Combating oxidative stress disorders with citrus flavonoid: Naringenin

Molecular and cellular basis of the anticancer activity of the prenylated flavonoid icaritin in hepatocellular carcinoma

The prenylated flavonoid icaritin (ICT) is currently undergoing phase 3 clinical trial for the treatment of advanced hepatocellular carcinoma (HCC), based on a solid array of preclinical and clinical data. The antitumor activity originates from the capacity of the drug to modulate several signaling effectors in cancer cells, mainly the estrogen receptor splice variant ERα36, the transcription factors STAT3 and NFκB, and the chemokine receptor CXCR4. Recent studies have implicated additional components, including different microRNAs, the generation of reactive oxygen species and the targeting of sphingosine kinase-1. ICT also engages the RAGE-HMGB1 signaling route and modulates the apoptosis/autophagy crosstalk to promote its anticancer activity. In addition, ICT exerts profound changes on the tumor microenvironment to favor an immune-response. Collectively, these multiple biochemical and cellular characteristics confer to ICT a robust activity profile which can be exploited to treat HCC, as well as other cancers, including glioblastoma and onco-hematological diseases such as chronic myeloid leukemia. This review provides an update of the pharmacological properties of ICT and its metabolic characteristics. It also addresses the design of derivatives, including both natural products and synthetic molecules, such as SNG1153 also in clinical trial. The prenylated flavonoid ICT deserves attention as a multifunctional natural product potentially useful to improve the treatment of advanced hepatocellular carcinoma.

Molecular mechanisms of action of naringenin in chronic airway diseases

Chronic airway inflammatory diseases are characterized by persistent proinflammatory responses in the respiratory tract. Although, several treatment strategies are currently available, lifelong therapy is necessary for most of these diseases. In recent years, phytophenols, namely, flavonoids, derived from fruits and vegetables have been gaining tremendous interest and have been extensively studied due to their low toxicological profile. Naringenin is a bioflavonoid abundantly found in citrus fruits. This substance has shown notable therapeutic potential in various diseases due to its promising diverse biological activities. In this review, we have attempted to review the published studies from the available literature, discussing the molecular level mechanisms of naringenin in different experimental models of airway inflammatory diseases including asthma, chronic obstructive pulmonary disease (COPD), lung cancer, pulmonary fibrosis and cystic fibrosis. Current evidences have proposed that the anti-inflammatory properties of naringenin play a major role in ameliorating inflammatory disease states. In addition, naringenin also possesses several other biological properties. Despite the proposed mechanisms suggesting remarkable therapeutic benefits, the clinical use of naringenin is, however, hampered by its low solubility and bioavailability. Furthermore, this review also discusses on the studies that utilise nanocarriers as a drug delivery system to address the issue of poor solubility.

Protective effects of Avena sativa against oxidative stress-induced kidney damage resulting from an estrogen deficiency in ovariectomized Swiss mice model

The aim of this study was to evaluate the antioxidant capacity of Avena sativa and to confirm its protective effects on estrogen deficiency in ovariectomized mice (OVX) model. Animals were treated during 21 and 60 days as follows: negative control, positive control treated with oat, ovariectomized, and ovariectomized receiving hormonal or oat treatments, respectively. 21 days post-surgery, our results showed that ovariectomy increases weight gain and urea level in plasma. After 60 days of treatment, OVX showed a gain in weight, high increases in relative kidney weight, plasmatic creatinine, glutathione peroxidase (GPX) activity, and protein oxidation as shown by elevated protein carbonyl (PCO) and advanced oxidation protein products (AOPP) levels. On the other side, a decrease was detected in catalase activity. Meanwhile, no significant changes in urea level, lipid peroxidation, SOD and GSH activity were detected. Conversely, supplementation with oat reduced weight gain, as well as oxidative stress and oxidation protein in the kidney of OVX mice. PRACTICAL APPLICATIONS: In our study, we removed the two ovaries of adult female mice in order to eliminate the essential source of steroid hormones. Deficiency in these sexual hormones, especially estrogen, leads to several physiological and morphological disturbances that are found in post-menopausal women. The gain in weight and oxidative kidney damages were the main health problems detected in ovariectomized animals. This work explored for the first time the use of oat grains as a safe natural remedy to treat all previous health problems and to avoid carcinogenic effects of the menopausal hormone therapy. Owing to its health benefits, this cereal species has recently gained attention as an important source of antioxidants and fibers. Thanks to these two components, it can be able to restore all indicated disturbances. Therefore, this cereal can be very useful in the prevention of obesity and kidney oxidative damage occurring during menopause.

Flavonoids as Anticancer Agents

Flavonoids are polyphenolic compounds subdivided into 6 groups: isoflavonoids, flavanones, flavanols, flavonols, flavones and anthocyanidins found in a variety of plants. Fruits, vegetables, plant-derived beverages such as green tea, wine and cocoa-based products are the main dietary sources of flavonoids. Flavonoids have been shown to possess a wide variety of anticancer effects: they modulate reactive oxygen species (ROS)-scavenging enzyme activities, participate in arresting the cell cycle, induce apoptosis, autophagy, and suppress cancer cell proliferation and invasiveness. Flavonoids have dual action regarding ROS homeostasis—they act as antioxidants under normal conditions and are potent pro-oxidants in cancer cells triggering the apoptotic pathways and downregulating pro-inflammatory signaling pathways. This article reviews the biochemical properties and bioavailability of flavonoids, their anticancer activity and its mechanisms of action.

Inclusion Complexes of Naringenin in Dimethylated and Permethylated β-Cyclodextrins: Crystal Structures and Molecular Dynamics Studies

The crystal structures of the inclusion complexes of naringenin in dimethylated and permethylated β-cyclodextrin (DM-β-CD and TM-β-CD) were determined and extensively analyzed. Naringenin is found with its 4-hydroxyphenyl residue fully immersed in the DM-β-CD cavity and its chromone group protruding from the narrow rim of the open-cone shaped host. The naringenin/DM-β-CD complex units are packed in a ‘herring bone’ fashion. In the case of naringenin/TM-β-CD, the complex units are arranged in a cage-type mode, the guest naringenin is partially encapsulated in the cavity of the closed-cone shaped host, with its chromone group laying equatorially and its 4-hydroxyphenyl protruding extensively from the wide rim of the host. Furthermore, the crystallographically-determined coordinates of both complexes were employed for Molecular Dynaimics simulations in explicit water solvent and in the absence of crystal contacts. The trajectories showed that naringenin rapidly penetrates the open narrow rim of DM-β-CD but not the closed narrow rim of TM-β-CD. Thus, in the latter case, the chromone group of naringenin is accommodated shallowly in the wide rim of the host, tethered via hydrogen bonds to the secondary methoxy groups of the host. Finally, a significantly higher binding affinity for naringenin in DM-β-CD than TM-β-CD was estimated by Molecular Mechanics/Generalized Born Surface Area calculations.

Hepatorenal protective effect of flaxseed protein isolate incorporated in lemon juice against lead toxicity in rats

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Flaxseed protein isolate (FPI) is a good source of protein with potent antioxidant activity.

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Solubility and scavenging radical activity of FPI increased in the acidic medium.

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Lead intoxication elevated lipid peroxidation of kidney, urinary protein and creatinine as well as kidney and liver functions.

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lemon juice and FPI are considered protective sources of kidney and liver against lead toxicity.

Finding renal and hepatoprotective agents preferably with antioxidant activities against environmental pollutants especially lead which can adversely affect liver and kidney is a great demand. In the current study, flaxseed protein isolate (FPI) was extracted from defatted flaxseed meal. Amino acids profile, antioxidant capacity and solubility of the extracted FPI were determined. The solubility of FPI in the acidic media was exploited in preparation of lemon juice with FPI. Twenty four male rats were assigned to four groups; normal control, lead intoxicated (oral daily dose of 60 mg/kg b.w. in distilled water for four weeks), lead intoxicated and orally administrated with daily dose equal 1 ml of lemon juice as well as lead intoxicated and orally administered with FPI (daily dose equal 100 mg/kg) in 1 ml of lemon juice. The oral administration of FPI incorporated in lemon juice suppressed the elevation in kidney functions, lipid peroxidation of kidney tissues, urinary protein and creatinine as well as liver functions caused by lead intoxication. Additionally, lemon juice with FPI combated the reduction of GSH of kidney tissues. It was revealed also that lemon juice without FPI suppressed the elevation in kidney and liver functions caused by lead. It can be concluded that flaxseed protein isolate is a good source of protein with potent antioxidant activity. Additionally, lemon juice and FPI are considered protective sources of kidney and liver against lead toxicity.

Naringenin improves mitochondrial function and reduces cardiac damage following ischemia-reperfusion injury: the role of the AMPK-SIRT3 signaling pathway

Mitochondrial dysfunction contributed greatly to myocardial ischemia-reperfusion (MI/R)-induced cardiomyocyte apoptosis. Naringenin is a flavonoid exhibiting potential protective effects on myocardial mitochondria under stress conditions. However, the detailed down-stream signaling pathway involved remains uncovered. This study was designed to elucidate naringenin's mitochondrial protective actions during MI/R with a focus on AMPK-SIRT3 signaling. Sprague-Dawley rats were administered with naringenin (50 mg kg-1 d-1) and subjected to MI/R surgery in the presence or absence of compound C (0.25 mg kg-1, Com.C, an AMPK inhibitor) co-treatment. An in vitro study was performed on H9c2 cardiomyoblasts subjected to simulated ischemia-reperfusion treatment. Before the treatment, the cells were administered with naringenin (80 μmol L-1) with or without SIRT3 siRNA/AMPK1α siRNA transfection. Naringenin improved post-reperfusion left ventricular systolic pressure and the instantaneous first derivative of left ventricular pressure, and reduced the infarction size and myocardial apoptosis index by suppressing mitochondrial oxidative stress damage (as evidenced by decreased mitochondrial cytochrome c release and oxidative markers) and enhancing mitochondrial biogenesis [as evidenced by increased NRF1, TFAM and oxidative phosphorylation subunit complexes (II, III and IV)]. These protective actions were abolished by Com.C (in vivo) or SIRT3 siRNA (in vitro) administration. Further investigation revealed that Com.C (in vivo) or AMPK1α siRNA (in vitro) markedly suppressed PGC-1α and SIRT3 levels while SIRT3 siRNA (in vitro) inhibited SIRT3 expression without significantly changing AMPK phosphorylation and PGC-1α levels. Taken together, we found that naringenin directly inhibits mitochondrial oxidative stress damage and preserves mitochondrial biogenesis, thus attenuating MI/R injury. Importantly, AMPK-SIRT3 signaling played a key role in this process.

Effectiveness of Eriomin® in managing hyperglycemia and reversal of prediabetes condition: A double-blind, randomized, controlled study

This study evaluated the potential effectiveness of different doses of Eriomin® on hyperglycemia and insulin resistance associated with other metabolic biomarkers in prediabetic individuals. Prediabetes patients (n = 103, 49 ± 10 years) were randomly divided into four parallel groups: (a) Placebo; (b) Eriomin 200 mg; (c) Eriomin 400 mg; and (d) Eriomin 800 mg. Assessment of biochemical, metabolic, inflammatory, hepatic, renal, anthropometric markers, blood pressure, and dietary parameters were performed during 12 weeks of intervention. Treatment with all doses of Eriomin (200, 400, and 800 mg) had similar effects and altered significantly the following variables: blood glucose (−5%), insulin resistance (−7%), glucose intolerance (−7%), glycated hemoglobin (−2%), glucagon (−6.5%), C‐peptide (−5%), hsCRP (−12%), interleukin‐6 (−13%), TNFα (−11%), lipid peroxidation (−17%), systolic blood pressure (−8%), GLP‐1 (+15%), adiponectin (+19%), and antioxidant capacity (+6%). Eriomin or placebo did not influence the anthropometric and dietary variables. Short‐term intervention with Eriomin, at doses of 200, 400, or 800 mg/day, benefited glycemic control, reduced systemic inflammation and oxidative stress, and reversed the prediabetic condition in 24% of the evaluated patients.

Identification of gene-phenotype connectivity associated with flavanone naringenin by functional network analysis

Naringenin, extracted from grapefruits and citrus fruits, is a bioactive flavonoid with antioxidative, anti-inflammatory, antifibrogenic, and anticancer properties. In the past two decades, the growth of publications of naringenin in PubMed suggests that naringenin is quickly gaining interest. However, systematically regarding its biological functions connected to its direct and indirect target proteins remains difficult but necessary. Herein, we employed a set of bioinformatic platforms to integrate and dissect available published data of naringenin. Analysis based on DrugBank and the Search Tool for the Retrieval of Interacting Genes/Proteins revealed seven direct protein targets and 102 indirect protein targets. The protein-protein interaction (PPI) network of total 109 naringenin-mediated proteins was next visualized using Cytoscape. What's more, all naringenin-mediated proteins were subject to Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis by the Database for Annotation, Visualization and Integrated Discovery, which resulted in three ESR1-related signaling pathways and prostate cancer pathway. Refined analysis of PPI network and KEGG pathway identified four genes (ESR1, PIK3CA, AKT1, and MAPK1). Further genomic analysis of four genes using cBioPortal indicated that naringenin might exert biological effects via ESR1 signaling axis. In general, this work scrutinized naringenin-relevant knowledge and provided an insight into the regulation and mediation of naringenin on prostate cancer.

Antidiabetic Properties of Naringenin: A Citrus Fruit Polyphenol

Type 2 diabetes mellitus (T2DM) is a metabolic disease characterized by insulin resistance and hyperglycemia and is associated with personal health and global economic burdens. Current strategies/approaches of insulin resistance and T2DM prevention and treatment are lacking in efficacy resulting in the need for new preventative and targeted therapies. In recent years, epidemiological studies have suggested that diets rich in vegetables and fruits are associated with health benefits including protection against insulin resistance and T2DM. Naringenin, a citrus flavanone, has been reported to have antioxidant, anti-inflammatory, hepatoprotective, nephroprotective, immunomodulatory and antidiabetic properties. The current review summarizes the existing in vitro and in vivo animal studies examining the anti-diabetic effects of naringenin.

Beneficial Effects of Citrus Flavonoids on Cardiovascular and Metabolic Health

The prevalence of cardiovascular disease (CVD) is increasing over time. CVD is a comorbidity in diabetes and contributes to premature death. Citrus flavonoids possess several biological activities and have emerged as efficient therapeutics for the treatment of CVD. Citrus flavonoids scavenge free radicals, improve glucose tolerance and insulin sensitivity, modulate lipid metabolism and adipocyte differentiation, suppress inflammation and apoptosis, and improve endothelial dysfunction. The intake of citrus flavonoids has been associated with improved cardiovascular outcomes. Although citrus flavonoids exerted multiple beneficial effects, their mechanisms of action are not completely established. In this review, we summarized recent findings and advances in understanding the mechanisms underlying the protective effects of citrus flavonoids against oxidative stress, inflammation, diabetes, dyslipidemia, endothelial dysfunction, and atherosclerosis. Further studies and clinical trials to assess the efficacy and to explore the underlying mechanism(s) of action of citrus flavonoids are recommended.

Antioxidant and Cytotoxicity Activities of Karamunting (Melastoma malabathricum L.) Fruit Ethanolic Extract and Quercetin

Melastoma malabathricum L. is a type of plant naturally grows in Kalimantan that has medicinal properties. Ethanolic extract of M. malabathricum L. flower has quercetin and kaempferol contents that have antioxidant and anticancer activities. But the antioxidant and cytotoxicity activities of M. malabathricum L. fruit ethanolic extract were not known. This study measured the quercetin and kaempferol level in M. malabathricum L. fruit ethanolic extract using HPLC MS/MS, antioxidant activity using DPPH method, and cytotoxicity activity using Brine Shrimp Lethality Test (BSLT) method. Results showed the level of quercetin and kaempferol from M. malabathricum L fruit ethanolic extract are 67.78 µg/g and 43.52 µg/g, respectively. Beside, the antioxidant activity with by IC50 was 16.82±0.24 ppm and 7.38±0.41 ppm. The cytotoxicity activities of M. malabathricum L. fruit ethanolic extract and quercetin are shown by the LC50 of 313.44 ppm (95%CI 283.97-344.43) and 37.24 ppm, respectively.

Activation of anti-oxidant of curcumin pyrazole derivatives through preservation of mitochondria function and Nrf2 signaling pathway

Oxidative stress is an important cause of neurodegenerative diseases. Antioxidant is an potential important method to treat such diseases. The aim of this study is to discover new and effective antioxidants and their mechanism. The neuroprotective effect of six curcumin pyrozole compounds were first evaluated on sodium nitroprusside (SNP) - induced PC12 cell injury by testing cell viability and LDH release. The results showed that four compounds (C1-C4) have more significant protective effects compared to curcumin and edaravone. Furthermore, compounds C1-C4 can attenuate the intracellular ROS, and compound C3 is the most effective one which can preservate the mitochondria function by inhibiting the mitochondrial membrane potential loss and enhance nuclear translocation of Nrf2 in PC12 cell. These results indicated that C3 may be a potential candidate drug for treating neurodegenerative diseases.

The Therapeutic Potential of Naringenin: A Review of Clinical Trials

Naringenin is a flavonoid belonging to flavanones subclass. It is widely distributed in several Citrus fruits, bergamot, tomatoes and other fruits, being also found in its glycosides form (mainly naringin). Several biological activities have been ascribed to this phytochemical, among them antioxidant, antitumor, antiviral, antibacterial, anti-inflammatory, antiadipogenic and cardioprotective effects. Nonetheless, most of the data reported have been obtained from in vitro or in vivo studies. Although some clinical studies have also been performed, the main focus is on naringenin bioavailability and cardioprotective action. In addition, these studies were done in compromised patients (i.e., hypercholesterolemic and overweight), with a dosage ranging between 600 and 800 μM/day, whereas the effect on healthy volunteers is still debatable. In fact, naringenin ability to improve endothelial function has been well-established. Indeed, the currently available data are very promising, but further research on pharmacokinetic and pharmacodynamic aspects is encouraged to improve both available production and delivery methods and to achieve feasible naringenin-based clinical formulations.