Aging is a complex biological process characterized by a progressive decline in physiological functions and an increased risk of chronic diseases. A key mechanism of this process is cellular senescence, the permanent arrest of the cell cycle in response to stress or damage, which contributes to the accumulation of dysfunctional cells in tissues. Recent research has highlighted the role of polyphenols, bioactive compounds present in numerous plant-based foods, in positively modulating these processes. Polyphenols exert antioxidant effects, regulate gene expression and improve mitochondrial function, helping to delay cellular aging and prevent age-related diseases. In addition, some polyphenols exhibit senolytic properties, selectively eliminating senescent cells and promoting tissue regeneration. This review summarizes the current evidence on the effects of polyphenols on aging and cellular senescence, exploring the underlying molecular mechanisms and discussing their potential in nutritional strategies aimed at promoting healthy aging.

Navelina oranges (Citrus sinensis) are rich in phytonutrients and bioactive compounds, especially flavonoids like hesperidin. This study investigates the anti-inflammatory and anti-fibrotic properties of hesperidin (HE) and a polyphenol mixture from Navelina oranges (OE) in human hepatocytes (Hepa-RG) and hepatic stellate cells (LX-2), in order to elucidate the underlying molecular mechanisms. In Hepa-RG cells, HE treatment increased expression of cannabinoid receptor 2 (CB2R), which was associated with down-regulation of p38 mitogen-activated protein kinases (p38 MAPK) but had minimal impact on cyclooxygenase-2 (COX-2) and transforming growth factor-β (TGF-β) levels. Conversely, OE treatment not only enhanced CB2R levels and reduced p38 MAPK, but also promoted a significant reduction in both COX-2 and TGF-β levels, suggesting that OE might be more effective in mitigating inflammatory and fibrotic processes than HE. In LX-2 cells, HE treatment caused a notable decrease in both COX-2 and TGF-β levels, reflecting its efficacy in targeting fibrosis-associated inflammation. OE treatment, on the other hand, reduced Nuclear Factor-Kappa B p65 (NF-κB) expression, a critical transcription factor involved in inflammatory responses, though it did not significantly affect COX-2. LX-2 cells induced to fibrosis with TGF-β and treated with HE and OE showed a reduction in the expression levels of several fibrosis markers. In addition, HE and OE showed antioxidant effects by increasing protein levels of Cu, Zn superoxide dismutase (SOD1), Mn superoxide dismutase (SOD2) and catalase (CAT) and influencing the state of lipid peroxidation. Further research is needed to explore the effects of the treatments in activated hepatic stellate cells and in vivo liver disease models.

We previously showed that the beta-3 adrenergic receptor (BAR3) is expressed in most segments of the nephron where its agonism promotes a potent antidiuretic effect. We localized BAR3 in distal convoluted tubule (DCT) cells expressing the thiazide-sensitive sodium-chloride cotransporter (NCC). Aim of this study is to investigate the possible functional role of BAR3 on NCC modulation in DCT cells. Here, we found that, in mice, the knockout of BAR3 was paralleled by a significant attenuation of NCC phosphorylation, paralleled by reduced expression and activation of STE-20/SPS1-related proline-alanine-rich kinase (SPAK) and WNKs the main kinases involved in NCC activation. Conversely, in BAR1/2 knockout mice, we found reduced NCC abundance with no changes in the phosphorylation state of NCC. Moreover, selective BAR3 agonism promotes both SPAK and NCC activation in wild-type mouse kidney slices. In conclusion, our findings suggest a novel role for BAR3 in the regulation of NCC in DCT.

Non-alcoholic fatty liver disease (NAFLD) is characterized by an accumulation of fat in hepatocytes, and it may progress, under additional triggering factors, to non-alcoholic steatohepatitis (NASH). Effective strategies to counteract this progression are essential, especially considering that at the moment, there is a lack of approved pharmacological therapies. Our previous study showed that the daily consumption of Navelina oranges significantly reduced hepatic steatosis in patients with Metabolic Dysfunction-Associated Fatty Liver Disease (MAFLD). Starting with our previous study, here, we have investigated the molecular targets through which Hesperidin (HE), a citrus flavanone, is able to prevent the progression of NAFLD to NASH using an in vitro model. In Hepa-RG cells exposed to NAFLD Promoting Agents, HE reduced lipid droplet accumulation (~35%) and suppressed de novo lipogenesis, with decreased expression of FASN (0.62 ± 0.06 vs. 0.39 ± 0.03 at 100 µg/mL) and SCD1 (0.05 ± 0.001 vs. 0.03 ± 0.004 at 50 µg/mL). HE also enhanced fatty acid oxidation by increasing SIRT1 (0.73 ± 0.16 vs. 2.36 ± 0.10 at 50 µg/mL) and PGC1α (0.71 ± 0.03 vs. 0.89 ± 0.003 at 50 µg/mL). In LX-2 cells, HE downregulated COL1A1 (1.48 ± 0.10 vs. 0.90 ± 0.11 at 100 µg/mL) and α-SMA (1.21 ± 0.16 vs. 0.76 ± 0.07 at 75 µg/mL) and upregulated MMP3 (0.64 ± 0.05 vs. 0.98 ± 0.07) and MMP9 (0.99 ± 0.005 vs. 2.61 ± 0.16 at 100 µg/mL). In conclusion, HE may offer a promising approach for NAFLD/NASH prevention and treatment, demonstrating in vitro its potential to reduce hepatic steatosis and fibrosis.

Background: Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) refers to fatty liver disease associated with metabolic syndrome. MASLD causes alterations in lipid metabolism, which can be regulated with a diet rich in polyphenols. The present study aims to evaluate the effects of daily consumption of 400 g of “Navelina” oranges for 4 weeks on serum lipid profiles in a group of 60 patients with MASLD, to identify specific lipid species associated with improvements in hepatic steatosis. Methods: Blood samples were collected from all participants, and biochemical measurements and a serum lipidomic profile were performed. Finally, a Spearman correlation analysis was used to assess the relationships between serum lipidomic fatty acids and biochemical lipid markers. Results: In the experimental treatment arm, serum lipidomic analysis showed a slight decrease in Arachidonic acid (AA) and the Arachidonic acid/Eicosapentaenoic acid ratio (AA/EPA ratio) but no significant interaction between time and treatment was detected. In the same group, Oleic acid, MUFAs and the AA/EPA ratio were significantly and negatively correlated with HDL (r = −0.368, p = 0.046), (r = −0.384, p = 0.036), and (r = −0.522, p = 0.003), respectively. Conversely, EPA and n-3 PUFAs were positively and significantly correlated with HDL (r = 0.447, p = 0.013) and (r = 0.403, p = 0.027) respectively. Conclusions: Furthermore, this study represents one of the first clinical trials to shed a light on the potential association of “Navelina” orange polyphenols on serum fatty acid profiles in patients with MASLD, supporting studies on the nutraceutical effect of oranges on lipid metabolism.

Liver fibrosis is characterized by an excessive accumulation of extracellular matrix (ECM) proteins as a wound-healing response to chronic liver injury, leading to tissue scarring and organ dysfunction. Natural compounds, including phytonutrients and polyphenols, have been shown to exert protective effects by reducing profibrotic biomarkers in vitro and in vivo models. Here, we provide the first evidence that the polyphenol hesperidin (HE) can counteract the onset of fibrotic responses in an ex vivo mouse liver fibrosis model induced by Transforming Growth Factor-β1 (TGF-β1) (5 ng/mL). Notably, HE drives early ECM remodeling in the fibrotic mouse liver tissue. Fibrosis-related parameters were assessed at both the transcriptional and translational levels after treatment with HE at increasing concentrations of 50, 75, and 100 µg/mL. Interestingly, HE at 75 µg/mL exerted the strongest beneficial effect, significantly decreasing the gene expression of α-SMA, SERPINH-1, FN-1, VIM and COL1A1 and counteracting the TGF-β1-induced upregulation of key fibrotic markers, including α-SMA, COL1A2, and VIM, reflecting its capacity to attenuate myofibroblast activation and ECM production and modulating membrane lipid peroxidation. Furthermore, HE inhibited SMAD2 phosphorylation, suggesting that its antifibrotic activity may involve the modulation of the TGF-β/SMAD signaling pathway. Moreover, it promoted an anti-inflammatory response, due to a decrease in IL-1β and IL-6 expression. Our study highlights the potential of the ex vivo model as a platform for evaluating the antifibrotic efficacy of natural molecules, and it suggests significant translational implications and new opportunities for developing innovative therapeutic strategies.