New Therapeutic Approach: Diphenyl Diselenide Reduces Mitochondrial Dysfunction in Acetaminophen-Induced Acute Liver Failure

The acute liver failure (ALF) induced by acetaminophen (APAP) is closely related to oxidative damage and depletion of hepatic glutathione, consequently changes in cell energy metabolism and mitochondrial dysfunction have been observed after APAP overdose. Diphenyl diselenide [(PhSe)₂], a simple organoselenium compound with antioxidant properties, previously demonstrated to confer hepatoprotection. However, little is known about the protective mechanism on mitochondria. The main objective of this study was to investigate the effects (PhSe)₂ to reduce mitochondrial dysfunction and, secondly, compare in the liver homogenate the hepatoprotective effects of the (PhSe)₂ to the N-acetylcysteine (NAC) during APAP-induced ALF to validate our model. Mice were injected intraperitoneal with APAP (600 mg/kg), (PhSe)₂ (15.6 mg/kg), NAC (1200 mg/kg), APAP+(PhSe)₂ or APAP+NAC, where the (PhSe)₂ or NAC treatment were given 1 h following APAP. The liver was collected 4 h after overdose. The plasma alanine and aspartate aminotransferase activities increased after APAP administration. APAP caused a remarkable increase of oxidative stress markers (lipid peroxidation, reactive species and protein carbonylation) and decrease of the antioxidant defense in the liver homogenate and mitochondria. APAP caused a marked loss in the mitochondrial membrane potential, the mitochondrial ATPase activity, and the rate of mitochondrial oxygen consumption and increased the mitochondrial swelling. All these effects were significantly prevented by (PhSe)₂. The effectiveness of (PhSe)₂ was similar at a lower dose than NAC. In summary, (PhSe)₂ provided a significant improvement to the mitochondrial redox homeostasis and the mitochondrial bioenergetics dysfunction caused by membrane permeability transition in the hepatotoxicity APAP-induced.     

Blockade of Nitric Oxide Overproduction and Oxidative Stress by <Emphasis Type="Italic">Nigella sativa</Emphasis> Oil Attenuates Morphine-Induced Tolerance and Dependence in Mice

The effects of Nigella sativa oil on morphine-induced tolerance and dependence in mice and possible mechanism(s) of these effects were investigated, for the first time, in this study. Repeated administration of Nigella sativa oil (4 ml/kg, p.o.) along with morphine (5 mg/kg, s.c.) attenuated the development of tolerance, as measured by the hot plate test, and dependence, as assessed by naloxone (5 mg/kg, i.p.)-precipitated withdrawal manifestations. Concomitantly, nitric oxide overproduction and increase in brain malondialdehyde level induced by repeated administration of morphine to mice or by administration of naloxone to morphine-dependent mice were inhibited by co-administration of the oil. Also, the decrease in brain intracellular reduced glutathione level and glutathione peroxidase activity induced by both treatments were inhibited by co-administration of the oil. The increase in brain glutamate level induced by both treatments was not inhibited by concurrent administration of the oil. The inhibitory effect of the oil on morphine-induced tolerance and dependence and on naloxone-induced biochemical alterations in morphine-dependent mice was enhanced by concurrent i.p. administration of the NMDA receptor antagonist, dizocilpine (0.25 mg/kg). Similarly, concurrent i.p. administration of the NO synthase inhibitors; L-N (G)-nitroarginine methyl ester (10 mg/kg), aminoguanidine (20 mg/kg) and 7-nitroindazole (25 mg/kg) or the antioxidant, N-acetylcysteine (50 mg/kg) enhanced this inhibitory effect of the oil. On the other hand, this effect was antagonized by concurrent i.p. administration of the nitric oxide precursor, L-arginine (300 mg/kg). These results provide evidence that Nigella sativa oil, through inhibition of morphine-induced NO overproduction and oxidative stress, appears to have a therapeutic potential in opioid tolerance and dependence.     

Brain mitochondria from rats treated with sulforaphane are resistant to redox-regulated permeability transition

Oxidative stress promotes Ca²⁺-dependent opening of the mitochondrial inner membrane permeability transition pore (PTP), causing bioenergetic failure and subsequent cell death in many paradigms, including those related to acute brain injury. One approach to pre-conditioning against oxidative stress is pharmacologic activation of the Nrf2/ARE pathway of antioxidant gene expression by agents such as sulforaphane (SFP). This study tested the hypothesis that administration of SFP to normal rats increases resistance of isolated brain mitochondria to redox-sensitive PTP opening. SFP or DMSO vehicle was administered intraperitoneally to adult male rats at 10 mg/kg 40 h prior to isolation of non-synaptic brain mitochondria. Mitochondria were suspended in medium containing a respiratory substrate and were exposed to an addition of Ca²⁺ below the threshold for PTP opening. Subsequent addition of tert-butyl hydroperoxide (tBOOH) resulted in a cyclosporin A-inhibitable release of accumulated Ca²⁺ into the medium, as monitored by an increase in fluorescence of Calcium Green 5N within the medium, and was preceded by a decrease in the autofluorescence of mitochondrial NAD(P)H. SFP treatment significantly reduced the rate of tBOOH-induced Ca²⁺ release but did not affect NAD(P)H oxidation or inhibit PTP opening induced by the addition of phenylarsine oxide, a direct sulfhydryl oxidizing agent. SFP treatment had no effect on respiration by brain mitochondria and had no effect on PTP opening or respiration when added directly to isolated mitochondria. We conclude that SFP confers resistance of brain mitochondria to redox-regulated PTP opening, which could contribute to neuroprotection observed with SFP.     

The antioxidant effect of Aronia melanocarpa extract in rats oxidative stress induced by cisplatin administration

BackgroundThe reactive oxygen species generated by numerous xenobiotic substances has as consequences the impairment of different organs normal function. Many plants pose antioxidant activity to counteract oxidative stress, among them being the chokeberry (Aronia melanocarpa). The purpose of present study was to determine if the use of A. melanocarpa extract can counteract the oxidative stress induced by cisplatin administration in rats.Material and methodsThe study was made on forty Wistar rats divided in four groups as follows: C (control): receiving i.p. 1 mL of saline solution; E1: receiving cisplatin 20 mg/kg bw, i.p.; E2: receiving cisplatin 20 mg/kg bw, i.p and A. melanocarpa berry 6 % aqueous extract as drinking water, and CB (control blank): i.p 1 mL saline solution and A. melanocarpa 6 % aqueous extract for four weeks. Results. Administration of Cisplatin was followed by the increase of serum superoxide dismutase (+21.18 %, P < 0.05), catalase (+25.44 %, P < 0.001), glutathione peroxidase (+17.88 %, P < 0.05) and thiobarbituric reactive substances (+28.17 %, P < 0.01) but significantly decreased glutathione reductase (−22.35 %, P < 0.001) level comparative to control, pointing out that administration of cisplatin induced oxidative stress in rats. In groups that received A. melanocarpa extract as drinking water, we noted that the levels of the oxidative stress biomarkers tended to be restored almost to normal levels, which could be a possible good antioxidant used in condition to cisplatin use. Also, we noted a significant (P < 0.001) decrease of total antioxidant capacity in liver and kidney of rats exposed to cisplatin, recovered in those that received chokeberry. Studied trace elements important for the stress oxidative enzymes (Cu, Zn, Fe and Mn) were decreased in cisplatin exposed groups compared to control and mainly all were almost to normal level in groups receiving A. melanocarpa. Conclusion. A. melanocarpa extract due to its antioxidants content could offer protection against free radicals produced as a consequence of cisplatin use.     

Protective effect of gallic acid and gallic acid-loaded Eudragit-RS 100 nanoparticles on cisplatin-induced mitochondrial dysfunction and inflammation in rat kidney

Cisplatin is used as a chemotherapy drug in the treatment of various types of cancer. Mitochondrial dysfunction, oxidative stress and inflammation have been identified as major mechanisms of cisplatin nephrotoxicity. The present study investigated the protective effects of pure gallic acid and nanoparticle gallic acid nanoparticles (nano-gallic acid) on cisplatin induced nephrotoxicity. Nano-gallic acid was prepared by double emulsions-solvent evaporation technique using Eudragit RS 100 polymer and polyvinyl alcohol as carrier. Then, the physicochemical characterization of the nanoparticles was examined. In the present study, renal mitochondria were isolated using different centrifugal methods. Our data indicated that the doses of 50 and 100 mg/kg gallic acid and 10 mg/kg nano-gallic acid significantly decreased mitochondrial reactive oxygen species (ROS) formation, mitochondrial membrane damage (ΔΨm), mitochondrial malondialdehyde (MDA), tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6) and significantly increased mitochondrial glutathione (GSH), mitochondrial superoxide dismutase (MnSOD), mitochondrial glutathione peroxidase (GPX) and mitochondrial catalase compared to the cisplatin treated group. Histopathological studies also confirmed biochemical tests. Finally, our results confirmed that the pure gallic acid and its nanoparticle improved renal oxidative stress, inflammation and mitochondrial dysfunction in acute nephrotoxicity induced by cisplatin in rat. Nano-gallic acid (10 mg/kg) was selected as the most effective dose. The findings of this study showed the superiority of nano-gallic acid against pure gallic acid. In conclusion, nano-gallic acid-loaded Eudragit-RS 100 as a novel antioxidant can be considered in the treatment of renal complications of cisplatin.     

Viscum album prevents haematological changes,electrolyte imbalance,changes in liver function enzymes and histological alterations in some selected tissues in cadmium chloride-intoxicated rats

BackgroundThe use of Viscum album to treat different diseases is popular in the practise of alternative medicine. We investigated the ability of the aqueous extract of V. album to protect against the toxic effects of cadmium.MethodsThirty rats used for the experiment were treated as follows; Group 1 – no cadmium or extract. Group 2–10 mg/kg body weight of cadmium chloride. Group 3–10 mg/kg body weight of cadmium chloride and 200 mg/kg body weight of aqueous extract of V. album. Group 4–10 mg/kg body weight of cadmium chloride and 400 mg/kg body weight of aqueous extract of V. album. Group 5–10 mg/kg body weight of cadmium chloride with 800 mg/kg body weight of aqueous extract of V. album. Group 6–10 mg/kg body weight of cadmium chloride and atorvastatin (100 mg/kg body weight).ResultsApart from WBC and platelets, other haematological parameters and electrolytes, urea and creatinine levels were not significantly affected by the administration of cadmium chloride along with the aqueous extract of V. album. Treatment with the extract caused significant decreases in the hepatosomatic index, cardiosomatic index, and increase in renosomatic index of the test rats. It also resulted in significant (P < 0.05) decrease in AST level. Histological report also shows that treatment with the extract restored the normal myocardium and vascular architecture of the heart, normal portal and vascular architecture of the liver and normal glomerular and tubular architecture of the kidney, in the cadmium-intoxicated experimental rats.ConclusionV. album protects against the toxic effects of cadmium chloride.     

Antiparkinsonian Effects of Aqueous Methanolic Extract of Hyoscyamus niger Seeds Result From its Monoamine Oxidase Inhibitory and Hydroxyl Radical Scavenging Potency

Hyoscyamus species is one of the four plants used in Ayurveda for the treatment of Parkinson’s disease (PD). Since Hyoscyamus niger was found to contain negligible levels of L-DOPA, we evaluated neuroprotective potential, if any, of characterized petroleum ether and aqueous methanol extracts of its seeds in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of PD in mice. Air dried authenticated H. niger seeds were sequentially extracted using petroleum ether and aqueous methanol and were characterized employing HPLC-electrochemistry and LCMS. Parkinsonian mice were treated daily twice with the extracts (125–500 mg/kg, p.o.) for two days and motor functions and striatal dopamine levels were assayed. Administration of the aqueous methanol extract (containing 0.03% w/w of L-DOPA), but not petroleum ether extract, significantly attenuated motor disabilities (akinesia, catalepsy and reduced swim score) and striatal dopamine loss in MPTP treated mice. Since the extract caused significant inhibition of monoamine oxidase activity and attenuated 1-methyl-4-phenyl pyridinium (MPP⁺)-induced hydroxyl radical (·OH) generation in isolated mitochondria, it is possible that the methanolic extract of Hyoscyamus niger seeds protects against parkinsonism in mice by means of its ability to inhibit increased ·OH generated in the mitochondria.     

Coenzyme Q,peroxidation and cytochrome oxidase features after Parkinson's-like disease by MPTP toxicity in intra-synaptic and non-synaptic mitochondria fromMacaca Fascicularis cerebral cortex and hippocampus: action of dihydroergocriptine

The effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administration on respiratory chain features were studied in synaptic and non-synaptic mitochondrial populations from cerebral cortex andhippocampus ofMacaca Fascicularis (Cynomolgus monkey). Enzymatic activity, cytochromea+a ₃ content and turnover numbers of Complex IV, contents of Coenzyme Q₁₀, of hydroperoxides and membrane fluidity were assessed in non-synaptic “perikaryal” and intra-synaptic “light” and “heavy” mitochondria isolated: (a) from the dopaminergic ascending terminal areas of cerebral cortex of monkeys treatedp.o. with dihydroergocriptine at the dose of 2, 6 or 20 mg/kg/day for 52 weeks; (b) from the dopaminergic terminal areas ofhippocampus of monkeys treatedp.o. with dihydroergocriptine at the dose of 12 mg/kg/day before and during the induction of a Parkinson's-like syndrome by MPTP administration (i.v., 0.3 mg/kg/day for 5 days). Dihydroergocriptine administration moderately increased both cytochrome oxidase activity and cytochromea+a ₃ content in “light” intra-synaptic mitochondria and hydroperoxides/CoQ₁₀ ratio in all the types of mitochondria, as a consequence of the enhanced energy metabolism. The Parkinson's-like syndrome by MPTP changed the biochemical investigated parameters, affecting both directly the respiratory chain structures,i.e. by respiratory chain complexes inhibition and indirectly,i.e. by free radical mediated damages. MPTP administration negatively influenced Complex IV activity and Turnover Number of intra-synaptic mitochondria, without affecting the total cytochromea+a ₃ amount. In all types of mitochondria and particularly on the “light” intra-synaptic ones, MPTP-induced lesion enhanced hydroperoxides/Coenzyme Q₁₀ molar ratio due to the fall in Coenzyme Q₁₀ levels and the concomitant increase in hydroperoxides. Dihydroergocriptine treatment appeared to be effective in MPTP-treated animals in improving those mitochondrial features that probably suffered free radical insults.     

Effects of Microdesmis keayana roots on sexual behavior of male rats

In the present study, the aphrodisiac properties of Microdesmis keayana J. Léonard root extract and major isolated alkaloids were evaluated by observing the sexual behavior of male rats.Aqueous extract (150 mg/kg body weight) and pure alkaloids (3 mg/kg body weight) were administered orally by gavage to male rats. Latent times of observation, intromission and ejaculation, mounting behavior, number of intromissions and mating performances were evaluated and compared to those obtained with untreated rats in the presence of receptive and non-receptive females. The results have shown that aqueous extract and alkaloids of M. keayana stimulate sexual parameters in rats’ sexual behavior.A short-term toxicity study undertaken to establish the therapeutic index of aqueous extract, showed that a high dose of the extract (2 g/kg body weight) caused no mortality or changes in rats’ behavior.     

Mitochondrial energetics is impaired in vivo in aged skeletal muscle

With aging, most skeletal muscles undergo a progressive loss of mass and strength, a process termed sarcopenia. Aging‐related defects in mitochondrial energetics have been proposed to be causally involved in sarcopenia. However, changes in muscle mitochondrial oxidative phosphorylation with aging remain a highly controversial issue, creating a pressing need for integrative approaches to determine whether mitochondrial bioenergetics are impaired in aged skeletal muscle. To address this issue, mitochondrial bioenergetics was first investigated in vivo in the gastrocnemius muscle of adult (6 months) and aged (21 months) male Wistar rats by combining a modular control analysis approach with ³¹P magnetic resonance spectroscopy measurements of energetic metabolites. Using this innovative approach, we revealed that the in vivo responsiveness (‘elasticity’) of mitochondrial oxidative phosphorylation to contraction‐induced increase in ATP demand is significantly reduced in aged skeletal muscle, a reduction especially pronounced under low contractile activities. In line with this in vivo aging‐related defect in mitochondrial energetics, we found that the mitochondrial affinity for ADP is significantly decreased in mitochondria isolated from aged skeletal muscle. Collectively, the results of this study demonstrate that mitochondrial bioenergetics are effectively altered in vivo in aged skeletal muscle and provide a novel cellular basis for this phenomenon.     

The effect of saffron, Crocus sativus stigma, extract and its constituents, safranal and crocin on sexual behaviors in normal male rats

In this study, the aphrodisiac activities of Crocus sativus stigma aqueous extract and its constituents, safranal and crocin, were evaluated in male rats. The aqueous extract (80, 160 and 320 mg/kg body wt.), crocin (100, 200 and 400 mg/kg body wt.), safranal (0.1, 0.2 and 0.4 ml/kg), sildenafil (60 mg/kg body wt., as a positive control) and saline were administered intraperitoneally to male rats. Mounting frequency (MF), intromission frequency (IF), erection frequency (EF), mount latency (ML), intromission latency (IL) and ejaculation latency (EL) were the factors evaluated during the sexual behavior study. Crocin, at all doses, and the extract, especially at doses 160 and 320 mg/kg body wt., increased MF, IF and EF behaviors and reduced EL, IL and ML parameters. Safranal did not show aphrodisiac effects. The present study reveals an aphrodisiac activity of saffron aqueous extract and its constituent crocin.     

Effect of the aqueous extract of Hyptis pectinata on liver mitochondrial respiration

Some studies have indicated that mitochondria may be the target organelle of plants. We therefore decided to assess the effects of the aqueous extract of Hyptis pectinata leaves on liver mitochondrial respiratory function in vitro. Eight rat livers were subjected to isolation of mitochondria by differential centrifugation. In an adequate medium, the plant extract was added at different concentrations. The analyzed data were: state 3, state 4 and respiratory control ratio (RCR). H. pectinata extract caused a statistically significant decrease in state 3 (at 0.05, 0.1 and 0.2 mg/mg protein) and RCR (at 0.05, 0.1 and 0.2 mg/mg protein). Respiratory state 4 was not altered by the increasing concentrations. In conclusion, the aqueous extract of H. pectinata leaves may not injure the mitochondrial inner membrane but decreases significantly the oxidative phosphorylation.     

Dimethylthiourea protects against mitochondrial oxidative damage induced by cisplatin in liver of rats

Cisplatin is one of the most effective chemotherapeutic agents. However, at higher doses liver injury may occur. The purpose of this study was to explore whether the hydroxyl radical scavenger dimethylthiourea (DMTU) protects against cisplatin-induced oxidative damage in vivo and to define the mitochondrial pathways involved in cytoprotection. Adult male Wistar rats (200–220 g) were divided into four groups of eight animals each. The control group was treated only with an intraperitoneal (i.p.) injection of saline solution (1 ml/100 g body weight). The DMTU group was given only DMTU (500 mg/kg body weight, i.p), followed by 125 mg/kg body weight, i.p. (twice a day) until sacrifice. The cisplatin group was given a single injection of cisplatin (10 mg/kg body weight, i.p.). The DMTU + cisplatin group was given DMTU (500 mg/kg body weight, i.p.), just before the cisplatin injection (10 mg/kg body weight, i.p.), followed by injections of DMTU (125 mg/kg body weight, i.p.) twice a day until sacrifice (72 h after the treatment). DMTU did not present any direct effect on mitochondria and substantially inhibited cisplatin-induced mitochondrial damage in liver, therefore preventing elevation of AST and ALT serum levels. DMTU protected against (a) decreased hepatic ATP levels; (b) lipid peroxidation; (c) cardiolipin oxidation; (d) sulfhydryl protein oxidation; (e) mitochondrial membrane rigidification; (f) GSH oxidation; (g) NADPH oxidation; (h) apoptosis. Results suggest that antioxidants, particularly hydroxyl radical scavengers, protect liver mitochondria against cisplatin-induced oxidative damage. Several mitochondrial changes were delineated and proposed as interesting targets for cytoprotective strategy.     

Adriamycin induced myocardial failure in rats: Protective role of Centella asiatica

Generation of reactive oxygen species and mitochondrial dysfunction has been implicated in adriamycin induced cardiotoxicity. Mitochondrial dysfunction is characterized by the accumulation of oxidized lipids, proteins and DNA, leading to disorganization of mitochondrial structure and systolic failure. The present study was aimed to evaluate the efficacy of Centella asiatica on the mitochondrial enzymes; mitochondrial antioxidant status in adriamycin induced myocardial injury. Adriamycin (2.5 mg/kg body wt., i.p.) induced mitochondrial damage in rats was assessed in terms of decreased activities (p< 0.05) of cardiac marker enzymes (lactate dehydrogenase, creatine phosphokinase, amino transferases), TCA cycle enzymes (isocitrate dehydrogenase, α-ketoglutarate dehydrogenase, malate dehydrogenase, respiratory marker enzymes (NADH-dehydrogenase, cytochrome-C-oxidase), mitochondrial antioxidant enzymes (GPx, GSH, SOD,CAT) and increased (p< 0.05) level of lipid peroxidation. Mitochondrial damage was confirmed by transmission electron microscopic examination. Pre-co-treatment with aqueous extract of Centella asiatica (200 mg/kg body wt, oral) effectively counteracted the alterations in mitochondrial enzymes and mitochondrial defense system. In addition, transmission electron microscopy study confirms the restoration of cellular normalcy and accredits the cytoprotective role of Centella asiatica against adriamycin induced myocardial injury. Our results demonstrated elevated oxidative stress and mitochondrial dysfunction in adriamycin treated rats. Moreover, on the basis of our findings it may be concluded that the aqueous extract of C. asiatica not only possesses antioxidant properties but it may also reduce the extent of mitochondrial damage     

Tolerability and efficacy of single dose albendazole,diethylcarbamazine citrate (DEC) or co-administration of albendazole with DEC in the clearance of <Emphasis Type="Italic">Wuchereria bancrofti</Emphasis>in asymptomatic microfilaraemic volunteers in Pondicherry,South India: a hospital-based study

Background  

The tolerability and efficacy of single dose albendazole (400 mg), diethylcarbamazine citrate (DEC) (6 mg/kg bodyweight) or co-administration of albendazole (400 mg) + DEC (6 mg/kg bodyweight) was studied in 54 asymptomatic Wuchereria bancrofti microfilaraemic volunteers in a double blind hospital-based clinical study.     

Acute treatment with Danshen-Gegen decoction protects the myocardium against ischemia/reperfusion injury via the redox-sensitive PKC?/mKATP pathway in rats

Danshen-Gegen (DG) decoction, an herbal formulation comprising Radix Salvia Miltiorrhiza and Radix Puerariae Lobatae, is prescribed for the treatment of coronary heart disease in Chinese medicine. Experimental and clinical studies have demonstrated that DG decoction can reduce the extent of atherosclerosis. In the present study, using an ex vivo rat model of myocardial ischemia/reperfusion (I/R) injury, we investigated the myocardial preconditioning effect of an aqueous DG extract prepared from an optimized weight-to-weight ratio of Danshen and Gegen. Short-term treatment with DG extract at a daily dose of 1 g/kg and 2 g/kg for 3 days protected against myocardial I/R injury in rats. The cardioprotection afforded by DG pretreatment was paralleled by enhancements in mitochondrial antioxidant status and membrane structural integrity, as well as a decrease in the sensitivity of mitochondria to Ca²⁺-stimulated permeability transition in vitro, particularly under I/R conditions. Short-term treatment with the DG extract also enhanced the translocation of PKC? from the cytosol to mitochondria in rat myocardium, and this translocation was inhibited by α-tocopherol co-treatment with DG extract in rats. Short-term DG treatment may precondition the myocardium via a redox-sensitive PKC?/mK_ATP pathway, with resultant inhibition of the mitochondrial permeability transition through the opening of mitochondrial K_ATP channels. Our results suggest that clinical studies examining the effectiveness of DG extract given prophylactically in affording protection against myocardial I/R injury would be warranted.     

Mitochondrial metabolic states and membrane potential modulate mtNOS activity

The mitochondrial metabolic state regulates the rate of NO release from coupled mitochondria: NO release by heart, liver and kidney mitochondria was about 40-45% lower in state 3 (1.2, 0.7 and 0.4 nmol/min mg protein) than in state 4 (2.2, 1.3 and 0.7 nmol/min mg protein). The activity of mtNOS, responsible for NO release, appears driven by the membrane potential component and not by intramitochondrial pH of the proton motive force. The intramitochondrial concentrations of the NOS substrates, l-arginine (about 310 μM) and NADPH (1.04-1.78 mM) are 60-1000 times higher than their K_M values. Moreover, the changes in their concentrations in the state 4-state 3 transition are not enough to explain the changes in NO release. Nitric oxide release was exponentially dependent on membrane potential as reported for mitochondrial H₂O₂ production [S.S. Korshunov, V.P. Skulachev, A.A. Satarkov, High protonic potential actuates a mechanism of production of reactive oxygen species in mitochondria. FEBS Lett. 416 (1997) 15-18.]. Agents that decrease or abolish membrane potential minimize NO release while the addition of oligomycin that produces mitochondrial hyperpolarization generates the maximal NO release. The regulation of mtNOS activity, an apparently voltage-dependent enzyme, by membrane potential is marked at the physiological range of membrane potentials.     

Effects of Pinus brutia bark extract and Pycnogenol® in a rat model of carrageenan induced inflammation

The present study was conducted to explore the anti-inflammatory activities of Pinus brutia bark extract and Pycnogenol^® in a rat model of carrageenan-induced inflammation. Firstly, the compositions of both samples were determined using HPLC. Then, carrageenan-induced paw edema was used to assess anti-inflammatory activity in mice. Paw volume was measured before and 1, 2, 3, 4, 5 and 6 h after the injection of carrageenan. Intraperitoneal administration of both the extract and Pycnogenol^® inhibited paw swelling dose-dependently at 2, 3, 4, 5 and 6 h after carrageenan injection. Both samples exhibited significant anti-inflammatory activities at doses of 75 and 100 mg/kg body wt. between 2 and 4 hours after administration (p<0.05), respectively. Additionally, P. brutia bark extract showed significantly better activity at doses of 75 and 100 mg/kg body wt. than indomethacine at the dose of 10 mg/kg body wt. (p<0.05). No acute toxicity was identified in intraplantar injection of the extract at a dose of 2000 mg/kg body wt.. Therefore, P. brutia bark extract possessing 3.3-fold more total catechins and 9.8-fold more taxifolin than Pycnogenol^® can be utilized as an anti-inflammatory agent.     

Inorganic polyphosphates in mitochondria

Current data concerning the crucial role of inorganic polyphosphates (polyP) in mitochondrial functions and dysfunctions in yeast and animal cells are reviewed. Biopolymers with short chain length (∼15 phosphate residues) were found in the mitochondria of Saccharomyces cerevisiae. They comprised 7–10% of the total polyP content of the cell. The polyP are located in the membranes and intermembrane space of mitochondria. The mitochondrial membranes possess polyP/Ca²⁺/polyhydroxybutyrate complexes. PolyP accumulation is typical of promitochondria but not of functionally active mitochondria. Yeast mitochondria possess two exopolyphosphatases splitting P_i from the end of the polyP chain. One of them, encoded by the PPX1 gene, is located in the matrix; the other one, encoded by the PPN1 gene, is membrane-bound. Formation of well-developed mitochondria in the cells of S. cerevisiae after glucose depletion is accompanied by decrease in the polyP level and the chain length. In PPN1 mutants, the polyP chain length increased under glucose consumption, and the formation of well-developed mitochondria was blocked. These mutants were defective in respiration functions and consumption of oxidizable carbon sources such as lactate and ethanol. Since polyP is a compound with high-energy bonds, its metabolism vitally depends on the cell bioenergetics. The maximal level of short-chain acid-soluble polyP was observed in S. cerevisiae under consumption of glucose, while the long-chain polyP prevailed under ethanol consumption. In insects, polyP in the mitochondria change drastically during ontogenetic development, indicating involvement of the polymers in the regulation of mitochondrial metabolism during ontogenesis. In human cell lines, specific reduction of mitochondrial polyP under expression of yeast exopolyphosphatase PPX1 significantly modulates mitochondrial bioenergetics and transport.     

FTIR Assessment of the Effect of <Emphasis Type="Italic">Ginkgo biloba</Emphasis> Leave Extract (EGb 761) on Mammalian Retina

Ginkgo biloba extract has been therapeutically used for several decades to increase peripheral and cerebral blood flow as well as for the treatment of dementia. The extract contains multiple compounds such as flavonoids and terpenoids that are thought to contribute to its neuroprotective and vasotropic effects. In this study, we investigated the effect of prolonged administration of EGb 761, up to 10 weeks, on mammalian retina using Fourier transform infrared spectroscopy (FTIR). Two main groups were involved in this study: the normal group (n = 10); and EGb-administrated group (n = 50) that received—orally—a dose of 40 mg/kg/day EGb 761. The results demonstrated that EGb administration was associated with different beneficial effects on the retinal constituents especially the underlying amide I protein secondary structure components as well as the NH-OH region. It concluded that the optimum daily administration period of EGb (40 mg/kg) for ophthalmic applications that targeting the retina ranges from 5 to 8 weeks.