Hesperetin protects against H2O2-triggered oxidative damage via upregulation of the Keap1-Nrf2/HO-1 signal pathway in ARPE-19 cells

Fractionation and identification of ocular protective compounds from kochiae fructus against oxidative damage in retinal pigment epithelium cells

ETHNOPHARMACOLOGICAL RELEVANCE

Kochiae Fructus, the ripe fruit of Kochia scoparia, is a traditional Chinese medicine commonly used to treat eye discomforts and vision problems. Although Kochiae Fructus is mentioned in many classical Chinese medical texts, its protective effects and the roles of its active phytochemicals in eye treatment still lack scientific exploration.

AIM OF THE STUDY

This study aimed to clarify the protective effects and identify the active fractions and compounds of Kochiae Fructus against oxidative stress-induced retinal pigment epithelium (RPE) cell death.

MATERIALS AND METHODS

Liquid-liquid partitioning was employed to prepare active fractions. Silica gel, RP-18, and Sephadex™ LH-20 gels were used as stationary phases to purify the compounds through column chromatography. Cell models were established by treating ARPE-19 (RPE cell line) with hydrogen peroxide (H₂O₂) and tert-butyl hydroperoxide (TBHP), respectively.

RESULTS

The methanol aqueous fraction from ethyl acetate-soluble extract (KSEM) alleviated oxidant-induced RPE cell death in a dose-dependent manner and activated the Nrf2/HO-1 pathway, a critical defense mechanism against oxidative damage. The isolated flavonols in fraction KSEM, hyperoside, quercetin, and kaempferol, reduced oxidant-induced cell mortality, with quercetin showing the strongest effect. Moreover, combination treatment revealed that hyperoside and kaempferol synergistically enhanced the protective effects of quercetin, making the combined treatment more efficient than quercetin alone.

CONCLUSIONS

The protective effects of Kochiae Fructus against oxidative damage in RPE cell was validated with the KSEM fraction. The compound quercetin was identified as the important contributor. However, the synergistic effect of the hyperoside, quercetin, and kaempferol mixture may play a dominant role in the protective action of Kochiae Fructus. Overall, these findings highlight the potential of Kochiae Fructus and its flavonol mixture as a basis for developing treatments targeting ocular diseases associated with oxidative damage in retina.

Research progress on pharmacological effects against liver and eye diseases of flavonoids present in Chrysanthum indicum L., Chrysanthemum morifolium Ramat., Buddleja officinalis Maxim. and Sophora japonica L

ETHNOPHARMACOLOGICAL RELEVANCE

Chrysanthemum indicum L., Chrysanthemum morifolium Ramat., Buddleja officinalis Maxim., and Sophora japonica L. have the effects of "Clearing the liver" and "Improving vision". Flavonoids are their main active ingredients, but there are few reports on their simultaneous liver and eye protective effects.

AIM OF THE STUDY

Overview of the role of flavonoids of the four medicinal flowers (FFMF) in the prevention and treatment of liver and eye diseases.

MATERIALS AND METHODS

The Web of Science, PubMed, CNKI, Google Scholar, and WanFang databases were searched for FFMF. Using "hepatitis", "liver fibrosis", "liver cancer", "dry eye syndrome", "cataracts", "glaucoma", "age-related macular degeneration", and "diabetic retinopathy" as the keywords, we summarized the main pathological mechanisms of these diseases and the role of FFMF in their prevention and treatment.

RESULTS

We found that the four medicinal flowers contained a total of 125 flavonoids. They can maintain liver and eye homeostasis by regulating pathological mechanisms such as oxidative stress, inflammation, endoplasmic reticulum stress, mitochondrial dysfunction, glucose and lipid metabolism disorders, and programmed cell death, exerting the effect of "clearing the liver and improving vision".

CONCLUSION

FFMF have a series of beneficial properties such as antioxidant, anti-inflammatory, antiviral, and antifibrotic activity, and the regulation of angiogenesis, glycolipid metabolism and programmed cell death, which may explain the efficacy of the four traditional Chinese medicines for "Clearing the liver" and "Improving vision".

Integrating larval zebrafish model and network pharmacology for screening and identification of edible herbs with therapeutic potential for MAFLD: A promising drug Smilax glabra Roxb

Metabolic-associated fatty liver disease (MAFLD) is becoming a prevalent chronic liver disease. Many medicinal and edible herbs exhibit remarkable biological activities in ameliorating MAFLD but lack a comprehensive assessment of their therapeutic efficacy. This study determined total phenolic and flavonoid contents and in vitro antioxidant properties of 34 edible herbs. Smilax glabra Roxb. (SGR), Coreopsis tinctoria Nutt., and Smilax china L. were obtained with the best bioactivity and antioxidant capacity. The high-cholesterol diet-induced larval zebrafish model was established to compare the anti-MAFLD activity of the three herb extracts mentioned above. In vivo experiments revealed that SGR intervention significantly decreased lipid accumulation, alleviated oxidative stress, and modulated intestinal microbiota composition in zebrafish. Furthermore, three potential active components in SGR and their possible mechanisms were explored through network pharmacology and molecular docking. Our study suggested that SGR is a potential candidate for developing new drugs or dietary supplements for MAFLD therapy.

Berries and Their Active Compounds in Prevention of Age-Related Macular Degeneration

Age-related macular degeneration (AMD) is a leading cause of vision loss in the elderly, significantly diminishing quality of life. Currently, there is no available treatment to reverse retinal degeneration and neuronal loss, prompting a focus on interventions that slow the progression of intermediate AMD and geographic atrophy. Berries are rich in bioactive compounds, including flavonoids, anthocyanins, carotenoids, and resveratrol, known for their antioxidant, anti-inflammatory, and anti-angiogenic properties. Preclinical studies suggest that extracts from various berries, such as aronia, honeysuckle, black currant, goji, and bilberry, can improve retinal health by reducing oxidative stress and inflammation. Although clinical trials are limited, emerging evidence indicates that dietary intake of these compounds may enhance visual function and slow the progression of AMD. This review summarizes findings from both animal studies and clinical trials to identify specific berries that have been validated to prevent or delay AMD progression, as well as those with potential therapeutic value. Furthermore, we examine the key phytochemicals present in these berries, their mechanisms of action on macular degeneration, and their distinct properties for therapeutic application. A deeper understanding of these characteristics could enable the rational appliance of berries, especially wolfberry, and berry-derived components, such as carotenoids and anthocyanins, to optimize better therapeutic outcomes in AMD management.

A critical appraisal on the involvement of plant-based extracts as neuroprotective agents (2012-2022): an effort to ease out decision-making process for researchers

The purpose of this review study is to provide a condensed compilation of 164 medicinal plants that have been investigated for their neuroprotective aspects by researchers between the years 2012 and 2022 which also includes a recent update of 2023-2024. After using certain keywords to retrieve the data from SCOPUS, it was manually sorted to eliminate any instances of duplication. The article is streamlined into three major segments. The first segment takes a dig into the current global trend and attempts to decrypt vital information related to plant names, families, plant parts used, and neurological disorders investigated. The second segment of the article makes an attempt to present a comprehensive insight into the various mechanistic pathways through which phytochemicals can intervene to exert neuroprotection. The final segment of the manuscript is a bibliometric appraisal of all researches conducted. The study is based on 256 handpicked articles based on decided inclusion criteria. Illustrative compilation of various pathways citing their activation and deactivation channels are also presented with possible hitting points of various phytochemicals. The present study employed Microsoft Excel 2019 and VOS viewer as data visualisation tools.

Comprehensive review of Hesperetin: Advancements in pharmacokinetics, pharmacological effects, and novel formulations

Hesperetin is a flavonoid compound naturally occurring in the peel of Citrus fruits from the Rutaceae family. Previous studies have demonstrated that hesperetin exhibits various pharmacological effects, such as anti-inflammatory, anti-tumor, antioxidative, anti-aging, and neuroprotective properties. In recent years, with the increasing prevalence of diseases and the rising awareness of traditional Chinese medicine, hesperetin has garnered growing attention for its wide-ranging pharmacological effects. To substantiate its health benefits and elucidate potential mechanisms, knowledge of pharmacokinetics is crucial. However, the limited solubility of hesperetin restricts its bioavailability, thereby diminishing its efficacy as a beneficial health agent. To enhance the bioavailability of hesperetin, various novel formulations have been developed, including nanoparticles, liposomes, and cyclodextrin inclusion complexes. This article reviews recent advances in the pharmacokinetics of hesperetin and methods to improve its bioavailability, as well as its pharmacological effects and mechanisms, aiming to provide a theoretical basis for clinical applications.

As shown hesperidin suppresses TGF-β2-induced proliferation and epithelial-mesenchymal transition of retinal pigment epithelial cells

This study investigates the potential therapeutic effects and molecular mechanisms of hesperidin treatment on cell migration and epithelial-mesenchymal transition, key stages of proliferative vitreoretinopathy (PVR). Human retinal pigment epithelial cells (ARPE-19) were treated with 10 ng/ml transforming growth factor-beta 2 (TGF-β2) alone or in combination with 1.56 μM hesperidin for 48 h. The impact of treatment on cell migration was evaluated using a wound healing assay. Apoptosis was assessed using DNA staining. mRNA and protein expression were evaluated using real-time PCR and Western blot, respectively. Hesperidin inhibits the proliferation and transformation of the cells by inducing apoptosis and reverses the cell morphology modified by TGF-β2. Hesperidin inhibits cell migration induced by TGF-β2. Upon treatment with hesperidin, the levels of mesenchymal markers upregulated by TGF-β2, such as MMP-1, -2, -9, fibronectin, α-SMA and the transcription factors Snail, Slug and ZEB-1, were downregulated. Conversely, the epithelial marker E-cadherin is upregulated with hesperidin treatment. Additionally, TIMP-1 and TIMP-2 expression levels, which are downregulated, increase with the treatment. These results suggest that hesperidin may inhibit the migration and EMT processes of RPE cells involved in the development of PVR, indicating its potential as a therapeutic agent for treating PVR.

Baicalin alleviates the injury of human retinal pigment epithelium cells and improves branch retinal vein occlusion in rats by inhibiting the HIF-1α/VEGFA axis

BACKGROUND

At present, relevant studies have found that baicalin can improve macular edema (ME) caused by glaucoma, but the effect on branch retinal vein occlusion (BRVO) is still unclear.

METHODS

The CoCl2-stimulated ARPE-19 cells were treated with different concentrations of baicalin and detected cell viability, apoptosis and oxidative stress. Next, the hypoxia-inducible factor-1α (HIF-1α) overexpression vector or siRNA were transfected into CoCl2-stimulated ARPE-19 cells, and the cell changes were detected. We searched the potential binding proteins of HIF-1α through the online database, and screened vascular endothelial growth factor A (VEGFA) as the research object. The CoCl2-stimulated ARPE-19 cells were treated with baicalin alone, or transfected with HIF-1α overexpression vector, or transfected with HIF-1α overexpression vector and VEGFA siRNA, and the cell changes were detected. Finally, we verified the therapeutic effect of baicalin on BRVO rats in vivo.

RESULTS

Baicalin inhibited CoCl2-induced apoptosis, inflammation and oxidative stress in ARPE-19 cells, and baicalin inhibited HIF-1α protein expression. In CoCl2-induced hypoxia cells, HIF-1α aggravated apoptosis, inflammation and oxidative stress, while HIF-1α silencing alleviated cell damage. Mechanism study showed that in baicalin-treated CoCl2-induced cells, VEGFA protein expression decreased and cell damage was improved, but this protective effect was counteracted by HIF-1α, and VEGFA silencing again inhibited apoptosis, inflammation and oxidative stress. Baicalin inhibited HIF-1α and VEGFA protein expression in the retinal tissue of BRVO rats, reduced injury, and promoted the recovery of ganglion cell layer.

CONCLUSIONS

Baicalin alleviated ARPE-19 cell injury and improved BRVO in rats by inhibiting HIF-1α/VEGFA axis in vivo and in vitro.

Selenomethionine and Allicin Synergistically Mitigate Intestinal Oxidative Injury by Activating the Nrf2 Pathway

Oxidative stress frequently contributes to intestinal barrier injury in animals and humans. It was reported that both Selenomethionine (SeMet) and allicin exhibit protective effects against a range of diseases caused by oxidative stress. This study aimed to investigate the synergistic antioxidant effects and underlying mechanisms of SeMet and allicin on a H2O2-induced intestinal barrier injury model using IPEC-J2 cells and mice. The results showed that H2O2 induced severe oxidative stress, including a decrease in cell viability, antioxidant level, migration capacity, and cell integrity. SeMet and allicin exhibited significant synergistic anti-oxidative effects on intestinal epithelial cells. The combined use of SeMet and allicin increased SOD activity, GSH content, and GSH/GSSG ratio while decreasing MDA, NO, and ROS content levels. Furthermore, we found that SeMet and allicin synergistically activated the nuclear factor erythroid-related factor 2 (Nrf2)-NAD(P)H dehydrogenase [quinone] 1 (NQO1) signaling pathway and down-regulated endoplasmic reticulum stress (ER stress)-related proteins. However, the synergistic antioxidative and intestinal barrier protective effects of SeMet and allicin were abolished by Nrf2 inhibitor ML385 in vitro and in vivo. In conclusion, SeMet and allicin synergistically attenuate intestinal barrier injury induced by excessively oxidative stress through the activation of the Nrf2 signaling pathway and inhibition ER stress. These findings support that the combined use of SeMet and allicin could enhance antioxidative properties and alleviate intestinal injury in further clinical practice.

Computational Analysis and Experimental Data Exploring the Role of Hesperetin in Ameliorating ADHD and SIRT1/Nrf2/Keap1/OH-1 Signaling

Attention deficit hyperactivity disorder (ADHD) manifests as poor attention, hyperactivity, as well as impulsive behaviors. Hesperetin (HSP) is a citrus flavanone with strong antioxidant and anti-inflammatory activities. The present study aimed to test hesperetin efficacy in alleviating experimental ADHD in mice and its influence on hippocampal neuron integrity and sirtuin 1 (SIRT1) signaling. An in silico study was performed to test the related proteins. Groups of mice were assigned as control, ADHD model, ADHD/HSP (25 mg/kg), and ADHD/HSP (50 mg/kg). ADHD was induced by feeding with monosodium glutamate (0.4 g/kg, for 8 weeks) and assessed by measuring the motor and attentive behaviors (open filed test, Y-maze test, and marble burying test), histopathological examination of the whole brain tissues, and estimation of inflammatory markers. The in-silico results indicated the putative effects of hesperetin on ADHD by allowing the integration and analysis of large-scale genomic, transcriptomic, and proteomic data. The in vivo results showed that ADHD model mice displayed motor hyperactivity and poor attention in the behavioral tasks and shrank neurons at various hippocampal regions. Further, there was a decline in the mRNA expression and protein levels for SIRT1, the erythroid 2-related factor-2 (Nrf2), kelch like ECH associated protein 1 (Keap1) and hemeoxygenase-1 (OH-1) proteins. Treatment with HSP normalized the motor and attentive behaviors, prevented hippocampal neuron shrinkage, and upregulated SIRT1/Nrf2/Keap1/OH-1 proteins. Taken together, HSP mainly acts by its antioxidant potential. However, therapeutic interventions with hesperetin or a hesperetin-rich diet can be suggested as a complementary treatment in ADHD patients but cannot be suggested as an ADHD treatment per se as it is a heterogeneous and complex disease.

Natural products for the treatment of age-related macular degeneration

BACKGROUND

Age-related macular degeneration (AMD) is a chronic retinal disease that significantly influences the vision of the elderly.

PURPOSE

There is no effective treatment and prevention method. The pathogenic process behind AMD is complex, including oxidative stress, inflammation, and neovascularization. It has been demonstrated that several natural products can be used to manage AMD, but systematic summaries are lacking.

STUDY DESIGN AND METHODS

PubMed, Web of Science, and ClinicalTrials.gov were searched using the keywords "Biological Products" AND "Macular Degeneration" for studies published within the last decade until May 2023 to summarize the latest findings on the prevention and treatment of age-related macular degeneration through the herbal medicines and functional foods.

RESULTS

The eligible studies were screened, and the relevant information about the therapeutic action and mechanism of natural products used to treat AMD was extracted. Our findings demonstrate that natural substances, including retinol, phenols, and other natural products, prevent the development of new blood vessels and protect the retina from oxidative stress in cells and animal models. However, they have barely been examined in clinical studies.

CONCLUSION

Natural products could be highly prospective candidate drugs used to treat AMD, and further preclinical and clinical research is required to validate it to control the disease.

Lutein Modulates Cellular Functionalities and Regulates NLRP3 Inflammasome in a H2O2-Challenged Three-Dimensional Retinal Pigment Epithelium Model

Excessive hydrogen peroxide (H2O2) generated during retinal cell metabolic activity could lead to oxidative degeneration of retinal pigment epithelium (RPE) tissue, a specific pathological process implicated in various retinal diseases resulting in blindness, which can be mitigated by taking dietary antioxidants to prevent inflammation and impaired cellular dysfunction. This study tested the hypothesis that damages induced by oxidative stresses can be mitigated by lutein in a H2O2-challenged model, which was based on an ARPE-19 cell monolayer cultured on three-dimensional (3D)-printed fibrous scaffolds. Pretreating these models with lutein (0.5 μM) for 24 h can significantly lower the oxidative stress and maintain phagocytosis and barrier function. Moreover, lutein can modulate the NLRP3 inflammasome, leading to a ∼40% decrease in the pro-inflammatory cytokine (IL-1β and IL-18) levels. Collectively, this study suggests that the 3D RPE model is an effective tool to examine the capability of lutein to modulate cellular functionalities and regulate NLRP3 inflammation.

Apelin-13 alleviates osteoclast formation and osteolysis through Nrf2-pyroptosis pathway

Wear particle-induced periprosthetic osteolysis is the key to aseptic loosening after artificial joint replacement. Osteoclastogenesis plays a central role in this process. Apelin-13 is a member of the adipokine family with anti-inflammatory effects. Here, we report that apelin-13 alleviates RANKL-mediated osteoclast differentiation and titanium particle-induced osteolysis in mouse calvaria. Mechanistically, apelin-13 inhibits NLRP3 inflammasome-mediated pyroptosis by activating the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. In summary, apelin-13 is expected to be a potential drug for relieving aseptic osteolysis. RESEARCH HIGHLIGHTS: This study reveals the molecular mechanism by which apelin-13 inhibits NLRP3 inflammasome activation and pyroptosis by promoting Nrf2. This study confirms that apelin-13 alleviates osteoclast activation by inhibiting pyroptosis. In vivo studies further confirmed that apelin-13 alleviated mouse skull osteolysis by inhibiting the activation of NLRP3 inflammasome.

Hesperetin ameliorates spinal cord injury in rats through suppressing apoptosis, oxidative stress and inflammatory response

Spinal cord injury (SCI), a fatal condition, is characterized by progressive tissue degradation and extreme functional deficits with limited treatment options. Hesperetin, a natural flavonoid with potent antioxidant, antiapoptotic and anti-inflammatory properties, has yet to be systematically investigated for its therapeutic effects on neurological damage in rat models of SCI. In this study, rats were given oral hesperetin once daily for 28 days, and their locomotion and histopathological changes were assessed. The findings demonstrated that hesperetin alleviates neurological damage caused by SCI. The observed behavioral improvement could be due to an increase in the survival rate of neurons and oligodendrocytes. This improvement further boosted the ability to repair tissue and form myelin after SCI, ultimately resulting in better neurological outcomes. Furthermore, the present study revealed that hesperetin possesses potent antioxidant capabilities in the context of SCI, reducing the levels of harmful oxygen free radicals and increasing the activity of antioxidant enzymes. Additionally, hesperetin markedly inhibited injury-induced apoptosis, as assessed by caspase-3 immunofluorescence staining and the expression level of caspase-3, indicating the ability of hesperetin to prevent cell death after SCI. Finally, after SCI, hesperetin treatment effectively reduced the expression of inflammatory factors, including IL-1β, TNFα, and NF-kB, demonstrating the anti-inflammatory effect of hesperetin. Together, our results suggest that hesperetin should be considered a valuable therapeutic aid following SCI, as its positive effects on the nervous system, including antioxidant, anti-inflammatory and antiapoptotic effects, may be crucial mechanisms through which hesperetin exerts neuroprotective effects against SCI.

Oxya chinensis sinuosa (OC) Extracts Protects ARPE-19 Cells against Oxidative Stress via Activation of the Mitogen-Activated Protein Kinases (MAPKs)/ Nuclear Factor-κB (NF-κB) Pathway

Oxya chinensis sinuosa (OC) is a well-known edible insect. Several researches on the health benefits of OC consumption have been performed to date; however, their effect on eye health remains largely unknown. This study aimed to assess the protective effects of OC extracts on the oxidative stress on the retinal pigment epithelium (RPE) cells. Oxidative damage has been identified as one of the key regulatory factors in age-related macular degeneration. H2O2-induced reactive oxygen species (ROS) production, a well-known oxidative stress factor, can cause cell death in retinal pigment epithelia cells. In this study, we found that three OC extracts effectively prevented H2O2-induced ROS production and subsequent death of ARPE-19 cells in a dose-dependent manner. In addition, the OC extracts inhibited the phosphorylation of mitogen-activated protein kinases including p38, JNK, and ERK. The OC extracts restored IκBα degradation induced by H2O2, indicating that OC extracts suppressed the activation of nuclear factor-κB. Furthermore, the three OC extracts were shown to have antioxidant effects by up-regulating the intracellular expression of key antioxidant proteins such as SOD, NQO, and HO-1. Here we demonstrated the antioxidant and anti-apoptotic effects of the OC extracts on ARPE-19, indicating their potential role in improving eye health. These results suggest that three OC extracts plays a critical role in oxidative stress-induced cell death protects in ARPE-19 cells.

Hesperidin ameliorates H2O2-induced bovine mammary epithelial cell oxidative stress via the Nrf2 signaling pathway

BACKGROUND

Hesperidin is a citrus flavonoid with anti-inflammatory and antioxidant potential. However, its protective effects on bovine mammary epithelial cells (bMECs) exposed to oxidative stress have not been elucidated.

RESULTS

In this study, we investigated the effects of hesperidin on H2O2-induced oxidative stress in bMECs and the underlying molecular mechanism. We found that hesperidin attenuated H2O2-induced cell damage by reducing reactive oxygen species (ROS) and malondialdehyde (MDA) levels, increasing catalase (CAT) activity, and improving cell proliferation and mitochondrial membrane potential. Moreover, hesperidin activated the Keap1/Nrf2/ARE signaling pathway by inducing the nuclear translocation of Nrf2 and the expression of its downstream genes NQO1 and HO-1, which are antioxidant enzymes involved in ROS scavenging and cellular redox balance. The protective effects of hesperidin were blocked by the Nrf2 inhibitor ML385, indicating that they were Nrf2 dependent.

CONCLUSIONS

Our results suggest that hesperidin could protect bMECs from oxidative stress injury by activating the Nrf2 signaling pathway, suggesting that hesperidin as a natural antioxidant has positive potential as a feed additive or plant drug to promote the health benefits of bovine mammary.

Green synthesis of zinc oxide nanoparticles using ethanolic extract of Gliricidia sepium (Jacq.) kunth. Ex. Walp., stem: Characterizations and their gastroprotective effect on ethanol-induced gastritis in rats

The study presents a significant advancement in drug delivery and therapeutic efficacy through the successful synthesis of Gliricidia sepium(Jacq.) Kunth. ex. Walp., stem zinc oxide nanoparticles(GSS ZnONPs). The phenolic compounds present in Gliricidia sepium stem (GSS) particularly vanillic acid, apegnin-7-O-glucoside, syringic acid, and p-coumaric acid which were identified by HPLC. These compounds shown antioxidant and anti-inflammatory properties. GSS ZnONPs demonstrate pronounced gastroprotective effects against ethanol-induced gastritis, evidenced by the reduction in gastric lesions and mucosal injury upon its treatment. Histopathological evaluation and immunohistochemical analysis of nuclear factor erythroid 2-related factor 2 (Nrf2) expression further validate these results, revealing the amelioration of ethanol-induced gastritis and improved gastric tissue condition due to their treatment. Noteworthy is the dose-dependent response of GSS ZnONPs, showcasing their efficacy even at lower doses against ethanol-induced gastritis which is confirmed by different biomarkers. These findings have substantial implications for mitigating dosage-related adverse effects while preserving therapeutic benefits, offering a more favorable treatment approach. This study aims to investigate the potential gastroprotective activity of GSS ZnONPs against gastritis.

Protective role of IL-17-producing γδ T cells in a laser-induced choroidal neovascularization mouse model

BACKGROUND

Vision loss in patients with wet/exudative age-related macular degeneration (AMD) is associated with choroidal neovascularization (CNV), and AMD is the leading cause of irreversible vision impairment in older adults. Interleukin-17A (IL-17A) is a component of the microenvironment associated with some autoimmune diseases. Previous studies have indicated that wet AMD patients have elevated serum IL-17A levels. However, the effect of IL-17A on AMD progression needs to be better understood. We aimed to investigate the role of IL-17A in a laser-induced CNV mouse model.

METHODS

We established a laser-induced CNV mouse model in wild-type (WT) and IL-17A-deficient mice and then evaluated the disease severity of these mice by using fluorescence angiography. We performed enzyme-linked immunosorbent assay (ELISA) and fluorescence-activated cell sorting (FACS) to analyze the levels of IL-17A and to investigate the immune cell populations in the eyes of WT and IL-17A-deficient mice. We used ARPE-19 cells to clarify the effect of IL-17A under oxidative stress.

RESULTS

In the laser-induced CNV model, the CNV lesions were larger in IL-17A-deficient mice than in WT mice. The numbers of γδ T cells, CD3+CD4+RORγt+ T cells, Treg cells, and neutrophils were decreased and the number of macrophages was increased in the eyes of IL-17A-deficient mice compared with WT mice. In WT mice, IL-17A-producing γδ T-cell numbers increased in a time-dependent manner from day 7 to 28 after laser injury. IL-6 levels increased and IL-10, IL-24, IL-17F, and GM-CSF levels decreased in the eyes of IL-17A-deficient mice after laser injury. In vitro, IL-17A inhibited apoptosis and induced the expression of the antioxidant protein HO-1 in ARPE-19 cells under oxidative stress conditions. IL-17A facilitated the repair of oxidative stress-induced barrier dysfunction in ARPE-19 cells.

CONCLUSIONS

Our findings provide new insight into the protective effect of IL-17A in a laser-induced CNV model and reveal a novel regulatory role of IL-17A-producing γδ T cells in the ocular microenvironment in wet AMD.

Hesperidin Attenuates Titanium Dioxide Nanoparticle-Induced Neurotoxicity in Rats by Regulating Nrf-2/TNF-α Signaling Pathway, the Suppression of Oxidative Stress, and Inflammation

Background: Titanium dioxide nanoparticles (TiO2NPs) are widely utilized and consumed mainly as food additives. Oxidative stress is considered to be the basic effect of TiO2NPs through biological interactions. Hesperidin (HSP) is a bioflavonoid (flavanone glycoside) with lipid-lowering, inflammation, oxidative stress suppression, antihypertensive, cancer-fighting, and antiedema effects. Objective: This study was to investigate the possible protective influences of HSP of subchronic oral TiO2NP exposure on the brains of rats, including neurotransmitters, oxidative stress/antioxidant parameters, inflammatory markers, and histological changes in the brains of adult male albino rats. Methodology: The experiment was executed on 80 albino rats. The animals were randomly divided into 4 equal groups. The first group served as a control; the second group was treated with oral doses of HSP (100 mg/kg Bw daily); the third group received TiO2NPs (200 mg/kg Bw orally daily); and the fourth group was treated with TiO2NPs and an oral dose of HSP daily for 8 weeks. Blood samples were obtained for biochemical analysis. Neurotransmitters, oxidative stress biomarker levels, and inflammatory markers were measured in brain homogenates. Histological examination of the brain was performed through H&E staining. Results: Coadministration of hesperidin with TiO2NPs orally for 8 weeks decreased the levels of MDA, TNF-α, AChE, and dopamine in brain homogenates, which were increased in the TiO2NP group. It increased the other oxidative biomarkers (SOD, CAT, and GPx) and Nrf-2 expression levels. Brain histological sections of the TiO2NP-treated group show degeneration, necrosis, congestion, and inflammatory cell infiltration that decreased markedly in the coadministration of hesperidin with the TiO2NP group. Conclusion: Hesperidin cotreatment offers significant protection against TiO2NP-induced oxidative stress and biochemical and histological alteration in the brain.

Hydrogen peroxide-induced oxidative damage and protective role of peroxiredoxin 6 protein via EGFR/ERK signaling pathway in RPE cells

Introduction

Damage to retinal pigment epithelium (RPE) cells caused by oxidative stress is closely related to the pathogenesis of several blinding retinal diseases, such as age-related macular degeneration (AMD), retinitis pigmentosa, and other inherited retinal degenerative conditions. However, the mechanisms of this process are poorly understood. Hence, the goal of this study was to investigate hydrogen peroxide (H₂O₂)-induced oxidative damage and protective role of peroxiredoxin 6 (PRDX6) protein via EGFR/ERK signaling pathway in RPE cells.

Methods

Cells from a human RPE cell line (ARPE-19 cells) were treated with H₂O₂, and then cell viability was assessed using the methyl thiazolyl tetrazolium assay. Cell death and reactive oxygen species (ROS) were detected by flow cytometry. The levels of PRDX6, epidermal growth factor receptor (EGFR), P38 mitogen-activated protein kinase (P38MAPK), c-Jun N-terminal kinase (JNK), and extracellular signal-regulated kinase (ERK) were detected by Western blot assay. PRDX6 and EGFR were also detected via immunofluorescence staining.

Results

Our results show that H₂O₂ inhibited cell viability, induced cell death, and increased ROS levels in ARPE-19 cells. It was also found that H₂O₂ decreased the levels of PRDX6, EGFR, and phosphorylated ERK but increased the levels of phosphorylated P38MAPK and JNK. PRDX6 overexpression was found to attenuate H₂O₂-induced inhibition of cell viability and increased cell death and ROS production in ARPE-19 cells. PRDX6 overexpression also increased the expression of EGFR and alleviated the H₂O₂-induced decrease in EGFR and phosphorylated ERK. Moreover, inhibition of epidermal growth factor-induced EGFR and ERK signaling in oxidative stress was partially blocked by PRDX6 overexpression.

Discussion

Our findings indicate that PRDX6 overexpression protects RPE cells from oxidative stress damage caused by decreasing ROS production and partially blocking the inhibition of the EGFR/ERK signaling pathway induced by oxidative stress. Therefore, PRDX6 shows promise as a therapeutic target for the prevention of RPE cell damage caused by oxidative stress associated with retinal diseases.

Evaluating the histomorphological and biochemical changes induced by Tributyltin Chloride on pituitary-testicular axis of adult albino rats and the possible ameliorative role of hesperidin

This study was performed to explore in detail the toxic effects of Tributyltin Chloride (TBT) on the pituitary-testicular axis and the possible amelioration with Hesperidin. Seventy-two adult male albino rats were divided into four groups: Control group (I), TBT-treated group (II), TBT+Hesperidin group (III), and Recovery group (IV). Body and testicular weights were measured. Blood samples were taken to estimate serum levels of testosterone, FSH and LH hormones by enzyme-linked immunosorbent assay (ELISA). Malondialdehyde (MDA) level was measured in testes homogenates. Tissue samples from the pituitary glands and testes were processed for light, electron microscope examination, and immunohistochemical detection of anti-FSH, and Ki67 proteins. Results showed a statistically significant decrease in testicular weight, serum testosterone, FSH and LH levels and a significant increase in tissue MDA in the TBT group when compared to the control group. TBT treatment caused severe histopathological changes with decreased area percent of PAS-stained basophils, and anti FSH immuno-stained gonadotrophs in the pituitary gland. The testes of group II also showed marked tissue damage, cell loss with decreased epithelial height and decreased number of proliferating spermatogenic cells. Hesperidin supplementation with TBT proved significant amelioration of the previously mentioned parameters in both glands which could improve male fertility. In conclusion: The flavonoid Hesperidin has the potential to protect against the reproductive damage induced by TBT in susceptible individuals.

Hesperetin ameliorates spinal cord injury by inhibiting NLRP3 inflammasome activation and pyroptosis through enhancing Nrf2 signaling

Neuroinflammation is a prominent feature of traumatic spinal cord injuries (SCIs). Hesperetin exhibits anti-inflammatory effects in neurological disorders; however, the potential neuroprotective effects of hesperetin in cases of SCI remain unclear. Sprague-Dawley rats with C5 hemi-contusion injuries were used as an SCI model. Hesperetin was administered to the experimental rats in order to investigate its neuroprotective effects after SCI, and BV2 cells were pretreated with hesperetin or silencing of nuclear factor erythroid 2-related factor 2 (siNrf2), and then stimulated with lipopolysaccharide (LPS) and adenosine triphosphate (ATP). The therapeutic impact and molecular mechanism of hesperetin were elucidated in a series of in vivo and in vitro investigations conducted using a combination of experiments. The results of the present in vivo experiment indicated that hesperetin improved functional recovery and protected spinal cord tissue after SCI. Hesperetin attenuated oxidative stress and microglial activation, lowered malondialdehyde (MDA) levels, and elevated catalase (CAT), glutathione (GSH)-Px, and superoxide dismutase (SOD) levels. Moreover, hesperetin downregulated the expression of advanced oxygenation protein products (AOPPs), ionized calcium-binding adapter molecule 1 (Iba-1), NOD-like receptor protein 3 (NLRP3), and interleukin-1 beta (IL-1β), but increased the expression of Nrf2. In vitro studies have shown that hesperetin inhibits the generation of reactive oxygen species (ROS), as well as the neuroinflammation associated with the upregulation of Nrf2 and heme oxygenase-1 (HO-1) in BV2 cells. The results of the present study indicated that hesperetin inhibited BV2 cell pyroptosis and significantly blocked the expression of NLRP3 inflammasome proteins (NLRP3 Caspase-1 p10 apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain [ASC]) and pro-inflammatory mediators (IL-18, IL-1β). Furthermore, the silencing of Nrf2 by small interfering ribonucleic acid (siRNA) partially abolished its antioxidant effect in the aforementioned cell experiments. Collectively, these findings illustrate that through an increase in Nrf2 signaling hesperetin reduces oxidative stress and neuroinflammation by suppressing NLRP3 inflammasome activation and pyroptosis.

Pharmacologic Comparison of High-Dose Hesperetin and Quercetin on MDCK II Cell Viability, Tight Junction Integrity, and Cell Shape

The modulation of tight junction (TJ) integrity with small molecules is important for drug delivery. High-dose baicalin (BLI), baicalein (BLE), quercetin (QUE), and hesperetin (HST) have been shown to open TJs in Madin-Darby canine kidney (MDCK) II cells, but the mechanisms for HST and QUE remain unclear. In this study, we compared the effects of HST and QUE on cell proliferation, morphological changes, and TJ integrity. HST and QUE were found to have opposing effects on the MDCK II cell viability, promotion, and suppression, respectively. Only QUE, but not HST, induced a morphological change in MDCK II into a slenderer cell shape. Both HST and QUE downregulated the subcellular localization of claudin (CLD)-2. However, only QUE, but not HST, downregulated CLD-2 expression. Conversely, only HST was shown to directly bind to the first PDZ domain of ZO-1, a key molecule to promote TJ biogenesis. The TGFβ pathway partially contributed to the HST-induced cell proliferation, since SB431541 ameliorated the effect. In contrast, the MEK pathway was not involved by both the flavonoids, since U0126 did not revert their TJ-opening effect. The results offer insight for using HST or QUE as naturally occurring absorption enhancers through the paracellular route.

Protective Effects of a Jellyfish-Derived Thioredoxin Fused with Cell-Penetrating Peptide TAT-PTD on H2O2-Induced Oxidative Damage

Thioredoxin (Trx) plays a critical role in maintaining redox balance in various cells and exhibits anti-oxidative, anti-apoptotic, and anti-inflammatory effects. However, whether exogenous Trx can inhibit intracellular oxidative damage has not been investigated. In previous study, we have identified a novel Trx from the jellyfish Cyanea capillata, named CcTrx1, and confirmed its antioxidant activities in vitro. Here, we obtained a recombinant protein, PTD-CcTrx1, which is a fusion of CcTrx1 and protein transduction domain (PTD) of HIV TAT protein. The transmembrane ability and antioxidant activities of PTD-CcTrx1, and its protective effects against H₂O₂-induced oxidative damage in HaCaT cells were also detected. Our results revealed that PTD-CcTrx1 exhibited specific transmembrane ability and antioxidant activities, and it could significantly attenuate the intracellular oxidative stress, inhibit H₂O₂-induced apoptosis, and protect HaCaT cells from oxidative damage. The present study provides critical evidence for application of PTD-CcTrx1 as a novel antioxidant to treat skin oxidative damage in the future.

Lutein loaded double-layered polymer nanocarrier modulate H2O2 and CoCl2 induced oxidative and hypoxia damage and angiogenic markers in ARPE-19 cells

Lutein plays a crucial role in the protection of retina by diminishing oxidative stress in diabetic retinopathy (DR). However, its poor aqueous solubility, chemical instability and low bioavailability edge its application. Also, beneficial effects of lutein supplementation and lower lutein levels in the serum and retina of DR patients created an interest in nanopreparation. Hence, lutein-loaded chitosan‑sodium alginate nanocarrier comprising oleic acid core (LNCs) was developed and examined its protective effect on hyperglycemia-mediated changes in oxidative stress and angiogenesis in ARPE-19 cells. Results showed that the LNCs have smaller size and a smooth spherical morphology and did not affect the ARPE-19 cell viability (up to 20 μM) and showed higher cellular uptake in both normal and H₂O₂-induced stress conditions. LNCs pre-treatment suppressed the H₂O₂-induced oxidative stress and CoCl₂-induced hypoxia-mediated elevation of intracellular reactive oxygen species, protein carbonyl and malondialdehyde levels by restoring antioxidant enzymes in ARPE-19 cells. Further, LNCs protected H₂O₂-mediated down-regulation of Nrf2 and its downstream antioxidant enzymes. LNCs also restored the H₂O₂-altered angiogenic (Vascular endothelial growth factor (VEGF), X-box binding protein 1 (XBP-1) and Hypoxia-inducible factor 1-alpha (HIF-1α)), endoplasmic reticulum stress (activating transcription factor-4 (ATF4)) and tight junction (Zona occludens 1 (ZO-1)) markers. To conclude, we could successfully develop biodegradable LNCs to improve the cellular uptake of lutein to treat DR by curtailing oxidative stress in retina.

Role of flavonoids in age-related macular degeneration

A common eye disorder known as age-related macular degeneration (AMD) eventually results in blindness and vision loss. AMD has a complicated and poorly understood aetiology. The main pathological processes associated with AMD include oxidative damage, inflammation, and neovascularization. Flavonoids are naturally occurring bioactive substances with extensive distribution and antioxidant, anti-inflammatory, and neovascularization inhibitory properties. Several in vitro and in vivo AMD-related models pertinent to vision and this ocular ailment have been used to assess the mechanisms of action of various flavonoids. This article will discuss the research progress of flavonoids in AMD, especially the characteristics and mechanism of flavonoids in treating AMD.

The benefits of hesperidin in central nervous system disorders, based on the neuroprotective effect

Disorders of central nervous system (CNS) disorders are considered serious health issues. The most common CNS diseases include neurodegenerative diseases, mental disorders, demyelinating disease, ischemia-reperfusion injury, and neuroinflammation. As a natural phenolic compound, hesperidin is a flavanone glycoside with various biological effects. Increasing evidence show that the growth of CNS diseases is hindered by hesperidin. Here, we have reviewed the related literature on neuropharmacological mechanisms for the preventive and therapeutic effects of hesperidin on CNS diseases. Several cellular and animal models have been developed to evaluate the underlying neuropharmacological mechanisms of hesperidin. Additionally, clinical evidence has confirmed its neuroprotective function. Hesperidin exerts its neuroprotective properties by decreasing neuro-inflammatory and apoptotic pathways. Hesperidin function has been studied in preclinical models for CNS diseases, but little is known about its definite effect in humans. Hesperidin can effectively alleviate depression and improve cognition and memory. It is urgent to explore and discover clinical trials for further confirmation of the neuroprotective efficacy of hesperidin and to evaluate its safety profile.

Chitooligosaccharides Derivatives Protect ARPE-19 Cells against Acrolein-Induced Oxidative Injury

Age-related macular degeneration (AMD) is the leading cause of vision loss among the elderly. The progression of AMD is closely related to oxidative stress in the retinal pigment epithelium (RPE). Here, a series of chitosan oligosaccharides (COSs) and N-acetylated derivatives (NACOSs) were prepared, and their protective effects on an acrolein-induced oxidative stress model of ARPE-19 were explored using the MTT assay. The results showed that COSs and NACOs alleviated APRE-19 cell damage induced by acrolein in a concentration-dependent manner. Among these, chitopentaose (COS–5) and its N-acetylated derivative (N–5) showed the best protective activity. Pretreatment with COS–5 or N–5 could reduce intracellular and mitochondrial reactive oxygen species (ROS) production induced by acrolein, increase mitochondrial membrane potential, GSH level, and the enzymatic activity of SOD and GSH-Px. Further study indicated that N–5 increased the level of nuclear Nrf2 and the expression of downstream antioxidant enzymes. This study revealed that COSs and NACOSs reduced the degeneration and apoptosis of retinal pigment epithelial cells by enhancing antioxidant capacity, suggesting that they have the potential to be developed into novel protective agents for AMD treatment and prevention.

Zebrafish: A Model Deciphering the Impact of Flavonoids on Neurodegenerative Disorders

Over the past century, advances in biotechnology, biochemistry, and pharmacognosy have spotlighted flavonoids, polyphenolic secondary metabolites that have the ability to modulate many pathways involved in various biological mechanisms, including those involved in neuronal plasticity, learning, and memory. Moreover, flavonoids are known to impact the biological processes involved in developing neurodegenerative diseases, namely oxidative stress, neuroinflammation, and mitochondrial dysfunction. Thus, several flavonoids could be used as adjuvants to prevent and counteract neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. Zebrafish is an interesting model organism that can offer new opportunities to study the beneficial effects of flavonoids on neurodegenerative diseases. Indeed, the high genome homology of 70% to humans, the brain organization largely similar to the human brain as well as the similar neuroanatomical and neurochemical processes, and the high neurogenic activity maintained in the adult brain makes zebrafish a valuable model for the study of human neurodegenerative diseases and deciphering the impact of flavonoids on those disorders.

An assessment of the ameliorative role of hesperidin in Drosophila melanogaster model of cadmium chloride-induced toxicity

Cadmium chloride (CdCl₂) is an important heavy metal widely regarded as an environmental contaminant. Hesperidin, a flavanone glycoside found in citrus fruits, has an established properties against free radicals, apoptosis, and inflammation. The present study investigated the protective actions of hesperidin on CdCl₂-induced oxidative damage and inflammation in Drosophila melanogaster. For 7 consecutive days via their diet regimen, the flies were exposed to CdCl₂ alone (0.05 mM) or in combination with hesperidin (50 and 100 μM). Exposure to CdCl₂ significantly (p < 0.05) increased mortality rate of flies, whereas the survived flies demonstrated significant oxidative toxicity from decreased activities of catalase and Glutathione S-transferase (GST) and Total Thiol (T-SH) and Non-Protein Thiols (NPSH) levels as well as accumulation of Nitric Oxide (NO (nitrite/nitrate)), protein carbonyl and Hydrogen Peroxide (H₂O₂). However, hesperidin-supplemented diet improved Acetylcholinesterase (AChE) activity, mitochondrial metabolic rate (cell viability), locomotor activity, and amelioration of oxidative damage and lipid peroxidation induced by CdCl₂. The hesperidin diet supplement boosted the antioxidant milieu and ameliorated the oxidative damage in the treated flies. Overall, the findings revealed that hesperidin improved antioxidative protective capacity in Drosophila melanogaster model of CdCl₂-induced toxicity. This suggests hesperidin as a potential therapeutic agent against oxidative stress disorders due to exposure to CdCl₂ and or related toxicants.

Enhancement on antioxidant, anti-hyperglycemic and antibacterial activities of blackberry anthocyanins by processes optimization involving extraction and purification

This research aimed to recover anthocyanin-rich extracts from blackberry (Rubus spp. Hull cultivar) by optimizing the processing conditions, and to characterize anthocyanin individuals and determine influences of optimization on enhancement of antioxidant and anti-hyperglycemic activities of anthocyanins as natural supplements. The ethanol concentration of 69.87%, HCl dosage of 0.53%, solid-to-liquid ratio of 1:19.06 at 47.68°C for 17.04 h were optimal to obtain the highest extraction yield of anthocyanins at 0.72 mg/g. By using AB-8 macroporous resins, the anthocyanin concentration of 3.0 mg/mL, ethanol concentration of 90%, and elution rate of 2.0 mL/min were selected to boost the anthocyanin purity up to be 60.11%. Moreover, the purified anthocyanin extracts from blackberry contained nine main pigments which could be divided into three aglycone-based forms, and cyanidin-3-O-glucoside was the most abundant among them. Due to the successive processes of extraction and purification, the blackberry purified anthocyanin extracts (BA-PAE) showed much higher bioactive capacities than the blackberry crude anthocyanin extracts (BA-CAE) and blackberry fruit slurry extracts (BA-FSE), e.g., DPPH and ABTS radical scavenging activities (EC₅₀ = 0.08 and 0.04, 0.32 and 0.24, and 1.31 and 0.41 mg/mL), oxygen radical absorbance capacity (1.60, 0.59, and 0.15 mmol TEAC/g), cytoprotective effects against oxidative stress in PC12 cells (1.69-, 1.58-, and 1.50-fold cell viability compared to oxidative group), α-amylase and α-glucosidase inhibitory activities (IC₅₀ = 0.10 and 0.06, 0.56 and 0.32, and 3.98 and 2.16 mg/mL), and antibacterial activity (93.23, 40.85, and 80.42% reduced biofilm).

Hesperidin Inhibits the p53-MDMXInteraction-Induced Apoptosis of Non-Small-Cell Lung Cancer and Enhances the Antitumor Effect of Carboplatin

Objective

This study aimed to observe the effect of hesperidin on the apoptosis, proliferation, and invasion of non-small-cell lung cancer, as well as to explore the possible mechanism. The inhibitory effect of hesperidin combined with carboplatin on non-small-cell lung cancer was also investigated.

Methods

A549 and NCI-H460 cells were treated with different concentrations of hesperidin (10, 50, and 100 μM). The effect of siRNA knockdown on MDMX on the antitumor effect of hesperidin was observed. CCK-8 was used to detect cell activity. The apoptosis rate was determined by TUNEL. The transwell assay detects the ability of cell migration and invasion. The expression levels of the apoptosis-related proteins p53, MDM2, MDMX, p21, PUMA, Bcl-2, and Bax were detected by qRT-PCR. Cell-proliferation and transwell assays were used to detect the effects of the combined use of hesperidin and carboplatin on lung cancer cells.

Results

Hesperidin significantly inhibited the activity and invasion of A549 and NCI-H460 cells in a dose-dependent manner. Hesperidin also induced the apoptosis of A549 and NCI-H460 cells. Hesperidin further inhibited the interaction between p53 and MDMX, increased the expression of p53, and played an anticancer role. The combination of hesperidin and carboplatin showed the most obvious antitumor effect.

Conclusion

Hesperidin can inhibit lung cancer by inhibiting the interaction between p53 and MDMX. Moreover, the combination of hesperidin and carboplatin can inhibit the migration and invasion of lung cancer cell lines through p53 upregulation, thereby increasing the antitumor effect of carboplatin.

Polyphenols Targeting Oxidative Stress in Spinal Cord Injury: Current Status and Future Vision

A spinal cord injury (SCI) occurs when the spinal cord is deteriorated or traumatized, leading to motor and sensory functions lost even totally or partially. An imbalance within the generation of reactive oxygen species and antioxidant defense levels results in oxidative stress (OS) and neuroinflammation. After SCI, OS and occurring pathways of inflammations are significant strenuous drivers of cross-linked dysregulated pathways. It emphasizes the significance of multitarget therapy in combating SCI consequences. Polyphenols, which are secondary metabolites originating from plants, have the promise to be used as alternative therapeutic agents to treat SCI. Secondary metabolites have activity on neuroinflammatory, neuronal OS, and extrinsic axonal dysregulated pathways during the early stages of SCI. Experimental and clinical investigations have noted the possible importance of phenolic compounds as important phytochemicals in moderating upstream dysregulated OS/inflammatory signaling mediators and axonal regeneration's extrinsic pathways after the SCI probable significance of phenolic compounds as important phytochemicals in mediating upstream dysregulated OS/inflammatory signaling mediators. Furthermore, combining polyphenols could be a way to lessen the effects of SCI.

The Effect of Polyphenols on Kidney Disease: Targeting Mitochondria

Mitochondrial function, including oxidative phosphorylation (OXPHOS), mitochondrial biogenesis, and mitochondria dynamics, are essential for the maintenance of renal health. Through modulation of mitochondrial function, the kidneys are able to sustain or recover acute kidney injury (AKI), chronic kidney disease (CKD), nephrotoxicity, nephropathy, and ischemia perfusion. Therapeutic improvement in mitochondrial function in the kidneys is related to the regulation of adenosine triphosphate (ATP) production, free radicals scavenging, decline in apoptosis, and inflammation. Dietary antioxidants, notably polyphenols present in fruits, vegetables, and plants, have attracted attention as effective dietary and pharmacological interventions. Considerable evidence shows that polyphenols protect against mitochondrial damage in different experimental models of kidney disease. Mechanistically, polyphenols regulate the mitochondrial redox status, apoptosis, and multiple intercellular signaling pathways. Therefore, this review attempts to focus on the role of polyphenols in the prevention or treatment of kidney disease and explore the molecular mechanisms associated with their pharmacological activity.

Hesperetin-Based Hydrogels Protect the Skin against UV Radiation-Induced Damage

UV radiation can cause damages, such as erythema, skin photoaging, and carcinogenesis. The adoption of protective measures against sun exposure is essential to prevent these damages, and the interest in using natural substances as an alternative for photoprotection is growing. Thus, hesperetin with antioxidant, anti-inflammatory, and anticancer properties is a promising substance to be used with photochemopreventive action and to protect the skin from damage induced by UV radiation. Therefore, the present study aimed to develop a topical formulation based on AAMVPC gel containing hesperetin and evaluate its photoprotective effect on the skin of rats exposed to UVA-UVB radiation. The animals were submitted to the irradiation protocol UVA-UVB, and at the end, erythema, lipid peroxidation, and activity of the antioxidant enzyme catalase and superoxide dismutase were evaluated. Additionally, it evaluated the activity of myeloperoxidase and histological changes. The formulation presented a rheological and spreadability profile suitable for cutaneous application. In vivo results demonstrated that the topical formulation of AAMVPC gel containing hesperetin at a concentration of 10% protected the skin from damage induced by UVA-UVB radiation, with the absence of erythema, lipid lipoperoxidation, and inflammation (low myeloperoxidase activity), and increased catalase and superoxide dismutase activities. The morphology and architecture of the dermo-epidermal tissue of these animals were like those observed under normal conditions (non-irradiated animals). Thus, the results showed that hesperetin was able to protect the animals' skin against UV radiation-induced skin damage and the protection mechanisms may be related to the antioxidant and anti-inflammatory properties of this natural product.

Neuroprotective Effects and Therapeutic Potential of the Citrus Flavonoid Hesperetin in Neurodegenerative Diseases

Neurodegenerative disorders affect more than fifty million Americans each year and represent serious health threats as the population ages. Neuroinflammation and oxidative stress are critical in the onset, progression, and pathogenesis of neurodegenerative diseases such as Alzheimer’s (AD), Parkinson’s (PD), and amyotrophic lateral sclerosis (ALS). A wide range of natural compounds has been investigated because of their antioxidant, anti-inflammatory, and neuroprotective properties. The citrus flavonoid hesperetin (HPT), an aglycone of hesperidin found in oranges, mandarins, and lemons, has been extensively reported to exert neuroprotective effects in experimental models of neurogenerative diseases. This review has compiled multiple studies on HPT in both in vivo and in vitro models to study neurodegeneration. We focused on the modulatory effects of hesperetin on the release of cellular anti-inflammatory and antioxidative stress mediators. Additionally, this review discusses the hesperetin effect in maintaining the levels of microRNA (miRNA) and modulating autophagy as it relates to hesperetin’s protective mechanisms against neurodegeneration. Moreover, this review is focused on providing experimental data for hesperetin’s potential as a neuroprotective compound and discusses reported evidence that HPT crosses the blood–brain barrier. In summary, this review shows the evidence available in the literature to indicate the efficacy of hesperetin in delaying the onset of neurodegenerative diseases.

Antidiabetic efficacy of Trifolium alexandrinum extracts hesperetin and quercetin in ameliorating carbohydrate metabolism and activating IR and AMPK signaling in the pancreatic tissues of diabetic rats

Diabetes is a metabolic disease that is mainly characterized by hyperglycemia. The present work investigated the efficacy of the flavanones hesperetin (HES) and quercetin (Q) extracted from Trifolium alexandrinum (TA) to treat type 2 diabetic rats. Wistar albino rats were supplemented with a high fat diet (HFD) for 2 weeks and then administered streptozotocin to induce diabetes. Diabetic rats were orally treated with Q, HES, and TA extract at concentrations of 40, 50, and 200 mg/kg BW, respectively, for 4 weeks. Various biochemical, molecular, and histological analysis were performed to evaluate the antidiabetic effects of these treatments. Q, HES, and TA extract treatments all significantly improved diabetic rats' levels of serum glucose, insulin, glucagon, liver function enzymes, hepatic glycogen, α-amylase, lipase enzymes, lipid profiles, oxidative stress indicators, and antioxidant enzymes as compared with control diabetic untreated rats. In addition, supplementation with Q, HES, and TA extract attenuated the activities of glucose-6-phosphate; fructose-1,6-bisphospahate; 6-phosphogluconate dehydrogenase; glucose-6-phosphate dehydrogenase; glucokinase; and hexokinase in pancreatic tissue, and they improved the levels of glucose transporter 2 and glucose transporter 4. Furthermore, these treatments modulated the expressions levels of insulin receptor (IR), phosphoinositide 3-kinase (PI3K), AMP-activated protein kinase (AMPK), caspase-3, and interleukin-1β (IL-1β). Enhancement of the histological alterations in pancreatic tissues provided further evidence of the ability of Q, HES, and TA extract to exert antidiabetic effects. Q, HES, and TA extract remedied insulin resistance by altering the IR/PI3K and AMPK signaling pathways, and they attenuated type 2 diabetes by improving the antioxidant defense system.

Compositional Analysis of Four Kinds of Citrus Fruits with an NMR-Based Method for Understanding Nutritional Value and Rational Utilization: From Pericarp to Juice

Citrus is one of the most important economic crops and is widely distributed across the monsoon region. Citrus fruits are deeply loved by consumers because of their special color, fragrance and high nutritional value. However, their health benefits have not been fully understood, especially the pericarps of citrus fruits which have barely been utilized due to their unknown chemical composition. In the present study, the pericarp and juices of four typical varieties of citrus fruits (lemon, dekopon, sweet orange and pomelo) were analyzed by NMR spectroscopy combined with pattern recognition. A total of 62 components from the citrus juices and 87 components from the citrus pericarps were identified and quantified, respectively. The different varieties of the citrus fruits could be distinguished from the others, and the chemical markers in each citrus juice and pericarp were identified by a combination of univariate and multivariate statistical analyses. The nutritional analysis of citrus juices offers favorable diet recommendations for human consumption and data guidance for their potential medical use, and the nutritional analysis of citrus pericarps provides a data reference for the subsequent comprehensive utilization of citrus fruits. Our results not only provide an important reference for the potential nutritional and medical values of citrus fruits but also provide a feasible platform for the traceability analysis, adulteration identification and chemical composition analysis of other fruits.

The Age-Related Macular Degeneration (AMD)-Preventing Mechanism of Natural Products

Age-related macular degeneration (AMD) is related to central visual loss in elderly people and, based on the increment in the percentage of the aging population, the number of people suffering from AMD could increase. AMD is initiated by retinal pigment epithelium (RPE) cell death, finally leading to neovascularization in the macula lutea. AMD is an uncurable disease, but the symptom can be suppressed. The current therapy of AMD can be classified into four types: device-based treatment, anti-inflammatory drug treatment, anti-vascular endothelial growth factor treatment, and natural product treatment. All these therapies have adverse effects, however early AMD therapy used with products has several advantages, as it can prevent RPE cell apoptosis in safe doses. Cell death (apoptosis) is caused by various factors, such as oxidative stress, inflammation, carbonyl stress, and a deficiency in essential components for cells, and RPE cell death is related to oxidative stress, inflammation, and carbonyl stress. Some natural products have anti-oxidative effects, anti-inflammation effects, and/or anti-carbonylation effects. The AMD preventive mechanism of natural products varies, with some natural products activating one or more anti-apoptotic pathways, such as the Nrf2/HO-1 anti-oxidative pathway, the anti-inflammasome pathway, and the anti-carbonyl pathway. As AMD drug candidates from natural products effectively inhibit RPE cell death, they have the potential to be developed as drugs for preventing early (dry) AMD.

Hulless Black Barley as a Carrier of Probiotics and a Supplement Rich in Phenolics Targeting Against H2O2-Induced Oxidative Injuries in Human Hepatocarcinoma Cells

Lactic acid bacteria can provide benefits to human beings and transform phenolic substances to improve their potential functionality. It was of interest to develop black barley as a carrier of probiotics and nutraceutical supplement rich in more antioxidants. Due to fermentation, bacterial counting and free phenolic content in black barley increased to 9.54 ± 0.22 log cfu/mL and 5.61 ± 0.02 mg GAE/mL, respectively. Eleven phenolic compounds, including nine isoflavones and two nitrogenous compounds were characterized using UPLC-QTOF-MS, among which epicatechin, hordatine, and pelargonidin aglycone were largely enriched. Moreover, free phenolic extracts from fermented barley (F-BPE) played a greater role in scavenging DPPH radicals, reducing Fe3+ to Fe2+, and increasing oxygen radical absorbance capacity, compared phenolic extracts from unfermented barley [UF-BPE (1.94-, 1.71-, and 1.35-fold at maximum for F-BPE vs. UF-BPE, respectively)]. In hepatocarcinoma cells, F-BPE also better inhibited ROS production and improved cell viability, cell membrane integrity, SOD activity, and non-enzymatic antioxidant GSH redox status (2.85-, 3.28-, 2.05-, 6.42-, and 3.99-fold at maximum for F-BPE vs. UF-BPE, respectively).

Non-neglectable therapeutic options for age-related macular degeneration: A promising perspective from traditional Chinese medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Age-related macular degeneration (AMD) is a chronic neurodegenerative disease which causes irreversible central vision loss among the elderly population. Traditional Chinese Medicine (TCM), including formulas, acupuncture and herbs, has been used in the treatment of AMD for thousands of years and is currently used by many AMD patients around the world.

AIM OF THE REVIEW

A comprehensive, in-depth literature review examining the use of TCM in the treatment of AMD has yet to be compiled. This review will improve current knowledge relating to the use of TCM and will open new avenues of exploration in developing new drugs for the treatment of AMD.

METHODS

A literature search of the PubMed database, Web of Science, Google Scholar and China National Knowledge Infrastructure (CNKI) was performed using relevant terms and keywords related to TCM in the treatment of AMD. Related books, PhD and master's theses were also researched.

RESULTS

The TCM-based interpretation of AMD has been used to establish a theoretical foundation for understanding the effect of TCM formulas and acupuncture on AMD. The possible mechanism of action of common Chinese herbs has also been discussed in detail.

CONCLUSION

TCM is a promising treatment option of AMD patients. However, lack of rigorous scientific evidence has limited the impact and uptake of TCM therapy. Future research should focus on improving understanding of the mechanism of action and bioactive components of TCM therapies.

Effects of Polyphenols on Oxidative Stress, Inflammation, and Interconnected Pathways during Spinal Cord Injury

Despite the progression in targeting the complex pathophysiological mechanisms of neurodegenerative diseases (NDDs) and spinal cord injury (SCI), there is a lack of effective treatments. Moreover, conventional therapies suffer from associated side effects and low efficacy, raising the need for finding potential alternative therapies. In this regard, a comprehensive review was done regarding revealing the main neurological dysregulated pathways and providing alternative therapeutic agents following SCI. From the mechanistic point, oxidative stress and inflammatory pathways are major upstream orchestras of cross-linked dysregulated pathways (e.g., apoptosis, autophagy, and extrinsic mechanisms) following SCI. It urges the need for developing multitarget therapies against SCI complications. Polyphenols, as plant-derived secondary metabolites, have the potential of being introduced as alternative therapeutic agents to pave the way for treating SCI. Such secondary metabolites presented modulatory effects on neuronal oxidative stress, neuroinflammatory, and extrinsic axonal dysregulated pathways in the onset and progression of SCI. In the present review, the potential role of phenolic compounds as critical phytochemicals has also been revealed in regulating upstream dysregulated oxidative stress/inflammatory signaling mediators and extrinsic mechanisms of axonal regeneration after SCI in preclinical and clinical studies. Additionally, the coadministration of polyphenols and stem cells has shown a promising strategy for improving post-SCI complications.

MiR-125b attenuates retinal pigment epithelium oxidative damage via targeting Nrf2/HIF-1α signal pathway

The retinal pigment epithelium cells (RPE) are sensitive to oxidative stimuli due to long-term exposure to various environmental stimuli. Thus, the oxidative injury of RPE cells caused by the imbalance of redox homeostasis is one of the main pathogenic factors of age-related macular degeneration (AMD). But the sophisticated mechanisms linking AMD to oxidative stress are not fully elucidated. Activation of Nrf2 signal pathway can protect RPE cells from oxidative damage. The present study investigated the regulating mechanism of miR-125b in Nrf2 cascade and evaluated its antioxidant capacity. The in vitro studies indicated that overexpression of miR-125b substantially inhibited Keap1 expression, enhanced Nrf2 expression and induced Nrf2 nuclear translocation. Importantly, functional studies demonstrated that forced expression of miR-125b could significantly elevate cell proliferation and superoxide dismutase (SOD) levels while reduce reactive oxygen species (ROS) overproduction and malondialdehyde (MDA) formation. Further studies showed that miR-125b had no effect when Nrf2 was silenced in ARPE-19 cells. Additionally, the results identified that Nrf2 silence induced ROS accumulation enhances HIF-1α protein expression, while miR-125b could offset this effect via promoting HIF-1α protein degradation. Subsequent in vivo studies demonstrated that sodium iodate induced outer retina thinner was reversed with exogenous supplementation of miR-125b, which was cancelled in Nrf2 knockout mice. In conclusion, this study illustrated that miR-125b can protect RPE from oxidative damage via targeting Nrf2/HIF-1α signal pathway and potentially may serve as a therapeutic agent of AMD.

A polysaccharide from Lycium barbarum L.: Structure and protective effects against oxidative stress and high-glucose-induced apoptosis in ARPE-19 cells

Lycium barbarum polysaccharides (LBPs) are beneficial for vision; however, relevant research has mainly focused on entire crude polysaccharides, with the basis and exact structure of the polysaccharide rarely explored. In this study, LICP009-3F-2a, a novel polysaccharide from Lycium barbarum L., was separated and then purified using anion-exchange and size-exclusion chromatography. Structural characteristics were investigated using chemical and spectroscopic methods, which revealed that LICP009-3F-2a has an Mw of 13720 Da and is an acidic heteropolysaccharide composed of rhamnose (39.1%), arabinose (7.4%), galactose (22.5%), glucose (8.3%), galacturonic acid (13.7%), and glucuronic acid (4.0%). Linkage and NMR data revealed that LICP009-3F-2a has the following backbone: →2)-α-L-Rha-(1→2,4)-α-L-Rha- (1→4)-α-D-GalAp-(1→3,6)-β-D-Galp-(1→3,6)-β-D-Galp-(1→6)-β-D-Galp-(1→, with three main branches, including: α-L-Araf-(1→5)-α-L-Araf-(1→6)-β-D-Glcp-(1→2,4)-α-L-Rha-(1→, β-D-Glcp-(1→4)-β-D-Glcp-(1→3,6)-β-D-Galp-(1→, and β-D-Galp-(1→3)-β-D-Galp-(1→3,6) -β-D-Galp-(1→. Differential scanning colorimetry and thermogravimetric analysis showed that LICP009-3F-2a is thermally stable, while X-ray diffractometry showed that LICP009-3F-2a has a semi-crystalline structure. In addition, LICP009-3F-2a protects ARPE-19 cells from H₂O₂-induced oxidative damage by regulating the expression of antioxidant SOD1 and CAT enzymes and down-regulating MMP2 expression. Moreover, LICP009-3F-2a promotes the proliferation of ARPE-19 cells in a concentration-dependent manner, and protects ARPE-19 cells from hyperglycemia by inhibiting apoptosis.

Fucoxanthin Pretreatment Ameliorates Visible Light-Induced Phagocytosis Disruption of RPE Cells under a Lipid-Rich Environment via the Nrf2 Pathway

Fucoxanthin, a special xanthophyll derived from marine algae, has increasingly attracted attention due to its diverse biological functions. However, reports on its ocular benefits are still limited. In this work, the ameliorative effect of fucoxanthin on visible light and lipid peroxidation-induced phagocytosis disruption in retinal pigment epithelium (RPE) cells was investigated in vitro. Marked oxidative stress, inflammation, and phagocytosis disruption were evident in differentiated RPE cells following their exposure to visible light under a docosahexaenoic acid (DHA)-rich environment. Following pretreatment with fucoxanthin, however, the activated nuclear factor erythroid-derived-2-like 2 (Nrf2) signaling pathway was observed and, furthermore, when the fucoxanthin -pretreated RPE cells were irradiated with visible light, intracellular reactive oxygen species (ROS), malondialdehyde (MDA) levels and inflammation were obviously suppressed, while phagocytosis was significantly improved. However, following the addition of Nrf2 inhibitor ML385, the fucoxanthin exhibited no ameliorative effects on the oxidative stress, inflammation, and phagocytosis disruption in the RPE cells, thus indicating that the ameliorative effect of fucoxanthin on the phagocytosis of RPE cells is closely related to the Nrf2 signaling pathway. In conclusion, these results suggest that fucoxanthin supplementation might be beneficial to the prevention of visible light-induced retinal injury.

Exopolysaccharides produced by Lactobacillus rhamnosus GG alleviate hydrogen peroxide-induced intestinal oxidative damage and apoptosis through the Keap1/Nrf2 and Bax/Bcl-2 pathways in vitro

The purpose of the study was to explore the effect of exopolysaccharides (EPSs) of Lactobacillus rhamnosus GG (LGG) on the antioxidative and antiapoptotic activities of intestinal porcine epithelial cells (IPEC-J2). EPSs exhibited promising antioxidative activities, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, hydroxyl radical (˙OH) and superoxide anion radical (O₂˙^-) scavenging, as well as ferrous ion chelating ability. Moreover, EPSs of LGG could effectively alleviate the IPEC-J2 oxidative damage induced by H₂O₂ through the Bcl-2-associated (Bax)/B cell lymphoma-2 (Bcl-2) and Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor-erythroid 2-related factor-2 (Nrf2) signaling pathways and up-regulated the intracellular tight junction (TJ)-related proteins. In addition, EPSs significantly improved the survival rates of H₂O₂-damaged IPEC-J2 cells and had no cytotoxic activity, suggesting that EPSs produced by LGG may be an effective drug for relieving oxidative stress. Our study provided a theoretical basis for exploration of the application of probiotic secondary metabolites in practice.

Hesperetin ameliorates diabetes-associated anxiety and depression-like behaviors in rats via activating Nrf2/ARE pathway

Diabetes-associated affective disorders are of wide concern, and oxidative stress plays a vital role in the pathological process. This study was to investigate the cerebroprotective effects of hesperetin against anxious and depressive disorders caused by diabetes, exploring the potential mechanisms related to activation of Nrf2/ARE pathway. Streptozotocin-induced diabetic rats were intragastrically administrated with hesperetin (0, 50, and 150 mg/kg) for 10 weeks. Forced swimming test, open field test, and elevated plus maze were used to evaluate the anxiety and depression-like behaviors of rats. The brain was collected for assays of Nrf2/ARE pathway. Moreover, high glucose-cultured SH-SY5Y cells were used to further examine the neuroprotective effects of hesperetin and underlying mechanisms. Hesperetin showed anxiolytic and antidepressant effects in diabetic rats according to the behavior tests, and increased p-Nrf2 in cytoplasm and Nrf2 in nucleus followed by elevations in mRNA levels and protein expression of glyoxalase 1 (Glo-1) and γ-glutamylcysteine synthetase (γ-GCS) in brain, known target genes of Nrf2/ARE signaling. Moreover, hesperetin attenuated high glucose-induced neuronal damages through activation of the classical Nrf2/ARE pathway in SH-SY5Y cells. Further study indicated that PKC inhibition or GSK-3β activation pretreatment attenuated even abolished the effect of hesperetin on the protein expression of Glo-1 and γ-GCS in high glucose-cultured SH-SY5Y cells. In summary, hesperetin ameliorated diabetes-associated anxiety and depression-like behaviors in rats, which was achieved through activation of the Nrf2/ARE pathway. Furthermore, an increase in nuclear Nrf2 phosphorylation from PKC activation and GSK-3β inhibition contributed to the activation of Nrf2/ARE pathway by hesperetin.

Medicine and food with particular reference to chinpi, dried citrus peel, and a component of Ninjin'yoeito

Kampo medicines contain many kinds of herbal drugs. Chinpi and Kippi, dried citrus peels, are components of a substantial number of Kampo medicine. They contain abundant flavonoids and studies on hesperidin, narirutin, and nobiletin as active ingredient have been conducted. Conversely, in Kagoshima prefecture, located in the southwestern part of the Japanese Islands, various citrus products are cultivated. Among them, Tankan and Daimasaki are specialies. In this study, we conducted high- performance liquid chromatography to determine the difference in flavonoid contents among Tankan, Daimasaki, Tankan related product, Chinpi, and Kippi. As a result, several active components, such as hesperidin, narirutin, nobiletin, and tangeretin, in common with crude drug, Chinpi, were detected in local citrus fruits. In addition, some active components little or not found in Chinpi, for example hesperetin and rutin, were detected in the local products. A detailed analysis of active components considering their genetic origin, the time of fruit collection, and different parts of the fruit used (peel, albedo, edible parts, and the whole) will need to be discussed to get the most out of the citrus fruits or make best use of them for health and longevity.