Quercetin and the mitochondria: A mechanistic view

An anti-senescence hydrogel with pH-responsive drug release for mitigating intervertebral disc degeneration and low back pain

Oxidative stress and aging lead to progressive senescence of nucleus pulposus (NP) cells, resulting in intervertebral disc (IVD) degeneration (IVDD). In some cases, degenerative IVD can further cause low back pain (LBP). Several studies have confirmed that delaying and rejuvenating the senescence of NP cells can attenuate IVDD. However, the relatively closed tissue structure of IVDs presents challenges for the local application of anti-senescence drugs. Here, we prepared an anti-senescence hydrogel by conjugating phenylboronic acid-modified gelatin methacryloyl (GP) with quercetin to alleviate IVDD by removing senescent NP cells. The hydrogel exhibited injectability, biodegradability, prominent biocompatibility and responsive release of quercetin under pathological conditions. In vitro experiments demonstrated that the hydrogel could reduce the expression of senescence markers and restore the metabolic balance in senescent NP cells. In vivo studies validated that a single injection of the hydrogel in situ could maintain IVD tissue structure and alleviate sensitivity to noxious mechanical force in the rat models, indicating a potential therapeutic approach for ameliorating IVDD and LBP. This approach helps prevent potential systemic toxicity associated with systemic administration and reduces the morbidity resulting from repeated injections of free drugs into the IVD, providing a new strategy for IVDD treatment.

Efficacy of Quercetin and Quercetin Loaded Chitosan Nanoparticles Against Cisplatin-Induced Renal and Testicular Toxicity via Attenuation of Oxidative Stress, Inflammation, and Apoptosis

BACKGROUND/OBJECTIVES

Flavonoids, including quercetin, have attracted much attention due to their potential health-promoting effects.

METHODS

The current experiment aims to see whether quercetin (QUE) in nanoparticle form could mitigate testicular and renal toxicity caused by cisplatin (CIS) more effectively than normally formulated QUE. Rats were randomly treated with CIS alone or in combination with QUE or QUE.NPs (Quercetin-loaded chitosan nanoparticles) for 4 weeks. QUE and QUE.NPs were given orally (10 mg/kg, three times a week), while CIS was given intraperitoneally (2 mg/kg, twice a week).

RESULTS

Compared to QUE- and CIS + QUE.NP-treated rats, CIS exposure induced anxiety and emotional stress as well as promoted oxidative stress in both testicular and renal tissues. Moreover, CIS reduced serum testosterone levels and diminished testicular IL-10, as well as CIS-induced renal failure, as indicated by hypokalemia, and increased levels of creatinine, urea, sodium, IL-18, and KIM-1. Further, severe histological changes were observed in the testis and kidney of CIS-intoxicated rats. Regarding immunohistochemical staining, CIS significantly upregulated Bax, downregulated Bcl-2, and moderately enhanced PCNA expression.

CONCLUSIONS

Our findings suggest that both QUE and QUE.NPs modulated emotional disturbance and improved testicular and renal functions via modulation of oxidation, inflammation, and apoptosis. However, QUE.NPs performed better than QUE-treated rats.

Smart Hydrogel Dressing Enhances the Healing of Chronic Infectious Diabetic Wounds through Dual-Barrier Drug Delivery Action

Chronic diabetic wounds struggle to heal due to drug-resistant bacterial infections, oxidative stress microenvironment, and immune dysfunction. At present, the disease has become a huge clinical challenge. Multifunctional hydrogels with antibacterial, antioxidant, and anti-inflammatory properties are becoming an emerging trend in the treatment of chronic wounds. However, matching different bioactive functions with the wound healing process to sequentially exert antibacterial, antioxidant, anti-inflammatory, and immunomodulatory functions remains a significant challenge. In this research, a hydrogel dressing with bactericidal and anti-inflammatory properties was synthesized by crafting a pH/ROS-responsive scaffold from phenylboronic acid-grafted hyaluronic acid (HA-PBA) and 4-arm-PEG-dopamine (4A-PEG-Dopa), employing dynamic borate ester bonds. This structure was then infused with the antimicrobial peptide (AMP) and ROS-sensitive micelle mPEG-TK-PLGA loaded with quercetin (QC). This dressing embodied a dual-barrier drug delivery mechanism, engineered for the prolonged and consistent liberation of QC. In the experiment, the hydrogel dissociated within the acidic microenvironment of diabetic wounds, thereby liberating the encapsulated micelles and AMP. Upon further dissociation, the micelles release QC due to the ROS-abundant microenvironment, which could relieve oxidative stress and encourage M2 polarization of macrophage via the Akt/STAT6 signaling pathway. Therefore, this smart delivery system, developed through our innovative approach, holds promise for treating chronic infectious diabetic wounds.

Association of Serum Bile Acid Profile with Diet and Physical Activity Habits in Japanese Middle-Aged Men

BACKGROUND/OBJECTIVES

Circulating bile acid (BA) profiles change with lifestyle and are closely related to intestinal BA metabolisms such as deconjugation and conversion to secondary BAs. The composition of BA in the blood is involved in systemic nutrient metabolism and intestinal health. Herein, we explored the associations of lifestyle and physical fitness with the circulating BA profile of middle-aged men.

METHODS

Data of 147 male participants (aged 50-64 years; BMI < 26 kg/m2; no medication for diabetes or dyslipidemia) from the Japan Multi-Institutional Collaborative Cohort study were analyzed. Serum concentrations of 15 types of BAs were examined for associations with variables on dietary habits, physical-activity habits, and physical fitness.

RESULTS

Green tea intake was positively associated with the deconjugation ratio of total BAs (p = 0.028) and negatively associated with secondary BA levels (free deoxycholic acid [DCA] (p = 0.078), glyco-DCA (p = 0.048), and tauro-DCA (p = 0.037)). In contrast, physical activity was negatively associated with the deconjugation ratio (p = 0.029) and secondary BA levels (free DCA (p = 0.098), and free lithocholic acid (p = 0.009)). Grip strength was also negatively associated with secondary BA levels (tauro-DCA (p = 0.041)) but was not associated with the deconjugation ratio. Energy and fat intake and skeletal muscle mass were not associated with the deconjugation ratio or secondary BA levels.

CONCLUSIONS

The study findings suggest that lifestyle-associated changes in serum deconjugated and secondary BAs indicate improvements in nutrient metabolism and the intestinal environment.

Quercetin Supplementation Alleviates Cadmium Induced Genotoxicity-Mediated Apoptosis in Caprine Testicular Cells

Being a common environmental pollutant, cadmium causes detrimental health effects, including testicular injury. Herein, we document the ameliorative potential of quercetin, a potent antioxidant, against cadmium-induced geno-cytotoxicity and steroidogenic toxicity in goat testicular tissue. Cadmium induced different comet types (Type 0 - Type 4), indicating the varying degree of DNA-damage in testicular cells. The quantitative analysis at 50 and 100 µM cadmium concentration revealed the DNA damage with per cent tail DNA as 75.78 ± 1.49 and 94.65 ± 0.95, respectively, in comparison to the control group (8.87 ± 0.48) post 8 h exposure duration. Cadmium caused a substantial decrease in the activity of key steroidogenic enzymes' (3β-HSD and 17β-HSD) along with reduction of testosterone level in testicular tissue. Furthermore, cadmium treatment induced various types of deformities in sperm, altered the Bax/Bcl-2 expression ratio in testicular tissue and thus suggesting the apoptosis-mediated death of testicular cells. Simultaneous quercetin supplementation, however, significantly (p < 0.05) averted the aforementioned cadmium-mediated damage in testicular tissue. Conclusively, the cadmium-induced DNA-damage and decrease in steroidogenic potential results in death of testicular cells via apoptosis, which was significantly counteracted by quercetin co-supplementation, and thus preventing the cadmium-mediated cytotoxicity of testicular cells.

Impact of quercetin on autophagy and apoptosis induced by a high concentration of CuSO4 in porcine ovarian granulosa cells

Copper is a vital micronutrient necessary for the maintenance of physiological functions. However, excessive amounts can lead to organ damage. Porcine ovarian granulosa cells are damaged by a high concentration of CuSO4, which can reduce the reproductive capacity of sows. Quercetin has shown remarkable efficacy in mitigating the harmful effects of heavy metals. Therefore, the aim of this study was to investigate the effects of a high concentration of CuSO4 on autophagy and apoptosis in porcine ovarian granulosa cells and to explore whether quercetin can counteract these toxic effect. Cell morphology, and the mRNA expression levels of autophagy-related genes (LC3-Ⅰ, ATG5, ATG7, ATG12, Beclin1, mTOR, LC3-Ⅱ and P62) were significantly changed upon treatment with 200 and 400 µM CuSO4. Treatment with 200 µM CuSO4 increased expression of P62 protein (P<0.05), promoted LC3-Ⅰ to LC3-Ⅱ conversion (P<0.05), and reduced PINK1 protein expression and the ATP content (P<0.05). In addition, expression of Caspase3 protein was increased and TUNEL staining indicated that the number of apoptotic cells was increased. However, co-treatment with 10 µM quercetin significantly decreased expression of P62 and conversion of LC3-Ⅰ to LC3-Ⅱ. Furthermore, flow cytometric analysis revealed that addition of 10 µM quercetin significantly reduced apoptosis induced by a high concentration of CuSO4. In summary, the results indicate that a high concentration of CuSO4 can trigger mitochondrial and autophagy dysfunction, activate mitochondrial apoptosis pathway, and exert cytotoxic effects. Quercetin can mitigate autophagy dysfunction, enhance autophagic processes, and alleviate apoptosis.

The multifaceted role of quercetin derived from its mitochondrial mechanism

Quercetin is a flavonoid with promising therapeutic applications; nonetheless, the phenotype exerted in some diseases is contradictory. For instance, anticancer properties may be explained by a cytotoxic mechanism, whereas antioxidant-related neuroprotection is a pro-survival process. According to the available literature, quercetin exerts a redox interaction with the electron transport chain (ETC) in the mitochondrion, affecting its membrane potential. It also affects ATP generation by oxidative phosphorylation, where ATP deprivation could partly explain its cytotoxic effect. Moreover, quercetin may support the generation of free radicals through redox reactions, causing a prooxidant effect. The nutrimental stress and prooxidant effect induced by quercetin might promote pro-survival properties such as antioxidant processes. Thus, in this review, we discuss the evidence supporting that quercetin redox interaction with the ETC could explain its beneficial and toxic properties.

Quercetin Modulates Ferroptosis via the SIRT1/Nrf-2/HO-1 Pathway and Attenuates Cartilage Destruction in an Osteoarthritis Rat Model

Osteoarthritis (OA) is the most common joint disease, causing symptoms such as joint pain, swelling, and deformity, which severely affect patients' quality of life. Despite advances in medical treatment, OA management remains challenging, necessitating the development of safe and effective drugs. Quercetin (QUE), a natural flavonoid widely found in fruits and vegetables, shows promise due to its broad range of pharmacological effects, particularly in various degenerative diseases. However, its role in preventing OA progression and its underlying mechanisms remain unclear. In this study, we demonstrated that QUE has a protective effect against OA development both in vivo and in vitro, and we elucidated the underlying molecular mechanisms. In vitro, QUE inhibited the expression of IL-1β-induced chondrocyte matrix metalloproteinases (MMP3 and MMP13) and inflammatory mediators such as INOS and COX-2. It also promoted the expression of collagen II, thereby preventing the extracellular matrix (ECM). Mechanistically, QUE exerts its protective effect on chondrocytes by activating the SIRT1/Nrf-2/HO-1 and inhibiting chondrocyte ferroptosis. Similarly, in an OA rat model induced by anterior cruciate ligament transection (ACLT), QUE treatment improved articular cartilage damage, reduced joint pain, and normalized abnormal subchondral bone remodeling. QUE also reduced serum IL-1β, TNF-α, MMP3, CTX-II, and COMP, thereby slowing the progression of OA. QUE exerts chondroprotective effects by inhibiting chondrocyte oxidative damage and ferroptosis through the SIRT1/Nrf-2/HO-1 pathway, effectively alleviating OA progression in rats.

Mini-encyclopedia of mitochondria-relevant nutraceuticals protecting health in primary and secondary care-clinically relevant 3PM innovation

Despite their subordination in humans, to a great extent, mitochondria maintain their independent status but tightly cooperate with the "host" on protecting the joint life quality and minimizing health risks. Under oxidative stress conditions, healthy mitochondria promptly increase mitophagy level to remove damaged "fellows" rejuvenating the mitochondrial population and sending fragments of mtDNA as SOS signals to all systems in the human body. As long as metabolic pathways are under systemic control and well-concerted together, adaptive mechanisms become triggered increasing systemic protection, activating antioxidant defense and repair machinery. Contextually, all attributes of mitochondrial patho-/physiology are instrumental for predictive medical approach and cost-effective treatments tailored to individualized patient profiles in primary (to protect vulnerable individuals again the health-to-disease transition) and secondary (to protect affected individuals again disease progression) care. Nutraceuticals are naturally occurring bioactive compounds demonstrating health-promoting, illness-preventing, and other health-related benefits. Keeping in mind health-promoting properties of nutraceuticals along with their great therapeutic potential and safety profile, there is a permanently growing demand on the application of mitochondria-relevant nutraceuticals. Application of nutraceuticals is beneficial only if meeting needs at individual level. Therefore, health risk assessment and creation of individualized patient profiles are of pivotal importance followed by adapted nutraceutical sets meeting individual needs. Based on the scientific evidence available for mitochondria-relevant nutraceuticals, this article presents examples of frequent medical conditions, which require protective measures targeted on mitochondria as a holistic approach following advanced concepts of predictive, preventive, and personalized medicine (PPPM/3PM) in primary and secondary care.

Ameliorative properties of quercetin in the treatment of traumatic brain injury: a mechanistic review based on underlying mechanisms

Traumatic brain injury (TBI) is a leading cause of disability worldwide, with an estimated annual incidence of 27-69 million. TBI is a severe condition that can lead to high mortality rates and long-term cognitive, behavioral, and physical impairments in young adults. It is a significant public health concern due to the lack of effective treatments available. Quercetin, a natural flavonoid found in various fruits and vegetables, has demonstrated therapeutic potential with anti-inflammatory, antioxidant, and neuroprotective properties. Recently, some evidence has accentuated the ameliorating effects of quercetin on TBI. This review discusses quercetin's ability to reduce TBI-related damage by regulating many cellular and molecular pathways. Quercetin in vitro and in vivo studies exhibit promise in reducing inflammation, oxidative stress, apoptosis, and enhancing cognitive function post-TBI. Further clinical investigation into quercetin's therapeutic potential as a readily available adjuvant in the treatment of TBI is warranted in light of these findings. This review adds to our knowledge of quercetin's potential in treating TBI by clarifying its mechanisms of action.

Qingfei xieding prescription ameliorates mitochondrial DNA-initiated inflammation in bleomycin-induced pulmonary fibrosis through activating autophagy

ETHNOPHARMACOLOGICAL RELEVANCE

Qingfei Xieding prescription was gradually refined and produced by Hangzhou Red Cross Hospital. The raw material includes Ephedra sinica Stapf, Morus alba L., Bombyx Batryticatus, Gypsum Fibrosum, Prunus armeniaca L. var. ansu Maxim., Houttuynia cordata Thunb. , Pueraria edulis Pamp. Paeonia L., Scutellaria baicalensis Georgi and Anemarrhena asphodeloides Bge. It is effective in clinical adjuvant treatment of patients with pulmonary diseases.

AIM OF THE STUDY

To explore the efficacy and underlying mechanism of Qingfei Xieding (QF) in the treatment of bleomycin-induced mouse model.

MATERIALS AND METHODS

TGF-β induced fibrotic phenotype in vitro. Bleomycin injection induced lung tissue fibrosis mouse model in vivo. Flow cytometry was used to detect apoptosis, cellular ROS and lipid oxidation. Mitochondria substructure was observed by transmission electron microscopy. Autophagolysosome and nuclear entry of P65 were monitored by immunofluorescence. Quantitative real-time PCR was performed to detect the transcription of genes associated with mtDNA-cGAS-STING pathway and subsequent inflammatory signaling activation.

RESULTS

TGF-β induced the expression of α-SMA and Collagen I, inhibited cell viability in lung epithelial MLE-12 cells that was reversed by QF-containing serum. TGF-β-mediated downregulation in autophagy, upregulation in lipid oxidation and ROS contents, and mitochondrial damage were rescued by QF-containing serum treatment, but CQ exposure, an autophagy inhibitor, prevented the protective role of QF. In addition to that, the decreased autophagolysosome in TGF-β-exposed MLE-12 cells was reversed by QF and restored to low level in the combination treatment of QF and CQ. Mechanistically, QF-containing serum treatment significantly inhibited mtDNA-cGAS-STING pathway and subsequent inflammatory signaling in TGF-β-challenged cells, which were abolished by CQ-mediated autophagy inhibition. In bleomycin-induced mouse model, QF ameliorated pulmonary fibrosis, reduced mortality, re-activated autophagy in lung tissues and restrained mtDNA-cGAS-STING inflammation pathway. However, the protective effects of QF in bleomycin-induced model mice were also abrogated by CQ.

CONCLUSION

QF alleviated bleomycin-induced pulmonary fibrosis by activating autophagy, inhibiting mtDNA-cGAS-STING pathway-mediated inflammation. This research recognizes the protection role of QF on bleomycin-induced mouse model, and offers evidence for the potentiality of QF in clinical application for pulmonary fibrosis treatment.

Quercetin prevents methylmercury-induced mitochondrial dysfunction in the cerebral cortex of mice

Methylmercury (MeHg) exposure can cause nerve damage and mitochondrial dysfunction. Mitochondrial dysfunction is mainly mediated by mitochondrial biogenesis and mitochondrial dynamics disorders. Quercetin (QE) plays an important role in activating silencing information regulator 2 related enzyme 1 (SIRT1), and SIRT1 activates peroxisome-proliferator-activated receptor-γ co-activator 1α (PGC-1α), which can regulate mitochondrial biogenesis and mitochondrial dynamics. The main purpose of this study was to explore the alleviating effects of QE on MeHg-induced nerve damage and mitochondrial dysfunction. The results showed that QE could reduce the excessive production of reactive oxygen species (ROS) and the loss of membrane potential induced by MeHg. Meanwhile, QE activated SIRT1 activity and SIRT1/PGC-1α signaling pathway, improved mitochondrial biogenesis and fusion and reduced mitochondrial fission. In summary, we hypothesized that QE prevents MeHg-induced mitochondrial dysfunction by activating SIRT1/PGC-1α signaling pathway.

Can Ganciclovir and Quercetin-P188 Ameliorate Cytomegalovirus Induced Hearing Loss?

OBJECTIVE

Determine whether combination therapy with ganciclovir (GCV) and a Quercetin-P188 solution improves hearing outcomes in a murine cytomegalovirus (CMV) model.

METHODS

BALB/c mice were infected with murine CMV on postnatal day 3 (p3). Quercetin was solubilized in saline using P188 (QP188). Treatment groups received either GCV, QP188, GCV and QP188, or P188 delivery vehicle BID at 12-hour intervals via intraperitoneal injection. All treatment groups were treated for 14 days starting at p3. Uninfected controls were treated with the combined regimen, saline or P188 delivery vehicle. Auditory thresholds were assessed using distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) testing at 4, 6, and 8 weeks of age. Temporal bones from separate CMV-infected groups were harvested at p10, and viral load was determined by quantitative polymerase chain reaction.

RESULTS

CMV-infected mice receiving combination therapy GCV+QP188 demonstrated statistically significant lower ABR (p < 0.001) and DPOAE thresholds (p < 0.001) compared with mice treated with GCV monotherapy, QP188 monotherapy, and P188 delivery vehicle at 4, 6, and 8 weeks of age. GCV+QP188 combination therapy, GCV monotherapy, and QP188 monotherapy resulted in a nonsignificant reduction in mean viral titers compared to P188 monotherapy (p = 0.08).

CONCLUSION

Combining GCV with the excipients quercetin and P188 effectively ameliorated CMV-induced sensorineural hearing loss in a murine model. This result may be partially explained by a reduction in viral titers in mouse temporal bones that correlate with in vitro studies demonstrating additive antiviral effect in cell culture.

LEVEL OF EVIDENCE

NA Laryngoscope, 134:1457-1463, 2024.

Elossaily G, Vellapandian C, Prajapati B. Investigating the Potential Impact of Air Pollution on Alzheimer's Disease and the Utility of Multidimensional Imaging for Early Detection

Pollution is ubiquitous, and much of it is anthropogenic in nature, which is a severe risk factor not only for respiratory infections or asthma sufferers but also for Alzheimer's disease, which has received a lot of attention recently. This Review aims to investigate the primary environmental risk factors and their profound impact on Alzheimer's disease. It underscores the pivotal role of multidimensional imaging in early disease identification and prevention. Conducting a comprehensive review, we delved into a plethora of literature sources available through esteemed databases, including Science Direct, Google Scholar, Scopus, Cochrane, and PubMed. Our search strategy incorporated keywords such as "Alzheimer Disease", "Alzheimer's", "Dementia", "Oxidative Stress", and "Phytotherapy" in conjunction with "Criteria Pollutants", "Imaging", "Pathology", and "Particulate Matter". Alzheimer's disease is not only a result of complex biological factors but is exacerbated by the infiltration of airborne particles and gases that surreptitiously breach the nasal defenses to traverse the brain, akin to a Trojan horse. Various imaging modalities and noninvasive techniques have been harnessed to identify disease progression in its incipient stages. However, each imaging approach possesses inherent limitations, prompting exploration of a unified technique under a single umbrella. Multidimensional imaging stands as the linchpin for detecting and forestalling the relentless march of Alzheimer's disease. Given the intricate etiology of the condition, identifying a prospective candidate for Alzheimer's disease may take decades, rendering the development of a multimodal imaging technique an imperative. This research underscores the pressing need to recognize the chronic ramifications of invisible particulate matter and to advance our understanding of the insidious environmental factors that contribute to Alzheimer's disease.

How Can Deep Eutectic Systems Promote Greener Processes in Medicinal Chemistry and Drug Discovery?

Chemists in the medicinal chemistry field are constantly searching for alternatives towards more sustainable and eco-friendly processes for the design and synthesis of drug candidates. The pharmaceutical industry is one of the most polluting industries, having a high E-factor, which is driving the adoption of more sustainable processes not only for new drug candidates, but also in the production of well-established active pharmaceutical ingredients. Deep eutectic systems (DESs) have emerged as a greener alternative to ionic liquids, and their potential to substitute traditional organic solvents in drug discovery has raised interest among scientists. With the use of DESs as alternative solvents, the processes become more attractive in terms of eco-friendliness and recyclability. Furthermore, they might be more effective through making the process simpler, faster, and with maximum efficiency. This review will be focused on the role and application of deep eutectic systems in drug discovery, using biocatalytic processes and traditional organic chemical reactions, as new environmentally benign alternative solvents. Furthermore, herein we also show that DESs, if used in the pharmaceutical industry, may have a significant effect on lowering production costs and decreasing the impact of this industry on the quality of the environment.

A multifunctional quercetin/polycaprolactone electrospun fibrous membrane for periodontal bone regeneration

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The efficacy of using metformin and/or quercetin for amelioration of gamma-irradiation induced tongue toxicity in diabetic rats

BACKGROUND

Diabetes is a common disease that cancer patients may suffer from and may aggravate side effects of radiotherapy. This study aimed to detect whether metformin and/or quercetin will improve gamma-irradiation induced tongue toxicity in diabetic rats.

METHODS

35 male albino rats were divided into five groups; NOR no streptozotocin, no radiation and no treatment was given, DR rats were subjected to streptozotocin then gamma-irradiation, DRM rats were subjected to streptozotocin then gamma-irradiation then metformin, DRQ rats were subjected to streptozotocin then gamma-irradiation then quercetin, DRMQ rats were subjected to streptozotocin then gamma-irradiation then metformin and quercetin. Rats were euthanized 24 h after last treatment dose. Mean blood glucose level was recorded. Tongue specimens were stained with H&E and CD68. Histomorphometric analysis of length, diameter and taste buds of lingual papillae and epithelial, keratin and lamina propria thickness and CD68 positive cells were calculated.

RESULTS

Blood glucose level of DRMQ was significantly lower than DR, DRM and DRQ, whereas higher than NOR. Metformin or quercetin partially restored tongue structure, papillae length and diameter and tongue layers thickness. The ameliorative effect was superior when metformin and quercetin were used together. Diabetes and irradiation significantly increased number of CD68 positive macrophages in submucosa and muscles. Metformin or quercetin significantly reduced number of lingual macrophages with more noticeable effect for quercetin. Treatment with metformin and quercetin significantly decreased number of macrophages.

CONCLUSIONS

Combined use of metformin and quercetin might help mitigate the harmful effects of radiotherapy and diabetes on lingual tissues.

Quercetin stimulates trophoblast fusion via the mitochondrial function

The fusion of mononuclear trophoblasts into multinucleate syncytiotrophoblasts is the critical event in the process of syncytialization, and its dysregulation can lead to pregnancy complications, notably hypertensive disorders of pregnancy (HDP). Oxidative stress may disrupt trophoblast syncytialization in HDP. Specifically, placentas with HDP exhibit impaired mitochondria, giving rise to the generation of reactive oxygen species (ROS) and subsequent oxidative stress. Quercetin, a bioflavonoid known for its antioxidant and anti-aging properties, has the potential to mitigate oxidative stress during trophoblast syncytialization. However, the precise mechanism underlying the action of quercetin in these processes remains to be elucidated. To explore the impact of quercetin on syncytialization, mitochondrial function, and ROS generation, cyclic AMP-stimulated BeWo cells were treated with quercetin. The expression of markers associated with cell fusion, mitochondrial function, and oxidative stress was determined using qPCR and western blotting. Additionally, morphological syncytialization and mitophagy (mitochondrial degradation) were assessed by immunofluorescence analysis. Our results revealed that quercetin increased the expression of syncytialization markers and promoted cell fusion. Furthermore, this compound also upregulated markers associated with mitophagy and mitochondrial fusion, which are corroborated by visual evidence of mitophagy through the fluorescence microscope. Cell fusion naturally stimulated ROS generation, which was attenuated by quercetin. Quercetin downregulated the expression of NRF2 and HO-1 during syncytialization, while increasing the expression of sirtuin1/3/6, which are known to play essential roles in antioxidant responses. In conclusion, quercetin effectively regulates mitochondrial function through its antioxidant properties and the suppression of ROS generation, ultimately promoting trophoblast fusion, suggesting that the flavonoid has the potential to ameliorate pregnancy-related disorder stemming from placental dysplasia.

Role of Mediterranean diet in endocrine diseases: a joint overview by the endocrinologist and the nutritionist

PURPOSE

The purpose of this review is to examine the current evidence on the potential role of Mediterranean diet (MD) in the prevention and management of endocrine disorders and to highlight the importance of interdisciplinary collaboration between endocrinologists and nutritionists.

METHODS

A literature search was conducted using PubMed and Google Scholar databases to identify relevant studies published in English. Studies were selected based on their relevance to the role of MD in the prevention and management of endocrine disorders. The search terms included "Mediterranean diet," "endocrine disorders," "thyroid disorders," "gonadal disorders," and "neuroendocrine tumors".

RESULTS

The studies reviewed suggest that MD may have a beneficial effect in the prevention and management of various endocrine disorders, including thyroid disorders, gonadal disorders, and neuroendocrine tumors. MD has been associated with decreased risk of nodular thyroid disease and thyroid cancer, improved male and female reproductive health, and a potential role in the management of neuroendocrine tumors. MD's anti-inflammatory and antioxidant properties, as well as its high levels of phytochemicals, may play a role in its beneficial effects.

CONCLUSION

Interdisciplinary collaboration between endocrinologists and nutritionists is essential for the optimal management of endocrine disorders, including the potential role of MD in their prevention and management. While further research is needed, the current evidence suggests that MD may have a protective effect against endocrine disorders, and its incorporation into dietary recommendations may be beneficial.

Quercetin Attenuates the Combined Effects of Zearalenone and Lipopolysaccharide on IPEC-J2 Cell Injury through Activating the Nrf2 Signaling Pathway

Zearalenone (ZEA) is a mycotoxin with an estrogen-like effect that is widely found in feed. Lipopolysaccharides (LPS) derived from Gram-negative bacteria are a common endotoxin, and both toxins have effects on human and livestock health. During animal feeding, ZEA as an exotoxin and LPS as an endotoxin have the potential to co-exist in organisms. At present, other studies have only focused on the hazards of single toxins, but there are fewer studies on the coexistence and interaction between ZEA and LPS. Therefore, a further study to investigate the combined toxic effects of different concentrations of ZEA and LPS is warranted. Quercetin (QUE) is a natural flavonoid compound with strong antioxidant and anti-inflammatory properties. It is unclear whether QUE can mitigate the combined effects of ZEA and LPS. IPEC-J2, isolated from the jejunum of non-breastfed neonatal piglets, is an ideal model for the study of epithelial cell transport, intestinal bacterial interactions, and the nutrient modulation of intestinal function. Therefore, the purpose of the present study was to demonstrate the effect of QUE in alleviating the combined toxic effect of ZEA and LPS on IPEC-J2 cell damage. Cell viability was measured after treating IPEC-J2 cells sequentially with 10, 20, 30, 40, 60, 80, and 100 μM ZEA, 1, 10, 50, and 100 μg/mL LPS, and 20, 40, 60, 80, 100, and 200 μM QUE for 24 h. Based on the cell viability results, 20 μM ZEA and 1 μg/mL LPS were selected as the most suitable concentrations for further analysis. For QUE, 20 μM increased the cell viability, while 40-200 μM QUE decreased the cell viability. Therefore, for the subsequent study, 20 μM QUE was selected in combination with 20 μM ZEA and 1 μg/mL LPS. The results showed that QUE increased the cellular viability and decreased the LDH content more compared to the effects of the ZEA+LPS group. At the gene level, QUE addition up-regulated the expression of Nrf2, HO-1, SOD2, and NQO1 at the gene or protein level compared to those of the ZEA+LPS group. The measurement of tight junction-related genes and proteins showed QUE up-regulated the expression of Claudin, ZO-1, and Occludin genes and proteins more than in the ZEA+LPS group. QUE addition reduced the rate of apoptosis more than that in the ZEA+LPS group. The expressions of Bcl-2 and Bax were examined at the gene level, and QUE addition significantly reduced the Bax gene expression level compared to that of the ZEA+LPS group, but there was no apparent variation in the expression level of Bcl-2. In summary, QUE can alleviate the combined toxic effects of ZEA and LPS on IPEC-J2 cells via modulating the Nrf2 signaling pathway, up-regulating the expression of antioxidative genes, and enhancing the intestinal barrier.

Anti-CMV therapy, what next? A systematic review

Human cytomegalovirus (HCMV) is one of the main causes of serious complications in immunocompromised patients and after congenital infection. There are currently drugs available to treat HCMV infection, targeting viral polymerase, whose use is complicated by toxicity and the emergence of resistance. Maribavir and letermovir are the latest antivirals to have been developed with other targets. The approval of letermovir represents an important innovation for CMV prevention in hematopoietic stem cell transplant recipients, whereas maribavir allowed improving the management of refractory or resistant infections in transplant recipients. However, in case of multidrug resistance or for the prevention and treatment of congenital CMV infection, finding new antivirals or molecules able to inhibit CMV replication with the lowest toxicity remains a critical need. This review presents a range of molecules known to be effective against HCMV. Molecules with a direct action against HCMV include brincidofovir, cyclopropavir and anti-terminase benzimidazole analogs. Artemisinin derivatives, quercetin and baicalein, and anti-cyclooxygenase-2 are derived from natural molecules and are generally used for different indications. Although they have demonstrated indirect anti-CMV activity, few clinical studies were performed with these compounds. Immunomodulating molecules such as leflunomide and everolimus have also demonstrated indirect antiviral activity against HCMV and could be an interesting complement to antiviral therapy. The efficacy of anti-CMV immunoglobulins are discussed in CMV congenital infection and in association with direct antiviral therapy in heart transplanted patients. All molecules are described, with their mode of action against HCMV, preclinical tests, clinical studies and possible resistance. All these molecules have shown anti-HCMV potential as monotherapy or in combination with others. These new approaches could be interesting to validate in clinical trials.

Therapeutic potential of senolytic agent quercetin in osteoarthritis: A systematic review and meta-analysis of preclinical studies

BACKGROUND

Quercetin, a natural flavonoid, has shown promise as a senolytic agent for various degenerative diseases. Recently, its protective effect against osteoarthritis (OA), a representative age-related disease of the musculoskeletal system, has attracted much attention. The aim of this study is to summarize and analyze the current literature on the effects of quercetin on OA cartilage in in vivo preclinical studies.

METHODS

The Medline (via/using PubMed), Embase, and Web of Science databases were searched up to March 10th, 2023. Risk of bias and the qualitative assessment including mechanisms of all eligible studies and a meta-analysis of cartilage histological scores among the applicable studies was performed.

RESULTS

A total of 12 in vivo animal studies were included in this systematic review. A random-effects meta-analysis was performed on six studies using the Osteoarthritis Research Society International (OARSI) scoring system, revealing that quercetin significantly improved OA cartilage OARSI scores (SMD, -6.30 [95% CI, -9.59 to -3.01]; P = 0.0002; heterogeneity: I2 = 86%). The remaining six studies all supported quercetin's protective effects against OA during disease and aging.

CONCLUSIONS

Quercetin has shown beneficial effects on cartilage during OA across animal species. Future double-blind randomized controlled clinical trials are needed to verify the efficacy of quercetin in the treatment of OA in humans.

Quercetin ameliorates oxidative stress-induced senescence in rat nucleus pulposus-derived mesenchymal stem cells via the miR-34a-5p/SIRT1 axis

BACKGROUND

Intervertebral disc degeneration (IDD) is a main contributor to low back pain. Oxidative stress, which is highly associated with the progression of IDD, increases senescence of nucleus pulposus-derived mesenchymal stem cells (NPMSCs) and weakens the differentiation ability of NPMSCs in degenerated intervertebral discs (IVDs). Quercetin (Que) has been demonstrated to reduce oxidative stress in diverse degenerative diseases.

AIM

To investigate the role of Que in oxidative stress-induced NPMSC damage and to elucidate the underlying mechanism.

METHODS

In vitro, NPMSCs were isolated from rat tails. Senescence-associated β-galactosidase (SA-β-Gal) staining, cell cycle, reactive oxygen species (ROS), real-time quantitative polymerase chain reaction (RT-qPCR), immunofluorescence, and western blot analyses were used to evaluated the protective effects of Que. Meanwhile the relationship between miR-34a-5p and Sirtuins 1 (SIRT1) was evaluated by dual-luciferase reporter assay. To explore whether Que modulates tert-butyl hydroperoxide (TBHP)-induced senescence of NPMSCs via the miR-34a-5p/SIRT1 pathway, we used adenovirus vectors to overexpress and downregulate the expression of miR-34a-5p and used SIRT1 siRNA to knockdown SIRT1 expression. In vivo, a puncture-induced rat IDD model was constructed, and X rays and histological analysis were used to assess whether Que could alleviate IDD in vivo.

RESULTS

We found that TBHP can cause NPMSCs senescence changes, such as reduced cell proliferation ability, increased SA-β-Gal activity, cell cycle arrest, the accumulation of ROS, and increased expression of senescence-related proteins. While abovementioned senescence indicators were significantly alleviated by Que treatment. Que decreased the expression levels of senescence-related proteins (p16, p21, and p53) and senescence-associated secreted phenotype (SASP), including IL-1β, IL-6, and MMP-13, and it increased the expression of SIRT1. In addition, the protective effects of Que on cell senescence were partially reversed by miR-34a-5p overexpression and SIRT1 knockdown. In vivo, X-ray, and histological analyses indicated that Que alleviated IDD in a puncture-induced rat model.

CONCLUSION

In summary, the present study provides evidence that Que reduces oxidative stress-induced senescence of NPMSCs via the miR-34a/SIRT1 signaling pathway, suggesting that Que may be a potential agent for the treatment of IDD.

The Role of Lifestyle and Dietary Factors in the Development of Premature Ovarian Insufficiency

Premature ovarian insufficiency (POI) is a condition that arises from dysfunction or early depletion of the ovarian follicle pool accompanied by an earlier-than-normal loss of fertility in young women. Oxidative stress has been suggested as an important factor in the decline of fertility in women and POI. In this review, we discuss the mechanisms of oxidative stress implicated in ovarian ageing and dysfunction in relation to POI, in particular mitochondrial dysfunction, apoptosis and inflammation. Genetic defects, autoimmunity and chemotherapy, are some of the reviewed hallmarks of POI that can lead to increased oxidative stress. Additionally, we highlight lifestyle factors, including diet, low energy availability and BMI, that can increase the risk of POI. The final section of this review discusses dietary factors associated with POI, including consumption of oily fish, mitochondria nutrient therapy, melatonin, dairy and vitamins that can be targeted as potential interventions, especially for at-risk women and in combination with personalised nutrition. Understanding the impact of lifestyle and its implications for POI and oxidative stress holds great promise in reducing the burden of this condition.

Uncovering ferroptosis in Parkinson's disease via bioinformatics and machine learning, and reversed deducing potential therapeutic natural products

Objective: Ferroptosis, a novel form of cell death, is closely associated with excessive iron accumulated within the substantia nigra in Parkinson's disease (PD). Despite extensive research, the underlying molecular mechanisms driving ferroptosis in PD remain elusive. Here, we employed a bioinformatics and machine learning approach to predict the genes associated with ferroptosis in PD and investigate the interactions between natural products and their active ingredients with these genes. Methods: We comprehensively analyzed differentially expressed genes (DEGs) for ferroptosis associated with PD (PDFerDEGs) by pairing 3 datasets (GSE7621, GSE20146, and GSE202665) from the NCBI GEO database and the FerrDb V2 database. A machine learning approach was then used to screen PDFerDEGs for signature genes. We mined the interacted natural product components based on screened signature genes. Finally, we mapped a network combined with ingredients and signature genes, then carried out molecular docking validation of core ingredients and targets to uncover potential therapeutic targets and ingredients for PD. Results: We identified 109 PDFerDEGs that were significantly enriched in biological processes and KEGG pathways associated with ferroptosis (including iron ion homeostasis, iron ion transport and ferroptosis, etc.). We obtained 29 overlapping genes and identified 6 hub genes (TLR4, IL6, ADIPOQ, PTGS2, ATG7, and FADS2) by screening with two machine learning algorithms. Based on this, we screened 263 natural product components and subsequently mapped the "Overlapping Genes-Ingredients" network. According to the network, top 5 core active ingredients (quercetin, 17-beta-estradiol, glycerin, trans-resveratrol, and tocopherol) were molecularly docked to hub genes to reveal their potential role in the treatment of ferroptosis in PD. Conclusion: Our findings suggested that PDFerDEGs are associated with ferroptosis and play a role in the progression of PD. Taken together, core ingredients (quercetin, 17-beta-estradiol, glycerin, trans-resveratrol, and tocopherol) bind well to hub genes (TLR4, IL6, ADIPOQ, PTGS2, ATG7, and FADS2), highlighting novel biomarkers for PD.

Inhibition of ATP synthase reverse activity restores energy homeostasis in mitochondrial pathologies

The maintenance of cellular function relies on the close regulation of adenosine triphosphate (ATP) synthesis and hydrolysis. ATP hydrolysis by mitochondrial ATP Synthase (CV) is induced by loss of proton motive force and inhibited by the mitochondrial protein ATPase inhibitor (ATPIF1). The extent of CV hydrolytic activity and its impact on cellular energetics remains unknown due to the lack of selective hydrolysis inhibitors of CV. We find that CV hydrolytic activity takes place in coupled intact mitochondria and is increased by respiratory chain defects. We identified (+)-Epicatechin as a selective inhibitor of ATP hydrolysis that binds CV while preventing the binding of ATPIF1. In cells with Complex-III deficiency, we show that inhibition of CV hydrolytic activity by (+)-Epichatechin is sufficient to restore ATP content without restoring respiratory function. Inhibition of CV-ATP hydrolysis in a mouse model of Duchenne Muscular Dystrophy is sufficient to improve muscle force without any increase in mitochondrial content. We conclude that the impact of compromised mitochondrial respiration can be lessened using hydrolysis-selective inhibitors of CV.

The Effects of Quercetin on Apoptosis and Antioxidant Activity in a Renal Ischemia/Reperfusion Injury Animal Model

Renal ischemia-reperfusion injury (IRI) is considered as one of the most prevalent causes of acute kidney injury (AKI), which can happen in various clinical situations including hypovolemic shock, injury, thrombo-embolism, and after a kidney transplant. This paper aims to evaluate the reno-protective effects of Quercetin in induced ischemia/reperfusion injury by regulating apoptosis-related proteins, inflammatory cytokines, MMP-2, MMP-9, and nuclear factor kappa-light-chain-enhancer inactivated B cells (NF-kB) in rats. The male Wistar rats (n=32) were randomly divided into Sham, untreated IR, and Quercetin-treated IR (gavage and intraperitoneal). Quercetin was given orally and intraperitoneally one hour before inducing ischemia-reperfusion injury . After reperfusion, blood samples and kidneys were collected to assess renal function and inflammatory cytokines, apoptotic signaling proteins, and antioxidants. Urea, creatinine, and MDA levels improved in Quercetin-treated groups with different administration methods. In addition, the activities of other antioxidant in Quercetin-treated rats were higher than those in the IR group. Further, Quercetin inhibited NF-kB signaling, apoptosis-associated factors and produced matrix metalloproteinase protein in the kidneys of rats. Based on the findings, the antioxidant, anti-inflammatory, and anti-apoptotic effects of the Quercetin diminished renal ischemia-reperfusion injury in the rats significantly. It is suggested that a single dosage of Quercetin have a reno-protective impact in the case of renal I/R injury.

The Role of Dietary Nutrients in Male Infertility: A Review

Male infertility is the main health issue with economic, psychological, and medical attributions. Moreover, it is characterized by an inability to produce a sufficient amount of sperm for the fertilization of an oocyte. Dietary nutrients (DN) have a great effect on male reproductive potential. Observations have indicated that adding DN may protect or treat male infertility. The scope of this criticism is to scrutinize the DN, such as omega-3 fatty acids, vitamins, minerals and other phytochemicals, in enhancing the semen attributes, sperm bioenergetics and sperm functionality in male infertility. It seems that diets rich in omega-3 fatty acids affect sperm quality and maintain the sperm membrane and mitochondria stability. An administration of phytochemicals caused an escalation in sperm mitochondrial function and a decrease in oxidative damage. Furthermore, sundry dietary natural phytochemicals differentially affect (negatively or positively) sperm motility, semen quality, and mitochondrial function, dependent on their levels. Vitamins and trace elements are also nutritional modulators in reducing oxidative stress, thereby enhancing sperm quality, which is accurately connected with sperm mitochondrial function. Also, we described the different types of DN as mitochondrial enhancer for sperm functionality and health. We believe that understanding the DN supports sperm mitochondria and epigenetic modulators that may be responsible for sperm quality and health, and will lead to more embattled and efficient therapeutics for male infertility.

Quercetin: Putative effects on the function of cryopreserved sperms in domestic animals

Quercetin is one of the most used antioxidant flavonoids and largely exists in many fruits and vegetables because of its capability to scavenge the free reactive oxygen species (ROSs) by repressing lipid peroxy radical fusion, metal ion chelating through enzyme inhibition, and adopting the repair mechanisms. It also exhibits various biological actions, including antioxidative, anti-inflammatory and antimicrobial activities. Furthermore, it contributes well to sustaining the endogenous cellular antioxidant defence system. The process of cryopreservation is associated with increased oxidative stress, and some steps are potential sources of ROSs, including the method of semen collection, handling, cryopreservation culture media, and thawing, which result in impaired sperm function. Several antioxidants have been proposed to counteract the harmful impact of ROS during semen cryopreservation. The antioxidant capability of quercetin has been verified in different animal species for providing valuable defence to sperm during the cryopreservation process. The beneficial properties of quercetin on various parameters of fresh and post-thaw sperm in different species are clarified in this review. More in-depth investigations are required to clarify quercetin's mechanism of action in different animal species.

Quercetin protects against iron overload-induced osteoporosis through activating the Nrf2/HO-1 pathway

AIMS

Eucommia is the tree bark of Eucommia japonica, family Eucommiaceae. In traditional Chinese medicine, Eucommia is often used to treat osteoporosis. Quercetin (QUE), a major flavonoid extract of Eucommia japonica, has been reported to have anti-osteoporosis effects. However, there are no studies reporting the mechanism of QUE in the treatment of iron overload-induced osteoporosis. This study set out to investigate the therapeutic effects of QUE against iron overload-induced bone loss and its potential molecular mechanisms.

MATERIALS AND METHODS

In vitro, MC3T3-E1 cells were used to study the effects of QUE on osteogenic differentiation, anti-apoptosis and anti-oxidative stress damage in an iron overload environment (FAC 200 μM). In vivo, we constructed an iron overload mouse model by injecting iron dextrose intraperitoneally and assessed the osteoprotective effects of QUE by Micro-CT and histological analysis.

KEY FINDINGS

In vitro, we found that QUE increased the ALP activity of MC3T3-E1 cells in iron overload environment, promoted the formation of bone mineralized nodules and upregulated the expression of Runx2 and Osterix. In addition, QUE was able to reduce FAC-induced apoptosis and ROS production, down-regulated the expression of Caspase3 and Bax, and up-regulated the expression of Bcl-2. In further studies, we found that QUE activated the Nrf2/HO-1 signaling pathway and attenuated FAC-induced oxidative stress damage. The results of the in vivo study showed that QUE was able to reduce iron deposition induced by iron dextrose and attenuate bone loss.

SIGNIFICANCE

Our results suggested that QUE protects against iron overload-induced osteoporosis by activating the Nrf2/HO-1 signaling pathway.

Polyphenols as potential metabolism mechanisms regulators in liver protection and liver cancer prevention

BACKGROUND

Liver cancer is one of the common malignancies. The dysregulation of metabolism is a driver of accelerated tumourigenesis. Metabolic changes are well documented to maintain tumour growth, proliferation and survival. Recently, a variety of polyphenols have been shown to have a crucial role both in liver disease prevention and metabolism regulation.

METHODS

We conducted a literature search and combined recent data with systematic analysis to comprehensively describe the molecular mechanisms that link polyphenols to metabolic regulation and their contribution in liver protection and liver cancer prevention.

RESULTS

Targeting metabolic dysregulation in organisms prevents and resists the development of liver cancer, which has important implications for identifying new therapeutic strategies for the management and treatment of cancer. Polyphenols are a class of complex compounds composed of multiple phenolic hydroxyl groups and are the main active ingredients of many natural plants. They mediate a broad spectrum of biological and pharmacological functions containing complex lipid metabolism, glucose metabolism, iron metabolism, intestinal flora imbalance, as well as the direct interaction of their metabolites with key cell-signalling proteins. A large number of studies have found that polyphenols affect the metabolism of organisms by interfering with a variety of intracellular signals, thereby protecting the liver and reducing the risk of liver cancer.

CONCLUSION

This review systematically illustrates that various polyphenols, including resveratrol, chlorogenic acid, caffeic acid, dihydromyricetin, quercetin, catechins, curcumin, etc., improve metabolic disorders through direct or indirect pathways to protect the liver and fight liver cancer.

Quercetin protects mouse oocytes against chromium-induced damage in vitro and in vivo

BACKGROUND

Chromium (Cr) is a naturally-occurring element that is used in various fields of industry. Humans may be exposed to hexavalent chromium [Cr(VI)], which is one of the stable valence states of the chromium through contaminated soil, air, and water. Exposure to Cr(VI) through contaminated drinking water, soil and air causes various cancers and also fertility problems in animals and humans. Quercetin (QCT), a common flavonoid compound, has numerous biological effects as an antioxidant and free radical scavenger, but its function and mechanisms in reproductive processes in various species remain unclear. This study aims to determine the chromium effects on mice oocyte quality and the ameliorative effect of QCT in both in vitro and in vivo experimental models.

METHODS

For the in vitro experiment, oocytes were collected and divided into the control, sham, QCT-treated, Cr(VI) (potassium dichromate), and treatment [Cr(VI)+QCT] groups. Collected oocytes were cultured in maturation medium with or without 10 µM quercetin and 10 µM Cr(VI) for 14 h based on the defined experimental design. For the in vivo experiment, the mice were randomly divided into the control, sham, QCT-treated, Cr(VI), and Cr(VI) + QCT groups. Control and sham mice received regular drinking water and diet. Cr(VI) group received Cr(VI) (50 ppm in drinking water) and Cr(VI) + QCT group received 50 ppm Cr(VI) with QCT (20 mg/kg body wt, through i.p) for a period of 21 days and then oocytes were collected and cultured for 14 h for in vitro maturation. For both experiments, at the end of the culture period, we examined the ameliorative effect of QCT on oocyte maturation, spindle formation, ROS production, mitochondrial function, and apoptosis.

RESULTS

Our in vitro and in vivo results showed that Cr(VI) disrupt the oocyte maturation and spindle formation (P < 0.001). Furthermore, we found that exposure to Cr(VI) significantly increased ROS levels and decreased mitochondrial membrane potential (P < 0.001). In addition, exposure to Cr(VI) induced early apoptosis and downregulated the Bcl-2 mRNA expression and upregulated the Caspase-3 and Bax mRNAs expression (P < 0.01). Finally, quercetin significantly restored the detrimental effects of Cr(VI).

CONCLUSION

The results indicated that quercetin protects the oocytes against Cr(VI) toxicity through the suppression of oxidative stress and apoptosis. The conclusions drawn from our study's findings suggest that quercetin might be useful agent for oocyte maturation in case of possible exposure to toxic substances such as chromium.

Quercetin alleviates cyclophosphamide-induced premature ovarian insufficiency in mice by reducing mitochondrial oxidative stress and pyroptosis in granulosa cells

BACKGROUND

Exposure to cyclophosphamide (CTX) induces premature ovarian insufficiency (POI). Quercetin is a natural flavonoid that exhibits anti-inflammatory and antioxidant properties, and its antioxidant activity is correlated with POI. However, the mechanism underlying its protective role in CTX-induced ovarian dysfunction is unclear. This study aimed to explore whether quercetin can protect ovarian reserves by activating mitochondrial biogenesis and inhibiting pyroptosis.

METHODS

Thirty-six female C57BL/6 mice were randomly subdivided into six groups. Except for the control group, all groups were injected with 90 mg/kg CTX to establish a POI model and further treated with coenzyme 10 or various doses of quercetin. The mice were sacrificed 48 h after 10 IU pregnant mare serum gonadotropin was injected four weeks after treatments. We used enzyme-linked immunosorbent assays to detect serum hormone expression and light and transmission electron microscopy to assess ovarian tissue morphology and mitochondria. Additionally, we tested oxidant and antioxidant levels in ovarian tissues and mitochondrial function in granulosa cells (GCs). The expression of mitochondrial biogenesis and pyroptosis-related proteins and mRNA was analyzed using western blotting and RT-qPCR.

RESULTS

Quercetin elevated serum anti-Müllerian hormone, estradiol, and progesterone levels, decreased serum follicle-stimulating hormone and luteinizing hormone levels, and alleviated ovarian pathology. It reduced the mitochondrial DNA content and mitochondrial membrane potential. Furthermore, it upregulated ATP levels and the mRNA and protein expression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α), mitochondrial transcription factor A, and superoxide dismutase 2. In addition, it suppressed NOD-like receptor pyrin domain containing 3, caspase-1, interleukin-1β, and gasdermin D levels in the GCs of POI mice.

CONCLUSIONS

Quercetin protected the ovarian reserve from CTX-induced ovarian damage by reversing mitochondrial dysfunction and activating mitochondrial biogenesis via the PGC1-α pathway. Moreover, quercetin may improve ovarian functions by downregulating pyroptosis in the CTX-induced POI model. Thus, quercetin can be considered a potential agent for treating POI.

Mitochondrial Aging and Senolytic Natural Products with Protective Potential

Living organisms do not disregard the laws of thermodynamics and must therefore consume energy for their survival. In this way, cellular energy exchanges, which aim above all at the production of ATP, a fundamental molecule used by the cell for its metabolisms, favor the formation of waste products that, if not properly disposed of, can contribute to cellular aging and damage. Numerous genes have been linked to aging, with some favoring it (gerontogenes) and others blocking it (longevity pathways). Animal model studies have shown that calorie restriction (CR) may promote longevity pathways, but given the difficult application of CR in humans, research is investigating the use of CR-mimetic substances capable of producing the same effect. These include some phytonutrients such as oleuropein, hydroxytyrosol, epigallo-catechin-gallate, fisetin, quercetin, and curcumin and minerals such as magnesium and selenium. Some of them also have senolytic effects, which promote the apoptosis of defective cells that accumulate over the years (senescent cells) and disrupt normal metabolism. In this article, we review the properties of these natural elements that can promote a longer and healthier life.

Identification of natural products and FDA-approved drugs for targeting cancer stem cell (CSC) propagation

Here, we report the identification of key compounds that effectively inhibit the anchorage-independent growth and propagation of cancer stem cells (CSCs), as determined via screening using MCF7 cells, a human breast adenocarcinoma cell line. More specifically, we employed the mammosphere assay as an experimental format, which involves the generation of 3D spheroid cultures, using low-attachment plates. These positive hit compounds can be divided into 5 categories: 1) dietary supplements (quercetin and glucosamine); 2) FDA-approved drugs (carvedilol and ciprofloxacin); 3) natural products (aloe emodin, aloin, tannic acid, chlorophyllin copper salt, azelaic acid and adipic acid); 4) flavours (citral and limonene); and 5) vitamins (nicotinamide and nicotinic acid). In addition, for the compounds quercetin, glucosamine and carvedilol, we further assessed their metabolic action, using the Seahorse to conduct metabolic flux analysis. Our results indicate that these treatments can affect glycolytic flux and suppress oxidative mitochondrial metabolism (OXPHOS). Therefore, quercetin, glucosamine and carvedilol can reprogram the metabolic phenotype of breast cancer cells. Despite having diverse chemical structures, these compounds all interfere with mitochondrial metabolism. As these compounds halt CSCs propagation, ultimately, they may have therapeutic potential.

Dual role of quercetin in enhancing the efficacy of cisplatin in chemotherapy and protection against its side effects: a review

Chemotherapy has opened a new window in cancer therapy. However, the resistance of cancer cells has dramatically reduced the efficacy of chemotherapy. Cisplatin is a chemotherapeutic agent and its potential in cancer therapy has been restricted by resistance of cancer cells. As a consequence, the scientists have attempted to find new strategies in elevating chemotherapy efficacy. Due to great anti-tumour activity, naturally occurring compounds are of interest in polychemotherapy. Quercetin is a flavonoid with high anti-tumour activity against different cancers that can be used with cisplatin to enhance its efficacy and also are seen to sensitise cancer cells into chemotherapy. Furthermore, cisplatin has side effects such as nephrotoxicity and ototoxicity. Administration of quercetin is advantageous in reducing the adverse effects of cisplatin without compromising its anti-tumour activity. In this review, we investigate the dual role of quercetin in enhancing anti-tumour activity of cisplatin and simultaneous reduction in its adverse effects.

Dual effect of the herbal matcha green tea (Camellia sinensis L. kuntze) supplement in EA.hy926 endothelial cells and Artemia salina

ETHNOPHARMACOLOGICAL RELEVANCE

Matcha green tea (Camellia sinensis) based-supplements have been widely used since they present a greater content of phenolic compounds than traditional green tea, which is popularly used in the treatment of diabetes. However, there are few studies on the effectiveness and safety of matcha supplements.

AIM OF THE STUDY

This work aimed to evaluate the efficacy and safety of this supplement in endothelial cells (EA.hy926) in the hyperglycemic model and in vivo Artemia salina.

MATERIALS AND METHODS

To assess the effect of Matcha herbal supplement (MHS), EA. hy926 endothelial cells were treated with 20 μg/mL of MHS for 24 h, in a hyperglycemic medium with 35 mM glucose. After treatment, cells were trypsinized and centrifuged at 4 °C and 47×g for 5 min. The pellet was used to determine the reaction products to thiobarbituric acid and the levels of nitric oxide. Electron transport chain activity and ATP levels were also evaluated. Intracellular pH, apoptosis, and mitochondrial membrane depolarization were evaluated by flow cytometry. MHS chemical characterization was performed by HPLC-UV and total phenolic content analysis. The evaluation of the antioxidant capacity of MHS was performed by 2,2-diphenyl-1-picrylhydrazyl radical scavenger assay. To determine the in vivo acute toxicity of MHS, an A. salina assay was conducted, using 0,2 mL of different concentrations of MHS (10, 50, 100, 250, 500, 750 and 1000 μg/mL). The LD₅₀ values were obtained by interpolation of 50% (y = 50) of the dead individuals in the trend curves.

RESULTS

Our data showed that MHS was able to avoid oxidative and nitrosative stress induced by hyperglycemia, demonstrating important antioxidant activity. However, it was observed that MHS reduced up to 90% the activity of the four-electron transport complexes, reducing the ATP production of the endothelial cells. In the toxicity assay performed in Artemia salina, MHS showed mild toxicity (LD₅₀ = 0,4 mg/mL). The major compounds found in MHS were epigallocatechin gallate, epicatechin, rutin, kaempferol, and quercetin.

CONCLUSIONS

This data draws attention to the fact that supplements with high content of phenolic compounds, capable of avoiding oxidative and nitrosative stress can have a dual effect and, simultaneously to antioxidant activity, can induce toxicity in different cell types.

Cytotoxicity of quercetin is related to mitochondrial respiration impairment in Saccharomyces cerevisiae

Quercetin is a flavonol ubiquitously present in fruits and vegetables that shows a potential therapeutic use in non-transmissible chronic diseases, such as cancer and diabetes. Although this phytochemical has shown promising health benefits, the molecular mechanism behind this compound is still unclear. Interestingly, quercetin displays toxic properties against phylogenetically distant organisms such as bacteria and eukaryotic cells, suggesting that its molecular target resides on a highly conserved pathway. The cytotoxicity of quercetin could be explained by energy depletion occasioned by mitochondrial respiration impairment and its concomitant pleiotropic effect. Thereby, the molecular basis of quercetin cytotoxicity could shed light on potential molecular mechanisms associated with its health benefits. Nonetheless, the evidence supporting this hypothesis is still lacking. Thus, this study aimed to evaluate whether quercetin supplementation affects mitochondrial respiration and whether this is related to quercetin cytotoxicity. Saccharomyces cerevisiae was used as a study model to assess the effect of quercetin on energetic metabolism. Herein, we provide evidence that quercetin supplementation: (1) decreased the exponential growth of S. cerevisiae in a glucose-dependent manner; (2) affected diauxic growth in a similar way to antimycin A (complex III inhibitor of electron transport chain); (3) suppressed the growth of S. cerevisiae cultures supplemented with non-fermentable carbon sources (glycerol and lactate); (4) promoted a glucose-dependent inhibition of the basal, maximal, and ATP-linked respiration; (5) diminished complex II and IV activities. Altogether, these data indicate that quercetin disturbs mitochondrial respiration between the ubiquinone pool and cytochrome c, and this phenotype is associated with its cytotoxic properties.

Quercetin Mediated TET1 Expression Through MicroRNA-17 Induced Cell Apoptosis in Melanoma Cells

A previous report suggested that the expression of ten-eleven translocation (TET) proteins is abnormal in certain cancers. Quercetin has been demonstrated as anti-cancer role in cancer development. In order to explore the inhibitory effect and mechanism of quercetin on uveal melanoma cells, the expression of TET proteins was analyzed in the present study. Our results suggest that the expression of TET1 was increased following treatment with quercetin in OCM-1, SK-MEL-1, and B16 cells. In addition, quercetin treatment induced apoptosis and inhibited migration and invasion. To further investigate the association of the expression of TET1 with cell growth, apoptosis, migration, and invasion, cell lines in which TET1 was knocked-down or overexpressed were constructed. The results showed that the increased expression of TET1-induced apoptosis, increased 5-hydroxymethylcytosine (5 hmC). and inhibited invasion. Our bioinformatics studies indicated that TET1 is a target gene of microRNA-17 (miR-17) Our results showed that inhibition of the expression of miR-17 resulted in increased TET1 expression in OCM-1 cells. Furthermore, our results indicated that quercetin treatment increased TET1 expression and inhibited melanoma growth in nude mice. Taken together, our results suggest that quercetin can regulate cell proliferation and apoptosis through TET1 via miR-17 in melanoma cells.

Quercetin Protects against MPP+/MPTP-Induced Dopaminergic Neuron Death in Parkinson's Disease by Inhibiting Ferroptosis

Ferroptosis, a novel form of regulated cell death, is caused by accumulation of lipid peroxides and excessive iron deposition. This process has been linked to the death of dopaminergic neurons in substantia nigra compacta (SNc) of Parkinson's disease (PD) patients. Quercetin (QCT), a natural flavonoid, has multiple pharmacological activities. However, it has not been established whether QCT can protect against dopaminergic neuron death by inhibiting ferroptosis. In this study, we investigated the potential antiferroptotic effects of QCT in cellular models established using specific ferroptosis inducers (Erastin and RSL-3) and MPP+. The effects were also explored using MPTP-induced PD mouse models. The cell counting kit-8 (CCK-8) assay was performed to assess cell viability. Variations in mitochondrial morphology were evaluated by transmission electron microscopy (TEM) while the mitochondrial membrane potential, mass, and ROS were measured by fluorescent probes. Lipid peroxidation levels were assayed through measurement of lipid ROS, MDA, GSH, and SOD levels. The effects of QCT on MPTP-induced behavioral disorders were examined by rotarod and open field tests. In vitro and in vivo, QCT significantly inhibited ferroptosis by activating the nuclear factor erythroid 2-related factor 2 (Nrf2) protein. Additionally, QCT ameliorated motor behavioral impairments and protected against the loss of dopaminergic neurons in MPTP-induced PD models. Interestingly, Nrf2 knockdown alleviated the protective effects of QCT against ferroptosis. In conclusion, these results demonstrate that ferroptosis is involved in MPP+/MPTP-induced PD, and QCT inhibits ferroptosis by activating the Nrf2 protein. Therefore, QCT is a potential agent for preventing the loss of dopaminergic neurons by targeting ferroptosis.

Morin and isoquercitrin protect against ischemic neuronal injury by modulating signaling pathways and stimulating mitochondrial biogenesis

OBJETIVE

The search for the etiology of Alzheimer's disease has revealed dysregulation of amyloid protein precursors, β-secretase, mitophagy, apoptosis, and Tau protein genes after ischemic brain injury. Due to this and the fact that some flavonoids have demonstrated anti-amyloidogenic effects on AD targets, we aimed to investigate whether they are effective against an ischemic neuronal injury not only by its antioxidant effects and clarify their mechanism.We simulated the energy depletion that characterizes ischemic processes using iodoacetic acid on HT22 cells. In vitro ischemic assays were also performed under OXPHOS inhibition using inhibitors of the different mitochondrial complexes and intracellular ATP, NADH and NADPH levels were determined. The signaling pathways of MAP kinase (MAPK) and of the PI3K/Akt mTOR were analyzed for its close association with post-ischemic survival.

RESULTS

Morin and isoquercitrin showed a significant neuroprotective effect against IAA toxicity, favored the activity of the mitochondrial complexes and prevented the decrease in ERK phosphorylation and activation of the stress proteins JNK and p38 caused by IAA treatment, as well as prevented satisfactorily mTOR and p70 dephosphorylation. They provide a considerable resistance to ischemic brain injury by modulating signaling pathways that stimulate mitochondrial biogenesis and promoting the activity of electron transport chain.

Quercetin Protects Ethanol-Induced Hepatocyte Pyroptosis via Scavenging Mitochondrial ROS and Promoting PGC-1α-Regulated Mitochondrial Homeostasis in L02 Cells

Alcoholic liver disease (ALD) is a multifaceted process that involves excessive lipid, reactive oxygen species (ROS) production, unbalanced mitochondrial homeostasis, and ultimate cell death. Quercetin is a dietary phytochemical presented in various fruits and vegetables, which has anti-inflammatory and antioxidant effects. According to recent advances in pharmanutritional management, the effects of quercetin on various mitochondrial processes have attracted attention. In the study, we explored whether quercetin could attenuate ethanol-induced hepatocyte pyroptosis by maintaining mitochondrial homeostasis and studied its hepatoprotective effect and the underlying mechanism. We chose L02 cells to establish an in vitro model with ethanol-induced hepatocyte pyroptosis. Then, the cells at approximately 80% confluence were treated with quercetin (80, 40, and 20 μM). The cell viability (CCK-8) was used to investigate the effect of quercetin on ethanol-induced L02 cell proliferation. Relative assay kits were used to measure oxidative stress index (OSI = TOS/TAS), lipid peroxidation (LPO) release, and mitochondrial membrane potential (δΨm). The morphology of mitochondria was characterized by transmission electron microscopy- (TEM-) based analysis. Mitochondrial dynamics (Mito Tracker Green), mitROS (MitoSOX Red Mitochondrial Superoxide) production, and nuclear DNA (nDNA) damage (γH2AX) markers were detected by immunofluorescence. The mRNA levels of mitochondrial function (including mitochondrial DNA (mtDNA) transcription genes TWNK, MTCO1, and MFND) and pyroptosis-related genes were detected by RT-qPCR, and the protein levels of NLRP3, ASC, caspase1, cleaved-caspase1, IL-18, IL-1β, and GSDMD-N were detected by western blot. The results showed that quercetin treatment downregulated redox status, lipid droplets, and LPO release, restored damaged mitochondrial membrane potential, and repaired mtDNA damage, PGC-1α nuclear transfer, and mitochondrial dynamics. The gene and protein expressions of NLRP3, ASC, cleaved-caspase1, IL-18, IL-1β, and GSDMD-N were decreased, which effectively inhibited cell pyroptosis. Therefore, the results indicated that quercetin protected ethanol-induced hepatocyte pyroptosis via scavenging mitROS and promoting PGC-1α-mediated mitochondrial homeostasis in L02 cells.

Silver@quercetin Nanoparticles with Aggregation-Induced Emission for Bioimaging In Vitro and In Vivo

Fluorescent materials based on aggregation-induced emission luminogens (AIEgens) have unique advantages for in situ and real-time monitoring of biomolecules and biological processes because of their high luminescence intensity and resistance to photobleaching. Unfortunately, many AIEgens require time-consuming and expensive syntheses, and the presence of residual toxic reagents reduces their biocompatibility. Herein, silver@quercetin nanoparticles (Ag@QCNPs), which have a clear core–shell structure, were prepared by redox reaction of quercetin (QC), a polyphenolic compound widely obtained from plants, including those used as foods, and silver ions. Ag@QCNPs show both aggregation-induced luminescence and the distinct plasma scattering of silver nanoparticles, as well as good resistance to photobleaching and biocompatibility. The Ag@QCNPs were successfully used for cytoplasmic labeling of living cells and for computerized tomography imaging in tumor-bearing mice, demonstrating their potential for clinical applications.

A non-retinol RAR-γ selective agonist-tectorigenin can effectively inhibit the UVA-induced skin damage

BACKGROUND AND PURPOSE

Long-term ultraviolet (UV) exposure can cause inflammation, pigmentation, and photoaging. All-trans-retinoic acid (ATRA) is a commonly used retinoic acid receptor (RAR) agonist in the clinical treatment of UV-induced skin problems; however, the use of such drugs is often accompanied by systemic adverse reactions caused by nonspecific activation of RARs. Therefore, this study is expected to screen for a novel RAR-γ-selective agonist with high safety.

EXPERIMENTAL APPROACH

Molecular docking, dynamic simulation, and Biacore were used to screen and obtain novel RAR-γ-selective agonists. RT-PCR, ELISA, western blotting, immunofluorescence staining, flow cytometry, and proteomic analysis were used to detect the effects of novel RAR-γ selective agonists on UVA-induced inflammation and photoaging cell models. UVA-induced mouse models were used to evaluate the effects of tectorigenin (TEC) on skin repair, aging, and inflammation.

KEY RESULTS

TEC is a novel RAR-γ-selective agonist. TEC inhibits UV-induced oxidative damage, inflammatory factor release, and matrix metalloproteinase (MMP) production. TEC can also reverse the UVA-induced loss of collagen. The results of the signalling pathway research showed that TEC mainly affects the MAPK/JNK/AP-1 pathway. In animal experiments, TEC showed better anti-inflammatory and anti-photoaging effects and caused less skin irritation than ATRA. Nano-particle loaded TEC, which significantly improved the utilization of TEC, is also presented.

CONCLUSIONS AND IMPLICATIONS

TEC is a non-retinol RAR-γ-selective agonist that can inhibit UV-induced skin damage and may be developed as a safe pharmaceutical component for the prevention of photoaging and skin inflammation.

Poloxamer 188 - quercetin formulations amplify in vitro ganciclovir antiviral activity against cytomegalovirus

Treatment of human cytomegalovirus (CMV) infection requires long-term administration of nucleoside analog antivirals such as ganciclovir (GCV), a therapy frequently limited by GCV-induced toxicity. Here, combining GCV treatment with two bioactive excipients, poloxamer 188 and quercetin, was investigated in vitro to reduce GCV dosage. Quercetin is a natural flavonoid exhibiting antiviral activity against CMV by a mechanism distinct from GCV, but is poorly soluble, limiting its use as a therapeutic. To overcome this challenge, quercetin was co-formulated with poloxamer 188 (P188, Pluronic ® F68). Quercetin-P188 (QP188) formulations yielded only modest CMV viral inhibition, with a selectivity index of 11.4, contrasted with a GCV selectivity index of 95. More significantly, when coadministered with GCV, QP188 exhibited an additive or synergistic interaction in subtherapeutic ranges of GCV. Fluorescence microscopy revealed QP188 accumulation in fibroblast mitochondria, suggesting that the excipient may modulate mitochondrial processes relevant to CMV infection. GCV antiviral therapy augmented with poloxamer-solubilized quercetin may be a viable approach to maintain CMV inhibition while lowering GCV doses, translating to reduced associated toxicity.

The Cooperative Anti-Neoplastic Activity of Polyphenolic Phytochemicals on Human T-Cell Acute Lymphoblastic Leukemia Cell Line MOLT-4 In Vitro

Acute lymphoblastic leukemia (ALL) is the most common hematological malignancy affecting pediatric patients. ALL treatment regimens with cytostatics manifest substantial toxicity and have reached the maximum of well-tolerated doses. One potential approach for improving treatment efficiency could be supplementation of the current regimen with naturally occurring phytochemicals with anti-cancer properties. Nutraceuticals such as quercetin, curcumin, resveratrol, and genistein have been studied in anti-cancer therapy, but their application is limited by their low bioavailability. However, their cooperative activity could potentially increase their efficiency at low, bioavailable doses. We studied their cooperative effect on the viability of a human ALL MOLT-4 cell line in vitro at the concentration considered to be in the bioavailable range in vivo. To analyze their potential side effect on the viability of non-tumor cells, we evaluated their toxicity on a normal human foreskin fibroblast cell line (BJ). In both cell lines, we also measured specific indicators of cell death, changes in cell membrane permeability (CMP), and mitochondrial membrane potential (MMP). Even at a low bioavailable concentration, genistein and curcumin decreased MOLT-4 viability, and their combination had a significant interactive effect. While resveratrol and quercetin did not affect MOLT-4 viability, together they enhanced the effect of the genistein/curcumin mix, significantly inhibiting MOLT-4 population growth in vitro. Moreover, the analyzed phytochemicals and their combinations did not affect the BJ cell line. In both cell lines, they induced a decrease in MMP and correlating CMP changes, but in non-tumor cells, both metabolic activity and cell membrane continuity were restored in time. (4) Conclusions: The results indicate that the interactive activity of analyzed phytochemicals can induce an anti-cancer effect on ALL cells without a significant effect on non-tumor cells. It implies that the application of the combinations of phytochemicals an anti-cancer treatment supplement could be worth further investigation regardless of their low bioavailability.

Pyrroloquinoline quinone (PQQ) protects mitochondrial function of HEI-OC1 cells under premature senescence

The aim of this study was to investigate the effects of pyrroloquinoline quinone (PQQ), an oxidoreductase cofactor, on the H₂O₂-induced premature senescence model in HEI-OC1 auditory cells and to elucidate its mechanism of action in vitro. Cells were treated with PQQ for 1 day before H₂O₂ (100 μM) exposure. Mitochondrial respiratory capacity was damaged in this premature senescence model but was restored in cells pretreated with PQQ (0.1 nM or 1.0 nM). A decrease in mitochondrial potential, the promotion of mitochondrial fusion and the accelerated movement of mitochondria were all observed in PQQ-pretreated cells. The protein expression of sirtuin 1 (SIRT1) and peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) were significantly decreased under H₂O₂ exposure while they were increased with PQQ pretreatment, and PGC-1α acetylation was significantly decreased. In conclusion, PQQ has a protective effect on the premature senescence model of HEI-OC1 auditory cells and is associated with the SIRT1/PGC-1α signaling pathway, mitochondrial structure, and mitochondrial respiratory capacity.

Ultrastructural analysis of cadmium-induced toxicity and its alleviation by antioxidant quercetin in caprine testicular germ cells in vitro

Increasing evidence has demonstrated that cadmium (Cd), a common environmental toxicant, has been associated with testicular toxicity. Quercetin, an efficient flavonoid, has been shown to exert cytoprotective effect in numerous pathological processes. The current study has employed ultrastructural analysis to examine the Cd-induced toxicity in goat testicular tissue along with the ameliorative action of quercetin in a dose- and time-dependent manner in-vitro. Results of transmission electron microscopy (TEM) revealed that at lower selected concentrations (10 and 50 µM), Cd induced apoptosis-mediated cytotoxicity in testicular tissue as supported by presence of various morphological attributes of apoptosis in testicular germ cells such as condensed and marginated chromatin followed by breakdown of chromatin material, swollen mitochondria, and vacuolization. At 100 µM concentration, along with apoptosis, Cd-induced cytotoxicity in testicular tissue was associated with induction of necrosis also. However, the simultaneous supplementation of antioxidant quercetin has markedly abrogated the testicular cytotoxicity as shown by restoration of Cd-evoked aberrant ultrastructure of testicular germ cells in a dose- and time-dependent manner, providing a basis for future studies to involve quercetin in management of Cd-induced reproductive toxicity in males.

Sesamol prevents mitochondrial impairment and pro-inflammatory alterations in the human neuroblastoma SH-SY5Y cells: role for Nrf2

Mitochondria are a primary source and a target of reactive oxygen species (ROS). Increased mitochondrial production of ROS is associated with bioenergetics decline, cell death, and inflammation. Here we investigated whether a pretreatment (for 24 h) with sesamol (SES; at 12.5-50 µM) would be efficient in preventing the mitochondrial collapse induced by hydrogen peroxide (H₂O₂, at 300 µM) in the human neuroblastoma SH-SY5Y cell line. We have found that a pretreatment with SES at 25 µM decreased the effects of H₂O₂ on lipid peroxidation, protein carbonylation, and protein nitration in membranes obtained from the mitochondria isolated from the SH-SY5Y cells. In this regard, SES pretreatment decreased the production of superoxide anion radical (O₂^-•) by the mitochondria of H₂O₂-treated cells. SES also prevented the mitochondrial dysfunction induced by H₂O₂, as assessed by analyzing the activity of the complexes I and V. The H₂O₂-induced reduction in the production of adenosine triphosphate (ATP) was also prevented by SES. The levels of the pro-inflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), as well as the activity of the transcription factor nuclear factor-κB (NF-κB) were downregulated by the SES pretreatment in the H₂O₂-challenged cells. Silencing of the nuclear factor erythroid 2-related factor 2 (Nrf2) transcription factor abolished the protection induced by SES regarding mitochondrial function and inflammation. Thus, SES depends on Nrf2 to promote mitochondrial protection in cells facing redox impairment.

Diet and Male Fertility: The Impact of Nutrients and Antioxidants on Sperm Energetic Metabolism

Diet might affect male reproductive potential, but the biochemical mechanisms involved in the modulation of sperm quality remain poorly understood. While a Western diet is considered a risk factor for male infertility, the Mediterranean diet seems to protect against male infertility; moreover, the role of a vegetarian habitus in the preservation of sperm quality is controversial. The aim of this review is to analyze the molecular effects of single nutrients on sperm quality, focusing on their involvement in biochemical mechanisms related to sperm bioenergetics. It appears that diets rich in saturated fatty acids (SFA) and low in polyunsaturated fatty acids (PUFA) negatively affect sperm quality, whereas unsaturated fatty acids supplementation ameliorates sperm quality. In fact, the administration of PUFA, especially omega-3 PUFA, determined an increase in mitochondrial energetic metabolism and a reduction in oxidative damage. Carbohydrates and proteins are also nutritional modulators of oxidative stress and testosterone levels, which are strictly linked to sperm mitochondrial function, a key element for sperm quality. Moreover, many dietary natural polyphenols differentially affect (positively or negatively) the mitochondrial function, depending on their concentration. We believe that an understanding of the biochemical mechanisms responsible for sperm quality will lead to more targeted and effective therapeutics for male infertility.