In Vitro Study of the Antioxidant Properties of Nimesulide and 4-Oh Nimesulide: Effects on Hrp- and Luminol-Dependent Chemiluminescence Produced by Human Chondrocytes

in Osteoarthritis and Cartilage (2000), 8(6), 419-25

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 ... [more ▼]

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. [less ▲]

In vitro study of the antioxydant properties of nonsteroidal anti-inflammatory drugs by chemiluminescence and electron spin resonance (ESR)

in Annals of the Rheumatic Diseases (2000), 59(S1), 187

In vitro study of the antioxidant properties of non steroidal anti-inflammatory drugs by chemiluminescence and electron spin resonance (ESR).

in Free Radical Research (2000), 33(5), 607-21

OBJECTIVES: To determine the antioxidant activities of nonsteroidal anti-inflammatory drugs (NSAIDS), we examined by chemiluminescence (CL) and electron spin resonance (ESR) their scavenging properties ... [more ▼]

OBJECTIVES: To determine the antioxidant activities of nonsteroidal anti-inflammatory drugs (NSAIDS), we examined by chemiluminescence (CL) and electron spin resonance (ESR) their scavenging properties towards lipid peroxides, hypochlorous acid and peroxynitrite. METHODS: The antioxidant properties of nimesulide (NIM), 4-hydroxynimesulide (4-HONIM), aceclofenac (ACLO), 4-hydroxyaceclofenac (4-HOA-CLO), diclofenac (DICLO) and indomethacin (INDO) were tested on four different reactive oxygen species (ROS) generating systems: (I) phorbol-myristate acetate (PMA)-activated neutrophils, (II) Fe2+/ascorbate-induced lipid peroxidation, (III) HOCl-induced light emission, (IV) the kinetics of ONOO- decomposition followed by spectrophotometry. ROS production was monitored by luminol-enhanced CL or by ESR using two different spin traps. RESULTS: At 10 microM, ACLO, NIM, 4-HONIM, 4-HOA-CLO, and DICLO decreased luminol-enhanced CL generated by PMA-activated neutrophils. Inversely, INDO increased the luminol enhanced CL. Interestingly, hydroxylated metabolites were more potent antioxidants than the parent drugs. Furthermore, all drugs tested, excepted ACLO, lowered lipid peroxidation induced by Fe2+/ascorbate system. ACLO and DICLO, even at the highest concentration tested (100 microM), did not significantly lower HOCl induced CL, whereas the other drugs were potent scavengers. Finally, all the NSAIDS accelerated decomposition of ONOO-, suggesting a potential capacity of the molecules to scavenge peroxynitrite. CONCLUSION: The NSAIDs possess variable degrees of antioxidant activities, linked to their ability to react with HOCl, lipid peroxides or ONOO-. These antioxidant activities could offer interesting targeted side-effects in the treatment of joint inflammatory diseases. [less ▲]

Le propofol agent anesthésique et agent antioxydant? Une étude spectroscopique des propriétés inhibitrices du propofol vis-à-vis de l'oxygène singulet

Conference (2000)

EGb 761 protects liver mitochondria against injury induced by in vitro anoxia/reoxygenation.

in Free Radical Biology & Medicine (1999), 27

The present study investigated the protective effects of Ginkgo biloba extract (EGb 761) on rat liver mitochondrial damage induced by in vitro anoxia/reoxygenation. Anoxia/reoxygenation was known to ... [more ▼]

The present study investigated the protective effects of Ginkgo biloba extract (EGb 761) on rat liver mitochondrial damage induced by in vitro anoxia/reoxygenation. Anoxia/reoxygenation was known to impair respiratory activities and mitochondrial oxidative phosphorylation efficiency. ADP/O (2.57 +/- 0.11) decreased after anoxia/reoxygenation (1.75 +/- 0.09, p < .01), as well as state 3 and uncoupled respiration (-20%, p < .01), but state 4 respiration increased (p < .01). EGb 761 (50-200 microg/ml) had no effect on mitochondrial functions before anoxia, but had a specific dose-dependent protective effect after anoxia/reoxygenation. When mitochondria were incubated with 200 microg/ml EGb 761, they showed an increase in ADP/O (2.09 +/- 0.14, p < .05) and a decrease in state 4 respiration (-22%) after anoxia/reoxygenation. In EPR spin-trapping measurement, EGb 761 decreased the EPR signal of superoxide anion produced during reoxygenation. In conclusion, EGb 761 specially protects mitochondrial ATP synthesis against anoxia/reoxygenation injury by scavenging the superoxide anion generated by mitochondria [less ▲]

Propofol Reacts with Peroxynitrite to Form a Phenoxyl Radical: Demonstration by Electron Spin Resonance

in Biochemical and Biophysical Research Communications (1998), 249(3), 833-7

Peroxynitrite (ONOO-), resulting from the reaction of nitric oxide with superoxide anion, is a powerful oxidant produced in activated macrophages, during ischemia-reperfusion processes as well as in ... [more ▼]

Peroxynitrite (ONOO-), resulting from the reaction of nitric oxide with superoxide anion, is a powerful oxidant produced in activated macrophages, during ischemia-reperfusion processes as well as in neurodegenerative disorders. This study investigated the reaction of the anesthetic agent propofol (PPF) with ONOO-, using electron spin resonance (ESR) and UV-visible spectrometry. Peroxynitrite was synthetized either from acidified hydrogen peroxide and nitrite, or from sodium azide and ozone. The addition of ONOO- to PPF in alkaline solution (pH 12) allowed to detect a, short lifetime, ESR signal corresponding to a phenoxyl radical. This finding was confirmed by a UV-visible study, resulting in the appearance of 427 nm peak and the disappearance of the peak located at 239 nm. The 291 nm peak remained unchanged. The identification of the end-product of the reaction of PPF with ONOO- needs further investigations. [less ▲]

The Antibiotic Ceftazidime Is a Singlet Oxygen Quencher as Demonstrated by Ultra-Weak Chemiluminescence and by Inhibition of Aap Consumption

in Biochimica et Biophysica Acta (1998), 1379(1), 61-8

We demonstrated that the cephalosporin antibiotic ceftazidime (CAZ) deactivated singlet oxygen (1O2). We then studied the mechanisms of the CAZ effects on the ultra weak chemiluminescence (uwCL ... [more ▼]

We demonstrated that the cephalosporin antibiotic ceftazidime (CAZ) deactivated singlet oxygen (1O2). We then studied the mechanisms of the CAZ effects on the ultra weak chemiluminescence (uwCL) associated with the energy decay of 1O2 generated by the Mallet reaction (H2O2 + HOCl --> HCl + H2O + 1O2), and on the anthracene-9,10-dipropionic acid (AAP) consumption by 1O2 generated by irradiation of Rose Bengal (RB). The uwCL generated by the Mallet reaction was amplified (6.2 times) by CAZ. The use of red and blue filters, which absorb radiation below 610 nm and between 470 and 700 nm respectively, demonstrated that CAZ increased the uwCL by a radiation emission at wavelengths shorter than the 633 and 704 nm wavelength emissions of 1O2. CAZ was excited by scavenging the energy excess of 1O2, which so returned to its fundamental state, while CAZ deactivated with light emission between 430-480 nm. CAZ also inhibited in a dose-dependent manner the consumption of AAP by 1O2 generated by the irradiation of RB. The protection of AAP by 5 x 10(-3) M CAZ was equivalent to that of 10(-3) M histidine and 3 X 10(-6) M sodium azide. This process of 1O2 deactivation will be useful in diseases characterized by an excessive PMN activation with a release of activated oxygen species. [less ▲]

The antibiotic ceftazidime is a singlet oxygen quencher as demonstrated by ultra-weak chemiluminescence and by inhibition of AAP consumption.

in Biochimica et Biophysica Acta (1998), 1379(1), 61-8

We demonstrated that the cephalosporin antibiotic ceftazidime (CAZ) deactivated singlet oxygen (1O2). We then studied the mechanisms of the CAZ effects on the ultra weak chemiluminescence (uwCL ... [more ▼]

We demonstrated that the cephalosporin antibiotic ceftazidime (CAZ) deactivated singlet oxygen (1O2). We then studied the mechanisms of the CAZ effects on the ultra weak chemiluminescence (uwCL) associated with the energy decay of 1O2 generated by the Mallet reaction (H2O2 + HOCl --> HCl + H2O + 1O2), and on the anthracene-9,10-dipropionic acid (AAP) consumption by 1O2 generated by irradiation of Rose Bengal (RB). The uwCL generated by the Mallet reaction was amplified (6.2 times) by CAZ. The use of red and blue filters, which absorb radiation below 610 nm and between 470 and 700 nm respectively, demonstrated that CAZ increased the uwCL by a radiation emission at wavelengths shorter than the 633 and 704 nm wavelength emissions of 1O2. CAZ was excited by scavenging the energy excess of 1O2, which so returned to its fundamental state, while CAZ deactivated with light emission between 430-480 nm. CAZ also inhibited in a dose-dependent manner the consumption of AAP by 1O2 generated by the irradiation of RB. The protection of AAP by 5 x 10(-3) M CAZ was equivalent to that of 10(-3) M histidine and 3 X 10(-6) M sodium azide. This process of 1O2 deactivation will be useful in diseases characterized by an excessive PMN activation with a release of activated oxygen species. [less ▲]

Propofol reacts with peroxynitrite to form phenoxyl radicals. Demonstration by ESR

Conference (1998)

Effects of sphingosine and sphingosine analogues on the free radical production by stimulated neutrophils: ESR and chemiluminescence studies.

in Mediators of Inflammation (1997), 6(5-6), 327-33

Sphingolipids inhibit the activation of the neutrophil (PMN) NADPH oxidase by protein kinase C pathway. By electron spin resonance spectroscopy (ESR) and chemiluminescence (CL), we studied the effects of ... [more ▼]

Sphingolipids inhibit the activation of the neutrophil (PMN) NADPH oxidase by protein kinase C pathway. By electron spin resonance spectroscopy (ESR) and chemiluminescence (CL), we studied the effects of sphingosine (SPN) and ceramide analogues on phorbol 12-myristate 13-acetate (PMA, 5 x 10(-7)M) stimulated PMN (6 x 10(6) cells). By ESR with spin trapping (100 mM DMPO: 5,5-dimethyl-1-pyrroline-Noxide), we showed that SPN (5 to 8 x 10(-6)M), C(2)-ceramide (N-acetyl SPN) and C(6)-ceramide (N-hexanoyl SPN) at the final concentration of 2 x 10(-5) and 2 x 10(-4)M inhibit the production of free radicals by stimulated PMN. The ESR spectrum of stimulated PMN was that of DMPO-superoxide anion spin adduct. Inhibition by 5 x 10(-6)M SPN was equivalent to that of 30 U/ml SOD. SPN (5 to 8 x 10(-6)M) has no effect on in vitro systems generating superoxide anion (xanthine 50 mM/xanthine oxidase 110 mU/ml) or hydroxyl radical (Fenton reaction: 88 mM H(2)O(2), 0.01 mM Fe(2+) and 0.01 mM EDTA). SPN and N-acetyl SPN also inhibited the CL of PMA stimulated PMN in a dose dependent manner (from 2 x 10(-6) to 10(-5)M), but N-hexanoyl SPN was less active (from 2 x 10(-5) to 2 x 10(-4)M). These effects were compared with those of known PMN inhibitors, superoxide dismutase, catalase and azide. SPN was a better inhibitor compared with these agents. The complete inhibition by SPN of ESR signal and CL of stimulated PMN confirms that this compound or one of its metabolites act at the level of NADPH-oxidase, the key enzyme responsible for production of oxygen-derived free radicals. [less ▲]