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1.
Food Res Int ; 173(Pt 1): 113260, 2023 11.
Article in English | MEDLINE | ID: mdl-37803573

ABSTRACT

Cytinus hypocistis(L.) L. is an edible parasitic plant that grows within the roots of its host. In addition to its use as famine food in the past, it is also tradidionally used for treating several illnesses such as intestinal problems, inflammations, tumors, and bleeding. This species is rich in hydrolysable tannins, compounds often associated with inhibiting starch digestion. Therefore, the present work investigated how effectively C. hypocistis tannin-rich extracts inhibited enzymes involved in starch digestion and if such effect also occurs in vivo. The latter premise was approached using the starch tolerance test in mice. Two optimized hydroethanolic extracts were used, a heat-assisted and an ultrasound-assisted extract, with known hydrolysable tannin content. Both extracts demonstrated potent inhibition of α-amylase. Inhibitions were of the mixed type with inhibitor constants in the 15 µg/mL range. The inhibition of the intestinal α-glucosidase was at least ten times less effective. The inhibition of the α-amylase was negatively affected by in vitro gastrointestinal digestion and bovine serum albumin. In vivo, both extracts inhibited starch digestion at doses between 100 and 400 mg/mL in healthy mice. The highest doses of the ultrasound and heat extracts diminished the peak glucose levels in the starch tolerance test by 46 and 59.3%, respectively. In streptozotocin diabetic mice, this inhibition occurred only at the dose of 400 mg/mL. Under this condition, diminution of the peak glucose concentration in the starch tolerance test was equal to 36.7% and 48.8% for the ultrasound and heat extracts, respectively. Maltose digestion was not inhibited by the C. hypocistis extracts. Qualitatively and quantitatively, thus, the actions of both extracts were similar. The results allow adding a new biological property to C. hypocistis, namely, the ability to decrease the hyper-glycemic excursion after a starch-rich meal, propitiating at the same time a diminished caloric intake.


Subject(s)
Diabetes Mellitus, Experimental , Tannins , Mice , Animals , Tannins/pharmacology , Starch , Plant Extracts/pharmacology , alpha-Amylases/pharmacology , Hydrolyzable Tannins , Glucose , Digestion
2.
Food Funct ; 10(9): 5682-5696, 2019 Sep 01.
Article in English | MEDLINE | ID: mdl-31435625

ABSTRACT

Healthy and adjuvant-induced arthritic rats were treated for 23 days with daily doses of 400 and 800 mg kg-1Ilex paraguariensis extract. This treatment (a) diminished the ROS levels in the liver and brain, (b) decreased oxidative protein and lipid damage in liver and brain, (c) increased the plasma antioxidant capacity, (d) increased the GSH levels and the GSH/GSSH ratio in both the liver and the brain, (e) almost restored the enzymatic activities linked to the metabolism of GSH-GSSG, and (f) reversed the modified activities of xanthine oxidase, superoxide dismutase and catalase. The anti-inflammatory actions (firstly) and the antioxidant actions (in the second place) of the yerba mate constituents (e.g., chlorogenic acid derivatives) are the causes of these beneficial effects. Daily ingestion of traditional yerba mate beverages may be effective in attenuating the symptoms of inflammatory diseases, especially in older adults.


Subject(s)
Anti-Inflammatory Agents/administration & dosage , Antioxidants/administration & dosage , Arthritis, Experimental/drug therapy , Ilex paraguariensis/chemistry , Plant Extracts/administration & dosage , Animals , Arthritis, Experimental/genetics , Arthritis, Experimental/immunology , Arthritis, Experimental/metabolism , Beverages/analysis , Catalase/metabolism , Humans , Liver/drug effects , Liver/metabolism , Male , Oxidative Stress/drug effects , Rats , Rats, Sprague-Dawley , Reactive Oxygen Species/metabolism , Superoxide Dismutase/metabolism
3.
Food Chem ; 294: 302-308, 2019 Oct 01.
Article in English | MEDLINE | ID: mdl-31126467

ABSTRACT

Pereskia aculeata Miller, known worldwide as ora-pro-nobis, is a highly nutritive species of the Cactaceae family from the Brazilian Atlantic Forest. In this work, we report inedited information on the phenolic profile of P. aculeata leaves, besides a broad study of their antioxidant potential using a set of five different methods. A total of ten phenolic compounds were identified, such as two phenolic acids (caffeic acid derivatives) and eight flavonoids (quercetin, kaempferol and isorhamnetin glycoside derivatives). Caftaric acid was the extract's major phenolic constituent, accounting for more than 49% of the phenolic content, followed by quercetin-3-O-rutinoside (14.99%) and isorhamnetin-O-pentoside-O-rutinoside (9.56%). Overall, the ora-pro-nobis leaf extract showed relevant values of antioxidant capacity, with higher activities than the Trolox in the DPPH and ABTS trials. The antimicrobial activity exhibited by the extract against both Gram-positive and Gram-negative bacteria suggests the presence of a broad spectrum of phytochemicals with antibiotic activity.


Subject(s)
Cactaceae/chemistry , Phytochemicals/chemistry , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/isolation & purification , Anti-Bacterial Agents/pharmacology , Antioxidants/chemistry , Brazil , Cactaceae/metabolism , Cells, Cultured , Flavonoids/chemistry , Flavonoids/isolation & purification , Flavonoids/pharmacology , Forests , Gram-Negative Bacteria/drug effects , Gram-Positive Bacteria/drug effects , Hepatocytes/cytology , Hepatocytes/drug effects , Hepatocytes/metabolism , Humans , Phenols/chemistry , Phenols/isolation & purification , Phenols/pharmacology , Phytochemicals/isolation & purification , Phytochemicals/pharmacology , Plant Extracts/chemistry , Plant Leaves/chemistry , Plant Leaves/metabolism
4.
Food Funct ; 10(2): 565-572, 2019 Feb 20.
Article in English | MEDLINE | ID: mdl-30702105

ABSTRACT

Operations for sorting mushrooms at the industrial level usually generate large amounts of bio-residues not conforming to strict morphological criteria for commercial purposes, even though their biological content is not compromised. In this context, the present work aimed at evaluating the potential for reutilizing industrially discarded Agaricus blazei Murill (ABM). Thus, the content of essential nutrients and the chemical composition were determined, and MTT and LDH assays were used to evaluate the viability and cell death of Caco-2 and HT29 cell lines of an ethanolic extract prepared from ABM (preliminary safety tests for nutraceutical applications). The extract was incorporated into a semi-solid base cosmetic cream and cell viability effects of the extract, and of the final cream formulation, on a keratinocyte cell line (HaCaT) were studied (preliminary safety tests for cosmeceutical applications). Essential nutrients, such as proteins and carbohydrates, and a low fat content were determined for ABM. Twenty-two fatty acids were detected, with polyunsaturated fatty acids (PUFA) (∼53%) being the most abundant fraction. The cell viabilities of Caco-2 and HT29 cells were maintained up to 100 µg mL-1. After incorporation into the base cream, a formulation with a pale yellow colour and favourable pH was obtained. The cell viability of HaCaT cells in the presence of the extract and the final cream formulation was maintained in a concentration dependent manner, which indicates the safety of this extract for cosmeceutical applications. The results suggest that ABM residues can be used as an inexpensive and sustainable source of nutraceutical and cosmeceutical ingredients.


Subject(s)
Agaricus/chemistry , Cosmeceuticals/adverse effects , Cosmeceuticals/analysis , Dietary Supplements/adverse effects , Dietary Supplements/analysis , Brazil , Caco-2 Cells , Cell Survival , HT29 Cells , Humans
5.
Food Chem ; 271: 393-400, 2019 Jan 15.
Article in English | MEDLINE | ID: mdl-30236693

ABSTRACT

The potential phytochemical losses occurring throughout the sequential steps of in-vitro gastrointestinal digestion and colonic fermentation of a rosemary aqueous extract were investigated. Crude (CE), digested (DE) and fermented (FE) extracts were characterized in terms of their phenolic profile and biological activities. Rosmarinic acid was the phytochemical that underwent the most significate transformation during digestion and fermentation, which amounted to 60% compared to the 26% degradation of the total phenolics. Overall, the simulated digestion step decreased the antioxidant activity estimated by DPPH, ABTS, FRAP, ORAC and TBARS assays. Both CE and DE did not present antiproliferative potential, however, FE exhibited a pronounced cytotoxic activity (GI50 = 116 µg/mL) against HeLa cells. CE and DE showed to be moderate inhibitors of methicillin-resistant Staphylococcus aureus (MRSA), methicillin-susceptible S. aureus (MSSA), S. aureus, Listeria monocytogenes, whilst the FE acted as a moderate inhibitor of MRSA and MSSA.


Subject(s)
Cinnamates/chemistry , Depsides/chemistry , Digestion , Fermentation , Rosmarinus/chemistry , Antioxidants , Cinnamates/pharmacology , Depsides/pharmacology , HeLa Cells , Humans , In Vitro Techniques , Methicillin-Resistant Staphylococcus aureus/drug effects , Plant Extracts , Staphylococcus aureus , Rosmarinic Acid
7.
Food Funct ; 9(3): 1465-1474, 2018 Mar 01.
Article in English | MEDLINE | ID: mdl-29488518

ABSTRACT

In recent years, mycosterols have emerged as potential functional ingredients for the development of sterol-enriched food products and dietary supplements. Agaricus blazei is a mushroom rich in bioactive compounds. For commercial purposes, their fruiting bodies must obey rigid morphological criteria. Those not conforming to these criteria are usually discarded, although this does not mean impairment of their content in bioactives. The aim of the present work was to propose the use of commercially discarded A. blazei fruiting bodies for obtaining an extract rich in ergosterol as a fortifier ingredient for yogurts. For extraction, the Soxhlet technology was used and the highest ergosterol yield (around 12%) was achieved in the 5th cycle, yielding 58.53 ± 1.72 µg of ergosterol per 100 g of mushroom (dry weight). The ergosterol rich extract presented notable antioxidant and antimicrobial properties, besides showing no hepatotoxicity. When added to the yogurts it significantly enhanced their antioxidant properties. Furthermore, it did not significantly alter the nutritional or the individual fatty acid profiles of the final dairy products. Thus, A. blazei fruiting bodies that do not conform to the commercial requirements of the market and are normally discarded could be exploited for obtaining a natural high added-value food additive, following the circular bioeconomy concept.


Subject(s)
Agaricus/chemistry , Ergosterol/isolation & purification , Food Ingredients/analysis , Food Preservation/methods , Food Preservatives/isolation & purification , Plant Extracts/isolation & purification , Vegetables/chemistry , Yogurt/analysis , Antioxidants/analysis , Ergosterol/analysis , Fatty Acids/analysis , Food Preservatives/analysis , Nutritive Value , Plant Extracts/analysis , Ultrasonics
8.
Food Funct ; 9(4): 2328-2340, 2018 Apr 25.
Article in English | MEDLINE | ID: mdl-29578222

ABSTRACT

Anti-inflammatory and antioxidant properties have been attributed to constituents of Rosmarinus officinalis. Considering the inflammatory nature of arthritis and the oxidative stress induced by the disease, this work aimed to investigate if R. officinalis is able to attenuate oxidative and inflammatory injuries caused by the disease. Rats with complete Freund's adjuvant induced arthritis were used. An aqueous extract of the rosemary leaves was administered orally. The parameters related to oxidative stress were measured in the liver, brain and plasma. The administration of the rosemary extract (RE) to arthritic rats diminished oxidative damage (e.g., less carbonylated proteins), improved the oxidative state (e.g., less reactive oxygen species) and also increased the antioxidant capacity by increasing the GSH level and the GSH/GSSG ratio and by almost normalizing the activity of several antioxidant enzymes. The treatment of arthritic rats with the extract also diminished paw edema, the number of leukocytes recruited in the femoro-tibial joint cavities and the weight of the lymph nodes and delayed the appearance of secondary lesions. Twelve phenolic compounds were identified and quantified in the aqueous RE, rosmarinic acid being the most abundant one. In addition, the extract also contains polysaccharides and proteins. The anti-inflammatory and antioxidant activities of the RE can be attributed, partly at least, to its content of polyphenolics with the strong possibility of synergistic interactions as well as metabolic activations. The results corroborate and amplify the general notion that rosemary aqueous extracts possess efficient anti-inflammatory agents and suggest that they are able to attenuate the oxidative stress inherent to arthritis.


Subject(s)
Anti-Inflammatory Agents/administration & dosage , Antioxidants/administration & dosage , Arthritis, Experimental/drug therapy , Plant Extracts/administration & dosage , Rosmarinus/chemistry , Animals , Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/isolation & purification , Antioxidants/chemistry , Antioxidants/isolation & purification , Arthritis, Experimental/genetics , Arthritis, Experimental/immunology , Arthritis, Experimental/metabolism , Humans , Male , Oxidative Stress/drug effects , Plant Extracts/chemistry , Plant Extracts/isolation & purification , Plant Leaves/chemistry , Rats
9.
Article in English | MEDLINE | ID: mdl-29446750

ABSTRACT

BACKGROUND: TNBS-induced colitis is an experimental immunopathology in rats that shares many features with human inflammatory bowel diseases. Copaiba oleoresin is extracted from plants of the genus Copaifera and is shown to reduce inflammation. OBJECTIVE: The aim of this study was to investigate the action of copaiba oil (C. reticulata Ducke) on inflammation and oxidative status in the distal colon of colitic rats. METHODS: Acute and subchronic colitis were induced in Wistar rats by an intracolonic enema with 2,4,6-trinitrobenzenesulfonic acid (TNBS). The colonic morphology was assessed by histological analysis and the oxidative stress parameters were measured in the intestinal homogenate. The liver damage markers were measured in the plasma. Control and colitic rats were orally treated either with one single dose (acute colitis) of copaiba oil (1.15 g Kg-1) or once a day during seven days (subchronic colitis). RESULTS: The intestinal morphology was severely modified by acute and subchronic colitis, as indicated by the intramural infiltration of polymorphonuclear cells and the increased thickness of all colon layers. The levels of TBARS, protein carbonyl groups and reactive oxygen species (ROS) were increased in the intestine of colitic rats. Copaiba oil did not attenuate the inflammatory damage in acute and subchronic colitis, but it decreased the activity of myeloperoxidase, leukocyte infiltration and oxidative stress in the colon. The level of plasma bilirubin and the activity of alkaline phosphatase were both increased in treated healthy and colitic rats. CONCLUSION: Copaiba oil decreased oxidative stress and inflammation but did not prevent intestinal damage in the colon of colitic rats. The alterations of plasma markers of hepatic damage caused by the oil seem to be associated to its harmful action on the liver.


Subject(s)
Colitis/chemically induced , Colitis/drug therapy , Fabaceae , Oxidative Stress/drug effects , Plant Oils/therapeutic use , Trinitrobenzenesulfonic Acid/toxicity , Animals , Colitis/metabolism , Colon/drug effects , Colon/metabolism , Inflammation/chemically induced , Inflammation/drug therapy , Inflammation/metabolism , Male , Oxidative Stress/physiology , Plant Oils/isolation & purification , Plant Oils/pharmacology , Rats , Rats, Wistar
10.
Crit Rev Food Sci Nutr ; 58(6): 942-957, 2018 Apr 13.
Article in English | MEDLINE | ID: mdl-27623718

ABSTRACT

Aging is an inevitable process influenced by genetic, lifestyle, and environmental factors. Indirect evidence shows that several phytochemicals can have anti-aging capabilities, although direct evidence in this field is still limited. This report aims to provide a critical review on aspects related to the use of novel phytochemicals as anti-aging agents, to discuss the obstacles found when performing most anti-aging study protocols in humans, and to analyze future perspectives. In addition to the extensively studied resveratrol, epicatechin, quercetin, and curcumin, new phytochemicals have been reported to act as anti-aging agents, such as the amino acid L-theanine isolated from green tea, and the lignans arctigenin and matairesinol isolated from Arctium lappa seeds. Furthermore, this review discusses the application of several new extracts rich in phytochemicals with potential use in anti-aging therapies. Finally, this review also discusses the most important biomarkers to test anti-aging interventions, the necessity of conducting epidemiological studies and the need of clinical trials with adequate study protocols for humans.


Subject(s)
Aging/drug effects , Phytochemicals/pharmacology , Plant Extracts/pharmacology , Antioxidants/pharmacology , Arctium/chemistry , Cell Line , Erythrocytes/drug effects , Furans/pharmacology , Humans , Life Style , Lignans/pharmacology , Models, Animal , Randomized Controlled Trials as Topic , Seeds/chemistry
11.
Food Chem ; 237: 453-460, 2017 Dec 15.
Article in English | MEDLINE | ID: mdl-28764019

ABSTRACT

Yerba mate (Ilex paraguariensis) is a plant that grows naturally in South America. From its leaves and thin stems different kinds of beverages are prepared (chimarrão, tererê and tea mate), all of them rich in bioactive substances. The aim of this study was to evaluate the influence of in vitro gastrointestinal digestion and colonic fermentation on the stability of the polyphenols and on the antioxidant, antimicrobial and antitumoral activities of the yerba mate beverages. The phenolic chromatographic profile revealed that both the in vitro digestion and the colonic fermentation caused a pronounced decrease in 3,5-O-dicaffeoylquinic acid and 5-O-caffeoylquinic acid in the preparations. However, 3-O-caffeoylquinic acid, 4-O-caffeoylquinic acid and salvianolic acid I were only barely affected in all preparations. Despite the decrease in the phytochemicals content, yerba mate beverages maintain their functional properties such as antioxidant, antibacterial and antitumoral activities.


Subject(s)
Fermentation , Ilex paraguariensis/metabolism , Beverages , Plant Extracts
12.
J Cell Biochem ; 118(10): 3409-3423, 2017 10.
Article in English | MEDLINE | ID: mdl-28322470

ABSTRACT

The present study investigated the action of copaiba oil (Copaifera reticulata) on the systemic inflammation, oxidative status, and liver cell metabolism of rats with adjuvant-induced arthritis. The later is an experimental autoimmune pathology that shares many features with the human rheumatoid arthritis. Holtzman rats were distributed into the following groups: control (healthy) rats; control rats treated with copaiba oil at the doses of 0.58 and 1.15 g · kg-1 , arthritic rats, and arthritic rats treated with copaiba oil (0.58 and 1.15 g · kg-1 ). The oil was administrated orally once a day during 18 days after arthritis induction. Both doses of copaiba oil improved the paw edema and the dose of 0.58 mg · kg-1 improved the swollen adrenals and lymph nodes besides decreasing the plasmatic myeloperoxidase activity (-30%) of arthritic rats. Copaiba oil (1.15 g · kg-1 ) abolished the increases of protein carbonyl groups and reactive oxygen species in the liver and both doses increased the liver GSH content and the catalase activity in arthritic rats. Copaiba oil (1.15 g · kg-1 ) decreased glycolysis (-65%), glycogenolysis (-58%), and gluconeogenesis (-30%) in the liver of arthritic animals. However, gluconeogenesis was also diminished by the treatment of control rats, which presented lower body weight gain (-45%) and diminished number of hepatocytes per liver area (-20%) associated to higher liver weight (+29%) and increased hepatocyte area (+13%). The results reveal that copaiba oil presented systemic anti-inflammatory and antioxidant actions in arthritic rats. These beneficial effects, however, were counterbalanced by harmful modifications in the liver cell metabolism and morphology of healthy control rats. J. Cell. Biochem. 118: 3409-3423, 2017. © 2017 Wiley Periodicals, Inc.


Subject(s)
Anti-Inflammatory Agents , Antioxidants , Arthritis, Experimental/drug therapy , Fabaceae/chemistry , Liver/metabolism , Plant Oils , Animals , Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/pharmacokinetics , Anti-Inflammatory Agents/pharmacology , Antioxidants/chemistry , Antioxidants/pharmacokinetics , Antioxidants/pharmacology , Arthritis, Experimental/metabolism , Arthritis, Experimental/pathology , Liver/pathology , Male , Plant Oils/chemistry , Plant Oils/pharmacokinetics , Plant Oils/pharmacology , Rats , Rats, Sprague-Dawley
13.
PLoS One ; 10(12): e0143005, 2015.
Article in English | MEDLINE | ID: mdl-26659064

ABSTRACT

We evaluated the effects of the supplementation with L-glutamine and glutamine dipeptide (GDP) on biochemical and morphophysiological parameters in streptozotocin-diabetic rats. For this purpose, thirty animals were distributed into six groups treated orally (gavage) during thirty days: non diabetic rats (Control) + saline, diabetic + saline; Control + L-glutamine (248 mg/kg), Diabetic + L-glutamine (248 mg/kg), Control + GDP (400 mg/kg), Diabetic + GDP (400 mg/kg). Diabetes was induced by an intravenous injection of streptozotocin (60 mg/kg) and confirmed by fasting glucose ≥ 200 mg/dL. Physiological parameters, i.e., body mass, food intake, blood glucose, water intake, urine and faeces were evaluated during supplementation. After the period of supplementation, the animals were euthanized. The blood was collected for biochemical assays (fructosamine, transaminases, lipid profile, total protein, urea, ammonia). Moreover, the jejunum was excised and stored for morphophysiological assays (intestinal enzyme activity, intestinal wall morphology, crypt proliferative index, number of serotoninergic cells from the mucosa, and vipergic neurons from the submucosal tunica). The physiological parameters, protein metabolism and intestinal enzyme activity did not change with the supplementation with L-glutamine or GDP. In diabetic animals, transaminases and fructosamine improved with L-glutamine and GDP supplementations, while the lipid profile improved with L-glutamine. Furthermore, both forms of supplementation promoted changes in jejunal tunicas and wall morphometry of control and diabetic groups, but only L-glutamine promoted maintenance of serotoninergic cells and vipergic neurons populations. On the other hand, control animals showed changes that may indicate negative effects of L-glutamine. Thus, the supplementation with L-glutamine was more efficient for maintaining intestinal morphophysiology and the supplementation with GDP was more efficient to the organism as a whole. Thus, we can conclude that local differences in absorption and metabolism could explain the differences between the supplementation with L-glutamine or GDP.


Subject(s)
Diabetes Mellitus, Experimental/drug therapy , Dipeptides/pharmacology , Glutamine/pharmacology , Jejunum/drug effects , Animals , Blood Glucose/metabolism , Diabetes Mellitus, Experimental/blood , Diabetes Mellitus, Experimental/metabolism , Dietary Supplements , Dipeptides/pharmacokinetics , Glutamine/pharmacokinetics , Intestinal Absorption/drug effects , Jejunum/metabolism , Jejunum/physiopathology , Male , Rats , Rats, Wistar
14.
Oxid Med Cell Longev ; 2014: 563179, 2014.
Article in English | MEDLINE | ID: mdl-24876914

ABSTRACT

Dysfunction of the mitochondrial respiratory chain and increased oxidative stress is a striking phenomenon in the brain of aged individuals. For this reason there has been a constant search for drugs and natural products able to prevent or at least to mitigate these problems. In the present study the effects of an aqueous extract of Agaricus blazei, a medicinal mushroom, on the oxidative state and on the functionality of mitochondria from the brain of old rats (21 months) were conducted. The extract was administered intragastrically during 21 days at doses of 200 mg/kg. The administration of the A. blazei extract was protective to the brain of old rats against oxidative stress by decreasing the lipid peroxidation levels and the reactive oxygen species content and by increasing the nonenzymic and enzymic antioxidant capacities. Administration of the A. blazei extract also increased the activity of several mitochondrial respiratory enzymes and, depending on the substrate, the mitochondrial coupled respiration.


Subject(s)
Agaricus/chemistry , Antioxidants/pharmacology , Brain/drug effects , Mitochondria/drug effects , Plant Extracts/pharmacology , Adenosine Triphosphatases/metabolism , Adenosine Triphosphate/metabolism , Agaricus/metabolism , Aging , Animals , Antioxidants/chemistry , Brain/enzymology , Brain/metabolism , Glutathione/metabolism , Lipid Peroxidation/drug effects , Male , Mitochondria/enzymology , Mitochondria/metabolism , Oxidoreductases/metabolism , Rats , Rats, Wistar , Reactive Oxygen Species/metabolism , Water/chemistry
15.
Chem Biol Interact ; 203(2): 502-11, 2013 Apr 25.
Article in English | MEDLINE | ID: mdl-23422721

ABSTRACT

Usnic acid is a naturally occurring dibenzofuran derivative found in several lichen species. The compound has been marketed as an ingredient of food supplements for weight reduction. There is evidence that the compound acts as an uncoupler of mitochondrial oxidative phosphorylation and it is also clear that consumption of the drug can lead to severe hepatotoxicity depending on the doses. Based on these and other ideas the objective of the present work was to investigate the possible effects of usnic acid on liver metabolism. Livers of male Wistar rats were perfused in a non-recirculating system. Usnic acid stimulated oxygen consumption at low concentrations, diminished the cellular ATP levels, increased the cytosolic but diminished the mitochondrial NADH/NAD(+) ratio, strongly inhibited gluconeogenesis from three different substrates (IC(50) between 1.33 and 3.61 µM), stimulated glycolysis, fructolysis, glycogenolysis and ammoniagenesis and inhibited ureogenesis. The (14)CO(2) production from [1-(14)C]octanoate and [1-(14)C]oleate was increased by usnic acid, but ketogenesis from octanoate was diminished and that from oleate was not affected. It may be concluded that the effects of usnic acid up to 2.5 µM reflect predominantly its activity as an uncoupler. At higher concentrations, however, several other effects may become significant, including inhibition of mitochondrial electron flow and inhibition of medium-chain fatty acid oxidation. In metabolic terms, toxicity of usnic acid can be predicted to be especially dangerous in the fasted state due to the combination of several deleterius events such as diminished hepatic glucose and ketone bodies output to the brain and increased ammonia production.


Subject(s)
Anti-Obesity Agents/adverse effects , Benzofurans/adverse effects , Liver/drug effects , Liver/metabolism , Adenine Nucleotides/metabolism , Alanine/metabolism , Animals , Fatty Acids/metabolism , Fructose/metabolism , Glucose/metabolism , Glycogen/metabolism , Glycolysis/drug effects , Lactic Acid/metabolism , Male , Rats , Rats, Wistar
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