Primaquine alters antioxidant enzyme profiles in rat liver and kidney

Chemotherapeutic and prophylactic antimalarial drugs induce cell death through mitochondrial-mediated apoptosis in murine models

Malaria is a parasitic disease that has defied many treatment plans. This study was carried out to investigate the host mitochondrial response to malarial infection and selected antimalarial chemotherapy using murine models. The effects of artesunate (ART) and proguanil (PRG) on mitochondrial Permeability Transition (mPT), mitochondrial ATPase (mATPase), level of malondialdehyde (MDA) and activities of antioxidant enzymes; catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), Xanthine oxidase (XO), glutathione S-transferase (GST) and reduced glutathione (GSH) were estimated in Plasmodium berghei-infected mice treated with ART and PRG. Besides, apoptotic markers, such as caspases 3, 9 and DNA fragmentation were estimated. Unparasitised (NORMAL) and parasitized but untreated (PU) animals were used as controls. The mPT pore opening fold of 9 (ART), 3 (PRG), and 4 (PU) were observed relative to calcium (23) for in vivo study. In vitro, graded concentrations (20, 40, 80 and 160 μg/mL) of ART gave mPT induction folds of 1, 21, 23 and 25, respectively, relative to calcium (9) while PRG did not have effect in the absence of calcium. In vivo, ART significantly (p < 0.001) enhanced mATPase activity than PRG. The PRG and ART increased the MDA levels in vivo. Oral administration of ART and PRG altered antioxidant enzymes status, Caspases 3 and 9 were significantly activated in PRG-treated groups; there was significant increase in DNA fragmentation in PU and PRG groups compared with the normal control. The results obtained showed that malaria parasite and antimalarial drugs cause mitochondrial-mediated apoptosis.

The antimalarial drug primaquine targets Fe-S cluster proteins and yeast respiratory growth

Malaria is a major health burden in tropical and subtropical countries. The antimalarial drug primaquine is extremely useful for killing the transmissible gametocyte forms of Plasmodium falciparum and the hepatic quiescent forms of P. vivax. Yet its mechanism of action is still poorly understood. In this study, we used the yeast Saccharomyces cerevisiae model to help uncover the mode of action of primaquine. We found that the growth inhibitory effect of primaquine was restricted to cells that relied on respiratory function to proliferate and that deletion of SOD2 encoding the mitochondrial superoxide dismutase severely increased its effect, which can be countered by the overexpression of AIM32 and MCR1 encoding mitochondrial enzymes involved in the response to oxidative stress. This indicated that ROS produced by respiratory activity had a key role in primaquine-induced growth defect. We observed that Δsod2 cells treated with primaquine displayed a severely decreased activity of aconitase that contains a Fe–S cluster notoriously sensitive to oxidative damage. We also showed that in vitro exposure to primaquine impaired the activity of purified aconitase and accelerated the turnover of the Fe–S cluster of the essential protein Rli1. It is suggested that ROS-labile Fe–S groups are the primary targets of primaquine. Aconitase activity is known to be essential at certain life-cycle stages of the malaria parasite. Thus primaquine-induced damage of its labile Fe–S cluster – and of other ROS-sensitive enzymes – could inhibit parasite development.

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The mode of action of the antimalarial drug primaquine is poorly understood.

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The yeast model is used to decipher its mechanism of action.

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SOD and respiratory function are key for yeast sensitivity to primaquine.

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Primaquine treatment impairs Fe–S containing enzyme aconitase.

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Its attack on Fe–S clusters could explain the primaquine-induced growth inhibition.

Effects of Organochlorine Insecticides on MAP Kinase Pathways in Human HaCaT Keratinocytes: Key Role of Reactive Oxygen Species

Organochlorine pesticides (OCs) are reported as potential carcinogens in humans. The aim of this study was to investigate the effects of four OCs (dieldrin, endosulfan, heptachlor, and lindane) on mitogen-activated protein kinase (MAPK) cascades and more specifically to identify the mechanism underlying OC-induced ERK1/2 activation. Organochlorine pesticides increased phosphorylated Raf, MEK1/2, ERK1/2, and c-Jun in human HaCaT cells, but they had no effect on p38 MAPK activation. Moreover, blockade of Raf, MEK1/2, or PKC activation with geldanamycin, U0126, or calphostin C inhibited ERK1/2 phosphorylation, demonstrating a PKC-Raf-MEK1/2 pathway. We also showed that these insecticides induced the production of reactive oxygen species (ROS). Pre-treatment with the antioxidant molecule N-acetyl cysteine sharply decreased the level of phospho-ERK1/2 and had no effect on Raf and MEK1/2 activation, suggesting a Raf-independent mechanism. This study indicates that OCs strongly activate the ERK1/2 pathway, and it identifies a critical role of ROS in OC-induced ERK activation, probably by stabilizing its phosphorylation.

Effect of antimalarials treatment on rat liver lysosomal function-Anin vivo study

Effects of treatmentin vivo with the antimalarials:chloroquine (CQ), primaquine (PQ) and quinine(Q) on lysosomal enzymes and lysosomal membrane integrity were examined. Treatment with the three antimalarials showed an apparent increase in the membrane stability. CQ treatment resulted in increase in both the 'free' and 'total' activities of all the enzymes i.e. acid phosphatase, RNase II, DNase II and cathepsin D. PQ treatment lowered the 'free' and 'total' activities of acid phosphatase and cathepsin D, but the DNase II activities increased. Treatment with Q resulted in increased 'free' and 'total' activities of RNase II and DNase II. While 'free' activities of acid phosphatase and cathepsin D were low; the 'total' activities increased significantly. Our results suggest that a generalized increase in free nucleases activities following prolonged treatment with antimalarials may lead to cell damage and/or necrosis.

Influence of chloroquine treatment and Plasmodium falciparum malaria infection on some enzymatic and non-enzymatic antioxidant defense indices in humans

BACKGROUND

It is known that malaria infection is accompanied by increased production of reactive oxygen species (ROS) and that malaria parasites are sensitive to oxidative damage. This has been proved by the efficacy of some antimalarial drugs that are known to act via generation of ROS when administered clinically or experimentally.

OBJECTIVE

There is lack of information on the effect of chloroquine on the antioxidant defense systems of normal and malaria infected humans. Since chloroquine has remained the mainstay of therapeutic regimen in malaria endemic zones, the present investigation was therefore undertaken to study the status of blood antioxidant defense mechanism, and oxidative stress following chloroquine treatment in normal and plasmodium infected humans.

METHODS

Ten healthy persons (5 males and 5 females) with the same age range (18-35 years) were taken as control group. Ten other individuals were treated with 25 mg/kg body with chloroquine over three days. Ten patients with malaria, not under antimalarial therapy were taken as another group, while another set of 10 patients with malaria were treated with 25 mg/kg body weight over three days.

RESULTS

The activity of superoxide dismutase was increased by 23% in individuals treated with chloroquine compared to controls while the activity of the enzyme decreased by 26% in malaria patients and by 43% in malaria patients treated with chloroquine. In all the treatment groups, the activities of catalase and glutathione peroxidase were lowered (P < 0.001). Similarly the levels of vitamins A, C, and beta-carotene were decreased in the treatment groups while plasma ceruloplasmin was increased in the groups. Glutathione and cholesterol levels were decreased while malondialdehyde level was increased significantly.

CONCLUSION

Chloroquine treatment mediated oxidative stress in the host and this effect was exacerbated in Plasmodium falciparum infected patients administered with the drug.

Modulation of antioxidant defence system by dietary fat in rats intoxicated with o-toluidine

o-Toluidine was administered to rats in the diet for four weeks at levels approximately 40, 80 and 160 mg/kg b.w. per day. Two types of diet have been used, standard (4% fat) and high fat (14% fat). Activity of antioxidant enzymes, level of glutathione and thiobarbituric acid reactive substances were measured in liver. Glutathione peroxidase was significantly increased in all treated groups while glutathione S-transferase and glutathione reductase were elevated in rats fed high-fat diet. o-Toluidine slightly enhanced catalase activity regardless of the kind of diet. Superoxide dismutase was the only enzyme whose activity was lowered in almost all treated groups. Enzymatic and nonenzymatic microsomal lipid peroxidation was enhanced 2- to 3-fold in both diet groups. Reduced glutathione level in liver was 2.3- to 4.0-fold increased in all treated groups. Our findings indicate that free radical processes can be involved in the toxic effects of o-toluidine and dietary fat can modify the response of some antioxidant enzymes to this compound.

Glucose-induced oxidative stress and programmed cell death in diabetic neuropathy

The Diabetes Control and Complications Trial (DCCT) established the importance of hyperglyemia and other consequences of insulin deficiency in the pathogenesis of diabetic neuropathy, but the precise mechanisms by which metabolic alterations produce peripheral nerve fiber damage and loss remain unclear. Emerging data from human and animal studies suggest that glucose-derived oxidative stress may play a central role, linking together many of the other currently invoked pathogenetic mechanisms such as the aldose reductase and glycation pathways, vascular dysfunction, and impaired neurotrophic support. These relationships suggest combinations of pharmacological interventions that may synergistically protect the peripheral nervous system (PNS) against the metabolic derangements of diabetes mellitus.

Effects of administration of the standardized Panax ginseng extract G115 on hepatic antioxidant function after exhaustive exercise

The effect of prolonged treatment with the standardized Panax ginseng extract G115 on the antioxidant capacity of the liver was investigated. For this purpose, rats that had received G115 orally at different doses for 3 months and untreated control rats were subjected to exhaustive exercise on a treadmill. A bell-shaped dose response on running time was obtained. The results showed that the administration of G115 significantly increases the hepatic glutathione peroxidase activity (GPX) and the reduced glutathione (GSH) levels in the liver, with a dose-dependent reduction of the thiobarbituric acid reactant substances (TBARS). After the exercise, there is reduced hepatic lipid peroxidation, as evidenced by the TBARS levels in both the controls and the treated animals. The GPX (glutathione peroxidase) and SOD (superoxide dismutase) activity are also significantly increased in the groups receiving G115, compared with the controls. The hepatic transaminase levels, ALT (Alanine-amino-transferase) and AST (Aspartate-amino-transferase), in the recuperation phase 48 h after the exercise, indicate a clear hepatoprotective effect related to the administration of the standardized Panax ginseng extract G115. At hepatic level, G115 increases the antioxidant capacity, with a marked reduction of the effects of the oxidative stress induced by the exhaustive exercise.