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1.
Photochem Photobiol Sci ; 22(2): 279-302, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36152272

RESUMO

Toluidine blue O (TBO) is a phenothiazine dye that, due to its photochemical characteristics and high affinity for biomembranes, has been revealed as a new photosensitizer (PS) option for antimicrobial photodynamic therapy (PDT). This points to a possible association with membranous organelles like mitochondrion. Therefore, here we investigated its effects on mitochondrial bioenergetic functions both in the dark and under photostimulation. Two experimental systems were utilized: (a) isolated rat liver mitochondria and (b) isolated perfused rat liver. Our data revealed that, independently of photostimulation, TBO presented affinity for mitochondria. Under photostimulation, TBO increased the protein carbonylation and lipid peroxidation levels (up to 109.40 and 119.87%, respectively) and decreased the reduced glutathione levels (59.72%) in mitochondria. TBO also uncoupled oxidative phosphorylation and photoinactivated the respiratory chain complexes I, II, and IV, as well as the FoF1-ATP synthase complex. Without photostimulation, TBO caused uncoupling of oxidative phosphorylation and loss of inner mitochondrial membrane integrity and inhibited very strongly succinate oxidase activity. TBO's uncoupling effect was clearly seen in intact livers where it stimulated oxygen consumption at concentrations of 20 and 40 µM. Additionally, TBO (40 µM) reduced cellular ATP levels (52.46%) and ATP/ADP (45.98%) and ATP/AMP (74.17%) ratios. Consequently, TBO inhibited gluconeogenesis and ureagenesis whereas it stimulated glycogenolysis and glycolysis. In conclusion, we have revealed for the first time that the efficiency of TBO as a PS may be linked to its ability to photodynamically inhibit oxidative phosphorylation. In contrast, TBO is harmful to mitochondrial energy metabolism even without photostimulation, which may lead to adverse effects when used in PDT.


Assuntos
Doença Hepática Induzida por Substâncias e Drogas , Mitocôndrias Hepáticas , Ratos , Animais , Mitocôndrias Hepáticas/metabolismo , Cloreto de Tolônio/metabolismo , Cloreto de Tolônio/farmacologia , Metabolismo Energético , Fármacos Fotossensibilizantes/farmacologia , Trifosfato de Adenosina/metabolismo , Doença Hepática Induzida por Substâncias e Drogas/metabolismo
2.
J Biol Inorg Chem ; 26(6): 641-658, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34304317

RESUMO

In the present work, the multiple-indicator dilution (MID) technique was used to investigate the kinetic mechanisms by which nickel (Ni2+) affects the calcium (Ca2+) transport in intact rat liver. 45Ca2+ and extra- and intracellular space indicators were injected in livers perfused with 1 mM Ni2+, and the outflow profiles were analyzed by a mathematical model. For comparative purposes, the effects of norepinephrine were measured. The influence of Ni2+ on the cytosolic Ca2+ concentration ([Ca2+]c) in human hepatoma Huh7 cells and on liver glycogen catabolism, a biological response sensitive to cellular Ca2+, was also evaluated. The estimated transfer coefficients of 45Ca2+ transport indicated two mechanisms by which Ni2+ increases the [Ca2+]c in liver under steady-state conditions: (1) an increase in the net efflux of Ca2+ from intracellular Ca2+ stores due to a stimulus of Ca2+ efflux to the cytosolic space along with a diminution of Ca2+ re-entry into the cellular Ca2+ stores; (2) a decrease in Ca2+ efflux from the cytosolic space to vascular space, minimizing Ca2+ loss. Glycogen catabolism activated by Ni2+ was transient contrasting with the sustained activation induced by norepinephrine. Ni2+ caused a partial reduction in the norepinephrine-induced stimulation in the [Ca2+]c in Huh7 cells. Our data revealed that the kinetic parameters of Ca2+ transport modified by Ni2+ in intact liver are similar to those modified by norepinephrine in its first minutes of action, but the membrane receptors or Ca2+ transporters affected by Ni2+ seem to be distinct from those known to be modulated by norepinephrine.


Assuntos
Cálcio/metabolismo , Fígado/metabolismo , Níquel/farmacologia , Animais , Transporte Biológico/efeitos dos fármacos , Carcinoma Hepatocelular/metabolismo , Linhagem Celular Tumoral , Fígado/efeitos dos fármacos , Neoplasias Hepáticas/metabolismo , Masculino , Modelos Biológicos , Norepinefrina/farmacologia , Ratos , Ratos Sprague-Dawley , Vasoconstritores/farmacologia
3.
Aging Male ; 23(5): 1296-1315, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32406295

RESUMO

Testosterone is the predominant androgen in men and the lack of it can be a trigger to the development of the metabolic syndrome. Here we review the relationship between testosterone deficiency, metabolic syndrome, and hepatic steatosis reported by studies with men and rodents. The prevalence of metabolic syndrome and testosterone deficiency is higher among older subjects. Low total and free testosterone levels were positively associated with disturbs on energy metabolism, changes in body fat distribution, and body composition. Studies reported visceral fat accumulation in men with hypogonadism and castrated rats. Despite some contradictions, the association between higher adiposity, low testosterone, and metabolic syndrome was a common point among the studies. Few studies evaluated the hepatic steatosis and found an association with hypogonadism. Most of the studies with rodents combined the castration with a high-fat diet to study metabolic disturbs. The importance of proper levels of testosterone for energy metabolism homeostasis in men was also underlined by studies that investigated the metabolic effects of testosterone replacement therapy and androgen deprivation therapy.


Assuntos
Hipogonadismo , Síndrome Metabólica , Neoplasias da Próstata , Antagonistas de Androgênios , Animais , Humanos , Hipogonadismo/complicações , Masculino , Síndrome Metabólica/etiologia , Ratos , Roedores , Testosterona
4.
Chem Biodivers ; 17(3): e1900694, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32022474

RESUMO

Studies of the phytotoxic effects between plants can be a crucial tool in the discovery of innovative compounds with herbicide potential. In this sense, we can highlight ruzigrass (Urochloa ruziziensis), which is traditionally used in the crop rotation system in order to reduce weed emergence. The aim of this work was to characterize the secondary metabolites of ruzigrass and to evaluate its phytotoxic effects. In total, eight compounds were isolated: friedelin, oleanolic acid, α-amyrin, 1-dehydrodiosgenone, sitosterol and stigmasterol glycosides, tricin and p-coumaric acid. Phytotoxic effects of the crude methanolic extract and fractions of ruzigrass were assessed using germination rate, initial seedling growth, and biomass of Bidens pilosa, Euphorbia heterophylla and Ipomoea grandifolia. Chemometric analysis discriminated the weed species into three groups, and B. pilosa was the most affected by fractions of ruzigrass. The phytotoxic activities of 1-dehydrodiosgenone, tricin, and p-coumaric acid are also reported, and p-coumaric acid and 1-dehydrodiosgenone were active against B. pilosa.


Assuntos
Bidens/efeitos dos fármacos , Euphorbia/efeitos dos fármacos , Ipomoea/efeitos dos fármacos , Componentes Aéreos da Planta/química , Extratos Vegetais/farmacologia , Poaceae/química , Bidens/crescimento & desenvolvimento , Euphorbia/crescimento & desenvolvimento , Ipomoea/crescimento & desenvolvimento , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação
5.
Biochim Biophys Acta Mol Basis Dis ; 1864(7): 2495-2509, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29653185

RESUMO

The present study was planned to improve our understanding about sex differences in the development of hepatic steatosis in cafeteria diet-induced obesity in young mice. Female (FCaf) and male (MCaf) mice fed a cafeteria diet had similar body weight gain and adiposity index, but FCaf had a more extensive steatosis than MCaf. FCaf livers exhibited a higher non-alcoholic fatty liver disease activity score, elevated lipid percentage area (+34%) in Sudan III staining and increased TG content (+25%) compared to MCaf. Steatosis in FCaf was not correlated with changes in the transcript levels of lipid metabolism-related genes, but a reduced VLDL release rate was observed. Signs of oxidative stress were found in FCaf livers, as elevated malondialdehyde content (+110%), reduced catalase activity (-36%) and increased Nrf2 and Hif1a mRNA expression compared to MCaf. Interestingly, fibroblast growth factor 21 (Fgf21) mRNA expression was found to be exclusively induced in MCaf, which also exhibited higher FGF21 serum levels (+416%) and hepatic protein abundance (+163%) than FCaf. Moreover, cafeteria diet increased Fgfr1, Fsp27 and Ucp1 mRNA expression in brown adipose tissue of males (MCaf), but not females (FCaf). FGF21 hepatic production by male mice seems to be part of a complex network of responses to the nutritional stress of the cafeteria diet, probably related to the unfolded protein response activation. Although aimed at the restoration of hepatic metabolic homeostasis, the branch involving Fgf21 upregulation seems to be impaired in females, rendering them incapable of reducing the hepatic lipid content and cellular oxidative stress.


Assuntos
Dieta/efeitos adversos , Metabolismo dos Lipídeos , Fígado/metabolismo , Hepatopatia Gordurosa não Alcoólica/metabolismo , Obesidade/metabolismo , Animais , Feminino , Fatores de Crescimento de Fibroblastos/biossíntese , Regulação da Expressão Gênica , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Fígado/patologia , Masculino , Camundongos , Fator 2 Relacionado a NF-E2/metabolismo , Hepatopatia Gordurosa não Alcoólica/etiologia , Hepatopatia Gordurosa não Alcoólica/patologia , Obesidade/etiologia , Obesidade/patologia
6.
J Chem Ecol ; 43(7): 725-738, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28711978

RESUMO

Senna obtusifolia L., a common weed in the tropical and subtropical regions of the world, is able to germinate under adverse environmental conditions, suggesting that this species has efficient stress-adaptation strategies. The aims of the present work were to examine the energy metabolism and the antioxidant defense system of the Senna obtusifolia L. during seed germination and initial growth, and the responses to allelochemical-induced stress. Respiratory activity, the activities of alcohol dehydrogenase (ADH), superoxide dismutase (SOD), catalase (CAT),guaicol peroxidase (POD), ascorbate peroxidase (APX), glutathione reductase (GR), lipoxygenase (LOX) and the content of malondialdehyde (MDA) and glutathione (GSSG and GSH) were measured. Shortly after seed imbibition, mitochondrial respiratory activity was active and the presence of SOD, CAT, GR and LOX activity in embryos, along with significant KCN-insensitive respiration, indicated that the production of reactive oxygen species (ROS) is initiated as soon as mitochondrial respiration resumes. Among the fourteen allelochemicals assayed, only coumarin significantly supressed the growth of S. obtusifolia seedlings. Although coumarin reduced the activities of CAT, POD and APX, the GSH, GSSG and MDA levels were not altered. Alpha-pinene, quercetin and ferulic acid did not modify the activity of the antioxidant enzymes or the contents of GSH, GSSH and MDA. Thus the antioxidant defense system of S. obstusifolia may be effective in counteracting the harmful effects of ROS generated during seed germination and initial growth in the presence of toxic allelochemicals.


Assuntos
Germinação , Estresse Oxidativo , Feromônios/metabolismo , Plantas Daninhas/crescimento & desenvolvimento , Senna/crescimento & desenvolvimento , Aclimatação , Ascorbato Peroxidases/metabolismo , Catalase/metabolismo , Glutationa/metabolismo , Lipoxigenase/metabolismo , Malondialdeído/metabolismo , Plantas Daninhas/enzimologia , Plantas Daninhas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Sementes/fisiologia , Senna/enzimologia , Senna/metabolismo , Superóxido Dismutase/metabolismo
7.
Biochim Biophys Acta ; 1832(1): 249-62, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23069390

RESUMO

The purpose of the present work was to investigate Ca(2+) transport and distribution under the conditions of the intact rat liver in health and disease (adjuvant-induced arthritis). The multiple-indicator dilution technique was used with the simultaneous injection of (45)Ca(2+) and indicators into the portal vein under defined conditions and analysis of the outflow profiles by means of a space-distributed variable transit time model. The best description of the (45)Ca(2+) outflow profiles corresponds to a model that assumes rapid distribution of (45)Ca(2+) between the vascular space and the cell surface and a slower transfer into the hepatocytes. In kinetic terms two distinct cellular pools were distinguishable, the cytosol and the endoplasmic reticulum. The concentration of Ca(2+) in the cytosol was much lower than in the vascular space and in the endoplasmic reticulum. The most prominent modification observed in the livers of arthritic rats was the increased Ca(2+) concentration in the hormone-sensitive cellular pool. Furthermore, reduced rates of Ca(2+) influx and efflux between the hormone-sensitive cellular pool and the cytosolic space were also detected in combination with a significantly reduced expression of the sarco-endoplasmic reticulum Ca(2+)-ATPase (SERCA2) protein. All these observations mean that in livers from arthritic rats more time is required to replenish the hormone sensitive Ca(2+) stores.


Assuntos
Artrite Experimental/metabolismo , Radioisótopos de Cálcio/metabolismo , Fígado/metabolismo , Animais , Transporte Biológico , Radioisótopos de Cálcio/química , Citosol/química , Citosol/metabolismo , Humanos , Cinética , Masculino , Perfusão , Ratos , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/genética , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/metabolismo
8.
Mol Cell Biochem ; 373(1-2): 265-77, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23117227

RESUMO

Most studies using a hypercaloric diet to induce obesity have focused on the metabolism of fat and carbohydrates. Less concern has been given to the metabolism of amino acids, despite evidence of modifications in nitrogen metabolism during obesity. The aim of this study was to evaluate amino acid metabolism in livers from cafeteria diet-induced obese rats. Blood parameters were analysed, and histological sections of livers were stained with Sudan III. The enzymatic activities of some enzymes were determined in liver homogenates. Gluconeogenesis, ureagenesis, and oxygen consumption were evaluated in rat livers perfused with glutamine, alanine, or ammonium chloride. Compared to control rats, cafeteria-fed rats demonstrated higher levels of triacylglycerol and glucose in the blood and greater accumulation of fat in livers. Gluconeogenesis and urea production in livers perfused with glutamine and alanine at higher concentrations showed a substantial reduction in cafeteria-fed rats. However, no significant difference was observed among groups perfused with ammonium chloride. The activities of the enzymes alanine aminotransferase, glutaminase, and aspartate aminotransferase in the livers were reduced in cafeteria-fed rats. Taken together, these data are consistent with the hypothesis that livers from cafeteria diet-induced obese rats exhibit a limitation in their maximal capacity to metabolise glutamine and alanine to glucose, ammonia, and urea, not because of an impairment in gluconeogenesis and/or ureagenesis, but rather due to a depression in the activities of enzymes that catalyse the initial steps of amino acid metabolism.


Assuntos
Aminoácidos/metabolismo , Fígado/metabolismo , Obesidade Abdominal/metabolismo , Amônia/metabolismo , Animais , Aspartato Aminotransferases/metabolismo , Glicemia , Colesterol/sangue , Dieta Hiperlipídica/efeitos adversos , Ingestão de Energia , Glutamato Desidrogenase/metabolismo , Técnicas In Vitro , Ácido Láctico/sangue , Metabolismo dos Lipídeos , Masculino , Obesidade Abdominal/etiologia , Consumo de Oxigênio , Ratos , Ratos Wistar , Triglicerídeos/sangue , Ureia/metabolismo
9.
Toxicol Lett ; 383: 1-16, 2023 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-37217012

RESUMO

Clomipramine, a tricyclic antidepressant used to treat depression and obsessive-compulsive disorder, has been linked to a few cases of acute hepatotoxicity. It is also recognized as a compound that hinders the functioning of mitochondria. Hence, the effects of clomipramine on mitochondria should endanger processes that are somewhat connected to energy metabolism in the liver. For this reason, the primary aim of this study was to examine how the effects of clomipramine on mitochondrial functions manifest in the intact liver. For this purpose, we used the isolated perfused rat liver, but also isolated hepatocytes and isolated mitochondria as experimental systems. According to the findings, clomipramine harmed metabolic processes and the cellular structure of the liver, especially the membrane structure. The considerable decrease in oxygen consumption in perfused livers strongly suggested that the mechanism of clomipramine toxicity involves the disruption of mitochondrial functions. Coherently, it could be observed that clomipramine inhibited both gluconeogenesis and ureagenesis, two processes that rely on ATP production within the mitochondria. Half-maximal inhibitory concentrations for gluconeogenesis and ureagenesis ranged from 36.87 µM to 59.64 µM. The levels of ATP as well as the ATP/ADP and ATP/AMP ratios were reduced, but distinctly, between the livers of fasted and fed rats. The results obtained from experiments conducted on isolated hepatocytes and isolated mitochondria unambiguously confirmed previous propositions about the effects of clomipramine on mitochondrial functions. These findings revealed at least three distinct mechanisms of action, including uncoupling of oxidative phosphorylation, inhibition of the FoF1-ATP synthase complex, and inhibition of mitochondrial electron flow. The elevation in activity of cytosolic and mitochondrial enzymes detected in the effluent perfusate from perfused livers, coupled with the increase in aminotransferase release and trypan blue uptake observed in isolated hepatocytes, provided further evidence of the hepatotoxicity of clomipramine. It can be concluded that impaired mitochondrial bioenergetics and cellular damage are important factors underlying the hepatotoxicity of clomipramine and that taking excessive amounts of clomipramine can lead to several risks including decreased ATP production, severe hypoglycemia, and potentially fatal outcomes.


Assuntos
Doença Hepática Induzida por Substâncias e Drogas , Clomipramina , Ratos , Animais , Clomipramina/toxicidade , Clomipramina/metabolismo , Metabolismo Energético , Fígado/metabolismo , Mitocôndrias/metabolismo , Trifosfato de Adenosina/metabolismo , Doença Hepática Induzida por Substâncias e Drogas/metabolismo , Mitocôndrias Hepáticas/metabolismo
10.
Plant Physiol Biochem ; 171: 26-37, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34971953

RESUMO

In order to assist sustainable agriculture, new strategies and methods are being used based on the utilization of new natural molecules. These natural compounds can be used as potential natural crop protectors and growth promoters, and the elucidation of their modes/mechanisms of action can represent a big step towards cleaner agriculture free of agrochemicals. In the present paper, the mechanisms underlying the effects of exogenous resveratrol (R), a natural phytoalexin found in plants, on Lactuca sativa metabolism were investigated through physiological and metabolomic approaches. The results highlighted that R stimulates the growth of lettuce. A reduction of the O2⋅- production in R-treated seedlings and an increase in the photosynthesis efficiency was observed, indicated by a higher Fv/Fm. The metabolomic analysis of lettuce seedlings treated with R identified 116 metabolites related to galactose, amino acids, sugar and nucleotide sugar, and ascorbate and aldarate metabolisms. Increased content of some polyamines and several metabolites was also observed, which may have contributed to scavenging free radicals and activating antioxidant enzymes, thus reducing oxidative damage and improving PSII protection in R-treated seedlings.


Assuntos
Lactuca , Plântula , Antioxidantes/metabolismo , Lactuca/metabolismo , Fotossíntese , Resveratrol/farmacologia , Plântula/metabolismo
11.
Chem Biol Interact ; 364: 110054, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-35872042

RESUMO

The current study sought to evaluate the acute effects of phloretin (PH) on metabolic pathways involved in the maintenance of glycemia, specifically gluconeogenesis and glycogenolysis, in the perfused rat liver. The acute effects of PH on energy metabolism and toxicity parameters in isolated hepatocytes and mitochondria, as well as its effects on the activity of a few key enzymes, were also evaluated. PH inhibited gluconeogenesis from different substrates, stimulated glycogenolysis and glycolysis, and altered oxygen consumption. The citric acid cycle activity was inhibited by PH under gluconeogenic conditions. Similarly, PH reduced the cellular ATP/ADP and ATP/AMP ratios under gluconeogenic and glycogenolytic conditions. In isolated mitochondria, PH inhibited the electron transport chain and the FoF1-ATP synthase complex as well as acted as an uncoupler of oxidative phosphorylation, inhibiting the synthesis of ATP. PH also decreased the activities of malate dehydrogenase, glutamate dehydrogenase, glucose 6-phosphatase, and glucose 6-phosphate dehydrogenase. Part of the bioenergetic effects observed in isolated mitochondria was shown in isolated hepatocytes, in which PH inhibited mitochondrial respiration and decreased ATP levels. An aggravating aspect might be the finding that PH promotes the net oxidation of NADH, which contradicts the conventional belief that the compound operates as an antioxidant. Although trypan blue hepatocyte viability tests revealed substantial losses in cell viability over 120 min of incubation, PH did not promote extensive enzyme leakage from injured cells. In line with this effect, only after a lengthy period of infusion did PH considerably stimulate the release of enzymes into the effluent perfusate of livers. In conclusion, the increased glucose release caused by enhanced glycogenolysis, along with suppression of gluconeogenesis, is the opposite of what is predicted for antihyperglycemic agents. These effects were caused in part by disruption of mitochondrial bioenergetics, a result that should be considered when using PH for therapeutic purposes, particularly over long periods and in large doses.


Assuntos
Gluconeogênese , Floretina , Trifosfato de Adenosina/metabolismo , Animais , Glicemia/metabolismo , Glucose/metabolismo , Fígado , Mitocôndrias Hepáticas/metabolismo , Floretina/farmacologia , Ratos , Ratos Wistar
12.
Exp Mol Pathol ; 91(3): 687-94, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21821020

RESUMO

The purpose of this work was to determine if mitochondrial dysfunction is involved in the development of non-alcoholic fatty liver disease (NAFLD). Using a model of obesity induced by the neonatal treatment of rats with monosodium L-glutamate (MSG), several parameters of liver mitochondrial function and their impact on liver redox status were evaluated. Specifically, fatty acid ß-oxidation, oxidative phosphorylation and Ca(2+)-induced mitochondrial permeability transition were assessed in isolated liver mitochondria, and reduced glutathione (GSH), linked thiol contents and the activities of several enzymes involved in the control of redox status were measured in the liver homogenate. Our results demonstrate that liver mitochondria from MSG-obese rats exhibit a higher ß-oxidation capacity and an increased capacity for oxidising succinate, without loss in the efficiency of oxidative phosphorylation. Also, liver mitochondria from obese rats were less susceptible to the permeability transition pore (PTP) opening induced by 1.0 µM CaCl(2). Cellular levels of GSH were unaffected in the livers from the MSG-obese rats, whereas reduced linked thiol contents were increased. The activities of glucose-6-phosphate dehydrogenase, glutathione reductase and glutathione peroxidase were increased, while catalase activity was unaffected and superoxide dismutase activity was reduced in the livers from the MSG-obese rats. In this model of obesity, liver fat accumulation is not a consequence of mitochondrial dysfunction. The enhanced glucose-6-phosphate dehydrogenase activity observed in the livers of MSG-obese rats could be associated with liver fat accumulation and likely plays a central role in the mitochondrial defence against oxidative stress.


Assuntos
Fígado Gorduroso/metabolismo , Mitocôndrias Hepáticas/metabolismo , Animais , Animais Recém-Nascidos , Fígado Gorduroso/induzido quimicamente , Fígado Gorduroso/complicações , Glucosefosfato Desidrogenase/metabolismo , Glutationa/metabolismo , Glutationa Peroxidase/metabolismo , Glutationa Redutase/metabolismo , Masculino , Hepatopatia Gordurosa não Alcoólica , Obesidade/induzido quimicamente , Obesidade/complicações , Obesidade/metabolismo , Oxirredução , Fosforilação Oxidativa , Ratos , Ratos Wistar , Glutamato de Sódio/toxicidade
13.
J Biochem Mol Toxicol ; 25(2): 117-26, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-20957679

RESUMO

Flavonols, which possess the B-catechol ring, as quercetin, are capable of producing o-hemiquinones and to oxidize NADH in a variety of mammalian cells. The purpose of this study was to investigate whether fisetin affects the liver energy metabolism and the mitochondrial NADH to NAD+ ratio. The action of fisetin on hepatic energy metabolism was investigated in the perfused rat liver and isolated mitochondria. In isolated mitochondria, fisetin decreased the respiratory control and ADP/O ratios with the substrates α-ketoglutarate and succinate. In the presence of ADP, respiration of isolated mitochondria was inhibited with both substrates, indicating an inhibitory action on the ATP-synthase. The stimulation of the ATPase activity of coupled mitochondria and the inhibition of NADH-oxidase activity pointed toward a possible uncoupling action and the interference of fisetin with mitochondrial energy transduction mechanisms. In livers from fasted rats, fisetin inhibited ketogenesis from endogenous sources. The ß-hydroxybutyrate/ acetoacetate ratio, which reflects the mitochondrial NADH/NAD+ redox ratio, was also decreased. In addition, fisetin (200 µM) increased the production of (14)CO2 from exogenous oleate. The results of this investigation suggest that fisetin causes a shift in the mitochondrial redox potential toward a more oxidized state with a clear predominance of its prooxidant activity.


Assuntos
Metabolismo Energético , Flavonoides/farmacologia , Fígado/metabolismo , Mitocôndrias Hepáticas/efeitos dos fármacos , Ácido 3-Hidroxibutírico/metabolismo , Acetoacetatos/metabolismo , Animais , Flavonóis , Ácidos Cetoglutáricos/metabolismo , Masculino , Mitocôndrias Hepáticas/metabolismo , NAD/metabolismo , Oxirredução/efeitos dos fármacos , Consumo de Oxigênio/efeitos dos fármacos , Quercetina/farmacologia , Ratos , Ratos Wistar
14.
J Chem Ecol ; 37(5): 500-13, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21503619

RESUMO

The relationships between changes in energy metabolism and the antioxidant defense system in the weed species Ipomoea triloba L. during seed germination and early seedling growth were investigated. The effects of some common allelochemicals on these parameters also were studied. Respiratory activity and the activities of alcohol dehydrogenase, superoxide dismutase, catalase, guaicol peroxidase, ascorbate peroxidase, glutathione reductase, and lipoxygenase were measured. Mitochondrial oxidative phosphorylation resumed shortly after the seed imbibition period, as indicated by considerable KCN-sensitive respiratory activity in embryos of I. triloba. The occurrence of superoxide dismutase, catalase, guaicol peroxidase, and lipoxygenase activities in the embryos, along with significant KCN-insensitive respiration, suggest that production of reactive oxygen species (ROS) is initiated as soon as mitochondrial respiration is resumed. All assayed antioxidant enzymes were present in the embryos except ascorbate peroxidase, which appeared only in primary roots. The activities of antioxidant enzymes increased after completion of germination, especially in primary roots. Superoxide dismutase, catalase, and guaicol peroxidase probably were the crucial enzymes involved in the neutralization of ROS, since they had higher levels of activity compared with other enzymes, such as ascorbate peroxidase and glutathione reductase. When seeds were grown in the presence of α-pinene, coumarin, quercetin, and ferulic acid, there was an additional increase in activities of antioxidant enzymes, as well as increases in lipoxygenase activity and KCN-insensitive respiration, suggesting a further increase in ROS generation. The antioxidant defense system of I. triloba was not effective in preventing lipid peroxidation caused by α-pinene. The data indicate that during seed germination and initial growth of I. triloba, a period when antioxidant enzyme activity increases to counteract the harmful ROS effects produced during mitochondrial metabolism resumption, the presence of allelochemicals, which cause further oxidative stress, may leave the seeds/seedlings more vulnerable to cellular dysfunction and cell death.


Assuntos
Antioxidantes/metabolismo , Ipomoea/crescimento & desenvolvimento , Feromônios/metabolismo , Plantas Daninhas/crescimento & desenvolvimento , Sementes/crescimento & desenvolvimento , Metabolismo Energético , Germinação , Ipomoea/metabolismo , Plantas Daninhas/metabolismo , Sementes/metabolismo
15.
Plants (Basel) ; 10(8)2021 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-34451648

RESUMO

To date, synthetic herbicides are the main tools used for weed control, with consequent damage to both the environment and human health. In this respect, searching for new natural molecules and understanding their mode of action could represent an alternative strategy or support to traditional management methods for sustainable agriculture. Protodioscin is a natural molecule belonging to the class of steroid saponins, mainly produced by monocotyledons. In the present paper, protodioscin's phytotoxic potential was assessed to identify its target and the potential mode of action in the model plant Arabidopsis thaliana. The results highlighted that the root system was the main target of protodioscin, which caused a high inhibitory effect on the primary root length (ED50 50 µM) with morphological alteration, accompanied by a significant increase in the lateral root number and root hair density. Through a pharmacological and microscopic approach, it was underlined that this saponin modified both auxin distribution and transport, causing an auxin accumulation in the region of root maturation and an alteration of proteins responsible for the auxin efflux (PIN2). In conclusion, the saponin protodioscin can modulate the root system of A. thaliana by interfering with the auxin transport (PAT).

16.
Environ Sci Pollut Res Int ; 28(47): 67711-67723, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34263402

RESUMO

Cadmium (Cd) inhibits soybean root growth, but its exact mode of action is still not completely understood. We evaluated the effects of Cd on growth, mitochondrial respiration, lipid peroxidation, total phenols, glutathione, and activities of lipoxygenase (LOX), superoxide dismutase (SOD), and catalase (CAT) in soybean roots. In primary roots, Cd stimulated KCN-insensitive respiration and KCN-SHAM-insensitive respiration, indicating the involvement of the alternative oxidase (AOX) pathway, while it decreased KCN-sensitive respiration, suggesting an inhibition of the cytochrome oxidase pathway (COX). In isolated mitochondria, Cd uncoupled the oxidative phosphorylation since it decreased state III respiration (coupled respiration) and ADP/O and respiratory control ratios, while it increased state IV respiration (depletion of exogenously added ADP). The uncoupling effect increased extramitochondrial LOX activity, lipid peroxidation, and oxidized and reduced glutathione, which induced an antioxidant response with enhanced SOD and CAT activities. In brief, our findings reveal that Cd acts as an uncoupler of the mitochondrial oxidative phosphorylation in soybean roots, disturbing cellular respiration and inducing oxidative cellular stress.


Assuntos
Cádmio , Fosforilação Oxidativa , Antioxidantes/metabolismo , Cádmio/metabolismo , Mitocôndrias/metabolismo , Estresse Oxidativo , Raízes de Plantas/metabolismo , Glycine max/metabolismo , Superóxido Dismutase/metabolismo
17.
Plant Physiol Biochem ; 166: 857-873, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34237604

RESUMO

Urochloa ruziziensis, a cover plant used in no-till systems, can suppress weeds in the field through their chemical compounds, but the mode of action of these compounds is still unknown. The present study aimed to investigate the effects of a saponin-rich butanolic extract from U. ruziziensis straw (BfUr) and one of its components, protodioscin on an eudicot Ipomoea grandifolia and a monocot Digitaria insularis weed. The anatomy and the morphology of the root systems and several parameters related to energy metabolism and antioxidant defense systems were examined. The IC50 values for the root growth inhibition by BfUr were 108 µg mL-1 in D. insularis and 230 µg mL-1 in I. grandifolia. The corresponding values for protodioscin were 34 µg mL-1 and 54 µg mL-1. I. grandifolia exhibited higher ROS-induced peroxidative damage in its roots compared with D. insularis. In the roots of both weeds, the BfUr and protodioscin induced a reduction in the meristematic and elongation zones with a precocious appearance of lateral roots, particularly in I. grandifolia. The roots also exhibited features of advanced cell differentiation in the vascular cylinder. These alterations were similar to stress-induced morphogenic responses (SIMRs), which are plant adaptive strategies to survive in the presence of toxicants. At concentrations above their IC50 values, the BfUr or protodioscin strongly inhibited the development of both weeds. Such findings demonstrated that U. ruziziensis mulches may contribute to the use of natural and renewable weed control tools.


Assuntos
Diosgenina , Saponinas , Diosgenina/análogos & derivados , Diosgenina/farmacologia , Plantas Daninhas , Poaceae , Saponinas/farmacologia
18.
Photodiagnosis Photodyn Ther ; 35: 102446, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34289416

RESUMO

BACKGROUND: The present study aimed to characterize the intrinsic and photodynamic effects of azure B (AB) on mitochondrial bioenergetics, as well as the consequences of its intrinsic effects on hepatic energy metabolism. METHODS: Two experimental systems were utilized: (a) isolated rat liver mitochondria and (b) isolated perfused rat liver. RESULTS: AB interacted with mitochondria regardless of photostimulation, but its binding degree was reduced by mitochondrial energization. Under photostimulation, AB caused lipid peroxidation and protein carbonylation and decreased the content of reduced glutathione (GSH) in mitochondria. AB impaired mitochondrial bioenergetics in at least three distinct ways: (1) uncoupling of oxidative phosphorylation; (2) photoinactivation of complexes I and II; and (3) photoinactivation of the FoF1-ATP synthase complex. Without photostimulation, AB also demonstrated mitochondrial toxicity, which was characterized by the induction of lipid peroxidation, loss of inner mitochondrial membrane integrity, and uncoupling of oxidative phosphorylation. The perfused rat liver experiments showed that mitochondria were one of the major targets of AB, even in intact cells. AB inhibited gluconeogenesis and ureagenesis, two biosynthetic pathways strictly dependent on intramitochondrially generated ATP. Contrariwise, AB stimulated glycogenolysis and glycolysis, which are required compensatory pathways for the inhibited oxidative phosphorylation. Similarly, AB reduced the cellular ATP content and the ATP/ADP and ATP/AMP ratios. CONCLUSIONS: Although the properties and severe photodynamic effects of AB on rat liver mitochondria might suggest its usefulness in PDT treatment of liver tumors, this possibility should be considered with precaution given the toxic intrinsic effects of AB on mitochondrial bioenergetics and energy-linked hepatic metabolism.


Assuntos
Fotoquimioterapia , Fármacos Fotossensibilizantes , Trifosfato de Adenosina/metabolismo , Animais , Corantes Azur , Metabolismo Energético , Fígado , Mitocôndrias/metabolismo , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/metabolismo , Fármacos Fotossensibilizantes/farmacologia , Ratos , Ratos Wistar
19.
Toxicology ; 455: 152766, 2021 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-33775737

RESUMO

Azure A (AA) is a cationic molecule of the class of phenothiazines that has been applied in vitro as a photosensitising agent in photodynamic antimicrobial chemotherapy. It is a di-demethylated analogue of methylene blue (MB), which has been demonstrated to be intrinsically and photodynamically highly active on mitochondrial bioenergetics. However, as far as we know, there are no studies about the photodynamic effects of AA on mammalian mitochondria. Therefore, this investigation aimed to characterise the intrinsic and photodynamic acute effects of AA (0.540 µM) on isolated rat liver mitochondria, isolated hepatocytes, and isolated perfused rat liver. The effects of AA were assessed by evaluating several parameters of mitochondrial bioenergetics, oxidative stress, cell viability, and hepatic energy metabolism. The photodynamic effects of AA were assessed under simulated hypoxic conditions, a suitable way for mimicking the microenvironment of hypoxic solid tumour cells. AA interacted with the mitochondria and, upon photostimulation (10 min of light exposure), produced toxic amounts of reactive oxygen species (ROS), which damaged the organelle, as demonstrated by the high levels of lipid peroxidation and protein carbonylation. The photostimulated AA also depleted the GSH pool, which could compromise the mitochondrial antioxidant defence. Bioenergetically, AA photoinactivated the complexes I, II, and IV of the mitochondrial respiratory chain and the F1FO-ATP synthase complex, sharply inhibiting the oxidative phosphorylation. Upon photostimulation (10 min of light exposure), AA reduced the efficiency of mitochondrial energy transduction and oxidatively damaged lipids in isolated hepatocytes but did not decrease the viability of cells. Despite the useful photobiological properties, AA presented noticeable dark toxicity on mitochondrial bioenergetics, functioning predominantly as an uncoupler of oxidative phosphorylation. This harmful effect of AA was evidenced in isolated hepatocytes, in which AA diminished the cellular ATP content. In this case, the cells exhibited signs of cell viability reduction in the presence of high AA concentrations, but only after a long time of incubation (at least 90 min). The impairments on mitochondrial bioenergetics were also clearly manifested in intact perfused rat liver, in which AA diminished the cellular ATP content and stimulated the oxygen uptake. Consequently, gluconeogenesis and ureogenesis were strongly inhibited, whereas glycogenolysis and glycolysis were stimulated. AA also promoted the release of cytosolic and mitochondrial enzymes into the perfusate concomitantly with inhibition of oxygen consumption. In general, the intrinsic and photodynamic effects of AA were similar to those of MB, but AA caused some distinct effects such as the photoinactivation of the complex IV of the mitochondrial respiratory chain and a diminution of the ATP levels in the liver. It is evident that AA has the potential to be used in mitochondria-targeted photodynamic therapy, even under low oxygen concentrations. However, the fact that AA directly disrupts mitochondrial bioenergetics and affects several hepatic pathways that are linked to ATP metabolism, along with its ability to perturb cellular membranes and its little potential to reduce cell viability, could result in significant adverse effects especially in long-term treatments.


Assuntos
Corantes Azur/toxicidade , Metabolismo Energético/efeitos dos fármacos , Fígado/efeitos dos fármacos , Mitocôndrias Hepáticas/efeitos dos fármacos , Trifosfato de Adenosina/metabolismo , Animais , Sobrevivência Celular/efeitos dos fármacos , Hepatócitos/efeitos dos fármacos , Hepatócitos/patologia , Peroxidação de Lipídeos/efeitos dos fármacos , Fígado/patologia , Masculino , Mitocôndrias Hepáticas/patologia , Consumo de Oxigênio/efeitos dos fármacos , Carbonilação Proteica/efeitos dos fármacos , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismo
20.
Cell Biochem Funct ; 28(2): 149-58, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20084677

RESUMO

Fisetin is a flavonoid dietary ingredient found in the smoke tree (Cotinus coggyria) and in several fruits and vegetables. The effects of fisetin on glucose metabolism in the isolated perfused rat liver and some glucose-regulating enzymatic activities were investigated. Fisetin inhibited glucose, lactate, and pyruvate release from endogenous glycogen. Maximal inhibitions of glycogenolysis (49%) and glycolysis (59%) were obtained with the concentration of 200 microM. The glycogenolytic effects of glucagon and dinitrophenol were suppressed by fisetin 300 microM. No significant changes in the cellular contents of AMP, ADP, and ATP were found. Fisetin increased the cellular content of glucose 6-phosphate and inhibited the glucose 6-phosphatase activity. Gluconeogenesis from lactate and pyruvate or fructose was inhibited by fisetin 300 microM. Pyruvate carboxylation in isolated intact mitochondria was inhibited (IC(50) = 163.10 +/- 12.28 microM); no such effect was observed in freeze-thawing disrupted mitochondria. It was concluded that fisetin inhibits glucose release from the livers in both fed and fasted conditions. The inhibition of pyruvate transport into the mitochondria and the reduction of the cytosolic NADH-NAD(+) potential redox could be the causes of the gluconeogenesis inhibition. Fisetin could also prevent hyperglycemia by decreasing glycogen breakdown or blocking the glycogenolytic action of hormones.


Assuntos
Flavonoides/farmacologia , Glucose/metabolismo , Fígado/metabolismo , Anacardiaceae/química , Animais , Flavonóis , Frutose/metabolismo , Glucagon/metabolismo , Gluconeogênese/efeitos dos fármacos , Glucose-6-Fosfatase/antagonistas & inibidores , Glucose-6-Fosfatase/metabolismo , Glicólise/efeitos dos fármacos , Lactatos/metabolismo , Masculino , Mitocôndrias Hepáticas/metabolismo , NAD/metabolismo , Piruvatos/metabolismo , Ratos , Ratos Wistar
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