Protective Effect Of Phloretin Research Articles

Protective Effect of Phloretin against Hydrogen Peroxide-Induced Oxidative Damage by Enhancing Autophagic Flux in DF-1 Cells.

Phloretin (PHL) is a dihydrochalcone flavonoid isolated from the peel and root bark of apples, strawberries, and other plants with antioxidative characteristic. In this study, we aimed to investigate the protective effect and the potential mechanism of PHL on hydrogen peroxide (H2O2)-induced oxidative damage in DF-1 cells. The results showed that PHL exhibited no cytotoxic effect on DF-1 cells at concentration below 20 μM. PHL markedly increased H2O2-reduced cell viability, decreased H2O2-induced apoptosis, as evidenced by reduced apoptosis rate, the upregulation of gene and protein level of Bcl-2, and the downregulation of gene and protein level of Bax and Cleaved caspase3. In addition, PHL reduced H2O2-induced reactive oxygen species (ROS) production and restored antioxidant enzymes activities as well as mitochondrial membrane potential in a dose-dependent manner. Moreover, PHL prior to H2O2 further increased LC3-II level, promoted p62 turnover and improved lysosomal function. Importantly, autophagy inhibitor chloroquine (CQ) reversed the protective effect of PHL, and increased H2O2-induced apoptosis. Furthermore, PHL inhibited the phosphorylation levels of ERK, p38, and JNK. Collectively, these results indicate that PHL could attenuate H2O2-induced oxidative injury and apoptosis by maintaining lysosomal function and promoting autophagic flux, and MAPKs pathway may be involved in this process. Our study provides evidence that PHL could as a new strategy to against oxidative damage in poultry industry.

The protective effect of phloretin in osteoarthritis: an in vitro and in vivo study.

Osteoarthritis (OA) is a degenerative joint disease characterized by the degradation and inflammation of cartilage. Phloretin, a type of dihydrochalcone mainly found in apples and apple-derived products, has been reported to possess various potent biological effects such as antioxidant, anticancer, anti-inflammatory, and immunomodulatory. However, the anti-inflammatory effects of phloretin on OA have not been reported. This study was aimed at assessing the effects of phloretin on human OA chondrocytes. Human OA chondrocytes were pretreated with phloretin (10, 30, and 100 μM) for 2 h and subsequently stimulated with IL-1β for 24 h. The production of NO, PGE2, TNF-α, and IL-6 was determined using the Griess reagent and ELISAs. The mRNA expression of COX-2, iNOS, MMP-3, MMP-13, and ADAMTS-5 was measured by real-time PCR. Changes in the protein expression of COX-2, iNOS, MMPs, ADAMTS, aggrecan, collagen-II, NF-κB, and the PI3K/Akt signaling pathway were detected by western blotting. In this study, we found that phloretin significantly inhibited the IL-1β-induced production of NO, PGE2, TNF-α, and IL-6, the expression of COX-2, iNOS, MMP-3, MMP-13, and ADAMTS-5, and the degradation of aggrecan and collagen-II in human OA chondrocytes. Furthermore, phloretin dramatically suppressed the IL-1β-stimulated phosphorylation of PI3K/Akt and activation of NF-κB in human OA chondrocytes. In addition, treatment with phloretin not only prevented the destruction of cartilage and the thickening of subchondral bone but also relieved synovitis in a mouse model of OA. Moreover, immunohistochemical results showed that phloretin significantly decreased the expression of MMP-13 and increased the expression of collagen-II in OA in mice. In conclusion, these results suggest that phloretin may be a potential agent for the treatment of OA.

Protective effect of phloretin on hyperglycemia mediated oxidative stress in experimental diabetic rats

Protective effect of phloretin on hyperglycemia mediated oxidative stress in experimental diabetic rats

Hepatotoxicity and endothelial dysfunction induced by high choline diet and the protective effects of phloretin in mice

The involvement of choline and its metabolite trimethylamine-N-oxide (TMAO) in endothelial dysfunction and atherosclerosis has been repeatedly confirmed. Phloretin, a dihydrochalcone flavonoid usually present in apples, possesses a variety of biological activities including vascular nutrition. This study was designed to investigate whether phloretin could alleviate or prevent high choline-induced vascular endothelial dysfunction and liver injury in mice. Mice were provided with 3% high choline water and given phloretin orally daily for 10 weeks. The high choline-treated mice showed the significant dyslipidemia and hyperglycemia with the impaired liver and vascular endothelium (p < 0.01). Administration of phloretin at 200 and 400 mg/kg bw significantly reduced the choline-induced elevation of serum TC, TG, LDL-C, AST, ALT, ET-1 and TXA2 (p < 0.01), and markedly antagonized the choline-induced decrease of serum PGI2, HDL-C and NO levels. Furthermore, phloretin elevated hepatic SOD and GSH-Px activities and decreased hepatic MDA levels of the mice exposed to high choline water. Moreover, histopathological test with the H&E and Oil Red O staining of liver sections confirmed the high choline diet-caused liver steatosis and the hepatoprotective effect of phloretin. These findings suggest that high choline causes oxidative damage, and phloretin alleviate vascular endothelial dysfunction and liver injury.

Phloretin derived from apple can reduce alpha-hemolysin expression in methicillin-resistant Staphylococcus aureus USA300.

Methicillin-resistant Staphylococcus aureus (MRSA) has become increasingly important because it is the most common cause of hospital-acquired infections, which have become globally epidemic. Our study specifically focused on the MRSA strain USA300, which was shown in 2014 to be responsible for the most current pandemic of highly virulent MRSA in the United States. We aimed to evaluate the in vitro effect of phloretin on USA300. Susceptibility testing, western blotting assays, hemolysis assays and real-time RT-PCR were employed to examine the in vitro effects of phloretin on alpha-hemolysin (Hla) production when the bacterium was co-cultured with phloretin. The protective effect of phloretin against the USA300-mediated injury of human alveolar epithelial cells (A549) was tested using the live/dead analysis and cytotoxicity assays. We showed that sub-inhibitory concentrations of phloretin have no effect on bacterial viability; however, they can markedly inhibit the production of Hla in culture supernatants and the transcriptional levels of hla (the gene encoding Hla) and agrA (the accessory gene regulator). Phloretin, at a final concentration of 16 µg/ml, could protect A549 cells from injury caused by USA300 in the co-culture system. Our study suggests that phloretin might have a potential application in the development of treatment for MRSA infections.

In vitro attenuation of acrolein-induced toxicity by phloretin, a phenolic compound from apple

In the current study, the protective effects of phloretin were investigated in acrolein-challenged amino acid, protein, and cell models. It was found that the formation of FDP-lysine (a typical acrolein–lysine adduct) was strongly inhibited in the presence of phloretin and the remaining electrophilic site in FDP-lysine was also blocked by phloretin. Moreover, direct trapping of acrolein by phloretin was found to be responsible for inhibiting the incorporation of carbonyl groups into BSA and oligomerisation in RNase A. Subsequently, the reduction of LDH release in human neuroblastoma SH-SY5Y cells under acrolein challenge suggested the cytoprotective effects of phloretin. Such protection might be mediated through inhibiting the increased cellular protein carbonyl level as revealed by Western blotting analysis. The present study highlighted an apple phenolic compound, phloretin as a promising candidate in prevention or treatment of acrolein-associated human diseases.

Anti-apoptotic effect of phloretin on cisplatin-induced apoptosis in HEI-OC1 auditory cells

Cisplatin is a highly effective chemotherapeutic agent, but it has significant ototoxic side effects. Apoptosis is an important mechanism of cochlear hair cell loss following exposure to cisplatin. The present study examined the effects of phloretin, a natural polyphenolic compound found in apples and pears, on cisplatin-induced apoptosis. We found that phloretin induced the expression of heme oxygenase-1 (HO-1) protein in a concentration- and time-dependent manner. Phloretin induced nuclear factor-E2-related factor 2 (Nrf2) nuclear translocation, and dominant-negative Nrf2 attenuated phloretin-induced expression of HO-1. Phloretin activated the JNK, ERK and p38 mitogen-activated protein kinase (MAPK) pathways, and the JNK pathway played an important role in phloretin-induced HO-1 expression. Phloretin protected the cells against cisplatin-induced apoptosis. The protective effect of phloretin was abrogated by zinc protoporphyrin IX (ZnPP IX), a HO inhibitor. Furthermore, phloretin pretreatment inhibited mitochondrial dysfunction and the activation of caspases. These results demonstrate that the expression of HO-1 induced by phloretin is mediated by both the JNK pathway and Nrf2; the expression inhibits cisplatin-induced apoptosis in HEI-OC1 cells.