Microneedles with Implantable Tip-Accumulated Therapeutics for the Long-Term Management of Psoriasis.

Methotrexate is successfully used as the gold standard for managing moderate-to-severe psoriasis. However, the low bioavailability and short half-life of the oral pills and the invasiveness of the parenteral injections make these suboptimal therapeutic options. Microneedles, bridging the advantages of the former forms, are successfully used to deliver methotrexate for different therapeutic purposes. However, the utilized dissolving microneedles demand frequent administration, potentially compromising patients' compliance. Additionally, the high toxicity of methotrexate prompts a quest for safer alternatives. Phloretin, a natural compound with confirmed antipsoriatic potential, emerges as a promising candidate. Herein, microneedle patches with separable, slow-degrading tips are developed for the sustained delivery of methotrexate and phloretin, as a comprehensive solution for long-term psoriasis management. Both compounds are individually loaded at varying doses and display sustained-release profiles. The developed microneedle patches demonstrate high mechanical strength, favorable drug delivery efficiency, and remarkable antipsoriatic potential both in vitro in keratinocytes and in vivo in a psoriasis mouse model. Comparative analysis with two subcutaneous injections reveals a similar antipsoriatic efficacy with a single patch of either compound, with prominent phloretin safety. Therefore, the developed patches present a superior alternative to methotrexate's current marketed forms and provide a viable alternative (phloretin) with comparable antipsoriatic efficacy and higher safety.

Phloretin alleviates sleep deprivation-induced cognitive impairment by reducing inflammation through PPARγ/NF-κB signaling pathway.

Sleep loss leads to significant pathophysiological consequences, including cognitive impairment. The neuroinflammation are pivotal factors in the pathogenesis of cognitive impairment induced by sleep loss. The phloretin (PHL), derived from peel of juicy fruits, has demonstrated potent anti-inflammatory properties. However, the precise influence of PHL on the cognitive impairment triggered by sleep loss and its underlying mechanism remain uncertain. In the present study, mice were subjected to sleep deprivation (SD) paradigm. Cognitive impairment induced by SD were significantly relieved by administration of PHL in a dose-dependent manner. Furthermore, PHL not only mitigated the synaptic losses but also enhanced dendritic spine density and neuronal activity within mice hippocampus following exposure to SD. Moreover, PHL treatment decreased the microglial numbers and altered microglial morphology in the hippocampus to restore the M1/M2 balances; these effects were accompanied by regulation of pro-/anti-inflammatory cytokine production and secretion in SD-exposed mice. Additionally, in vivo and in vitro studies showed PHL might attenuate the inflammation through the PPARγ/NF-κB pathway. Our findings suggest that PHL exerts inhibitory effects on microglia-mediated neuroinflammation, thereby providing protection against cognitive impairment induced by SD through a PPAR-γ dependent mechanism. The results indicate PHL is expected to provide a valuable candidate for new drug development for SD-induced cognitive impairment in the future.

Phloretin@cyclodextrin/natural silk protein/polycaprolactone nanofiber wound dressing with antioxidant and antibacterial activities promotes diabetic wound healing.

In patients with diabetes, chronic hyperglycemia impairs immune function at wound sites, increasing susceptibility to infections, prolonging inflammation, and delaying healing. This study aimed to develop wound dressings that control bacterial infections and accelerate healing. Phloretin (PHL), which has antibacterial and anti-inflammatory properties, was encapsulated with γ-cyclodextrin (γ-CD) to form a PHL@CD complex with enhanced bioavailability. This complex was incorporated into nanofiber wound dressings composed of polycaprolactone and natural silk protein. The resulting dressings exhibited favorable physical and chemical properties, including nutrient transport and gas exchange, which are essential for wound healing. The nanofiber membranes exhibited antibacterial activity against Staphylococcus aureus (90.31 ± 4.41 % inhibition), with high antioxidant capacity (91.48 ± 0.33 % ABTS scavenging) and blood compatibility. The membranes also promoted cell viability. Importantly, the nanofiber dressings accelerated wound healing in a diabetic mouse model by reducing the duration of inflammation. The novel nanofiber wound dressing can significantly improve the treatment of diabetic wounds.

Singlet Oxygen Produced by Aspalathin and Ascorbic Acid Leads to Fragmentation of Dihydrochalcones and Adduct Formation.

Singlet oxygen-mediated fragmentation of various dihydrochalcones and chalcones was reported. (Dihydro)cinnamic acids formed in the fragmentation showed a B-ring substitution pattern of the precursor (dihydro)chalcone. For the first time, the intrinsic generation of singlet oxygen by aspalathin and ascorbic acid under mild aqueous conditions (37 °C, pH 7.0) and exclusion of light was verified using HPLC-(+)-APCI-MS2 experiments. If a 4 molar excess of aspalathin or ascorbic acid was used, fragmentation of dihydrochalcones with monohydroxy and o-hydroxymethoxy B-ring substitution was induced up to 2 mol %, respectively. Incubations of the dihydrochalcone phloretin with ascorbic acid not only led to p-dihydrocoumaric acid but also to a novel ascorbyl adduct, which was isolated and identified as 2,4,6-trihydroxy-5-[3-(4-hydroxyphenyl)propanoyl]-2-[(1R, 2S)-1,2,3-trihydroxypropyl]-1-benzofuran-3(2H)-one. The impact of different structural elements on adduct formation was evaluated and verified to be a phloroglucinol structure linked to an acyl moiety. Formation of the ascorbyl adduct was shown to occur in apple puree when both ascorbic acid and phloretin were present at the same time.

Mechanism of Phloretin Accumulation in Malus hupehensis Grown at High Altitudes: Evidence from Quantitative 4D Proteomics.

Phloretin is a natural dihydrochalcone (DHC) that exhibits various pharmacological and therapeutic activities. Malus hupehensis Rehd. (M. hupehensis) is widely planted in the middle of China and its leaves contain an extremely high content of phloridzin, a glycosylated derivative of phloretin. In the present study, we observed a significant increase in phloretin content in the leaves of M. hupehensis planted at high altitudes. To investigate the mechanisms of phloretin accumulation, we explored changes in the proteome profiles of M. hupehensis plants grown at various altitudes. The results showed that at high altitudes, photosynthesis- and DHC biosynthesis-related proteins were downregulated and upregulated, respectively, leading to reduced chlorophyll content and DHC accumulation in the leaves. Moreover, we identified a novel phloridzin-catalyzing glucosidase whose expression level was significantly increased in high-altitude-cultivated plants. This work provided a better understanding of the mechanism of phloretin accumulation and effective and economic strategies for phloretin production.

Combined Phloretin and Human Platelet-rich Plasma Effectively Preserved Integrities of Brain Structure and Neurological Function in Rat after Traumatic Brain Damage.

BACKGROUND: This study tested whether phloretin (a brain-edema inhibitors) would augment therapeutic impact of human-derived platelet-rich plasma (hPRP) on attenuating brain-hemorrhagic volume (BHV) and preserving the neurologic function in rodent following acute traumatic brain damage (TBD). METHODS: Rats (n=40) were separated into group-1 (sham-control), group-2 (TBD), group-3 [TBD + phloretin (80mg/kg/dose by intra-peritoneal administration at 30min and days 2/3 followed-by TBD), group-4 (TBD + PRP/80µL by left intra-carotid-artery injection at 3h after TBD) and group-5 (TBD + phloretin + hPRP) and cerebral tissues were harvested by day 28 after TBD. RESULTS: The brain MRI at day 28 revealed that the BHV was lowest in group 1, highest in group 2 and significantly lower in group 5 than in groups 3/4, but it was similar between groups 3/4, whereas neurological function displayed a opposite pattern of BHV among the groups (all p<0.0001). By 72h, the protein levels of upstream (HGMB1/TLR-2/TLR-4/MyD88/Mal/TRAM/ TRIF/TRAF6/IKK-α/IKK-ß/p-NF-κB) and downstream (IL-1ß/TNF-α/iNOS) inflammation signalings, apoptosis (caspase3/PARP) and fibrosis (Smad3/TGF-ß) biomarkers and flow cytometric assessment of inflammation cells (CD11b/c+//Ly6G+/PMO+) and early (AN-V+/PI-)/late (AN-V+/PI+) mononuclear-cell apoptosis displayed a similar manner of BHV among the groups (all p<0.0001). Cell number of inflammatory (CD68+/MMP9+) and brain-swelling/myelin-damaged (AQP4+/ GFAP+) mediators revealed a similar way, whereas the neuronal-myelin (Doublecortin+/NeuN/nestin) mediators exhibited an inverse manner of BHV among the groups (all p<0.0001). CONCLUSION: Combination of phloretin and hPRP regimen was better than just one treatment to offer synergic benefits for protecting the brain against TBD.

Attenuation of chromium (VI) and arsenic (III)-induced oxidative stress and hepatic apoptosis by phloretin, biochanin-A, and coenzyme Q10 via activation of SIRT1/Nrf2/HO-1/NQO1 signaling.

Heavy metal contamination is an alarming concern on a global scale, as drinking tainted water significantly increases human susceptibility to heavy metals. In a realistic scenario, humans are often exposed to a combination of harmful chemicals rather than a single toxicant. Phloretin (PHL), biochanin-A (BCA), and coenzyme Q10 (CoQ10) are bioactive compounds owning plentiful pharmacological properties. Henceforth, the current research explored the putative energizing effects of selected nutraceuticals in combined chromium (Cr) and arsenic (As) intoxicated Swiss albino mice. Potassium dichromate (75 ppm) and sodium meta-arsenite (100 ppm) were given in the drinking water to induce hepatotoxicity, conjugated with PHL and BCA (50 mg/kg each), and CoQ10 (10 mg/kg) intraperitoneally for 2 weeks. After the statistical evaluation, it was observed that the hepato-somatic index, metal load, and antioxidant activity (lipid peroxidation and protein carbonyl content) increased along with the concomitant decrease in the antioxidants (catalase, glutathione-S-transferase, superoxide dismutase, reduced glutathione, and total thiol) in the Cr and As intoxicated mice. Additionally, light microscopy observations, DNA breakages, decreased silent information regulator 1 (SIRT1), nuclear factor (erythroid-derived 2)-like 2 (Nrf2), heme oxygenase (HO-1), and NAD(P)H quinone dehydrogenase 1 (NQO1) gene expressions, together with stimulated apoptotic cell death manifested by the increased expressions of caspase 8 and caspase 3, thus, proved consistency with the aforementioned outcomes. Importantly, the treatment with nutraceuticals not only restored the antioxidant activity but also favorably altered the expressions of SIRT1, Nrf2, HO-1, and NQO1 signaling and apoptosis markers. These findings highlight the crucial role of the PHL, BCA, and CoQ10 combination in reducing Cr and As-induced hepatotoxicity in mice. By averting the triggered apoptosis in conjunction with oxidative stress, this combination increases the SIRT1, Nrf2, HO-1, and NQO1 signaling, thereby reassuringly maintaining the cellular equilibrium.

Antiproliferative and Anti-Inflammatory Effects of the Polyphenols Phloretin and Balsacone C in a Coculture of T Cells and Psoriatic Keratinocytes.

Plaque psoriasis is a chronic inflammatory skin disease causing red inflamed lesions covered by scales. Leukocytes, including dendritic cells and T cells, participate in the inflammation of the skin by producing multiple cytokines, thus contributing to the hyperproliferation of keratinocytes. Lack of effectiveness and toxic side effects are the main concerns with conventional treatments, and research involving new antipsoriatic molecules is essential. In this study, the anti-inflammatory and antiproliferative effects of two natural polyphenols, phloretin and balsacone C, were investigated using the coculture of T cells and psoriatic keratinocytes. Phloretin exerted antiproliferative activity by regulating the expression of antigen Ki67 and proliferating cell nuclear antigen (PCNA). These effects were comparable to those of methotrexate, a reference treatment for moderate to severe psoriasis. With balsacone C, the expression of Ki67 was also reduced. Additionally, phloretin decreased the levels of multiple pro-inflammatory cytokines: monocyte chemoattractant protein-1 (MCP-1/CCL2), macrophage inflammatory protein-1α (MIP-1α), granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-1 alpha (IL-1α), interleukin-1 beta (IL-1ß), interleukin-6 (IL-6), interleukin-17A (IL-17A), and tumor necrosis factor alpha (TNF-α). The increased interleukin-2 (IL-2) levels with phloretin and methotrexate also represented anti-inflammatory activity. Balsacone C and methotrexate decreased the levels of IL-1α and IL-1ß, but methotrexate exerted a higher reduction. In summary, the anti-inflammatory effects of phloretin were more pronounced than those of methotrexate and balsacone C. In addition, the expression of lymphocyte common antigen (CD45) was more similar to that of the healthy condition after using phloretin or methotrexate. Finally, phloretin stood out from the other compounds and appears promising for psoriasis treatment.

Chemical reversion of age-related oocyte dysfunction fails to enhance embryo development in a bovine model of postovulatory aging.

PURPOSE: There are no clinical treatments to prevent/revert age-related alterations associated with oocyte competence decline in the context of advanced maternal age. Those alterations have been attributed to oxidative stress and mitochondrial dysfunction. Our study aimed to test the hypothesis that in vitro maturation (IVM) medium supplementation with antioxidants (resveratrol or phloretin) may revert age-related oocyte competence decline. METHODS: Bovine immature oocytes were matured in vitro for 23 h (young) and 30 h (aged). Postovulatory aged oocytes (control group) and embryos obtained after fertilization were examined and compared with oocytes supplemented with either 2 µM of resveratrol or 6 µM phloretin (treatment groups) during IVM. RESULTS: Aged oocytes had a significantly lower mitochondrial mass and proportion of mitochondrial clustered pattern, lower ooplasmic volume, higher ROS, lower sirtuin-1 protein level, and a lower blastocyst rate in comparison to young oocytes, indicating that postovulatory oocytes have a lower quality and developmental competence, thus validating our experimental model. Supplementation of IVM medium with antioxidants prevented the generation of ROS and restored the active mitochondrial mass and pattern characteristic of younger oocytes. Moreover, sirtuin-1 protein levels were also restored but only following incubation with resveratrol. Despite these findings, the blastocyst rate of treatment groups was not significantly different from the control group, indicating that resveratrol and phloretin could not restore the oocyte competence of postovulatory aged oocytes. CONCLUSION: Resveratrol and phloretin can both revert the age-related oxidative stress and mitochondrial dysfunction during postovulatory aging but were insufficient to enhance embryo developmental rates under our experimental conditions.

Antimicrobial Effect of Honey Phenolic Compounds against E. coli-An In Vitro Study.

Growing concern over antimicrobial resistance in chronic wound patients necessitates the exploration of alternative treatments from natural sources. This study suggests that honey's phenolic compounds may offer antimicrobial benefits, warranting further investigation for therapeutic development. The main aim of this study was to investigate the antimicrobial activity of phenolic compounds and to determine the effects of their sub-inhibitory concentrations against Escherichia coli (E. coli). 3-phenyllactic acid (PLA), p-coumaric acid (PCA), and phloretin were tested against the bacterial strain of E. coli ATCC 25922. Comparison of the antimicrobial activity of honey constituents in vitro was performed using a broth culture assay. Measurement of the inhibitory properties of constituents in vitro was conducted using disc and well diffusion assays. The effects of sub-inhibitory concentrations of PCA on the susceptibility of E. coli ATCC 25922 to penicillin-streptomycin were tested. The results demonstrated that PLA was the most efficient antimicrobial agent, followed by PCA, whereas phloretin, at lower (2 mg/mL) concentrations, led to an increase in the growth of E. coli. Various modifications of the agar diffusion assay did not reveal the antibacterial properties of the studied phytochemicals. The enhancing effect of a sub-inhibitory concentration of PCA in cooperation with penicillin-streptomycin was shown. These findings might be helpful for the further investigation and development of new antimicrobial agents for the treatment of skin infections and wounds.

Phloretin prolongs lifespan of Caenorhabditis elegans via inhibition of NDUFS1 and NDUFS6 at mitochondrial complex â .

Phloretin has been widely perceived as an antioxidant. However, the bioavailability of phloretin in vivo is generally far too low to elicit a direct antioxidant effect by scavenging reactive oxygen species (ROS). Here we showed that administration of phloretin of apple polyphenols extended lifespan of Caenorhabditis elegans and promoted fitness. Specially phloretin enhanced the survival rates of nematodes under oxidants in an inverted U-shaped dose-response manner. The lifespan-extending effects of phloretin were mediated by ROS via mitochondrial complex I inhibition. The increase of ROS stimulated p38 MAPK/PMK-1 as well as transcription factors of NRF2/SKN-1 and FOXO/DAF-16. Consistent with the involvement of NRF2/SKN-1 and FOXO/DAF-16 in lifespan-extending effects, activities of superoxide dismutase (SOD) and catalase (CAT) were enhanced by phloretin. The exogenous application of antioxidants butylated hydroxyanisole and N-acetylcysteine abolished the increase of ROS, the enhancement of SOD and CAT activities, and the lifespan extending effects of phloretin. Meanwhile, with the inhibition of mitochondrial complex I, ATP was instantly decreased. Both energy sensors of AMPK/AAK-2 and SIRT1/SIR-2.1 were involved in the lifespan extension by phloretin. Transcriptomic, real-time qPCR and molecular docking analyses demonstrated that the binding of phloretin at complex I located at NDUFS1/NUO-5, NDUFS2/GAS-1, and NDUFS6/NDUF-6. The molecular dynamic simulation and binding free energy calculations showed that phloretin had high binding affinities towards NDUFS1 (-7.21 kcal/mol) and NDUFS6 (-7.02 kcal/mol). Collectively, our findings suggested phloretin had effects of life expectancy enhancement and fitness promotion via redox regulations in vivo. NDUFS1/NUO-5 and NDUFS6/NDUF-6 might be new targets in the lifespan and wellness regulations.

Optimization of Phloretin-loaded Nanospanlastics for Targeting of FAS/SREBP1c/AMPK/ OB-Rb Signaling Pathway in HFD-induced Obesity.

OBJECTIVES: Obese patients are at increased risk for CVD, which is the main cause of premature death and has been a major cause of disability and ill health in recent years. PTN, a natural dihydrochalcone flavonoid, has a variety of pharmacological characteristics. This article aimed to prepare PTN-NSLs to evaluate their anti-obesity activity. METHODS: Morphology, Particle size, zeta potential, UV-vis, entrapment efficiency, FT-IR spectra, and an in vitro release study of PTN-NSLs were described. PTN-NSLs were also tested for their anti-obesity properties in obese rats. The LD50 of PTN-NSLs was calculated, as was the 1/20 LD50 prepared for the treatment of obese rats. Also, the level of glycemic, oxidative stress and inflammatory biomarkers were estimated in the obese rat's model. RESULTS: The synthesized PTN-NSLs were uniform, spherically shaped, and well dispersed with no aggregation noted, with a size range of 114.06 ± 8.35 nm. The measured zeta potential value of PTN-NSLs was -32.50.8 mv. Also, the UV spectra of PTN and PTN-NSLs have strong absorption at 225 and 285 nm. Also, the LD50 of PTN-NSLs was found to be 2750 mg/kg.b.w. Moreover, administrating obese rats with PTN-NSLs resulted in improved glycemic features as well as GSH, SOD, GPx, GR, IL10, TBARs, and IL-6 levels, as well as attenuated FAS, SREBP1c, AMPK, ACO, CPT1, and OB-Rb gene expression. CONCLUSIONS: Administration of PTN-NSLs significantly attenuated the levels of glycemic, oxidative stress, and inflammatory biomarkers. The biochemical and PCR findings are aided by histological investigations. Also, the present findings imply that PTN-NSLs might be a promising pharmacological tool for the treatment of obesity-related diseases.

Phloretin inhibits transmissible gastroenteritis virus proliferation via multiple mechanisms.

Transmissible gastroenteritis virus (TGEV), an enteropathogenic coronavirus, has caused huge economic losses to the pig industry, with 100% mortality in piglets aged 2 weeks and intestinal injury in pigs of other ages. However, there is still a shortage of safe and effective anti-TGEV drugs in clinics. In this study, phloretin, a naturally occurring dihydrochalcone glycoside, was identified as a potent antagonist of TGEV. Specifically, we found phloretin effectively inhibited TGEV proliferation in PK-15 cells, dose-dependently reducing the expression of TGEV N protein, mRNA, and virus titer. The anti-TGEV activity of phloretin was furthermore refined to target the internalization and replication stages. Moreover, we also found that phloretin could decrease the expression levels of proinflammatory cytokines induced by TGEV infection. In addition, we expanded the potential key targets associated with the anti-TGEV effect of phloretin to AR, CDK2, INS, ESR1, ESR2, EGFR, PGR, PPARG, PRKACA, and MAPK14 with the help of network pharmacology and molecular docking techniques. Furthermore, resistant viruses have been selected by culturing TGEV with increasing concentrations of phloretin. Resistance mutations were reproducibly mapped to the residue (S242) of main protease (Mpro). Molecular docking analysis showed that the mutation (S242F) significantly disrupted phloretin binding to Mpro, suggesting Mpro might be a potent target of phloretin. In summary, our findings indicate that phloretin is a promising drug candidate for combating TGEV, which may be helpful for developing pharmacotherapies for TGEV and other coronavirus infections.

Network pharmacology combined with molecular docking and dynamics to assess the synergism of esculetin and phloretin against acute kidney injury-diabetes comorbidity.

Acute kidney injury (AKI) is a global health concern with high incidence and mortality, where diabetes further worsens the condition. The available treatment options are not uniformly effective against the complex pathogenesis of AKI-diabetes comorbidity. Hence, combination therapies based on the multicomponent, multitarget approach can tackle more than one pathomechanism and can aid in AKI-diabetes comorbidity management. This study aimed to investigate the therapeutic potential of esculetin and phloretin combination against AKI-diabetes comorbidity by network pharmacology followed by validation by molecular docking and dynamics. The curative targets for diabetes, AKI, esculetin, and phloretin were obtained from DisGeNET, GeneCards, SwissTargetPrediction database. Further, the protein-protein interaction of the potential targets of esculetin and phloretin against AKI-diabetes comorbidity was investigated using the STRING database. Gene ontology and pathway enrichment analysis were performed with the help of the DAVID and KEGG databases, followed by network construction and analysis via Cytoscape. Molecular docking and dynamic simulations were performed to validate the targets of esculetin and phloretin against AKI-diabetes comorbidity. We obtained 6341 targets for AKI-diabetes comorbidity. Further, a total of 54 and 44 targets of esculetin and phloretin against AKI-diabetes comorbidity were retrieved. The top 10 targets for esculetin selected based on the degree value were AKR1B1, DAO, ESR1, PLK1, CA3, CA2, CCNE1, PRKN, HDAC2, and MAOA. Similarly, phloretin's 10 key targets were ACHE, CDK1, MAPK14, APP, CDK5R1, CCNE1, MAOA, MAOB, HDAC6, and PRKN. These targets were enriched in 58 pathways involved in the pathophysiology of AKI-diabetes comorbidity. Further, esculetin and phloretin showed an excellent binding affinity for these critical targets. The findings of this study suggest that esculetin and phloretin combination as a multicomponent multitarget therapy has the potential to prevent AKI-diabetes comorbidity.

Transcriptomic and Physiological Analysis of the Effects of Exogenous Phloretin and Pterostilbene on Resistance Responses of Stylosanthes against Anthracnose.

Anthracnose caused by Colletotrichum gloeosporioides is a destructive disease of Stylosanthes (stylo). Combination treatment of phloretin and pterostilbene (PP) has been previously shown to effectively inhibit the conidial germination and mycelial growth of C. gloeosporioides in vitro. In this study, the effects of PP treatment on the growth of C. gloeosporioides in vivo and the biocontrol mechanisms were investigated. We found that exogenous PP treatment could limit the growth of C. gloeosporioides and alleviate the damage of anthracnose in stylo. Comparative transcriptome analysis revealed that 565 genes were up-regulated and 239 genes were down-regulated upon PP treatment during the infection by C. gloeosporioides. The differentially expressed genes were mainly related to oxidative stress and chloroplast organization. Further physiological analysis revealed that application of PP after C. gloeosporioides inoculation significantly reduced the accumulation of O2•- level and increased the accumulation of antioxidants (glutathione, ascorbic acid and flavonoids) as well as the enzyme activity of total antioxidant capacity, superoxide dismutase, catalase, glutathione reductase, peroxidase and ascorbate peroxidase. PP also reduced the decline of chlorophyll a + b and increased the content of carotenoid in response to C. gloeosporioides infection. These results suggest that PP treatment alleviates anthracnose by improving antioxidant capacity and reducing the damage of chloroplasts, providing insights into the biocontrol mechanisms of PP on the stylo against anthracnose.

Gallic Acid-Based Hydrogels for Phloretin Intestinal Release: A Promising Strategy to Reduce Oxidative Stress in Chronic Diabetes.

Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia caused by abnormalities in insulin secretion and/or action. In patients with diabetes, complications such as blindness, delayed wound healing, erectile dysfunction, renal failure, heart disease, etc., are generally related to an increase in ROS levels which, when activated, trigger hyperglycemia-induced lesions, inflammation and insulin resistance. In fact, extensive cell damage and death occurs mainly due to the effect that ROS exerts at the level of cellular constituents, causing the deterioration of DNA and peroxidation of proteins and lipids. Furthermore, elevated levels of reactive oxygen species (ROS) and an imbalance of redox levels in diabetic patients produce insulin resistance. These destructive effects can be controlled by the defense network of antioxidants of natural origin such as phloretin and gallic acid. For this reason, the objective of this work was to create a nanocarrier (hydrogel) based on gallic acid containing phloretin to increase the antioxidant effect of the two substances which function as fundamental for reducing the mechanisms linked to oxidative stress in patients suffering from chronic diabetes. Furthermore, since the bioavailability problems of phloretin at the intestinal level are known, this carrier could facilitate its release and absorption. The obtained hydrogel was characterized using Fourier transform infrared spectroscopy (FT-IR). Its degree of swelling (a%) and phloretin release were tested under pH conditions simulating the gastric and intestinal environment (1.2, 6.8 and 7.4). The antioxidant activity, inhibiting lipid peroxidation in rat liver microsomal membranes induced in vitro by a free radical source, was evaluated for four hours. All results showed that gallate hydrogel could be applied for releasing intestinal phloretin and reducing the ROS levels.

Optimizing Trilobatin Production via Screening and Modification of Glycosyltransferases.

Trilobatin (TBL) is a key sweet compound from the traditional Chinese sweet tea plant (Rubus suavissimus S. Lee). Because of its intense sweetness, superior taste profile, and minimal caloric value, it serves as an exemplary natural dihydrochalcone sweetener. It also has various health benefits, including anti-inflammatory and glucose-lowering effects. It is primarily produced through botanical extraction, which impedes its scalability and cost-effectiveness. In a novel biotechnological approach, phloretin is used as a precursor that is transformed into TBL by the glycosyltransferase enzyme ph-4'-OGT. However, this enzyme's low catalytic efficiency and by-product formation limit the large-scale synthesis of TBL. In our study, the enzyme Mdph-4'-OGT was used to screen 17 sequences across species for TBL synthesis, of which seven exhibited catalytic activity. Notably, PT577 exhibited an unparalleled 97.3% conversion yield within 3 h. We then optimized the reaction conditions of PT577, attaining a peak TBL bioproduction of 163.3 mg/L. By employing virtual screening, we identified 25 mutation sites for PT577, thereby creating mutant strains that reduced by-products by up to 50%. This research enhances the enzymatic precision for TBL biosynthesis and offers a robust foundation for its industrial-scale production, with broader implications for the engineering and in silico analysis of glycosyltransferases.

Transcriptome analysis reveals the inhibitory mechanism of phloretin on virulence expression of Staphylococcus aureus and its application in cooked chicken.

Staphylococcus aureus (S. aureus) enterotoxins have aroused great concern to food safety owing to its increased risk of food poisoning. The current research aimed to investigate the anti-virulence mechanisms of phloretin against S. aureus in terms of toxin activity and gene expression. The results indicated that phloretin could effectively inhibit the production of hemolysins and enterotoxins, and its anti-virulence effect was exerted in a concentration-dependent manner. Transcriptome results indicated that phloretin could downregulate the transcription level of majority virulence factors related genes (68 %) of S. aureus, including the quorum sensing-related genes (agrB, agrC, agrA, sspA, splF, splD and others) and bacterial secretion system-related genes (secDF, secY2, and yidC). In addition, it was speculated that phloretin was most likely to bind to the AgrA DNA binding domain, thereby affecting the expression of downstream virulence genes (hla, seb, spa, rot, geh, etc) based on molecular docking. Finally, the application in cooked chicken indicated that phloretin could effectively decrease the content of enterotoxins and improve the storage quality of cooked chicken. These findings not only evidenced the feasible anti-virulence activity of phloretin, but also provided a new strategy to prevent S. aureus food poisoning in cooked meat preservation.

Phloretin Inhibits the Proliferation of Breast Cancer Cells Through the Down-regulation of Estrogen Receptor α.

BACKGROUND/AIM: Phloretin is a natural flavonoid compound found in some plants, such as apples and pears, as well as in the bark of apple trees. Phloretin has been shown to have inhibitory effects on glucose transporters in cells and can potentially inhibit the growth of cancer cells. However, the mechanism by which phloretin regulates the expression of estrogen receptor alpha (ERα), a key transcription factor in breast cancer, is still unclear. This study investigated how phloretin affects the growth of ERα positive human breast cancer cells. MATERIALS AND METHODS: The growth of breast cancer cell lines, including MCF7 and T47D, was examined using cell proliferation and colony formation assays. Western blotting and semi-quantitative RT-PCR were used to examine protein and mRNA levels, respectively. Localization of cellular proteins was analyzed using subcellular fractionation. Transient transfection and reported gene assays were used to elucidate the impact of phloretin on cell proliferation and ERα transactivation. RESULTS: Phloretin decreased ERα expression at the mRNA and protein levels in MCF7 and T47D cells. It also inhibited the binding of ERα to the estrogen response element present in the promoter of target genes. Moreover, treatment with phloretin inhibited the expression of cyclin D1 and breast cancer marker gene pS2, which are known ERα target genes. Consequently, it inhibited the growth of ERα-positive human breast cancer cells. Furthermore, inhibition of breast cancer growth by phloretin was found to be mediated through both the ERα and ERK1/ERK2 pathways. CONCLUSION: Phloretin, a dihydrochalcone extracted from natural sources, exhibits the ability to regulate ERα function and suppress breast cancer cell proliferation.