↗

PubMed1993

Luminol and lucigenin as detectors for O2.-.

Univalent oxidation of luminol and univalent reduction of lucigenin must precede reaction with O2.- if that reaction is to lead to luminescence. The assumption that luminol or lucigenin, per se, reacts with O2.- in a way leading to luminescence is incorrect, and leads to misinterpretation of results. The chemical reactions leading to the O2(.-)-dependent luminescences of luminol and of lucigenin are discussed.

Acridines↗

PubMed2005

Indirect chemiluminescence detection for capillary zone electrophoresis of monoamines and catechol using luminol-k3[Fe(CN)6] system.

Indirect chemiluminescence (ICL) detection for capillary electrophoresis (CE) of monoamines and catechol using luminol-K3 [Fe(CN)6] system was described. A strong and stable background chemiluminescence (CL) signal can be generated by luminol-K3 [Fe(CN)6] reaction. Based on the principle of that some phenolic compounds may be oxidized in the presence of K3 [Fe(CN)6], quenching effect of catecholamines for luminol-K3[Fe(CN)6] CL reaction results in a quantifiable decrease in the background signal. The conditions for CE separation and the CL detection for four standard catecholamines were systematically investigated using a homemade CE-ICL system. Under the optimum conditions, the detection limits of dopamine (DA), epinephrine (EP), norepinephrine (NE) and catechol (CA) were determined to be 0.18 mciroM 0.39 microM 0.48 microM and 0.09 microM, respectively. It also has been successfully applied to analyze seven pharmaceutical samples and seven human urine samples.

Adult↗

PubMed1988

Luminol-dependent photoemission from single neutrophil stimulated by phorbol ester and calcium ionophore--role of degranulation and myeloperoxidase.

Luminol-dependent photonic burst from phorbol ester-treated single neutrophil was visually investigated by using an ultrasensitive photonic image intensifier microscope. Neutrophils stimulated by phorbol myristate acetate (0.1 microgram/ml) alone produced a negligible level of photonic activities in the presence of luminol (10 micrograms/ml). The additional application of 0.1 microM Ca2+ ionophore A23187 induced explosive changes of photonic burst corresponding to the distribution of neutrophils, and these photonic activities were gradually spread to extracellular space. Sodium azide, which prevents myeloperoxidase activity, inhibited Ca2+ ionophore-induced photonic burst from phorbol ester-treated neutrophil. These findings suggest a prerequisite role of degranulation and myeloperoxidase release in luminol-dependent photoemission from stimulated neutrophils.

Azides↗

PubMed2003

Evaluation of the probes 2',7'-dichlorofluorescin diacetate, luminol, and lucigenin as indicators of reactive species formation.

This study attempts to provide a critical assessment of three different common approaches to identifying teactive species formed in biological systems: the 2',7'-dichlorofluorescin diacetate (DCFH-DA) assay, and the luminol- and lucigenin-amplified chemiluminescence assays. There have been several contradictory reports about the specificity of these methods. Our results show that DCFH is oxidized to the fluorescent compound 2',7'-dichlorofluorescin (DCF) in human neutrophils exposed to the following compounds: Aroclor (A)1242, hydrogen peroxide (H(2)O(2)), nitric oxide (NO), and FeSO(4). Use of a cell-free DCFH system showed increased formation of DCF by peroxynitrite (ONOO(-)), horseradish peroxidase (HRP) alone, and HRP in combination with H(2)O(2), FeSO(4) alone, and a mixture of FeSO(4) and H(2)O(2). The hydroxyl radical (z.rad;OH) scavenger formate and the iron ion chelator deferoxamine reduced the DCF formation induced by FeSO(4) in combination with H(2)O(2). DCFH was insensitive to NO and H(2)O(2) in the cell-free system. In the presence of neutrophils, the A1242-induced luminol chemiluminescence was decreased by the superoxide dismutase inhibitor diethyldithiocarbamic acid (DDC) and the myeloperoxidase inhibitor salicylhydroxamic acid (SHA). Exposure of the neutrophils to NO, FeSO(4), or H(2)O(2) alone did not have any effect. A1242-induced lucigenin chemiluminescence in the neutrophils was increased slightly by DDC, but was not affected by SHA, NO, FeSO(4), or H(2)O(2). In conclusion, we suggest that the DCF assay is only suitable for measurements of ONOO(-), H(2)O(2) in combination with cellular peroxidases, and z.rad;OH. Luminol is sensitive towards HOCl, while lucigenin is oxidized by O(2)z.rad;(-).

Acridines↗

PubMed1987

Stimulation of alveolar macrophages by mineral dusts in vitro: luminol-dependent chemiluminescence study.

Luminol-dependent chemiluminescence (CL) of normal (nonactivated) rabbit alveolar macrophages (AMs) was measured in suspension upon stimulation by various size fractions of one quartz dust sample or by various mineral dusts (quartz, corundum, anatas, and chrysotile asbestos as an example of fibrous dust). The CL-triggering capacity of the tested dusts was inhibited by their preincubation with autologous serum. The intensity of luminol-dependent CL induced by particulate dusts upon their action on AMs depended on the kind of dust, on the dust particle sizes, and on the ratio of the number of particles to the number of cells in a given suspension. The cytotoxicity and/or fibrogenicity of the dust and its capacity to trigger the luminol-dependent CL of nonadherent AMs were not directly correlated.

Animals↗

PubMed1996

Oxygenation activity of chicken blood phagocytes as measured by luminol- and lucigenin-dependent chemiluminescence.

Luminol- and lucigenin-dependent chemiluminescence (CL) was used to compare activation of the respiratory burst of chicken peripheral blood monocytes and heterophils after stimulation with various agents. Monocytes and heterophils were obtained from the blood of three specific-pathogen-free chickens at 14 months of age and purified by a two-step discontinuous Percoll gradient. All cells responded to phorbol 12-myristate 13-acetate (PMA), zymosan A and calcium ionophore A23187 producing CL. The time course of luminol- and lucigenin-dependent CL was similar for both monocytes and heterophils after stimulation with PMA or zymosan A. Heterophils at lower cell number than monocytes responded with similar or higher peak maximum (PM) values. At the concentrations of stimuli used, the order of mean PM values was: zymosan A > PMA > A23187. Addition of 4 x 10(-6) M N-formyl-1-L-methionyl-L-leucyl-L-phenylalanine (fMLP) showed weak but significant CL activity at 1 x 10(6) monocytes per tube with luminol and at 5 x 10(6) monocytes per tube with lucigenin. No significant response to fMLP was observed with heterophils. The results indicate that the respiratory burst of chicken monocytes and heterophils can be measured by CL.

Acridines↗

PubMedDate not supplied

Evaluation of scavenging activity assessed by Co(II)/EDTA-induced luminol chemiluminescence and DPPH* (2,2-diphenyl-1-picrylhydrazyl) free radical assay.

The scavenging activities of three standard antioxidants, quercetin, ascorbic acid, and trolox, were evaluated by Co(II)/ethylenediamine-tetraacetic acid (EDTA)-induced luminol chemiluminescence and the 2,2-diphenyl-1-picrylhydrazyl (DPPH*) free radical assay. Therefore, the aim of this study was to characterise an enzyme-free and time-independent chemiluminescence method for the assessment of the scavenging profile of compounds in a cell-free system using the Co(II)/EDTA-luminol-peroxide system. These results showed that the three standards were efficient and effective in inhibiting both Co(II)/EDTA-induced luminol chemiluminescence and the free radical DPPH*. For all the data obtained in this work, the scavenging activity for the standards tested decreased in the following order: quercetin > trolox > ascorbic acid. The present study has applied a simple and precise procedure for the study of hydroxyl radical scavenging activity by Co(II)/EDTA-induced luminol chemiluminescence, and this was assessed by DPPH* free radical scavenging.

Antioxidants↗

PubMed2001

Chemiluminescence of luminol in the presence of iron(II) and oxygen: oxidation mechanism and implications for its analytical use.

The validity of chemiluminescence-based methods relies upon the uniqueness of the relationship between the concentration of the analyte and the intensity of chemiluminescence produced. We have examined the chemiluminescence of luminol (5-amino-2,3-dihydro-1,4-phthalazinedione) in the presence of O2, without added H202, to measure nanomolar concentrations of total Fe(II) (both inorganically and organically complexed) in aqueous samples. To test the validity of the method, we have developed a kinetic model that describes the two-step oxidation of luminol by superoxide and hydroxyl (or hydroxyl-like) radicals produced from the oxidation of Fe-(II) by O2 by synthesis of existing published data. This model was coupled with a model for Fe(II) oxidation by O2 in the presence and absence of the naturally occurring Suwannee River fulvic acid (SRFA). The production of chemiluminescence depended upon the concentrations of free radicals in both the sample and luminol reagent and the pH at which the reactions were performed. The relationship between Fe(II) concentration and chemiluminescence intensity was found to be unique at Fe(II) concentrations from 1 nM to 1 microM without organic complexation and from 1 to 32 nM in the presence of SRFA despite strong signal quenching in the latter case. This type of behavior will likely ensure a similarly unique relationship in the presence of a wide range of organic compounds; however, when other systems are being investigated, the technique should be carefully evaluated.

Benzopyrans↗

PubMed1996

Induction of luminol chemiluminescence by the manganese cluster of the photosystem II water-oxidizing complex to the S0, S1, S2, and S3 states.

Luminol chemiluminescence (CL) (lambda(max) = 425 nm) induced by the manganese cluster of photosystem II (PSII) (t(max) = 1-5 min) along with CL induced by mono-, di-, or tetranuclear manganese coordination complexes (t(max) = 2-40 s) is observed when either 200 mM sodium phosphate or 1 M Tris-HCl + 200 microM EDTA are present in the reaction medium (pH 8.5) containing peroxidase. This light emission is not observed when Tris is used in the reaction medium without EDTA. The yield of a given CL without peroxidase is 5%-20% of that with peroxidase. The peroxidase-dependent CL is inhibited by catalase (I50 = 0.14-0.17 mu M), while the peroxidase-independent CL is not inhibited by 100 mM ethanol, 1 mM NaN3, 20 mu M Cyt c, or 0.6 mu M catalase. The CL induced by the Mn cluster of the water-oxidizing complex (WOC) in the S3 or S2 state exceeds that of lower S states by 15-20-fold. The magnitude of CL induced by Mn complexes is dependent on the ligand type of the complex. The ligand types of the Mn complexes and the WOC in different S states are ranked according to the magnitude of the induced CL: 1,10-phenanthroline > 2.2'-bipyridine > WOC (S3 or S2) > hydrotris(pirazolyl) borate > WOC (S0-2 or S0, S1) > 1,4,7-triazacyclononane. It is concluded that CL is caused by H2O2 formed as a result of the oxidation of luminol by triplet molecular oxygen. The Mn cluster of WOC and manganese coordination complexes, acting as catalysts of this reaction, show oxidase activity. Upon S2-S3 or S1-S2 transition, changes occur in the ligand environment of the Mn cluster of WOC influencing the induction of luminol CL.

Chlorophyll↗

PubMed2001

Long-term chemiluminescent signal is produced in the course of luminol peroxidation catalyzed by peroxidase isolated from leaves of african oil palm tree.

Optimal conditions were found for the oxidation of luminol by hydrogen peroxide in the presence of peroxidase isolated from leaves of the African oil palm tree Elaeis guineensis (AOPTP). The pH range for maximal chemiluminescence intensity (8.3-8.6) is similar for AOPTP, horseradish, and Arthromyces ramosus peroxidases and slightly different from that for tobacco peroxidase (9.3). Increasing the buffer concentration decreases the chemiluminescence intensity. As in the case of other anionic peroxidases, the catalytic efficiency of AOPTP does not depend on the presence of enhancers (4-iodophenol and 4-hydroxycinnamic acid) in the reaction medium. The detectable limit of AOPTP assayed by luminol peroxidation is 2.10(-12) M. The long-term chemiluminescence signal produced during AOPTP-dependent luminol peroxidation is a characteristic feature of the African oil palm enzyme. This feature in combination with its very high stability suggests that AOPTP will be a promising tool in analytical practice.

Enzyme Stability↗

PubMed2000

Enhancement of luminol chemiluminescence by cysteine and glutathione.

Cysteine enhancement of cobalt(II)-catalysed chemiluminescence of hydrogen peroxide and luminol occurs in carbonate buffer (but not in borate buffer), whether cysteine mixes with hydrogen peroxide before it mixes with luminol-cobalt(II) or vice versa. Enhancement was measured by the ratio of the signals in the presence and absence of cysteine; standard errors were generally < 5% of the mean ratio. Cystine in sufficiently acidic solution also enhances the chemiluminescence but otherwise diminishes the emission. The emission is also inhibited by glutathione. A mixed solution of cysteine and cystine gives rise to enhanced signals. In all the above cases, enhancement occurs only in the presence of a cobalt(II) catalyst. Luminol-peroxynitrite chemiluminescence is enhanced by cysteine and by glutathione without the presence of a catalyst.

Cobalt↗

PubMed2000

In vitro study of the antioxidant properties of nimesulide and 4-OH nimesulide: effects on HRP- and luminol-dependent chemiluminescence produced by human chondrocytes.

OBJECTIVES: Reactive oxygen species (ROS) are now recognized to play an important role in the pathogenesis of rheumatic diseases and constitute an interesting therapeutic target for drugs. This in vitro study was designed to evaluate the antioxidant properties of nimesulide (NIM), a nonsteroidal antiinflammatory drug of the sulfonanilide class, and its main metabolite 4-OH nimesulide (4-OHNIM). METHODS: The scavenging effects of NIM and 4-OH NIM on hydroxyl radical ((.)OH) and superoxide anions (O(minusd)(2)) were investigated by electron spin resonance (ESR), using 5, 5-dimethylpyrroline-N-oxide (DMPO) as the spin trap agent. The quenching properties of these drugs on hypochlorite anion was studied by luminol enhanced chemiluminescence. Finally, the effects of NIM and 4-OHNIM on the reactive oxygen species production by human articular chondrocytes were recorded by HRP and luminol-enhanced chemiluminescence. RESULTS: By this method it has been demonstrated that NIM and 4-OHNIM, at concentrations ranging from 10 to 100 microM, are potent scavengers of(.)OH whereas only 4-OHNIM was capable to scavenge O(minusd)(2). Chemiluminescence generated by HOCl was also significantly and dose-dependently inhibited by both NIM and 4-OHNIM. Nevertheless, at each concentration tested, the inhibitory effect of 4-OHNIM was significantly more marked, even at the highest concentration (100 microM). Furthermore, when chondrocytes were pre-incubated for 48-96 h with NIM or 4-OHNIM, the luminol- and HRP-dependent CL produced by the cells was significantly inhibited in a dose-dependent manner. CONCLUSIONS: NIM and 4-OHNIM may protect cartilage against oxidative stress, not only by scavenging ROS but also by inhibiting their production by chondrocytes.

Aged↗