In vitro antioxidant properties of dantrolene sodium

Dantrolene can reduce secondary damage after spinal cord injury

The aim of this experimental study was to investigate the possible protective effects of dantrolene on traumatic spinal cord injury (SCI). Twenty-four New Zealand rabbits were divided into three groups: Sham (no drug or operation, n = 8), Control (SCI + 1 mL saline intraperitoneally (i.p.), n = 8), and DNT (SCI + 10 mg/kg dantrolene in 1 mL, i.p., n = 8). Laminectomy was performed at T10 and balloon catheter was applied extradurally. Four and 24 h after surgery, rabbits were evaluated according to the Tarlov scoring system. Blood, cerebrospinal fluid and tissue sample from spinal cord were taken for measurements of antioxidant status or detection of apoptosis. After 4 h SCI, all animals in control or DNT-treated groups became paraparesic. Significant improvement was observed in DNT-treated group, 24 h after SCI, with respect to control. Traumatic SCI led to an increase in the lipid peroxidation and a decrease in enzymic or non-enzymic endogenous antioxidative defense systems, and increase in apoptotic cell numbers. DNT treatment prevented lipid peroxidation and augmented endogenous enzymic or non-enzymic antioxidative defense systems. Again, DNT treatment significantly decreased the apoptotic cell number induced by SCI. In conclusion, experimental results observed in this study suggest that treatment with dantrolene possess potential benefits for traumatic SCI.

Antioxidant activity of L-adrenaline: a structure-activity insight

L-adrenaline belongs to a group of the compounds known as catecholamines, which play an important role in the regulation of physiological process in living organisms. The antioxidant activity and antioxidant mechanism of L-adrenaline was clarified using various in vitro antioxidant assays including 1,1-diphenyl-2-picryl-hydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), N,N-dimethyl-p-phenylenediamine (DMPD(+)), and superoxide anion radicals (O(2)(-)) scavenging activity, hydrogen peroxide (H(2)O(2)), total antioxidant activity, ferric ions (Fe(3+)) and cupric ions (Cu(2+)) reducing ability, ferrous ions (Fe(2+)) chelating activity. L-adrenaline inhibited 74.2% lipid peroxidation of a linoleic acid emulsion at 30 microg/mL concentration. On the other hand, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), alpha-tocopherol and trolox displayed 83.3, 82.1, 68.1 and 81.3% inhibition on the peroxidation of linoleic acid emulsion at the same concentration, respectively. BHA, BHT, alpha-tocopherol and trolox were used as reference antioxidants and radical scavenger compounds. Moreover, this study will bring an innovation for further studies related to antioxidant properties of L-adrenaline. According to present study, L-adrenaline had effective in vitro antioxidant and radical scavenging activity.

Bioprotective properties of seaweeds: in vitro evaluation of antioxidant activity and antimicrobial activity against food borne bacteria in relation to polyphenolic content

BACKGROUND

For many years chemical preservatives have been used in food, to act as either antimicrobials or antioxidants or both. In general, consumers regard additive-free foods as safer since preservatives can cause health hazards like asthma and cancer and are suspected to be mutagenic and neurotoxic. The present study was carried out to evaluate the antimicrobial and antioxidant activity of methanolic extracts of seaweeds, with a view to developing safer food preservatives.

METHODS

Ten edible seaweeds, which have wide pharmaceutical application, were collected from Central Marine Fisheries Research Institute, Tamil Nadu, India and evaluated for antioxidant and antimicrobial activity against food borne pathogens.

RESULTS

The results indicate that Gelidiella acerosa has the highest antioxidant activity while Haligra sps exhibited antibacterial activity against Staphylococcus aureus (MTCC 96).

CONCLUSION

Quantitative analysis of the total phenolic content of the seaweeds indicated that Gelidella acerosa and Haligra sps have high phenolic contents, which correlated to their respective antioxidant and antimicrobial activity.

Antioxidant and radical scavenging properties of curcumin

Curcumin (diferuoyl methane) is a phenolic compound and a major component of Curcuma longa L. In the present paper, we determined the antioxidant activity of curcumin by employing various in vitro antioxidant assays such as 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH*) scavenging, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, N,N-dimethyl-p-phenylenediamine dihydrochloride (DMPD) radical scavenging activity, total antioxidant activity determination by ferric thiocyanate, total reducing ability determination by the Fe(3+)-Fe(2+) transformation method, superoxide anion radical scavenging by the riboflavin/methionine/illuminate system, hydrogen peroxide scavenging and ferrous ions (Fe(2+)) chelating activities. Curcumin inhibited 97.3% lipid peroxidation of linoleic acid emulsion at 15 microg/mL concentration (20 mM). On the other hand, butylated hydroxyanisole (BHA, 123 mM), butylated hydroxytoluene (BHT, 102 mM), alpha-tocopherol (51 mM) and trolox (90 mM) as standard antioxidants indicated inhibition of 95.4, 99.7, 84.6 and 95.6% on peroxidation of linoleic acid emulsion at 45 microg/mL concentration, respectively. In addition, curcumin had an effective DPPH* scavenging, ABTS*(+) scavenging, DMPD*(+) scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe(3+)) reducing power and ferrous ions (Fe(2+)) chelating activities. Also, BHA, BHT, alpha-tocopherol and trolox, were used as the reference antioxidant and radical scavenger compounds. According to the present study, curcumin can be used in the pharmacological and food industry because of these properties.

Evaluation of Antioxidant Properties of Phaulopsis fascisepala C.B.Cl. (Acanthaceae)

The antioxidant activities of crude extract of Phaulopsis fascisepala leaf were evaluated and compared with alpha-tocopherol and BHT as synthetic antioxidants and ascorbic acid as natural-based antioxidant. In vitro, we studied its antioxidative activities, radical-scavenging effects, Fe(2+)-chelating ability and reducing power. The total phenolic content was determined and expressed in gallic acid equivalent. The extract showed variable activities in all of these in vitro tests. The antioxidant effect of P. fascisepala was strongly dose dependent, increased with increasing leaf extract dose and then leveled off with further increase in extract dose. Compared to other antioxidants used in the study, alpha-Tocopherol, ascorbic acid and BHT, P. fascisepala leaf extract showed less scavenging effect on alpha,alpha,-diphenyl-beta-picrylhydrazyl (DPPH) radical and less reducing power on Fe(3+)/ferricyanide complex but better Fe(2+)-chelating ability. These results revealed the in vitro antioxidant activity of P. fascisepala. Further investigations are necessary to verify these activities in vivo.

Comparison of in vitro antioxidant and antiradical activities of L-tyrosine and L-Dopa

Phenolic compounds are interesting because of their antioxidant properties. In the present study, the antioxidant properties of L-tyrosine as a monophenolic and L-Dopa as a diphenolic amino acid were investigated by using different antioxidant assays: (i) 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH*) scavenging; (ii) 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation decolorization assay; (iii) total antioxidant activity by ferric thiocyanate method; (iv) ferric ions (Fe3+) reducing power; (v) superoxide anion radical (O2*-) scavenging; (vi) hydrogen peroxide (H2O2) scavenging, and (vii) ferrous ions (Fe2+) chelating activities. Butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), alpha-tocopherol and trolox, a water-soluble analogue of tocopherol, were used as the reference antioxidant compounds. At the same concentration (20 microg/mL), L-tyrosine and L-Dopa showed 30.6 and 67.9% inhibition of lipid peroxidation of linoleic acid emulsion, respectively. On the other hand, BHA, BHT, alpha-tocopherol and trolox indicated inhibitions of 74.4, 71.2, 54.7 and 20.1% on the peroxidation of linoleic acid emulsion, respectively, at the above-mentioned concentration. In addition, L-tyrosine and L-Dopa had an effect on DPPH radical scavenging, ABTS radical scavenging, superoxide anion radical scavenging, H2O2 scavenging, total ferric ions reducing power and metal chelating on ferrous ions activities.

Screening of antiradical and antioxidant activity of monodesmosides and crude extract from Leontice smirnowii tuber

Leontice smirnowii is a member of the Berberidaceae family. In the current study we investigated the possible antiradical and antioxidant activity of the monodesmosides (MLS) and crude extract (CELS) of Leontice smirnowii using different antioxidant tests: 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging, scavenging of superoxide anion radical-generated non-enzymatic system, ferric thiocyanate (FTC) method, reducing power, hydrogen peroxide scavenging and metal chelating activities. Experiment revealed that MLS and CELS have an antioxidant effect concentration-dependently. Total antioxidant activity was performed according to FTC method. At the 30mug/ml concentration, the inhibition effects of MLS and CELS on peroxidation of linoleic acid emulsion were found to be 95.3% and 95.6%, respectively. On the other hand, percentage inhibition of butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), alpha-tocopherol and trolox were found to be 98.2%, 98.5%, 84.0% and 87.9% inhibition of peroxidation of linoleic acid emulsion, respectively, at the same concentration. In addition, MLS and CELS had effective DPPH radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, reducing power and metal chelating activities. Also, these various antioxidant activities were compared with BHA, BHT, alpha-tocopherol and trolox which were accepted as references antioxidants.

Disruption of endoplasmic reticulum calcium stores is involved in neuronal death induced by glycolysis inhibition in cultured hippocampal neurons

Disturbances in neuronal calcium homeostasis have been implicated in a variety of neuropathological conditions, including cerebral ischemia, hypoglycemia, and epilepsy, and possibly constitute part of the cell death process associated with chronic neurodegenerative disorders. We investigated if endoplasmic reticulum (ER) calcium stores participate in neuronal death triggered by moderate glycolysis inhibition induced by iodoacetate, an inhibitor of glyceraldehyde-3-phosphate dehydrogenase, in cultured hippocampal neurons. Results show that exposure to iodoacetate leads to a slow partial decrease in cell survival, which is significantly prevented in the absence of Ca(2+) or in the presence of the calcium chelator BAPTA-AM. Treatment with caffeine and a low (1 microM) concentration of ryanodine, which activates the ryanodine receptor (RyR), exacerbates neuronal death, whereas dantrolene and 25 microM ryanodine, which antagonizes RyR, prevents damage. Xestospongin C (XeC), an antagonist of the inositol-3-phosphate (IP(3)) receptor (IP(3)R) also prevents neuronal damage. Inhibitors of the ER calcium ATPase (sarcoendoplasmic reticulum Ca(2+) ATPase; SERCA) have no effect. The decrease in ATP levels induced by iodoacetate is potentiated by caffeine and prevented by dantrolene. Although only a slight increase in glutamate extracellular levels is observed 3.5 hr after iodoacetate exposure, the N-methyl-D-aspartate (NMDA) glutamate receptor antagonist, MK-801, efficiently prevents neuronal damage. Taken together, the data suggest that neuronal death induced during moderate glycolysis inhibition involves calcium influx through NMDA receptors and calcium release from intracellular ER stores. These results might be relevant to the understanding the mechanisms involved in neuronal damage related to aging and chronic neurodegenerative diseases, which have been associated with decreased glucose metabolism.

Effect of dantrolene on lipid peroxidation, lutathione and glutathione-dependent enzyme activities in experimental otitis media with effusion in guinea pigs

The aims of our study were to assess whether the increased oxidative stress in experimental otitis media with effusion (OME) induced by histamine was reflected erythrocytes and middle ear effusion fluid by lipid peroxidation; to survey the alterations in antioxidant enzyme activities in experimental OME; and to determine the effect of dantrolene on this oxidative stress. Erythrocyte and middle ear effusion malondialdehyde (MDA) level, erythrocyte glutathione (GSH) and glutathione peroxidase (GSH-Px), glutathione reductase (GRD) and glutathione-S-transferase (GST) activities were measured in three groups of seven guinea pigs, 3 hours after injection of 0.1 mL of histamine (or saline) into the middle ear in guinea pigs with OME (experimental group), in a dantrolene sodium group and in a control group. Erythrocyte and effusion MDA levels in the dantrolene group were significantly lower than those of the experimental group. Erythrocyte GSH-Px, GST, GRD activities, and GSH levels were significantly higher in the dantrolene group than in the experimental group. Dantrolene sodium decreased the erythrocyte and effusion MDA levels, on the other hand, it increased the GSH and GSH-dependent enzymes. These findings suggest that reactive oxygen species (ROS) play a role in histamine-induced OME. Pre-treatment with dantrolene sodium increases antioxidant enzymes activities and decreases formation of MDA, the indicator of lipid peroxidation, in histamine-induced OME.

The antioxidant activity of a triterpenoid glycoside isolated from the berries ofHedera colchica: 3-O-(β-d-glucopyranosyl)-hederagenin

The antioxidant activity of a triterpenoid glycoside [3-O-(beta-D-glucopyranosyl)-hederagenin; OGH] isolated from the berries of Hedera colchica, an ivy species endemic in Georgia, was investigated. The antioxidant properties of OGH were evaluated using different antioxidant assays: 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH.) scavenging, total antioxidant activity, reducing power, superoxide anion radical (O2*-)) scavenging, hydrogen peroxide (H2O2) scavenging and metal chelating activities. The total antioxidant activity was measured according to the ferric thiocyanate method. alpha-Tocopherol and trolox, a water-soluble analogue of tocopherol, were used as reference antioxidant compounds. At a 30 microg/mL concentration, the inhibitory effects of OGH on the peroxidation of linoleic acid emulsion was found to be 95.3%, whereas alpha-tocopherol and trolox exhibited 88.8% and 86.2% inhibition of peroxidation in the system, respectively. In addition, OGH had effective DPPH. scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, total reducing power and metal chelation of ferrous ions activities. These various antioxidant activities were compared with alpha-tocopherol and trolox.

Antioxidant and antiradical activities of L-carnitine

L-carnitine plays an important regulatory role in the mitochondrial transport of long-chain free fatty acids. In this study, the antioxidant activity of L-carnitine was investigated as in vitro. The antioxidant properties of the L-carnitine were evaluated by using different antioxidant assays such as 1, 1-diphenyl-2-picryl-hydrazyl free radical (DPPH.) scavenging, total antioxidant activity, reducing power, superoxide anion radical scavenging, hydrogen peroxide scavenging and metal chelating activities. Total antioxidant activity was measured according to ferric thiocyanate method. alpha-tocopherol and trolox, a water-soluble analogue of tocopherol, were used as the reference antioxidant compounds. At the concentrations of 15, 30 and 45 microg/mL, l-carnitine showed 94.6%, 95.4% and 97.1% inhibition on lipid peroxidation of linoleic acid emulsion, respectively. On the other hand, 45 microg/mL of standard antioxidant such as alpha-tocopherol and trolox indicated an inhibition of 88.8% and 86.2% on peroxidation of linoleic acid emulsion, respectively. In addition, L-carnitine had an effective DPPH. scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, total reducing power and metal chelating on ferrous ions activities. Also, those various antioxidant activities were compared to alpha-tocopherol and trolox as references antioxidants.

Antiradical and antioxidant activity of total anthocyanins from Perilla pankinensis decne

The purpose of this work comprise the assessment of the antioxidant activity of total anthocyanins from Perilla pankinensis samples (TAPP) by different analytical methods: 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging, total antioxidant activity, total reducing activity, superoxide anion radical scavenging, hydrogen peroxide scavenging and metal chelating activities. Total antioxidant activity was measured according to ferric thiocyanate method. alpha-Tocopherol and trolox, which water-soluble analogue of tocopherol were used as references antioxidant compounds. At the concentrations of 30 and 45 microg/mL, TAPP showed 91.9 and 96.4% inhibition on lipid peroxidation of linoleic acid emulsion, respectively. In comparison, 45 microg/mL of standard antioxidant such as alpha-tocopherol and trolox exhibited 88.8 and 86.2% inhibition on peroxidation of linoleic acid emulsion, respectively. In addition, TAPP have found effective on DPPH scavenging, superoxide anion radical and hydrogen peroxide scavenging, total reducing power and metal chelating on ferrous ions activities. Also, these various antioxidant effects were compared to alpha-tocopherol and trolox.

Determination of in vitro antioxidant and radical scavenging activities of propofol

Propofol (2,6-diisopropylphenol) is a hypnotic intravenous agent with in vivo antioxidant properties. This study was undertaken to examine the in vitro antioxidant activity of propofol using different antioxidant tests including by 1,1-diphenyl-2-picryl-hydrazil (DPPH.) radical scavenging, metal chelating, hydrogen peroxide scavenging, superoxide anion radical scavenging, reducing power and total antioxidant activities. At the concentrations of 25, 50, and 75 microg/ml, propofol exhibited 97.7, 98.6 and 100% inhibition on peroxidation of linoleic acid emulsion, respectively. On the other hand, at the 75 microg/ml concentration of standard antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and alpha-tocopherol exhibited 88.7, 94.5, and 70.4% inhibition on peroxidation of linoleic acid emulsion, respectively. In addition, at same concentrations, propofol was shown that it had effective reducing power, DPPH. free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging and metal chelating activities. These various antioxidant activities were compared to standard antioxidants such as BHA, BHT and alpha-tocopherol. These results indicate that propofol prevents lipid peroxidation and radicalic chain reactions. At the same time, propofol revealed more effective antioxidant capacity than BHA, BHT and alpha-tocopherol.

Antioxidant and antimicrobial activities of Bauhinia racemosa L. stem bark

The present study was carried out to evaluate the antioxidant and antimicrobial activities of a methanol extract of Bauhinia racemosa (MEBR) (Caesalpiniaceae) stem bark in various systems. 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) radical, superoxide anion radical, nitric oxide radical, and hydroxyl radical scavenging assays were carried out to evaluate the antioxidant potential of the extract. The antioxidant activity of the methanol extract increased in a concentration-dependent manner. About 50, 100, 250, and 500 microg MEBR inhibited the peroxidation of a linoleic acid emulsion by 62.43, 67.21, 71.04, and 76.83%, respectively. Similarly, the effect of MEBR on reducing power increased in a concentration-dependent manner. In DPPH radical scavenging assays the IC50 value of the extract was 152.29 microg/ml. MEBR inhibited the nitric oxide radicals generated from sodium nitroprusside with an IC50 of 78.34 microg/ml, as opposed to 20.4 microg/ml for curcumin. Moreover, MEBR scavenged the superoxide generated by the PMS/NADH-NBT system. MEBR also inhibited the hydroxyl radical generated by Fenton's reaction, with an IC50 value of more than 1000 microg/ml, as compared to 5 microg/ml for catechin. The amounts of total phenolic compounds were also determined and 64.7 microg pyrocatechol phenol equivalents were detected in MEBR (1 mg). The antimicrobial activities of MEBR were determined by disc diffusion with five Gram-positive, four Gram-negative and four fungal species. MEBR showed broad-spectrum antimicrobial activity against all tested microorganisms. The results obtained in the present study indicate that MEBR can be a potential source of natural antioxidant and antimicrobial agents.

Protective effects of dantrolene against myocardial injury induced by isoproterenol in rats: biochemical and histological findings

PURPOSE

We investigated whether dantrolene might protect the heart against myocardial injury (MI) induced by isoproterenol (ISO), using an experimental model in rats.

METHODS

Twenty-eight rats were randomized to treatment with saline only (control group, n=8), ISO only (ISO group, n=8), low-dose dantrolene (LDD)+ISO (LDD group, n=6) and high-dose dantrolene (HDD)+ISO (HDD group, n=6). ISO (150 mg/kg/day, s.c.), LDD (5 mg/kg/day, i.p.) and HDD (10 mg/kg/day, i.p.) were given once a day for two consecutive days. At the end of the second day, blood samples were taken from abdominal aorta shortly after the rats were anesthetised for cardiac troponins T (cTnT) and I (cTnI) assay, and the hearts were removed and observed microscopically.

RESULTS

cTnT and cTnI levels were increased in the ISO group when compared with the control group (p<0.001). LDD and HDD significantly reduced cTnT and cTnI levels when compared with the ISO group. Elevations of cTnT and cTnI appeared to relate to the severity of histological changes. The rate of animals that exhibited marked MI was higher in the ISO group than in the control group (p<0.001). The rats in both LDD and HDD groups showed less histological changes when compared to the ISO group (p<0.01). There was no significant difference between the control group and both LDD and HDD groups.

CONCLUSIONS

This study shows that dantrolene has a significant effect in the protection of the heart against MI induced by ISO. We believe that pretreatment with dantrolene may contribute to developing novel strategies in the cardiotoxicity animal models and in the prevention of the cardiotoxic effects of elevated levels of catecholamines.

Prevention of acute adriamycin cardiotoxicity by dantrolene in rats

Possible preventive effect of dantrolene against the peroxidative damage in rat heart which was induced by the administration of an acute dose of adriamycin (ADR, 20 mg/kg, i.p.) has been examined. Forty-eight hours after ADR administration, biochemical changes including the activities of serum creatine kinase isoenzyme (CK-MB), lactate dehydrogenase (LDH) and aspartate aminotransferase (AST) and the levels of malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in heart tissue were measured. Pretreatment of rats with dantrolene, given i.p. 30 min prior to ADR injection, substantially reduced the peroxidative damage in the myocardium, and markedly lowered the serum CK-MB, LDH and AST. The protective effects obtained by dantrolene administration, however, were not complete and did not reach those of the control group. Dantrolene, at 5 mg/kg, was useful to obtain significant protective effects, while the protector effect of higher dantrolene dosing level (10 mg/kg) was weak or absent. These results suggest that, at least in part, due to antioxidative properties, dantrolene may provide a significant protective effect against acute ADR-induced cardiotoxicity.

Antioxidant, antimicrobial, antiulcer and analgesic activities of nettle (Urtica dioica L.)

In this study, water extract of nettle (Urtica dioica L.) (WEN) was studied for antioxidant, antimicrobial, antiulcer and analgesic properties. The antioxidant properties of WEN were evaluated using different antioxidant tests, including reducing power, free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, and metal chelating activities. WEN had powerful antioxidant activity. The 50, 100 and 250 microg amounts of WEN showed 39, 66 and 98% inhibition on peroxidation of linoleic acid emulsion, respectively, while 60 microg/ml of alpha-tocopherol, exhibited only 30% inhibition. Moreover, WEN had effective reducing power, free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, and metal chelating activities at the same concentrations. Those various antioxidant activities were compared to standard antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), quercetin, and alpha-tocopherol. In addition, total phenolic compounds in the WEN were determined as pyrocatechol equivalent. WEN also showed antimicrobial activity against nine microorganisms, antiulcer activity against ethanol-induced ulcerogenesis and analgesic effect on acetic acid-induced stretching.

In Vitro and in Vivo Effects of Dantrolene on Carbonic Anhydrase Enzyme Activities

The effects of dantrolene were investigated on carbonic anhydrase (CA) enzyme activities in in vitro human and in in vivo Sprague-Dawley rat erythrocytes. For in vitro study, human carbonic anhydrase-I (HCA-I) and -II (HCA-II) were purified by Sepharose 4B-L-tyrosine-sulfanylamide affinity chromatography, rats were used for in vivo study. In vivo and in vitro CA enzyme activity was determined colorimetrically using the CO(2)-hydration method of Wilbur and Anderson. Dantrolene (1.64 x 10(-5)-6.56 x 10(-5) M) showed in vitro inhibitory effects on HCA-I and HCA-II hydratase activity, when determined using the CO(2)-hydratase method. 50% inhibitory concentration (IC(50)) was 4.09 x 10(-5) M for HCA-I and 3.24 x 10(-5) M for HCA-II. Rat erythrocyte CA activity was significantly inhibited by 10 mg/kg dantrolene for up to 3 h (p<0.001) following intraperitoneal administration. In conclusion, Dantrolene inhibited the carbonic anhydrase enzyme activity under in vitro and in vivo conditions.

Dantrolene protects erythrocytes against oxidative stress during whole-body irradiation in rats

In our study, we examined the radioprotective effects of dantrolene against gamma irradiation-induced damage of blood cells after total body irradiation of rats. Rats were divided into three groups of eight rats each. The first group was the control group receiving no dantrolene or irradiation, the second group received total body irradiation (RT) with 5 Gy of gamma irradiation only, and the third group received dantrolene at a dose of 5 mg x kg(-1) plus RT. Dantrolene was given intraperitoneally 30 min before RT. All groups were sacrificed 2 h after RT, and blood samples were taken. Leukocyte, and thrombocyte counts and hemoglobin levels were measured. Furthermore, malondialdehyde (MDA) levels in plasma and erythrocytes and superoxide dismutase (SOD) and glutathione peroxidase activities (GSH-Px) in erythrocytes were determined. It was found that pretreatment with dantrolene at a dose of 5 mg x kg(-1) significantly reduced the MDA levels and increased the antioxidant SOD and GSH-Px activities, and prevented the decrease in leukocyte and thrombocyte counts. We conclude that dantrolene has clear antioxidant properties when given prior to radiation exposure and the protective effect of dantrolene against damage inflicted by radiation, depends, at least in part, on the decrease in lipid peroxidation and increase in the activity of antioxidant enzymes SOD and GSH-Px.

Metal chelating and hydrogen peroxide scavenging effects of melatonin

Antioxidant activity of a molecule is attributed to various mechanisms such as prevention of chain initiation, binding of transition metal ion catalysts and decomposition of peroxides. This study was aimed at evaluating the metal chelating and hydrogen peroxide (H2O2) scavenging activity of melatonin. The metal chelating and H2O2 scavenging activity increased with increasing concentrations of melatonin (20-60 micro g/mL). alpha-Tocopherol, butylated hydroxyanisole (BHA), and butylated hydroxytoluene (BHT) were used as standards. Sixty micrograms per milliliter concentration of melatonin exhibited 95% chelating effect on ferrous ions and scavenged 83% of H2O2. On the other hand, the same concentration of alpha-tocopherol, BHA, and BHT exhibited 58, 61, and 72% inhibition, respectively, of the formation of the Fe2+-ferrozine complex and scavenged 48, 20, and 23%, respectively, of H2O2. Based on these results, it is concluded that melatonin is an effective metal chelating agent and scavenger of H2O2. These properties may be major reasons for the melatonin's ability to inhibit lipid peroxidation.

Antioxidant and analgesic activities of turpentine of Pinus nigra Arn. subsp. pallsiana (Lamb.) Holmboe

The aim of this study is to examine possible antioxidant and analgesic activities of turpentine exudes from Pinus nigra Arn. subsp. pallsiana (Lamb.) Holmboe (TPN). Total antioxidant activity, reducing power, superoxide anion radical scavenging, free radical scavenging, metal chelating, and hydrogen peroxide scavenging activities were studied. The total antioxidant activity increased with the increasing amount of extracts (100, 300, and 500 microg) added to linoleic acid emulsion. All of the doses of TPN showed higher antioxidant activity than alpha-tocopherol. The samples showed 49, 70, and 91% inhibition on peroxidation of linoleic acid emulsion, respectively. On the other hand, the 300 microg of alpha-tocopherol showed 40% inhibition on peroxidation of linoleic acid emulsion. There is correlation between antioxidant activity and the reducing power, superoxide anion radical scavenging, free radical scavenging, metal chelating, and hydrogen peroxide scavenging activities. Like antioxidant activity, the reducing power, superoxide anion radical scavenging, free radical scavenging, metal chelating, and hydrogen peroxide scavenging activities of TPN depending on concentration and increasing with increased concentration of TPN. These properties may be the major reasons for the inhibition of lipid peroxidation. The results obtained in the present study indicate that the TPN has a potential source of natural antioxidant. In addition, analgesic effect of TPN was investigated in present study and TPN had strong analgesic effect. The analgesic effect of TPN compared with metamizol as a standard analgesic compound.

Anti-inflammatory and antinociceptive properties of dantrolene sodium in rats and mice

Our study aimed at examining the possible anti-inflammatory and antinociceptive effects of dantrolene sodium in rats and mice. The anti-inflammatory effect of dantrolene sodium (2.5, 5 and 10 mg kg (-1)) was investigated and compared with diclofenac sodium (5 mg kg (-1)) using the formalin-, histamine-, and carrageenan-induced paw oedema and cotton pellet granuloma tests. Analgesic effects of dantrolene sodium were evaluated and compared with metamizol (200 mg kg (-1)) in acetic acid-induced writhing and formalin-induced paw licking tests. It was found that dantrolene sodium significantly diminished the nociceptive response in mice, showing at the same time considerable anti-inflammatory properties in rats.

Mechanism of the beneficial effects of dantrolene sodium on ethanol-induced acute gastric mucosal injury in rats

In our study, we examined anti-ulcerogen and antioxidant effects of dantrolene sodium on ethanol-induced gastric lesions in rats. Dantrolene sodium was administered intraperitoneally (i.p.) in several doses, and famotidine was used at a dose of 20 mg kg (-1). It was found that pretreatment with dantrolene sodium at doses of 1, 5 and 10 mg kg(-1) significantly reduced ethanol-induced gastric damage and malondialdehyde levels, and significantly increased antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities. We conclude that dantrolene sodium clearly has antioxidant properties and that the protective effect of dantrolene sodium against ethanol-induced gastric mucosal lesion, at least in part, depends upon the reduction in the lipid peroxidation and an increase in the activity of antioxidant enzymes SOD and GSH-Px.