Naringin, a grapefruit flavanone, protects V79 cells against the bleomycin-induced genotoxicity and decline in survival

Whole Genome Analysis and Assessment of the Metabolic Potential of Streptomyces carpaticus SCPM-O-B-9993, a Promising Phytostimulant and Antiviral Agent

This work aimed to study the genome organization and the metabolic potential of Streptomyces carpaticus strain SCPM-O-B-9993, a promising plant-protecting and plant-stimulating strain isolated from brown semi-desert soils with very high salinity. The strain genome contains a linear chromosome 5,968,715 bp long and has no plasmids. The genome contains 5331 coding sequences among which 2139 (40.1%) are functionally annotated. Biosynthetic gene clusters (BGCs) of secondary metabolites exhibiting antimicrobial properties (ohmyungsamycin, pellasoren, naringenin, and ansamycin) were identified in the genome. The most efficient period of SCPM-O-B-9993 strain cultivation was 72 h: during this period, the culture went from the exponential to the stationary growth phase as well as exhibited excellent phytostimulatory properties and antiviral activity against the cucumber mosaic virus in tomatoes under laboratory conditions. The Streptomyces carpaticus SCPM-OB-9993 strain is a biotechnologically promising producer of secondary metabolites exhibiting antiviral and phytostimulatory properties.

Modulatory effect of myricitrin against chromosome instability and cytostasis induced by bleomycin and oxaliplatin in CHO-K1 cells

Myricitrin (MYR), a flavonol consumed in the leaves and fruits of plants of the Myrtaceae family, presents anti-proliferative, anti-inflammatory, anti-diabetic, and antioxidant properties in humans. However, there are few studies regarding the cyto-genotoxicity and the chemopreventive potential of MYR. Using the in vitro Micronucleus test, the cytostasis, mutagenicity, and modulatory effect of MYR in CHO-K1 cells were assessed. The concentrations of 39 and 78 µg/mL (p < 0.001.) of MYR decrease the cytokinesis-block proliferation index (CBPI) in the short exposure treatment (4 h), while in the extended treatment (24 h), concentrations of 4.8, 9.7, 19.5, 39 and 78 µg/mL (p < 0.001.) decreased the CBPI. MYR associated with oxaliplatin decreased CBPI at all tested concentrations in the pre-(p < 0.001) and post-treatments (p < 0.001), but there was no decrease when associated with bleomycin. As for chromosome instability, MYR did not increase the frequency of micronuclei (MNi), nucleoplasmic bridges (NPBs), or nuclear buds (NBUDs) in the 4 h exposure time, however, in the 24 h treatment, MYR increased the frequency of MNi and NPBs at concentration 19.5 µg/mL (p < 0.001). As for the modulatory effect, MYR associated with bleomycin decreased the frequency of MNi, NPBs, and NBUDs at all concentrations in the pretreatment (MNi and NPBs p < 0.001, NBUDs p < 0.05) and simultaneously (MNi, NPBs and NBUDs p < 0.001). When associated with oxaliplatin, the simultaneous treatment decreased the frequency of MNi (p < 0.001) and NBUDs (p < 0.01) at all concentrations, however, in the post-treatment, MYR increased MNi (p < 0.001) and NPBs p < 0.05) in CHO-K1 cells, when compared to oxaliplatin alone. The results demonstrated that MYR could modulate the mutagenic and cytostatic actions of bleomycin and oxaliplatin, demonstrating distinct behaviors, depending on the mechanism of action of the chemotherapeutic agent.

Effects of 2',4'-Dihydroxy-6'-methoxy-3',5'-dimethylchalcone from Syzygium nervosum Seeds on Antiproliferative, DNA Damage, Cell Cycle Arrest, and Apoptosis in Human Cervical Cancer Cell Lines

2',4'-Dihydroxy-6'-methoxy-3',5'-dimethylchalcone (DMC), a natural product derived from Syzygium nervosum A. Cunn. ex DC., was investigated for its inhibitory activities against various cancer cell lines. In this work, we investigated the effects of DMC and available anticervical cancer drugs (5-fluorouracil, cisplatin, and doxorubicin) on three human cervical cancer cell lines (C-33A, HeLa, and SiHa). DMC displayed antiproliferative cervical cancer activity in C-33A, HeLa, and SiHa cells, with IC50 values of 15.76 ± 1.49, 10.05 ± 0.22, and 18.31 ± 3.10 µM, respectively. DMC presented higher antiproliferative cancer activity in HeLa cells; therefore, we further investigated DMC-induced apoptosis in this cell line, including DNA damage, cell cycle arrest, and apoptosis assays. As a potential anticancer agent, DMC treatment increased DNA damage in cancer cells, observed through fluorescence inverted microscopy and a comet assay. The cell cycle assay showed an increased number of cells in the G0/G1 phase following DMC treatment. Furthermore, DMC treatment-induced apoptosis cell death was approximately three- to four-fold higher compared to the untreated group. Here, DMC represented a compound-induced apoptosis for cell death in the HeLa cervical cancer cell line. Our findings suggest that DMC, a phytochemical agent, is a potential candidate for antiproliferative cervical cancer drug development.

Comparative Molecular Mechanisms of Biosynthesis of Naringenin and Related Chalcones in Actinobacteria and Plants: Relevance for the Obtention of Potent Bioactive Metabolites

Naringenin and its glycosylated derivative naringin are flavonoids that are synthesized by the phenylpropanoid pathway in plants. We found that naringenin is also formed by the actinobacterium Streptomyces clavuligerus, a well-known microorganism used to industrially produce clavulanic acid. The production of naringenin in S. clavuligerus involves a chalcone synthase that uses p-coumaric as a starter unit and a P₄₅₀ monoxygenase, encoded by two adjacent genes (ncs-ncyP). The p-coumaric acid starter unit is formed by a tyrosine ammonia lyase encoded by an unlinked, tal, gene. Deletion and complementation studies demonstrate that these three genes are required for biosynthesis of naringenin in S. clavuligerus. Other actinobacteria chalcone synthases use caffeic acid, ferulic acid, sinapic acid or benzoic acid as starter units in the formation of different antibiotics and antitumor agents. The biosynthesis of naringenin is restricted to a few Streptomycess species and the encoding gene cluster is present also in some Saccharotrix and Kitasatospora species. Phylogenetic comparison of S. clavuligerus naringenin chalcone synthase with homologous proteins of other actinobacteria reveal that this protein is closely related to chalcone synthases that use malonyl-CoA as a starter unit for the formation of red-brown pigment. The function of the core enzymes in the pathway, such as the chalcone synthase and the tyrosine ammonia lyase, is conserved in plants and actinobacteria. However, S. clavuligerus use a P₄₅₀ monooxygenase proposed to complete the cyclization step of the naringenin chalcone, whereas this reaction in plants is performed by a chalcone isomerase. Comparison of the plant and S. clavuligerus chalcone synthases indicates that they have not been transmitted between these organisms by a recent horizontal gene transfer phenomenon. We provide a comprehensive view of the molecular genetics and biochemistry of chalcone synthases and their impact on the development of antibacterial and antitumor compounds. These advances allow new bioactive compounds to be obtained using combinatorial strategies. In addition, processes of heterologous expression and bioconversion for the production of naringenin and naringenin-derived compounds in yeasts are described.

NF-κB and COX-2 repression with topical application of hesperidin and naringin hydrogels augments repair and regeneration of deep dermal wounds

INTRODUCTION

Wound injury is common and causes serious complications if not treated properly. The moist dressing heals wounds faster than other dressings. Therefore, we sought to study the effect of hesperidin/naringin hydrogel wound dressing or their combinations on the deep dermal wounds in mice.

METHODS

A rectangular full thickness skin flap of 2.5 × 1.5 cm was excised from depilated mice dorsum and the wound was fully covered with 5% hesperidin/5% naringin hydrogel or both in the ratio of 1:1, 2:1, or 1:2, respectively once daily until complete healing of the wound. Data were collected on wound contraction, mean wound healing time, collagen, DNA, and nitric oxide syntheses, glutathione concentration, superoxide dismutase activity, and lipid peroxidation throughout healing. Expression of NF-κB and COX-2 were also estimated in the regenerating granulation tissue using Western blot.

FINDINGS

Dressing of wounds with 5% hesperidin hydrogel led to a higher and early wound contraction and significantly reduced mean wound healing time by 5.7 days than 5% naringin or combination of hesperidin and naringin hydrogels in the ratio of 1:1, 2:1, or 1:2. Hesperidin hydrogel wound dressing caused higher collagen and DNA syntheses than other groups at all times after injury. Glutathione concentration and superoxide dismutase activity increased followed by a decline in lipid peroxidation in regenerating wounds after hesperidin/naringin hydrogel application and a maximum effect was observed for hesperidin alone. The hesperidin/naringin hydrogel suppressed NF-κB and COX-2 expression on days 6 and 12.

CONCLUSIONS

Application of 5% hesperidin hydrogel was more effective than 5% naringin or combination of hesperidin and naringin gels (1:1, 2:1 or 1:2) indicated by a greater wound contraction, reduced mean wound healing time, elevated collagen and DNA syntheses, rise in glutathione concentration, and superoxide dismutase activity followed by reduced lipid peroxidation, and NF-κB, and COX-2 expression.

Dimethoate Induces DNA Damage and Mitochondrial Dysfunction Triggering Apoptosis in Rat Bone-Marrow and Peripheral Blood Cells

Dimethoate (DM) is an organophosphorus (OP) pesticide with wide use in the pest control. Its persistence in crops and soils could possibly cause adverse health consequences in humans as well as other non-target species. Since molecular studies confirming potential genotoxicity of DM have not been previously reported, the acute in vivo toxicological impact was evaluated in Wistar rats. Significant micronuclei induction and metaphase chromosome abnormalities in bone marrow cells exposed to three different DM doses (20, 40 and 60 mg/kg-bw) at multiple treatment durations (24, 48 and 72 h) indicated positive dose response relationship, confirming its genotoxic and cytotoxic potential. Significant mitotic index decrease was seen in dosed animals compared to vehicle control. The study used peripheral blood comet assay, indicating DM-mediated damage to DNA at all exposure levels in a time responsive manner. These assays were found to be an effective, precise, and fast technique with applied value in biomonitoring studies. Cell cycle and apoptosis along with mitochondrial membrane potential (MMP) in flow cytometric analyses confirmed DM exposure decreased MMP, affected the cell cycle, and inflicted DNA damage, which led to cellular apoptosis of leukocytes culminating into immunotoxic effects. The in silico experiments consequently augmented that DM showed acceptable binding energy value for Cyclin A2, suggesting that it could inhibit the cell cycle progression by inhibiting cyclin A2.

Genome-Protecting Compounds as Potential Geroprotectors

Throughout life, organisms are exposed to various exogenous and endogenous factors that cause DNA damages and somatic mutations provoking genomic instability. At a young age, compensatory mechanisms of genome protection are activated to prevent phenotypic and functional changes. However, the increasing stress and age-related deterioration in the functioning of these mechanisms result in damage accumulation, overcoming the functional threshold. This leads to aging and the development of age-related diseases. There are several ways to counteract these changes: 1) prevention of DNA damage through stimulation of antioxidant and detoxification systems, as well as transition metal chelation; 2) regulation of DNA methylation, chromatin structure, non-coding RNA activity and prevention of nuclear architecture alterations; 3) improving DNA damage response and repair; 4) selective removal of damaged non-functional and senescent cells. In the article, we have reviewed data about the effects of various trace elements, vitamins, polyphenols, terpenes, and other phytochemicals, as well as a number of synthetic pharmacological substances in these ways. Most of the compounds demonstrate the geroprotective potential and increase the lifespan in model organisms. However, their genome-protecting effects are non-selective and often are conditioned by hormesis. Consequently, the development of selective drugs targeting genome protection is an advanced direction.

Metformin protects Escherichia coli from bleomycin-induced bactericide via enhanced generation of hydrogen peroxide

Bleomycin is a glycopeptide antibiotic that is widely employed in the therapy of a range of lymphomas and germ cell tumours. But the therapeutic efficacy of bleomycin is limited by development of lung fibrosis. The cytotoxicity of bleomycin is mostly ascribed to mitochondrial DNA (mtDNA) damage, while a protective effect of metformin against bleomycin-induced lung fibrosis results from the inhibition of mitochondrial complex I. Since mitochondria and bacteria have certain similarities in structure and function, we used Escherichia coli for simplification in the present work to investigate the relationship between metformin and bleomycin with apparently opposite effects on mitochondrial DNA damage. Bleomycin lethality to E. coli was ameliorated by metformin treatment accompanying further increase of the level of reactive oxygen species. Catalase but not superoxide dismutases attenuated the protective effect of metformin. Meanwhile, treatment with hydrogen peroxide enhanced the protection, indicating that metformin may protect E. coli from bleomycin-induced bactericide via enhanced generation of hydrogen peroxide. Moreover, silibinin, a hepatoprotective polyphenolic flavonoid attenuates the cytotoxicity of bleomycin to E. coli via enhanced generation of hydrogen peroxide as well. This bacterial model in place of mitochondria can provide us with easier screening for the molecules with capability of reducing the bleomycin side effect.

Involvement of the nitric oxide signaling in modulation of naringin against intranasal manganese and intracerbroventricular β-amyloid induced neurotoxicity in rats

Manganese -induced aggregation of the amyloid-β peptide (Aβ) is a hallmark molecular feature of Alzheimer's disease (AD). The current study was designed to investigate the effects of chronic administration of naringin against β-A_1-42 and manganese induced experimental model. Wistar rats received intracerebroventricular (ICV) β-A_1-42 once, intranasal manganese, naringin and nitric oxide modulators for 21 days and behavioral alterations were assessed. Mitochondrial enzymes, oxidative parameters, TNF-α, β-A_1-42 acetylcholinesterase (AChE) levels and manganese concentration were measured. ICV β-A_1-42 and intranasal manganese treated rats showed a memory deficit and significantly increased in β-A_1-42 level and manganese concentration, mitochondrial oxidative damage, AChE level and inflammatory mediator in the hippocampus and cortex. Chronic administration of naringin (40 and 80 mg/kg) significantly improved memory performance and attenuated the oxidative damage and mitochondrial dysfunction in Aβ with Mn treated rats. In addition, naringin also attenuates the pro-inflammatory cytokines like TNF-α, AChE, Amyloid deposition and Mn concentration. Further, pretreatment of N(G)-Nitro-L-arginine methyl ester (L-NAME) with (5 mg/kg) with lower dose of naringin significantly potentiated its protective effect. These results demonstrate that naringin offers protection against ICV β-A_1-42 and intranasal manganese induced memory dysfunction possibly due to its antioxidant, anti-inflammatory, anti-amyloidogenesis therefore, could have a therapeutic potential in Alzheimer's disease.

Possible neuroprotective mechanisms of action involved in the neurobehavioral property of naringin in mice

Flavonoids are naturally occurring bioactive phytochemical metabolites widely known to prevent and suppress several human diseases, and are important sources of therapeutic compounds from plants. Evidence derived from previous studies suggests that naringin, a neuroactive flavonoid possess functional beneficial neurobehavioral effects including anxiolytic, antidepressant and memory enhancing properties. However, literature search revealed that no studies have been carried out to evaluate the possible biochemical mechanisms involved in the neurobehavioral property of naringin alone following repeated treatment. Hence, this study was designed to evaluate the possible neuro-biochemical mechanisms involved in the neurobehavioral property of naringin following repeated administration in mice. The effects of naringin (2.5, 5 and 10 mg/kg), diazepam (2 mg/kg), imipramine (15 mg/kg) and donepezil (1 mg/kg) or vehicle on neurobehavioral and biochemical effects were evaluated in mice following repeated intraperitoneal injection for 7 consecutive days. Neurobehavioral activities consisting of open-field (locomotor), elevated-plus maze (anxiolytic), forced swim and social interaction (antidepressant and social preference), and Y-maze (memory enhancing) tests were assessed. Thereafter, brains levels of biomarkers of oxidative, nitrosative and cholinergic parameters were determined. Repeated treatment with naringin produced increased locomotor activity, and demonstrated antidepressant-like effects evidenced by decreased immobility time in forced swim test and increased % social preference in the social interaction test relative to controls. Also, naringin induced anxiolytic-like effect and increased cognitive performance in mice. Mechanistically, naringin significantly increased the activities of superoxide dismutase and catalase, and glutathione concentration relative to vehicle-controls. However, naringin significantly decreased malondialdehyde and nitrite contents, and reduced brain acetylcholinesterase activity in mice brains in a significant manner relative to controls. Taken together, these findings suggest that treatment with naringin might be useful to produce functional behavioral effects via mechanisms related to enhancement of cholinergic transmission, antioxidant defense systems, inhibition of lipid peroxidation and nitrosative processes.

DNA and chromosome damage induced by bleomycin in mammalian cells: An update

Bleomycin (BLM) is an antibiotic isolated from Streptomyces verticillus. It has radiomimetic actions on DNA thus it has been widely used in clinical chemotherapy for the treatment of different types of cancer, including head and neck tumors, lymphomas, squamous-cell carcinomas and germ-cell tumors. Because of this, the study of BLM genotoxicity is of practical interest. This antibiotic is an S-independent clastogen and an agent that generates free radicals and induces single- and double-strand breaks in DNA. In the present review, we will summarize our current knowledge concerning the DNA and chromosome damage induced by BLM in mammalian cells, with emphasis on new developments published since 1991.

OptPipe - a pipeline for optimizing metabolic engineering targets

BACKGROUND

We propose OptPipe - a Pipeline for Optimizing Metabolic Engineering Targets, based on a consensus approach. The method generates consensus hypotheses for metabolic engineering applications by combining several optimization solutions obtained from distinct algorithms. The solutions are ranked according to several objectives, such as biomass and target production, by using the rank product tests corrected for multiple comparisons.

RESULTS

OptPipe was applied in a genome-scale model of Corynebacterium glutamicum for maximizing malonyl-CoA, which is a valuable precursor for many phenolic compounds. In vivo experimental validation confirmed increased malonyl-CoA level in case of ΔsdhCAB deletion, as predicted in silico.

CONCLUSIONS

A method was developed to combine the optimization solutions provided by common knockout prediction procedures and rank the suggested mutants according to the expected growth rate, production and a new adaptability measure. The implementation of the pipeline along with the complete documentation is freely available at https://github.com/AndrasHartmann/OptPipe .

Heated naringin mitigate the genotoxicity effect of Mitomycin C in BALB/c mice through enhancing the antioxidant status

A major problem with cancer chemotherapy is its severe toxic effects on non-target tissues. Assessment of natural products for their protective effect against anticancer drugs induced toxicity is gaining importance in cancer biology. The aim of the present study was to evaluate the effect of native and thermal treated naringin on the protective effect against mitomycin C (MMC) induced genotoxicity. The genotoxicity in liver kidney and brain cells isolated from Balb/C mice were evaluated by performing the comet assay. Antioxidant and lipid peroxidation assays were carried out to understand the protective effects of these compounds. The comet assay showed that heated and native naringin were not genotoxic at the tested dose (40 mg/kg b.w) on liver, kidney and brain cells. A significant decrease in DNA damages was observed, at the tested doses (20 mg/kg b.w and 40 mg/kg b.w) suggesting a protective role of these molecules against the genotoxicity induced by mitomycin C on liver, kidney and brain cells. Moreover, administration of MMC (6 mg/kg b.w.) altered the activities of glutathione peroxidase and superoxide dismutase accompanied by a significant increase of lipid peroxidation. Pretreatment of mouse with heated and native naringin before MMC administration significantly raised the glutathione peroxidase and superoxide dismutase activities followed by a reduced MMC-induced lipid peroxidation. Our study demonstrated that heat treatment of naringin preserve activities of native naringin. The genoprotective properties of heated and native naringin against MMC could be attributed to its antioxidant activities and its inhibitory effect on lipid peroxidation.

Naringin protects viscera from ischemia/reperfusion injury by regulating the nitric oxide level in a rat model

We investigated the effects of naringin on small intestine, liver, kidney and lung recovery after ischemia/reperfusion (I/R) injury of the gut. Rats were divided randomly into four groups of eight. Group A was the sham control; group B was ischemic for 2 h; group C was ischemic for 2 h and re-perfused for 2 h (I/R); group D was treated with 50 mg/kg naringin after ischemia, then re-perfused for 2 h. Endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) expressions were detected by immunolabeling. We also measured arginase activity, amounts of nitric oxide (NO) and total protein. iNOS was increased significantly in the small intestine, liver and kidney in group C. iNOS was decreased significantly only in small intestine and lung in group D. eNOS was increased significantly in the small intestine, liver and lung in group C. eNOS was decreased in small intestine, liver and lung in group D; however, eNOS was decreased in the kidney in group C and increased in the kidney in group D. The amount of NO was decreased significantly in all tissues in group D, but arginase activity was decreased in the small intestine and lung, increased in the kidney and remained unchanged in the liver in group D. The total protein increased in the small intestine and liver in group D, but decreased significantly in the kidney and lung in group D. Naringin had significant, salutary effects on the biochemical parameters of I/R by decreasing the NO level, equilibrating iNOS and eNOS expressions, and decreasing arginase activity.

Evidence of Some Natural Products with Antigenotoxic Effects. Part 1: Fruits and Polysaccharides

Cancer is one of the leading causes of deaths worldwide. The agents capable of causing damage to genetic material are known  as genotoxins and, according to their mode of action, are classified into mutagens, carcinogens or teratogens. Genotoxins are  involved in the pathogenesis of several chronic degenerative diseases including hepatic, neurodegenerative and cardiovascular  disorders, diabetes, arthritis, cancer, chronic inflammation and ageing. In recent decades, researchers have found novel bioactive  phytocompounds able to counteract the effects of physical and chemical mutagens. Several  studies  have  shown potential antigenotoxicity in a variety of fruits. In this review (Part 1), we present an overview of research conducted on some fruits (grapefruit, cranberries, pomegranate, guava, pineapple, and mango) which are frequentl consumed by humans, as well as  the  analysis of some phytochemicals extracted from fruits and yeasts which have demonstrated antigenotoxic capacity in various  tests, including the Ames assay, sister chromatid exchange, chromosomal aberrations, micronucleus and comet assay.

Toxicogenetic evaluation of dichlorophene in peripheral blood and in the cells of the immune system using molecular and flow cytometric approaches

Dichlorophene; a halogenated phenolic compound with wide applications as a fungicide, bactericide and antiprotozoan. Dichlorophene spray also has therapeutic use in the disease digital dermatitis. In guinea pigs, a few studies obtained mixed results in dicholorophene sensitization tests. In consideration of the fact, that the mechanism of its genotoxicity has not been adequately elucidated lead to present study assessing the acute in vivo toxicological impact in Rattus norvegicus. A systematic research has been made encompassing the use of molecular and flow cytometric approaches. The study was designed on blood cells for comet assay which revealed dichlorophene induced DNA damage in all exposures understandable in time dependent manner. The feasibility of this assay was also established as an effective, fast and accurate method with a great potential in biomonitoring. Contemporary molecular techniques were further engaged using leukocytes for the cell apoptosis/cycle and mitochondrial membrane potential employing propidium iodide staining and rhodamine 123 respectively. The effect on cell cycle phases and mitochondrial membrane permeability was analyzed through flow cytometry. These indicators exposed that dichlorophene decreased the mitochondrial membrane potential, altered the cell cycle and confirmed the DNA damage leading to apoptosis of the cells of the immune system accountable for immunotoxic effects of dichlorophene on rat leukocytes.

Genotoxicity and immunotoxic effects of 1,2-dichloroethane in Wistar rats

Dichloroethane is widely used as a solvent, degreasing agent and in a variety of commercial products, and is known for being a ubiquitous contaminant in the environment. Important sources principally include the emissions from industrial processes, improper consumption, storage, and disposal methods. In view of the fact that the mechanism of its genotoxicity has not been satisfactorily elucidated, the acute in vivo toxicological impact is assessed in Rattus norvegicus. A systematic investigation has been made involving the use of conventional methods along with molecular and flow cytometric approaches. The micronucleus and chromosomal aberration frequencies were significantly elevated in bone marrow cells exposed to three concentrations at multiple treatment durations indicating positive time- and dose-response relationships. The mitotic index significantly decreased in similar concentrations in contrast to normal control. Separate studies were performed on blood cells for comet assay. It revealed dichloroethane-induced DNA damage in all exposures readily explainable in a dose- and time-dependent manner. Recent molecular techniques were further employed using leukocytes for the cell apoptosis/cycle and mitochondrial membrane potential employing propidium iodide staining and rhodamine-123, respectively. The effect on mitochondrial membrane permeability, cell cycle phases, and the DNA damage was analyzed through flow cytometry. These indicators revealed dichloroethane treatment decreased the mitochondrial membrane potential, affected the cell cycle, and confirmed the DNA damage, leading to apoptosis of the cells of the immune system responsible for immunotoxic effects of dichloroethane on rat leukocytes.

The Protective Effect of Naringin against Bleomycin-Induced Pulmonary Fibrosis in Wistar Rats

The aim of the current study was to investigate the protective effect of naringin on bleomycin-induced pulmonary fibrosis in rats. Twenty-four Wistar rats randomly divided into four groups (control, bleomycin alone, bleomycin + naringin 40, and bleomycin + naringin 80) were used. Rats were administered a single dose of bleomycin (5 mg/kg; via the tracheal cannula) alone or followed by either naringin 40 mg/kg (orally) or naringin 80 mg/kg (orally) or water (1 mL, orally) for 14 days. Rats and lung tissue were weighed to determine the lung index. TNF-α and IL-1β levels, hydroxyproline content, and malondialdehyde (MDA) levels were assayed. Glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities were determined. Tissue sections were stained with hematoxylin-eosin, Masson's trichrome, and 0.1% toluidine blue. TNF-α, IL-1β, and MDA levels and hydroxyproline content significantly increased (p < 0.01) and GPx and SOD activities significantly decreased in bleomycin group (p < 0.01). Naringin at a dose of 80 mg/kg body weight significantly decreased TNF-α and IL-1β activity, hydroxyproline content, and MDA level (p < 0.01) and increased GPx and SOD activities (p < 0.05). Histological evidence supported the results. These results show that naringin has the potential of reducing the toxic effects of bleomycin and may provide supportive therapy for conventional treatment methods for idiopathic pulmonary fibrosis.

Molecular genetics of naringenin biosynthesis, a typical plant secondary metabolite produced by Streptomyces clavuligerus

Background

Some types of flavonoid intermediates seemed to be restricted to plants. Naringenin is a typical plant metabolite, that has never been reported to be produced in prokariotes. Naringenin is formed by the action of a chalcone synthase using as starter 4-coumaroyl-CoA, which in dicotyledonous plants derives from phenylalanine by the action of a phenylalanine ammonia lyase.

Results

A compound produced by Streptomyces clavuligerus has been identified by LC–MS and NMR as naringenin and coelutes in HPLC with a naringenin standard. Genome mining of S. clavuligerus revealed the presence of a gene for a chalcone synthase (ncs), side by side to a gene encoding a P450 cytochrome (ncyP) and separated from a gene encoding a Pal/Tal ammonia lyase (tal). Deletion of any of these genes results in naringenin non producer mutants. Complementation with the deleted gene restores naringenin production in the transformants. Furthermore, naringenin production increases in cultures supplemented with phenylalanine or tyrosine.

Conclusion

This is the first time that naringenin is reported to be produced naturally in a prokariote. Interestingly three non-clustered genes are involved in naringenin production, which is unusual for secondary metabolites. A tentative pathway for naringenin biosynthesis has been proposed.

Electronic supplementary material

The online version of this article (doi:10.1186/s12934-015-0373-7) contains supplementary material, which is available to authorized users.

Ameliorative effect of naringin against doxorubicin-induced acute cardiac toxicity in rats

CONTEXT

Doxorubicin (Dox) is one of the most active chemotherapeutic agents used to treat various types of cancers. Its clinical utility is compromised due to fatal cardiac toxicity characterized by an irreversible cardiomyopathy.

OBJECTIVE

This study evaluates the cardioprotective potential of naringin (NR) against Dox-induced acute cardiac toxicity in rats.

MATERIALS AND METHODS

Male Wistar rats were randomly divided into five groups. NR (50 and 100 mg/kg) was administered intraperitoneally (i.p.) daily from 0 to 14 d. Doxorubicin (15 mg/kg, i.p.) was given as a single dose on the 10th day. On the 14th day, all animals were sacrificed and oxidative stress parameters that include malondialdehyde (MDA), glutathione (GSH) level, superoxide dismutase (SOD), catalase (CAT) activities, and all mitochondrial complexes (I-IV) activities were evaluated along with histopathological studies of the heart.

RESULTS

Doxorubicin-induced cardiotoxicity was confirmed by increased (p < 0.05) MDA, decreased (p < 0.05) GSH levels, SOD, and CAT activities, mitochondrial complexes (I-IV) activities in the heart tissue. NR (100 mg/kg) showed cardioprotection as evident from significant decreased MDA (p < 0.001) level, raised (p < 0.001) GSH level, SOD and CAT activities and increased mitochondrial complexes I (p < 0.01), II (p < 0.001), III (p < 0.001), and IV (p < 0.05) activities. Further, Dox-induced cardiotoxicity was confirmed by histopathological studies. These obtained results indicated the protective role of NR against Dox-induced cardiac toxicity in rats.

CONCLUSION

NR can be used in combination with Dox due to its high cardioprotective effect against Dox-induced cardiomyopathy.

Anti-genotoxic effect of naringin against bleomycin-induced genomic damage in human lymphocytes in vitro

Naringin is a flavonoid found in grapefruit and other citrus fruits that shows antioxidant activity. The aim of the present study was to determine the anti-genotoxic and protective effects of naringin on the chemotherapeutic/radiomimetic agent bleomycin (BLM) in human blood lymphocyte cultures in vitro using micronucleus test and chromosomal aberrations (CA) assay. We tested the three doses of naringin (1, 2, 3 µg/mL) and a single dose of BLM (20 µg/mL). BLM significantly increased the total CAs and micronucleus frequency at a concentration of 20 µg/mL. Naringin did not show any toxicity in doses of 1, 2, and 3 µg/mL. Combined treatments of BLM and naringin (2 and 3 µg/mL) significantly reduced micronucleus formation. Naringin dose-dependently decreased the total chromosome aberrations frequency induced by BLM. These results indicate that naringin could prevent BLM (20 µg/mL)-induced genotoxicity.

Safety evaluation of naringenin upon experimental exposure on rat gastrointestinal epithelium for novel optimal drug delivery

OBJECTIVE

To assess the effect of naringenin on the intestinal biochemical composition, function and histology for gastrointestinal toxicity since it has not yet been adequately exploited for safety through standard assays.

METHODS

Here, we describe naringenin (1 mM, 10 mM and 100 mM, respectively) or sodium deoxycholate (10 mM) effects on isolated brush border membrane from intestinal segments with single pass intestinal perfusion using lactate dehydrogenase, alkaline phosphatase and protein assays. MTT assay was used for cytotoxicity studies. Everted gut sac studies were used for evaluating the transport of nutrients across the intestinal segments. Lucifer yellow was used for paracellular permeability, followed by histological changes and surface characteristic studies of intestinal sacs.

RESULTS

The results indicated no significant alterations with naringenin, although significant (p < 0.01) changes were noticed with sodium deoxycholate in the activity of the rat intestinal brush border associated enzymes such as LDH, followed by intact cell viability with marked decrease in the villi height of the intestinal segments.

CONCLUSIONS

These observations indicate that naringenin was harmless upon exposure to rat gastrointestinal epithelium, clearly demonstrating the potential use of naturally occurring bioflavonoid as safe and novel pharmaceutical adjuvant in oral dosage forms as P-gp inhibitor.

Continual naringin treatment benefits the recovery of traumatic brain injury in rats through reducing oxidative and inflammatory alterations

Naringin is neuroprotective in ischemia and other disease models. However, the effects of naringin are unknown after traumatic brain injury (TBI). The present study explored the role of naringin for neuroprotection in TBI rats. TBI was performed with the weight drop technique, and naringin was given orally at a dose of 100 mg/kg/day. The neurological scores, tissue edema, and oxidative stress/inflammation parameters [malondialdehyde (MDA), superoxide dismutase, nitric oxide, inducible nitric oxide synthase (iNOS), as well as interleukin-1β (IL-1β)] were measured. Compared to sham controls, TBI rats displayed obvious sensorimotor dysfunction, significant brain edema, and elevated oxidative and inflammatory molecules. Although a 7-day pre-treatment of naringin was unable to reverse these pathological changes, a 14-day continual treatment (7 days before and 7 days after the TBI) attenuated the increases in MDA and nitric oxide; enhanced the activation of superoxide dismutase; depressed the over-activation of iNOS; down-regulated the over-expression of IL-1β; and reduced the cortex edema. Additionally, the TBI-induced behavioral dysfunction was reduced. These results suggest that naringin treatment can attenuate cellular and histopathological alterations and improve the sensorimotor dysfunction of TBI rats, which may be partly due to the attenuation of oxidative and inflammatory damages.

Micronuclei in genotoxicity assessment: from genetics to epigenetics and beyond

Micronuclei (MN) are extra-nuclear bodies that contain damaged chromosome fragments and/or whole chromosomes that were not incorporated into the nucleus after cell division. MN can be induced by defects in the cell repair machinery and accumulation of DNA damages and chromosomal aberrations. A variety of genotoxic agents may induce MN formation leading to cell death, genomic instability, or cancer development. In this review, the genetic and epigenetic mechanisms of MN formation after various clastogenic and aneugenic effects on cell division and cell cycle are described. The knowledge accumulated in literature on cytotoxicity of various genotoxins is precisely reflected and individual sensitivity to MN formation due to single gene polymorphisms is discussed. The importance of rapid MN scoring with respect to the cytokinesis-block micronucleus assay is also evaluated.

Naringin protects memory impairment and mitochondrial oxidative damage against aluminum-induced neurotoxicity in rats

Aluminum has been indicated in neurodegenerative disorders and naringin, a bioflavonoid has been used to reduce neurotoxic effects of aluminum against aluminum chloride-induced rats. Therefore, present study has been designed to explore the possible role of naringin against aluminum-induced cognitive dysfunction and oxidative damage in rats. Aluminum (100 mg/kg) and naringin (40 and 80 mg/kg) drug treatment were administered orally for six weeks to male wistar rats. Various behavioral performance tasks, biochemical, mitochondrial oxidative parameters, and aluminum concentration in the brain were assessed. Aluminum chloride treatment significantly caused cognitive dysfunction and mitochondria oxidative damage as compared to vehicle treated control group. Besides, aluminum chloride treatment significantly increased acetyl cholinesterase activity and aluminum concentration in the brain as compared to sham. Chronic administration of naringin significantly improved cognitive performance and attenuated mitochondria oxidative damage, acetyl cholinesterase activity, and aluminum concentration in aluminum-treated rats as compared to control rats. Results of the study demonstrate neuroprotective potential of naringin against aluminum chloride-induced cognitive dysfunction and mitochondrial oxidative damage.

Inhibitory effect of grapefruit juice on the genotoxicity induced by hydrogen peroxide in human lymphocytes

By means of the comet assay we demonstrated a strong effect by hydrogen peroxide (HP) and no damage by grapefruit juice (GJ) in human lymphocytes. Cells exposed to HP and treated with three concentrations of GJ (10-90 min) showed an increase of DNA damage by HP over the control level, and a decrease of such damage by GJ. With the comet assay plus formamidopyrimidine-DNA-glycosylase we found the strongest increase of DNA damage by HP over the control level, and the strongest reduction of such damage by GJ. By applying the comet/FISH method we determined 98% of the p53 gene signals in the comet head of control cells along the experiment (10-90 min), in contrast with about 90% signals in the comet tail of cells exposed to HP. Cells treated with both agents showed a significant, concentration/time dependent return of p53 signals to the head, suggesting enhancement of the gene repair. Finally, with the annexin V assay we found an increase in apoptosis and necrosis by HP, and no effect by GJ; when GJ was added to HP treated cells no modification was observed in regard to apoptosis, although a decrease of necrosis was observed.

Alleviation of iron induced oxidative stress by the grape fruit flavanone naringin in vitro

Iron is an essential element that participates in several metabolic activities of cells; however, excess iron is a major cause of iron-induced oxidative stress and several human diseases. The protective effect of naringin, a grape fruit flavanone, was studied in iron overloaded isolated mouse liver mitochondria, where the isolated mitochondrial fraction was incubated with various concentrations of naringin before ferric ion loading. Iron overloading of mitochondrial fraction resulted in an increase in lipid peroxidation, protein oxidation, and DNA damage, whereas iron overload reduced the glutathione (GSH) concentration, glutathione-S-transferase (GST), glutathione peroxidase (GSHPx), catalase and superoxide dismutase (SOD) activities. Pretreatment of mitochondrial fraction with naringin inhibited iron-induced lipid peroxidation, protein oxidation, and DNA damage. Conversely, naringin supplementation arrested iron-induced depletion in the GSH contents, GSHPx, GST, SOD and catalase activities significantly. Ferric iron reduction assay revealed that naringin could not reduce ferric iron into ferrous iron indicating that it did not exhibit prooxidant activity. Iron free coordination site assay indicated that naringin was unable to occupy all the active sites of iron indicating that naringin did not completely chelate iron. Our study demonstrates that naringin was able to share the burden of endogenous oxidants by inhibiting the iron-induced depletion of all important antioxidant enzymes as well as GSH and may act as a good antioxidant.

Antioxidant properties, radical scavenging activity and biomolecule protection capacity of flavonoid naringenin and its glycoside naringin: a comparative study

BACKGROUND

This study was designed to evaluate and compare antioxidant capacity and radical scavenging activity of naringin and its aglycone by different in vitro assays. The effects of flavanones on lipid peroxidation, glutathione (GSH) oxidation and DNA cleavage were also assessed.

RESULTS

The results showed that naringenin exhibited higher antioxidant capacity and hydroxyl and superoxide radical scavenger efficiency than naringin. Our results evidenced that glycosylation attenuated the efficiency in inhibiting the enzyme xanthine oxidase and the aglycone could act like a more active chelator of metallic ions than the glycoside. Additionally, naringenin showed a greater effectiveness in the protection against oxidative damage to lipids in a dose-dependent manner. Both flavanones were equally effective in reducing DNA damage. However, they show no protective effect on oxidation of GSH.

CONCLUSION

The data obtained support the importance of characterizing the ratio naringin/naringenin in foods when they are evaluated for their health benefits.