Flavonoid antioxidants: rate constants for reactions with oxygen radicals

Protective Effects of Aspirin Supplemented With Quercetin in L-NAME-Induced Preeclampsia-Like Rats

Aspirin supplemented with quercetin was reported to enhance the therapeutic effects of aspirin in a rat model of preeclampsia. In this study, the underlying mechanisms were further explored. Preeclampsia was induced by L-NAME (50 mg/kg/day) via oral gavage from gestation day (GD)14 to GD19. Aspirin (1.5 mg/kg/day) administration was performed using aspirin mixed with rodent dough from GD0 to GD19. The administration of quercetin (2 mg/kg/day) was performed by intraperitoneal infusion from GD0 to GD19. Protein levels were evaluated using ELISA or Western blot, and microRNA (miRNA) level was evaluated by RT-PCR. Aspirin supplemented with quercetin ameliorated the increase of systolic blood pressure (SBP), proteinuria, tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) levels, and improved the pregnancy outcomes in preeclampsia rats. Aspirin supplemented with quercetin inhibited miR-155 expression in preeclampsia rats. The decreased miR-155 level in placenta further increased the protein level of SOCS1 and inhibited the phosphorylation of p65. In this study, we demonstrated that aspirin supplemented with quercetin enhanced the effects of aspirin for the treatment of preeclampsia.

An Update of Kaempferol Protection against Brain Damage Induced by Ischemia-Reperfusion and by 3-Nitropropionic Acid

Kaempferol, a flavonoid present in many food products, has chemical and cellular antioxidant properties that are beneficial for protection against the oxidative stress caused by reactive oxygen and nitrogen species. Kaempferol administration to model experimental animals can provide extensive protection against brain damage of the striatum and proximal cortical areas induced by transient brain cerebral ischemic stroke and by 3-nitropropionic acid. This article is an updated review of the molecular and cellular mechanisms of protection by kaempferol administration against brain damage induced by these insults, integrated with an overview of the contributions of the work performed in our laboratories during the past years. Kaempferol administration at doses that prevent neurological dysfunctions inhibit the critical molecular events that underlie the initial and delayed brain damage induced by ischemic stroke and by 3-nitropropionic acid. It is highlighted that the protection afforded by kaempferol against the initial mitochondrial dysfunction can largely account for its protection against the reported delayed spreading of brain damage, which can develop from many hours to several days. This allows us to conclude that kaempferol administration can be beneficial not only in preventive treatments, but also in post-insult therapeutic treatments.

Arbuscular Mycorrhizal Symbiosis Improves Ex Vitro Acclimatization of Sugarcane Plantlets (Saccharum spp.) under Drought Stress Conditions

The symbiotic associations between arbuscular mycorrhizal fungi (AMF) and plants can induce drought stress tolerance. In this study, we evaluated the effect of Glomus intraradices, a mycorrhizal fungus, on the ex vitro development and survival of sugarcane plantlets subjected to drought stress during the acclimatization stage of micropropagation. In vitro obtained sugarcane plantlets (Saccharum spp. cv Mex 69-290) were inoculated with different doses of G. intraradices (0, 100, and 200 spores per plantlet) during greenhouse acclimatization. Sixty days after inoculation, plantlets were temporarily subjected to drought stress. We evaluated the survival rate, total chlorophyll, total protein, carotenoids, proline, betaine glycine, soluble phenolic content, and antioxidant capacity every 3 days for 12 days. Symbiotic interaction was characterized by microscopy. Our results showed that the survival rate of inoculated plants was higher in 45% than the treatment without mycorrhizae. Total chlorophyll, protein, proline, betaine glycine content, and antioxidant capacity were increased in AMF inoculated plants. The soluble phenolic content was higher in non-inoculated plants than the treatment with mycorrhizae during the drought stress period. Microscopy showed the symbiotic relationship between plant and AMF. The early inoculation of 100 spores of G. intraradices per sugarcane plantlet during the acclimatization stage could represent a preconditioning advantage before transplanting into the field and establishing basic seedbeds.

Mitochondrial bioenergetics and redox dysfunction in nephrotoxicity induced by pyrethroid permethrin are ameliorated by flavonoid-rich fraction

The present study was designed to evaluate in vitro and in vivo the potential anti-inflammatory and nephroprotective potential of ethyl acetate fraction extracted from Fumaria officinalis (EAF) against permethrin (PER). Male wistar rats were treated daily by gavage during 7 days as follows: group C: negative control rats received 2 mL/kg bw of corn oil, group EAF: positive control rats received EAF at a dose of 200 mg/kg bw dissolved in water, group PER: rats received PER at a dose of 34.05 mg/kg bw and group (PER + EAF): rats received PER (34.05 mg/kg bw) and EAF (200 mg/kg bw). In vitro study showed the ability of EAF to inhibit protein denaturation and heat-induced hemolysis confirming its anti-inflammatory activity. In vivo, PER treatment decreased calcium (Ca) and phosphorus (P) levels and increased lactate dehydrogenase (LDH) activity in plasma. It induced oxidative stress objectified by an increase in the lipid peroxidation and protein oxidation and a perturbation of antioxidant system in kidney and mitochondria. The activities of NADH-ubiquinone reductase, ubiquinol-cytochrome C reductase and cytochrome C oxidase activities were reduced. These alterations were confirmed by histopathological studies. Co-treatment with EAF improved the antioxidant status and mitochondrial bioenergetics. The nephroprotective effects of EAF could be attributed to its modulation of detoxification enzymes and/or free radical scavenging actions.

Arbuscular Mycorrhizal Fungi Induce Tolerance to Salinity Stress in Taro Plantlets (Colocasia esculenta L. Schott) during Acclimatization

Soil salinity is a problem that affects soil fertility and threatens agri-food crop production worldwide. Biotechnology, through plant micropropagation and the use of biofertilizers such as arbuscular mycorrhizal fungi (AMF), is an alternative to increase productivity and induce tolerance to salinity stress in different crops. This study aimed to evaluate the effect of different doses of the fungus Glomus intraradices on the ex vitro development of taro (Colocasia esculenta L. Schott cv. Criolla) plantlets under salinity stress during the acclimatization stage. In vitro-obtained C. esculenta plantlets were inoculated at different doses (0, 100, and 200 spores per plantlet) of G. intraradices during acclimatization. At 60 d of acclimatization in the greenhouse, plantlets were exposed to 100 mM NaCl salinity stress for 10 d. After the stress period, plantlet development, colonization percentage, and biomass were evaluated. In addition, the content of chlorophyll, carotenoids, proteins, proline, glycine-betaine, soluble phenols, and antioxidant capacity were quantified. The results showed differences in the developmental, physiological, and biochemical variables evaluated; however, no changes in total protein content were observed. Spore colonization showed that the symbiotic association has positive effects on the development of plantlets with or without salinity stress. This symbiotic interaction contributes to salinity stress tolerance in C. esculenta plantlets. The early application of AMF in in vitro-obtained taro plantlets is an alternative to increase or maintain the productivity of this crop in saline soils.

Epicatechin ameliorative effects on methotrexate-induced hepatotoxicity in mice

BACKGROUND

Due to the fact that methotrexate is widely used both as an immunosuppressive drug and as a chemotherapy agent, many studies are needed to reduce the side effects of this drug on non-target organs.

PURPOSE

This study was designed to investigate the effects of epicatechin (Epi) on MTX (methotrexate)-induced hepatotoxicity in mice.

RESEARCH DESIGN

After 1 week for adaptation, we randomly divided 42 male Naval Medical Research Institute mice into six groups: (I) control; (II) Epi (100 mg/kg, po); (III) MTX (20 mg/kg, i.p.) on the fifth day; and (IV, V, and VI) Epi (25, 50, and 100 mg/kg, po) + MTX (20 mg/kg, i.p.) on the fifth day. At day 10, the mice were sacrificed and serum factors, oxidative stress markers, and inflammatory cytokines were measured.

RESULTS

MTX increased activity level of serum enzymes (alanine aminotransferase and aspartate aminotransferase), lipid peroxidation marker (malondialdehyde), and inflammatory factors including interleukin-1 beta, tumor necrosis factor-alpha, and nitric oxide. Furthermore, MTX decreased glutathione level and activity level of catalase, superoxide dismutase, and glutathione peroxidase. Epi was able to reduce the destructive effects of oxidative/antioxidant system imbalance and inflammatory reactions and also histopathological damage in MTX intoxicated mice. Epi pretreatment reduced liver dysfunction by improving the antioxidant defense system, anti-inflammatory effects, and alleviation of histopathological damage in MTX hepatotoxicity.

CONCLUSIONS

Accordingly, Epi can be used as a therapeutic agent in hepatotoxicity associated with MTX chemotherapy.

Potential of natural products in osteosarcoma treatment: Focus on molecular mechanisms

Osteosarcoma is the most frequent type of bone cancer found in children and adolescents, and commonly arises in the metaphyseal region of tubular long bones. Standard therapeutic approaches, such as surgery, chemotherapy, and radiation therapy, are used in the management of osteosarcoma. In recent years, the mortality rate of osteosarcoma has decreased due to advances in treatment methods. Today, the scientific community is investigating the use of different naturally derived active principles against various types of cancer. Natural bioactive compounds can function against cancer cells in two ways. Firstly they can act as classical cytotoxic compounds by non-specifically affecting macromolecules, such as DNA, enzymes, and microtubules, which are also expressed in normal proliferating cells, but to a greater extent by cancer cells. Secondly, they can act against oncogenic signal transduction pathways, many of which are activated in cancer cells. Some bioactive plant-derived agents are gaining increasing attention because of their anti-cancer properties. Moreover, some naturally-derived compounds can significantly promote the effectiveness of standard chemotherapy drugs, and in certain cases are able to ameliorate drug-induced adverse effects caused by chemotherapy. In the present review we summarize the effects of various naturally-occurring bioactive compounds against osteosarcoma.

Biosynthesis of zinc oxide nanoparticles using Phoenix dactylifera and their effect on biomass and phytochemical compounds in Juniperus procera

Biosynthesized nanoparticles have played vital role recently, as suggested to be alternative to physical and chemical methods. In this study, biosynthesis of zinc oxide nanoparticles (ZnO NPs) were carried out using leaf extracts of Phoenix dactylifera L. and Zinc nitrate. The effect of ZnO nanoparticles on biomass and biochemical parameters was investigated. Biosynthesized ZnO nanostructure was characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-visible spectrophotometer and Fourier transform infrared spectroscopy (FTIR). Which resulted in spherical shape with size ranging between 16 to 35 nm of Biosynthesized ZnO nanoparticles and UV absorption beak at 370.5 nm with clear peaks of functional groups. The impact of different concentrations (0.0 mg/L, 80 mg/L and 160 mg/L) of biosynthesized ZnO nanoparticles on biomass and bioactive compounds production of Juniperus procera in vitro was investigated. The results showed that, biosynthesized ZnO NPs (80 mg/L and 160 mg/L) concentrations were boosted the growth of J. Procera with significantly compared to non-treated plants in vitro. The highest concentration (160 mg/L) of ZnO NPs was enhanced the growth of plant at beginning period, one month later shoots became yellow and callus turned to be brownish. Moreover, the influence of ZnO NPs on phytochemical compounds in callus of Juniperus procera was examined using GC-MS analysis. The differences among treatments were recoded. Overall, zinc oxide nanoparticles substantially improved the growth of shoots and callus with increasing of biochemical parameters such as chlorophyll a, total phenolic and flavonoids contents, besides the total protein and, SOD, CAT and APX activity. ZnO NPs might be induced some phytochemical compounds as well as inhibit.

STL1, a New AKT Inhibitor, Synergizes with Flavonoid Quercetin in Enhancing Cell Death in A Chronic Lymphocytic Leukemia Cell Line

Using a pharmacophore model based on the experimental structure of AKT-1, we recently identified the compound STL1 (ZINC2429155) as an allosteric inhibitor of AKT-1. STL1, was able to reduce Ser473 phosphorylation, thus inhibiting the PI₃K/AKT pathway. Moreover, we demonstrated that the flavonoid quercetin downregulated the phosphorylated and active form of AKT. However, in this case, quercetin inhibited the PI₃K/AKT pathway by directly binding the kinases CK2 and PI₃K. In the present work, we investigated the antiproliferative effects of the co-treatment quercetin plus STL1 in HG-3 cells, derived from a patient affected by chronic lymphocytic leukemia. Quercetin and STL1 in the mono-treatment maintained the capacity to inhibit AKT phosphorylation on Ser473, but did not significantly reduce cell viability. On the contrary, they activated a protective form of autophagy. When the HG-3 cells were co-treated with quercetin and STL1, their association synergistically (combination index < 1) inhibited cell growth and induced apoptosis. The combined treatment caused the switch from protective to non-protective autophagy. This work demonstrated that cytotoxicity could be enhanced in a drug-resistant cell line by combining the effects of different inhibitors acting in concert on PI₃K and AKT kinases.

Surface refined AuQuercetin nanoconjugate stimulates dermal cell migration: possible implication in wound healing

Refining nutraceutical conjugated metal nanoparticles (NPs) and understanding their interactions with the cellular micro-environment is necessary for their application in nanomedicine. In the present experiment, we studied the effect of quercetin functionalized gold nanoparticles (Au^QurNP) on skin fibroblast and keratinocyte cell migration. Spherical shaped Au^QurNPs of 47 nm in size were formed due to the interaction of hydroxyl and carbonyl groups of quercetin with Au atoms as revealed by incremental algorithm-based analysis. Au^QurNP containing up to 5 μg l⁻¹ of Au with quercetin (5.2 ± 1.6 ng ml⁻¹) was least toxic to fibroblasts. Au^QurNP effectively reduced the generation of intracellular ROS (up to 63%) through free-radical scavenging activity. Au^QurNP also enhanced the rate of migration of fibroblasts (24 h) and keratinocytes (20 h) in artificially created wounds. The rate of migration of the cells towards the wound edge was in the order of Au^QurNP > control > quercetin > AuNP. Au^QurNP also significantly increased the expression of TGFβ1 protein, thereby inducing the downstream SMAD complex (SMAD 2–4). Downregulation of the inhibitory protein SMAD 7 by Au^QurNP helped in the nuclear translocation of SMADs 3 and 4. Collectively, the present in vitro study demonstrates the action of Au^QurNP on the SMAD family and the interconnected molecular mechanism leading to the cell migration process.

Au^Quercetin nano conjugates enhances cell migration via TGFβ1.

Effect of Daily Ingestion of Quercetin-Rich Onion Powder for 12 Weeks on Visceral Fat: A Randomised, Double-Blind, Placebo-Controlled, Parallel-Group Study

Quercetin, which is frequently found in vegetables such as onion, is widely found to have biological activities such as visceral fat reduction. Therefore, we performed this randomised double-blind placebo-controlled parallel-group study and analysed the effects of daily intake of quercetin-rich onion on visceral fat for 12 weeks. Seventy healthy Japanese subjects whose body mass index (BMI) was ≥23 and <30 were recruited and randomly assigned to either the quercetin-rich onion group or placebo group. The subjects ingested 9 g of onion powder per day for 12 weeks. We conducted medical interviews, hematological and biological tests; measured body composition and vital signs; and analysed the Food Frequency Questionnaire weeks 0, 4, 8, and 12. Abdominal fat area was measured using computed tomography scanning at weeks 0 and 12. No significant differences in visceral fat area (VFA) were observed between the two groups. However, in subjects whose high-density lipoprotein cholesterol was lower, VFA was significantly lower in the quercetin-rich onion group. In addition, alanine aminotransferase was significantly lower in the quercetin-rich onion group than in the placebo group. Thus, the results suggest that quercetin-rich onion may be beneficial for preventing obesity and improving liver function.

Theoretical Study of the Antioxidant Activity of Quercetin Oxidation Products

It was recently shown that, when tested in cellular systems, quercetin oxidized products (Qox) have significantly better antioxidant activity than quercetin (Q) itself. The main Qox identified in the experiments are either 2,5,7,3',4'-pentahydroxy-3,4-flavandione (Fl) or its tautomer, 2-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxy-3(2H)-benzofuranone (Bf). We have now performed a theoretical evaluation of different physicochemical properties using density functional theory (DFT) calculations on Q and its main Qox species. The most stable structures (for Q and Qox) were identified after a structural search on their potential energy surface. Since proton affinities (PAs) are much lower than the bond dissociation enthalpies (BDEs) of phenolic hydrogens, we consider that direct antioxidant activity in these species is mainly due to the sequential proton loss electron transfer (SPLET) mechanism. Moreover, our kinetic studies, according to transition state theory, show that Q is more favored by this mechanism. However, Qox have lower PAs than Q, suggesting that antioxidant activity by the SPLET mechanism should be a result of a balance between proclivity to transfer protons (which favors Qox) and the reaction kinetics of the conjugated base in the sequential electron transfer mechanism (which favors Q). Therefore, our results support the idea that Q is a better direct antioxidant than its oxidized derivatives due to its kinetically favored SPLET reactions. Moreover, our molecular docking calculations indicate a stabilizing interaction between either Q or Qox and the kelch-like ECH-associated protein-1 (Keap1), in the nuclear factor erythroid 2-related factor 2 (Nrf2)-binding site. This should favor the release of the Nrf2 factor, the master regulator of anti-oxidative responses, promoting the expression of the antioxidant responsive element (ARE)-dependent genes. Interestingly, the computed Keap1-metabolite interaction energy is most favored for the Bf compound, which in turn is the most stable oxidized tautomer, according to their computed energies. These results provide further support for the hypothesis that Qox species may be better indirect antioxidants than Q, reducing reactive oxygen species in animal cells by activating endogenous antioxidants.

The effect of Delphinium denudatum (Jadwar) on fatigue: A randomized double blind placebo-controlled clinical trial

OBJECTIVES

Fatigue is a common problem in modern-day life. The aim of this study was to evaluate the effect of Delphinium denudatum (Jadwar) on fatigue.

METHODS

This study was a randomized double-blind placebo-controlled clinical trial between healthy normal university students. In each group, participants were given one capsule of either WEACURE® (containing 500 mg of Jadwar root powder) or placebo for 15 consecutive days. Multidimensional Fatigue Inventory (MFI) questionnaire was used before and after the intervention to evaluate different aspects of fatigue.

RESULTS

A total number of 64 participants completed the study. Data analysis showed decrease in the scores of all five domains of fatigue in Jadwar group (13.31 ± 3.05-7.75 ± 2.66, 12.31 ± 3.55-7.63 ± 2.62, 12.22 ± 4.26-6.97 ± 2.06, 11.56 ± 4.21 to 7.28 ± 2.37, 12.91 ± 3.09-7.34 ± 2.13 in general fatigue, physical fatigue, reduced activity, reduced motivation, and mental fatigue domains, respectively) which was statistically significant (P value<0.0001). This situation was significantly superior to the placebo group. Prescribed dosage of WEACURE® capsule was well tolerated.

CONCLUSION

As a complementary tonic agent, Jadwar have a potential to reduce fatigue in normal population. However, objective evaluation of its anti-fatigue effect should be further evaluated.

Ameliorative effects of pre-eclampsia by quercetin supplement to aspirin in a rat model induced by L-NAME

As an inflammatory disease, pre-eclampsia is correlated with elevation of pro-inflammatory cytokines and maternal endothelial dysfunction. Aspirin plays an important role in the prevention and therapy of pre-eclampsia. Quercetin is a bioflavonoid which has anti-oxidant and reno-protective abilities. We aimed to figure out the effects of quercetin supplement to aspirin on the therapy against pre-eclampsia. Female pregnant Sprague-Dawley rats were divided into five groups according to the drug treatment. Aspirin [1.5 mg/kg body weight (BW)] or quercetin (2 mg/kg BW) treatment was administered from gestational day (GD) 4 to GD19. Rat model of pre-eclampsia was induced by NG-nitro-Larginine-methyl-ester (L-NAME). In pre-eclampsia rats induced by L-NAME, systolic blood pressures (SBP), proteinuria, malonyldialdehyde (MDA), and inflammatory cytokines levels were decreased by the treatment of quercetin supplement to aspirin. In the uterus, quercetin supplement to aspirin prevented the expression of VEGF and sFlt-1 mRNA. The treatment of quercetin supplement to aspirin rescued the declined survival rate and weight of pups caused by L-NAME-induced pre-eclampsia. Based on our study, compared with the treatment of aspirin alone, quercetin supplement to aspirin enhanced the therapeutic effects of aspirin on pre-eclampsia rats induced by L-NAME.

(+)-Catechin inhibits heart mitochondrial complex I and nitric oxide synthase: functional consequences on membrane potential and hydrogen peroxide production

The aim was to study thein vitroeffect of nM to low μM concentration of (+)-catechin on the enzymatic activities of mitochondrial complex I and mtNOS, as well as the consequences on the membrane potential and H₂O₂production rate.

Genetic diversity among and within Ferula asafoetida H. Karst. populations using molecular and phytochemical markers

Ferula asafoetida is an herbaceous, perennial and monocarpic species of the Apiaceae family with medicinal properties. In this study, the genetic diversity of F. asafetida populations was assessed using SCoT and SRAP molecular markers. Nine SCoT and nine SRAP primer combinations amplified 211 and 194 bands, showing 96.07% and 92.87% of polymorphism, respectively. The dendrograms generated from Jaccard's similarity matrix and the UPGMA method revealed that genetic relationships among the F. asafoetida genotypes were not related to their geographical regions. The analysis also revealed a relatively acceptable differentiation in allele frequencies, illustrating the high genetic diversity and gene flows among the populations. The high percent of diversity among the populations indicated a rich resource of germplasm for breeding programs. Moreover, STRUCTURE analysis showed the high admixture of the studied accessions. According to AMOVA analysis, higher genetic variation occurred within the populations. Total phenolic content was also assessed using the folin-ciocalteu method, observing a relatively extent variety (0.163-0.938 mg TA/g DW) among the populations. In addition, HPLC analysis defined eleven compounds in which p-coumaric and 1,3- caffeoylquinic acids were the most abundant phenolic acids. Finally, Feragheh population possessed the highest TPC (total phenolic content) and gene diversity. Karaj population also exhibited the highest amount of flavonoids and phenolic acids such as kaempferol and p-coumaric acids.

Quercetin-Induced Lifespan Extension in Podospora anserina Requires Methylation of the Flavonoid by the O-Methyltransferase PaMTH1

Quercetin is a flavonoid that is ubiquitously found in vegetables and fruits. Like other flavonoids, it is active in balancing cellular reactive oxygen species (ROS) levels and has a cyto-protective function. Previously, a link between ROS balancing, aging, and the activity of O-methyltransferases was reported in different organisms including the aging model Podospora anserina. Here we describe a role of the S-adenosylmethionine-dependent O-methyltransferase PaMTH1 in quercetin-induced lifespan extension. We found that effects of quercetin treatment depend on the methylation state of the flavonoid. Specifically, we observed that quercetin treatment increases the lifespan of the wild type but not of the PaMth1 deletion mutant. The lifespan increasing effect is not associated with effects of quercetin on mitochondrial respiration or ROS levels but linked to the induction of the PaMth1 gene. Overall, our data demonstrate a novel role of O-methyltransferase in quercetin-induced longevity and identify the underlying pathway as part of a network of longevity assurance pathways with the perspective to intervene into mechanisms of biological aging.

Influence of light quality on growth, secondary metabolites production and antioxidant activity in callus culture of Rhodiola imbricata Edgew

Rhodiola imbricata is a rare medicinal herb well-known for its adaptogenic and antioxidant properties due to the presence of a diverse array of secondary metabolites, including phenylethanoids and phenylpropanoids. These secondary metabolites are generating considerable interest due to their potential applications in pharmaceutical and nutraceutical industries. The present study investigated the influence of light quality on growth, production of industrially important secondary metabolites and antioxidant activity in callus cultures of Rhodiola imbricata. Callus cultures of Rhodiola imbricata were established under different light conditions: 100% red, 100% blue, 100% green, RGB (40% red: 40% green: 20% blue) and 100% white (control). The results showed that the callus cultures grown under red light accumulated maximum amount of biomass (7.43 g/l) on day 21 of culture, as compared to other light conditions. Maximum specific growth rate (0.126 days^-1) and doubling time (132.66 h) was observed in callus cultures grown under red light. Reverse phase-high performance liquid chromatographic (RP-HPLC) analysis revealed that the callus cultures exposed to blue light accumulated maximum amount of Salidroside (3.12 mg/g DW) on day 21 of culture, as compared to other light conditions. UV-Vis spectrophotometric analysis showed that the callus cultures exposed to blue light accumulated maximum amount of total phenolics (11.84 mg CHA/g DW) and total flavonoids (5.53 mg RE/g DW), as compared to other light conditions. Additionally, callus cultures grown under blue light displayed enhanced DPPH free radical scavenging activity (53.50%). Callus cultures grown under different light conditions showed no significant difference in ascorbic acid content (11.05-13.90 mg/g DW) and total antioxidant capacity (27.37-30.17 mg QE/g DW). The correlation analysis showed a positive correlation between total phenolic content and DPPH free radical scavenging activity in callus cultures (r = 0.85). Taken together, these results demonstrate the remarkable potential of light quality on biomass accumulation and production of industrially important secondary metabolites in callus cultures of Rhodiola imbricata. This study will open new avenues and perspectives towards abiotic elicitation strategies for sustainable growth and enhanced production of bioactive compounds in in-vitro cultures of Rhodiola imbricata.

Quercetin Oxidation Paradoxically Enhances its Antioxidant and Cytoprotective Properties

Quercetin oxidation is generally believed to ultimately result in the loss of its antioxidant properties. To test this assertion, quercetin oxidation was induced, and after each of its major metabolites was identified and isolated by HPLC-DAD-ESI-MS/MS, the antioxidant (dichlorodihydrofluorescein oxidation-inhibiting) and cytoprotective (LDH leakage-preventing) properties were evaluated in Hs68 and Caco2 cells exposed to indomethacin. Compared to quercetin, the whole mixture of metabolites (Q_OX) displayed a 20-fold greater potency. After resolution of Q_OX into 12 major peaks, only one (peak 8), identified as 2,5,7,3',4'-pentahydroxy-3,4-flavandione or its 2-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxy-3(2H)-benzofuranone tautomer, could account for the antioxidant and cytoprotective effects afforded Q_OX. Peak 8 exerted such effects at a 50 nM concentration, revealing a potency 200-fold higher than that of quercetin. The effects of peak 8 were seen regardless of whether it was added to the cells 40 min before or simultaneously with the oxygen-reactive species-generating agent, suggesting an intracellular ability to trigger early antioxidant responses. Thus, the present study is the first to reveal that in regard to the intracellular actions of quercetin, attention should be extended toward some of its oxidation products.

Antitumor effect of Quercetin on Y79 retinoblastoma cells via activation of JNK and p38 MAPK pathways

Background

Quercetin (QCT) is a flavonol present in many vegetables, it is proved to show chemo preventive effect against lung, cervical, prostate, breast and colon cancer due to its anti-inflammatory, anti-tumor and anti-oxidant property. Looking into the reported chemo-preventive effect we speculated antitumor activity in retinoblastoma (RB) Y79 cells, we also studied the molecular mechanism for antitumor activity.

Methods

The effect of QCT on Y79 cell viability count was done by cell counting kit, cell cycle distribution, apoptosis studies and mitochondrial membrane potential was evaluated by flow cytometry. Protein expression was done by western blot analysis.

Results

The outcomes of study showed that QCT reduced Y79 cell viability and caused arrest of G1 phase in cell cycle via decreasing the expression levels of cyclin-dependent kinase (CDK)2/6 and cyclin D3 and by increasing the levels of both CDK inhibitor proteins p21 and p27. Apoptosis of Y79 cells mediated by QCT occurred via activation of both caspases-3/-9. Flow cytometry studies showed that QCT caused collapse in mitochondrial membrane potential (ΔΨm) in Y79 cells. Western blot studies confirmed that QCT brought about phosphorylation of c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK). We also established that inhibitors of JNK and p38 MAPK suppressed QCT mediated activation of both caspases-3/-9 and subdued the apoptosis of cancerous Y79 cells.

Conclusion

All the results of the study suggest that QCT induced the apoptosis of Y79 cells via activation of JNK and p38 MAPK pathways, providing a novel treatment approach for human RB.

Identification of a flavonoid C-glycoside as potent antioxidant

Flavonoids have been documented to have good antioxidant activities in vitro. However, reports on the cellular antioxidant activities of flavonoid C-glycosides are very limited. In this work, an apigenin C-glycoside was purified from Artocarpus heterophyllus by column chromatography and was identified to be 2″-O-β-D-xylosylvitexin by nuclear magnetic resonance spectroscopy. The cellular antioxidant activity and anticancer activity of 2″-O-β-D-xylosylvitexin were evaluated for the first time. The quantitative structure-activity relationship was analysed by molecular modeling. Apigenin presented an unexpected cellular antioxidation behaviour. It had an antioxidant activity at low concentration and a prooxidant activity at high concentration, whereas 2″-O-β-D-xylosylvitexin showed a dose-dependent cellular antioxidant activity. It indicated that C-glycosidation improved the cellular antioxidation performance of apigenin and eliminated the prooxidant effect. The ortho-dihydroxyl at C-3'/C-4' and C-3 hydroxyl in the flavonoid skeleton play important roles in the antioxidation behaviour. The cell proliferation assay revealed a low cytotoxicity of 2″-O-β-D-xylosylvitexin.

Molecular interaction study of flavonoids with human serum albumin using native mass spectrometry and molecular modeling

Noncovalent interactions between proteins and small-molecule ligands widely exist in biological bodies and play significant roles in many physiological and pathological processes. Native mass spectrometry (MS) has emerged as a new powerful tool to study noncovalent interactions by directly analyzing the ligand-protein complexes. In this work, an ultrahigh-resolution native MS method based on a 15-T SolariX XR Fourier transform ion cyclotron resonance mass spectrometer was firstly used to investigate the interaction between human serum albumin (HSA) and flavonoids. Various flavonoids with similar structure were selected to unravel the relationship between the structure of flavonoids and their binding affinity for HSA. It was found that the position of the hydroxyl groups and double bond of flavonoids could influence the noncovalent interaction. Through a competitive experiment between HSA binding site markers and apigenin, the subdomain IIA (site 1) of HSA was determined as the binding site for flavonoids. Moreover, a cooperative allosteric interaction between apigenin and ibuprofen was found from their different HSA binding sites, which was further verified by circular dichroism spectroscopy and molecular docking studies. These results show that native MS is a useful tool to investigate the molecular interaction between a protein and its ligands. Graphical abstract Unravel the relationship between the structure of flavonoids and their binding affinity to HSA by native MS.

Overexpression of snapdragon Delila (Del) gene in tobacco enhances anthocyanin accumulation and abiotic stress tolerance

BACKGROUND

Rosea1 (Ros1) and Delila (Del) co-expression controls anthocyanin accumulation in snapdragon flowers, while their overexpression in tomato strongly induces anthocyanin accumulation. However, little data exist on how Del expression alone influences anthocyanin accumulation.

RESULTS

In tobacco (Nicotiana tabacum 'Xanthi'), Del expression enhanced leaf and flower anthocyanin production through regulating NtCHS, NtCHI, NtF3H, NtDFR, and NtANS transcript levels. Transgenic lines displayed different anthocyanin colors (e.g., pale red: T0-P, red: T0-R, and strong red: T0-S), resulting from varying levels of biosynthetic gene transcripts. Under salt stress, the T2 generation had higher total polyphenol content, radical (DPPH, ABTS) scavenging activities, antioxidant-related gene expression, as well as overall greater salt and drought tolerance than wild type (WT).

CONCLUSION

We propose that Del overexpression elevates transcript levels of anthocyanin biosynthetic and antioxidant-related genes, leading to enhanced anthocyanin production and antioxidant activity. The resultant increase of anthocyanin and antioxidant activity improves abiotic stress tolerance.

Preparation of efficient quercetin delivery system on Zn-modified mesoporous SBA-15 silica carrier

Mesoporous silica material type SBA-15 was modified with different amounts of Zn (2 and 4wt.%) by incipient wetness impregnation method in ethanol. The parent, Zn-modified and quercetin loaded samples, were characterized by XRD, N₂ physisorption, TEM, thermal gravimetric analysis, UV-vis and FT-IR spectroscopies and in vitro release of quercetin at pH5.5 which is typical of dermal formulations. By this loading method anhydrous quercetin was formed on the silica carrier It was found that the different hydrate forms of quercetin (dihydrate, monohydrate, anhydrite) significantly influence the physico-chemical properties of the delivery system. It was found that hydrate forms of quercetin can be differentiated by XRD and by FT-IR spectroscopic methods. Thus, by evaluating the interaction of the drug with the silica carrier the changes due to its hydration state always have to be taken into account. Formation of Zn-quercetin complex was evidenced on zinc modified SBA-15 silica by FT-IR spectroscopy. High quercetin loading capacity (over 40wt.%) could be achieved on the parent and Zn-containing SBA-15 samples. The in-vitro release process at pH=5.5 showed slower quercetin release from Zn-modified SBA-15 samples compared to the parent one. Additionally, the comparative cytotoxic experiments evidenced that quercetin encapsulated in Zn-modified silica carriers has superior antineoplastic potential against HUT-29 cells compared to free drug. Zn-modified SBA-15 silica particles could be promising carriers for dermal delivery of quercetin.

Comparative effects of catechin, epicatechin and N-Ω-nitroarginine on quinolinic acid-induced oxidative stress in rat striatum slices

The aim of this work was to compare the effects of catechin (CAT), epicatechin (EPI) and N-ω-l-nitroarginine (L-NARG) on different endpoints of oxidative stress induced by quinolinic acid (QUIN) in a simple tissue preparation, rat striatal slices - with particular emphasis in the glutathione system - in order to provide revealing information on the antioxidant efficacy of these agents in an excitotoxic model.

METHODS

Rat striatal slices were incubated for 1h in the presence of 100 μM QUIN and/or 85 μM CAT or EPI, or 100 μM L-NARG. Lipid peroxidation (LP) and the levels of reduced and oxidized glutathione (GSH and GSSG) were determined.

RESULTS

The three agents tested completely blocked the QUIN-induced lipid peroxidation and recovered the QUIN-induced altered GSH/GSSG balance. No statistical differences were detected among the protective effects exerted by these antioxidants, suggesting similar efficacy and common antioxidant mechanisms. The antioxidant properties exhibited by these molecules on the excitotoxic model tested herein support an active role of glutathione and prompt their use as therapeutic tools in models of neurodegenerative disorders.

Application of Bioactive Quercetin in Oncotherapy: From Nutrition to Nanomedicine

Phytochemicals as dietary constituents are being explored for their cancer preventive properties. Quercetin is a major constituent of various dietary products and recently its anti-cancer potential has been extensively explored, revealing its anti-proliferative effect on different cancer cell lines, both in vitro and in vivo. Quercetin is known to have modulatory effects on cell apoptosis, migration and growth via various signaling pathways. Though, quercetin possesses great medicinal value, its applications as a therapeutic drug are limited. Problems like low oral bioavailability and poor aqueous solubility make quercetin an unreliable candidate for therapeutic purposes. Additionally, the rapid gastrointestinal digestion of quercetin is also a major barrier for its clinical translation. Hence, to overcome these disadvantages quercetin-based nanoformulations are being considered in recent times. Nanoformulations of quercetin have shown promising results in its uptake by the epithelial system as well as enhanced delivery to the target site. Herein we have tried to summarize various methods utilized for nanofabrication of quercetin formulations and for stable and sustained delivery of quercetin. We have also highlighted the various desirable measures for its use as a promising onco-therapeutic agent.

Quercetin: A flavonol with multifaceted therapeutic applications?

Great interest is currently centered on the biologic activities of quercetin a polyphenol belonging to the class of flavonoids, natural products well known for their beneficial effects on health, long before their biochemical characterization. In particular, quercetin is categorized as a flavonol, one of the five subclasses of flavonoid compounds. Although flavonoids occur as either glycosides (with attached glycosyl groups) or as aglycones, most altogether of the dietary intake concerning quercetin is in the glycoside form. Following chewing, digestion, and absorption sugar moieties can be released from quercetin glycosides. Several organs contribute to quercetin metabolism, including the small intestine, the kidneys, the large intestine, and the liver, giving rise to glucuronidated, methylated, and sulfated forms of quercetin; moreover, free quercetin (such as aglycone) is also found in plasma. Quercetin is now largely utilized as a nutritional supplement and as a phytochemical remedy for a variety of diseases like diabetes/obesity and circulatory dysfunction, including inflammation as well as mood disorders. Owing to its basic chemical structure themost obvious feature of quercetin is its strong antioxidant activity which potentially enables it to quench free radicals from forming resonance-stabilized phenoxyl radicals. In this review the molecular, cellular, and functional bases of therapy will be emphasized taking strictly into account data appearing in the peer-reviewed literature and summarizing the main therapeutic applications of quercetin; furthermore, the drug metabolism and the main drug interaction as well as the potential toxicity will be also spotlighted.

EGCG prevents tryptophan oxidation of cataractous ocular lens human γ-crystallin in presence of H2O2

Disruption of the short range order of proteins present in the ocular lens leads to cataract resulting in a loss of transparency. Human γ-crystallin (HGC), a water soluble protein present in the lens is known to aggregate with aging. A modified form of HGC (HGC(c)) was isolated from cataractous human ocular lens extract and the number of Trp residues that undergo oxidation was determined. The extent of oxidized Trp (N-formyl kynurenine) in HGC due to cataract formation was determined, primarily using fluorescence spectroscopy. The ability of (-)-epigallocatechin gallate (EGCG) to retain its antioxidant effect even in the presence of H2O2 was investigated. This was monitored by its ability to prevent the modification of intact Trp residues in HGC(c) isolated from cataractous human eye lens. Significant Trp fluorescence quenching occurs on interaction of the green tea component, EGCG with HGC(c) accompanied by a red shift. Docking studies were employed to substantiate the experimental results. As eye lens proteins are prone to oxidative stress it is essential that a clear understanding of the effects of the components generated in vivo vis-à-vis the antioxidant effects of natural polyphenols be obtained.

Salt stress mitigation by seed priming with UV-C in lettuce plants: growth, antioxidant activity and phenolic compounds

Seeds of Lactuca sativa L. 'Romaine' were subjected to priming treatments with UV-C radiation at 0.85 or 3.42 kJ m(-2). Seedlings obtained from both primed (Pr) and non-primed (NPr) seeds were grown in an hydroponic culture system supplemented with 0 (control) or 100 mM NaCl. After 21 days of NaCl treatment, root and leaf biomass, root lengths, leaf numbers, and leaf surface area were measured. Ions (Na(+) and K(+)) accumulation was determined in roots and leaves. Total phenolic compound and flavonoid concentrations, as well as antioxidant and antiradical activities were measured in L. sativa leaves. Salt stress resulted in a lower increase in fresh weight of roots and leaves, which was more pronounced in roots than in leaves, due to reduced root elongation, leaf number and leaf expansion, as well as leaf thickness. The lower increase in fresh weight was accompanied by a restriction in tissue hydration and K(+) ion uptake, as well as an increase in Na(+) ion concentrations in all organs. These effects were mitigated in plants from the UV-C primed seeds. The mitigating effect of UV-C was more pronounced at 0.85 than at 3.42 kJ m(-2). Salt stress also resulted in an increase in total phenolic compounds and flavonoid concentrations and in the total antioxidant capacity in leaves. The highest diphenylpicrylhydrazyl radical (DPPH) scavenging activity was found in the leaves of plants from both Pr seeds. Our results suggest that plants grown from seed primed by exposure to moderate UV-C radiation exhibited a higher tolerance to salinity stress.

Osteogenic differentiation of adipose-derived stem cells promoted by quercetin

OBJECTIVES

The present study aimed to investigate overall effect of quercetin on proliferation and osteogenic differentiation of mouse adipose stem cells (mASCs) in vitro.

MATERIALS AND METHODS

Mouse adipose stem cells were isolated from subcutaneous fat pads and induced into the osteogenic lineage. Effects of quercetin on cell proliferation were assessed using MTT assay. Then they were treated by quercetin for 3, 7 and 11 days in a range of concentrations. Finally, effects of quercetin on osteogenic differentiation of mASCs were analysed by real-time PCR.

RESULTS

Data of MTT assay showed that quercetin did not enhance mASC proliferation in a dose-dependent or time-dependent manner. Results of qPCR indicated that quercetin promoted expressions of Osx, Runx2, BMP-2, Col-1, OPN and OCN at the mRNA level in the presence of osteo-induction medium.

CONCLUSIONS

Our data demonstrated that quercetin was not active in terms of enhancing mASCs proliferation; however, it increased osteogenesis of mASCs by up-regulation of genes including Osx, Runx2, BMP-2, Col-1, OPN and OCN.

Synthetic or food-derived vitamin C--are they equally bioavailable?

Vitamin C (ascorbate) is an essential water-soluble micronutrient in humans and is obtained through the diet, primarily from fruits and vegetables. In vivo, vitamin C acts as a cofactor for numerous biosynthetic enzymes required for the synthesis of amino acid-derived macromolecules, neurotransmitters, and neuropeptide hormones, and is also a cofactor for various hydroxylases involved in the regulation of gene transcription and epigenetics. Vitamin C was first chemically synthesized in the early 1930s and since then researchers have been investigating the comparative bioavailability of synthetic versus natural, food-derived vitamin C. Although synthetic and food-derived vitamin C is chemically identical, fruit and vegetables are rich in numerous nutrients and phytochemicals which may influence its bioavailability. The physiological interactions of vitamin C with various bioflavonoids have been the most intensively studied to date. Here, we review animal and human studies, comprising both pharmacokinetic and steady-state designs, which have been carried out to investigate the comparative bioavailability of synthetic and food-derived vitamin C, or vitamin C in the presence of isolated bioflavonoids. Overall, a majority of animal studies have shown differences in the comparative bioavailability of synthetic versus natural vitamin C, although the results varied depending on the animal model, study design and body compartments measured. In contrast, all steady state comparative bioavailability studies in humans have shown no differences between synthetic and natural vitamin C, regardless of the subject population, study design or intervention used. Some pharmacokinetic studies in humans have shown transient and small comparative differences between synthetic and natural vitamin C, although these differences are likely to have minimal physiological impact. Study design issues and future research directions are discussed.

Influence of arbuscular mycorrhiza on the growth and antioxidative activity in cyclamen under heat stress

The influence of the arbuscular mycorrhizal (AM) fungus, Glomus fasciculatum, on the growth, heat stress responses and the antioxidative activity in cyclamen (Cyclamen persicum Mill.) plants was studied. Cyclamen plants (inoculated or not with the AM fungus) were placed in a commercial potting media at 17-20 °C for 12 weeks in a greenhouse and subsequently subjected to two temperature conditions in a growth chamber. Initially, plants were grown at 20 °C for 4 weeks as a no heat stress (HS-) condition, followed by 30 °C for another 4 weeks as a heat stress (HS+) condition. Different morphological and physiological growth parameters were compared between G. fasciculatum-inoculated and noninoculated plants. The mycorrhizal symbiosis markedly enhanced biomass production and HS + responses in plants compared to that in the controls. A severe rate of leaf browning (80-100%) was observed in control plants, whereas the mycorrhizal plants showed a minimum rate of leaf browning under HS + conditions. The mycorrhizal plants showed an increase activity of antioxidative enzymes such as superoxide dismutase and ascorbate peroxidase, as well as an increase in ascorbic acid and polyphenol contents. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity also showed a greater response in mycorrhizal plants than in the control plants under each temperature condition. The results indicate that in cyclamen plants, AM fungal colonisation alleviated heat stress damage through an increased antioxidative activity and that the mycorrhizal symbiosis strongly enhanced temperature stress tolerance which promoted plant growth and increased the host biomass under heat stress.

Formulation optimization and topical delivery of quercetin from solid lipid based nanosystems

The presence of large amounts of reactive oxygen species (ROS) leads to oxidative stress that can damage cell membranes, lead to DNA breakage and cause inactivation of free radical scavenger enzymes, eventually resulting in skin damage. Quercetin is a natural flavonoid that has been shown to have the highest anti-radical activity, along with the ability to act as a scavenger of free radicals and an inhibitor of lipid peroxidation. In this research work, a solvent-free solid lipid based nanosystem has been developed and evaluated for topical delivery of quercetin. Systematic screening of the formulation and process parameters led to the development of a solid lipid (glyceryl dibehenate) based nanosystem using a probe ultrasonication method. The selected variant demonstrated good physical stability for up to 8 weeks at 2-8 °C. Transmission electron microscopy (TEM) images showed spherical particles in the nanometer range. In vitro release studies showed biphasic release of quercetin from the SLN formulation, with an initial burst release followed by prolonged release for up to 24h. In vitro permeation studies using full thickness human skin showed higher amounts of quercetin to be localized within the skin compared to a control formulation with particles in the micrometer range. Such accumulation of quercetin in the skin is highly desirable since the efficacy of quercetin in delaying ultra-violet radiation mediated cell damage and eventual necrosis mainly occurs in the epidermis.

Quercetin improves hepatic fibrosis reducing hepatic stellate cells and regulating pro-fibrogenic/anti-fibrogenic molecules balance

BACKGROUND AND AIM

Development of hepatic cirrhosis involves oxidative stress, inflammation, hepatic stellate cells (HSC)s activation and fibrosis. On the other hand, quercetin, a natural flavonoid is a potent antioxidant and activator of superoxide dismutase and catalase. The aim was to determinate the effect of quercetin on HSCs and development of hepatic fibrosis.

METHODS

Wistar male rats were chronically intoxicated with CCl(4) for 8 weeks and concomitantly treated with 100 mg/kg per day of quercetin. Oxidative state, inflammation and fibrosis were evaluated. Effect of quercetin on apoptosis of HSC was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling reaction.

RESULTS

Sixty percent of reduction in fibrosis index was observed with quercetin treatment compared with control animals. Considerable reduction on hepatic enzymes was detected in the quercetin group. Expression of pro-fibrotic genes (transforming growth factor-β [TGF-β], Collagen 1α [Col-1α] and connective tissue growth factor [CTGF]) were decreased by quercetin. Quercetin increased gene expression and functional activity of antioxidant enzymes superoxide dismutase and catalase. Inflammatory index was highly reduced as determined by H-E staining and pro-inflammatory cytokines expression and nuclear factor-κB activation were also inhibited. A significant reduction of 65% on activated HSC number was detected when rats were treated with quercetin. Quercetin also induced activation of matrix metalloproteinases MMP2 and MMP9 contributing to decreased index of fibrosis.

CONCLUSIONS

Treatment with quercetin reduces oxidation and inflammation and also prevents liver fibrosis, through induction of HSC apoptosis and activation of MMPs.

Spectrophotometric studies of the reaction of quercetin with peroxynitrite at different pH

Peroxynitrite (ONOOH/ONOO-) which is formed in vivo under oxidative stress is a strong oxidizing and nitrating agent. It has been reported that several flavonoids, including quercetin, inhibit the peroxynitrite-induced oxidation and/or nitration of several molecules tested; however, the mechanism of their protective action against peroxynitrite is not univocally resolved. The kinetics of the reaction of quercetin with peroxynitrite was studied by stopped-flow as well as by conventional spectrophotometry under acidic, neutral and alkaline pH. The obtained results show that the protective mechanism of quercetin against peroxynitrite toxicity cannot be explained by direct scavenging of peroxynitrite. We propose that quercetin acts via scavenging intermediate radical products of peroxynitrite decomposition (it is an excellent scavenger of ·NO2) and/or via reduction of target radicals formed in the reaction with peroxynitrite.

Preparation and evaluation of quercetin-loaded lecithin-chitosan nanoparticles for topical delivery

BACKGROUND

The purpose of this study was to investigate lecithin-chitosan nanoparticles as a topical delivery system for quercetin.

METHODS

Tocopheryl propylene glycol succinate was chosen to be the surfactant for the nanosystem. The mean particle size of the nanoparticles was 95.3 nm, and the entrapment efficiency and drug loading for quercetin were 48.5% and 2.45%, respectively. Topical delivery in vitro and in vivo of the quercetin-loaded nanoparticles was evaluated using quercetin propylene glycol solution as the control.

RESULTS

Compared with quercetin solution, the quercetin-loaded nanoparticles showed higher permeation ability, and significantly increased accumulation of quercetin in the skin, especially in the epidermis. Microstructure observation of the skin surface after administration indicated that the interaction between ingredients of the nanoparticles and the skin surface markedly changed the morphology of the stratum corneum and disrupted the corneocyte layers, thus facilitating the permeation and accumulation of quercetin in skin.

CONCLUSION

Lecithin-chitosan nanoparticles are a promising carrier for topical delivery of quercetin.

Opposite effects of statins on mitochondria of cardiac and skeletal muscles: a 'mitohormesis' mechanism involving reactive oxygen species and PGC-1

AIMS

Statins protect against cardiovascular-related mortality but induce skeletal muscle toxicity. To investigate mechanisms of statins, we tested the hypothesis that statins optimized cardiac mitochondrial function but impaired vulnerable skeletal muscle by inducing different level of reactive oxygen species (ROS).

METHODS AND RESULTS

In atrium of patients treated with statins, ROS production was decreased and oxidative capacities were enhanced together with an extensive augmentation of mRNAs expression of peroxisome proliferator-activated receptor gamma co-activator (PGC-1) family. However, in deltoid biopsies from patients with statin-induced muscular myopathy, oxidative capacities were decreased together with ROS increase and a collapse of PGC-1 mRNA expression. Several animal and cell culture experiments were conducted and showed by using ROS scavengers that ROS production was the triggering factor responsible of atorvastatin-induced activation of mitochondrial biogenesis pathway and improvement of antioxidant capacities in heart. Conversely, in skeletal muscle, the large augmentation of ROS production following treatment induced mitochondrial impairments, and reduced mitochondrial biogenesis mechanisms. Quercetin, an antioxidant molecule, was able to counteract skeletal muscle deleterious effects of atorvastatin in rat.

CONCLUSION

Our findings identify statins as a new activating factor of cardiac mitochondrial biogenesis and antioxidant capacities, and suggest the importance of ROS/PGC-1 signalling pathway as a key element in regulation of mitochondrial function in cardiac as well as skeletal muscles.