Docosahexaenoic acid ester of phloridzin inhibit lipopolysaccharide-induced inflammation in THP-1 differentiated macrophages

Effects of Phaffia rhodozyma on microbial community dynamics and tobacco quality during tobacco fermentation

Introduction

Carotenoids are important precursors of various aroma components in tobacco and play an important role in the sensory quality of tobacco. Phaffia rhodozyma is a species of Xanthophyllomyces capable of synthesizing a highly valuable carotenoid-astaxanthin, but has not yet been used in improving tobacco quality.

Methods

The dynamic changes of microbial community and metabolites during tobacco fermentation were analyzed in combination with microbiome and metabolome, and the quality of tobacco after fermentation was evaluated by sensory scores.

Results

P. rhodozyma could grow and produce carotenoids in tobacco extract, with a maximum biomass of 6.50 g/L and a maximum carotenoid production of 36.13 mg/L at 100 g/L tobacco extract. Meanwhile, the correlation analysis combined with microbiome and metabolomics showed that P. rhodozyma was significantly positively correlated with 11 metabolites such as 6-hydroxyluteolin and quercetin. Furthermore, the contents of alcohols, ketones and esters, which were important aromatic components in fermented tobacco, reached 77.57 μg/g, 58.28 μg/g and 73.51 μg/g, increasing 37.39%, 265.39% and 266.27% compared to the control group, respectively. Therefore, the aroma and flavor, and taste scores of fermented tobacco increased by 0.5 and 1.0 points respectively.

Discussion

This study confirmed that P. rhodozyma fermentation could effectively improve the sensory evaluation of tobacco, and provided a novel microbial fermentation method to improve tobacco quality.

Phloridzin Docosahexaenoate Inhibits Spheroid Formation by Breast Cancer Stem Cells and Exhibits Cytotoxic Effects against Paclitaxel-Resistant Triple Negative Breast Cancer Cells

The eradication of cancer stem cells (CSCs) is vital to successful cancer treatment and overall disease-free survival. CSCs are a sub-population of cells within a tumor that are defined by their capacity for continuous self-renewal and recapitulation of new tumors, demonstrated in vitro through spheroid formation. Flavonoids are a group of phytochemicals with potent anti-oxidant and anti-cancer properties. This paper explores the impact of the flavonoid precursor phloridzin (PZ) linked to the ω-3 fatty acid docosahexaenoate (DHA) on the growth of MCF-7 and paclitaxel-resistant MDA-MB-231-TXL breast cancer cell lines. Spheroid formation assays, acid phosphatase assays, and Western blotting were performed using MCF-7 cells, and the cell viability assays, Annexin-V-488/propidium iodide (PI) staining, and 7-aminoactinomycin D (7-AAD) assays were performed using MDA-MB-231-TXL cells. PZ-DHA significantly reduced spheroid formation, as well as the metabolic activity of MCF-7 breast cancer cells in vitro. Treatment with PZ-DHA also suppressed the metabolic activity of MDA-MB-231-TXL cells and led to apoptosis. PZ-DHA did not have an observable effect on the expression of the drug efflux transporters ATP-binding cassette super-family G member 2 (ABCG2) and multidrug resistance-associated protein 1 (MRP1). PZ-DHA is a potential treatment avenue for chemo-resistant breast cancer and a possible novel CSC therapy. Future pre-clinical studies should explore PZ-DHA as a chemo-preventative agent.

Lipopolysaccharide Tolerance in Human Primary Monocytes and Polarized Macrophages

Innate immune memory allows macrophages to adequately respond to pathogens to which they have been pre-exposed. To what extent different pattern recognition receptors, cytokines and resolution signals influence innate immune memory needs further elucidation. The present study assessed whether lipopolysaccharide (LPS) tolerance in monocytes and macrophages is affected by these factors. Human CD14+ cells were isolated from peripheral blood, stimulated by LPS and re-stimulated after 3 days of resting. Hereafter, immune-responsive gene 1 (IRG-1), heme oxygenase 1 (HO-1), tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6) expression were assessed. Our study revealed the following findings: (1) While pre-stimulation with the Toll-like receptor 4 ligand LPS inhibits the induction of IRG-1, TNF-α and IL-6 expression, pre-stimulation with TLR 1/2 ligands only affects cytokine production but not IRG-1 expression upon subsequent TLR4 engagement. (2) Prior TNF-α stimulation does not affect LPS tolerance but rather increases LPS-mediated cytokine expression. (3) Dimethyl itaconate (DMI) inhibits the expression of IRG-1 in a dose-dependent manner but does not affect TNF-α or IL-6 expression. (4) Docosahexaenoic acid (DHA) partly inhibits IRG-1 expression in monocytes but not in M(IFNγ) and M(IL-4) polarized macrophages. LPS tolerance is not affected in these cells by DHA. The data presented in this study partly corroborate and extend previous findings on innate immune memory and warrant further studies on LPS tolerance to gain a better understanding of innate immune memory at the molecular level.

Biocatalytic Approaches for an Efficient and Sustainable Preparation of Polyphenols and Their Derivatives

Many sectors of industry, such as food, cosmetics, nutraceuticals, and pharmaceuticals, have increased their interest in polyphenols due to their beneficial properties. These molecules are widely found in Nature (plants) and can be obtained through direct extraction from vegetable matrices. Polyphenols introduced through the diet may be metabolized in the human body via different biotransformations leading to compounds having different bioactivities. In this context, enzyme-catalyzed reactions are the most suitable approach to produce modified polyphenols that not only can be studied for their bioactivity but also can be labeled as green, natural products. This review aims to give an overview of the potential of biocatalysis as a powerful tool for the modification of polyphenols to enhance their bioaccessibility, bioavailability, biological activity or modification of their physicochemical properties. The main polyphenol transformations occurring during their metabolism in the human body have been also presented.

Effects of Eye Drops Containing Hyaluronic Acid-Nimesulide Conjugates in a Benzalkonium Chloride-Induced Experimental Dry Eye Rabbit Model

Dry eye syndrome (DES) is a common ocular disease worldwide. Currently, anti-inflammatory agents and immunosuppressive drugs, such as cyclosporine A, have been widely used to treat this chronic condition. However, the multifactorial etiology of DES, poor tolerance, low bioavailability, and prolonged treatment to response time have limited their usage. In this study, nimesulide, a cyclooxygenase (COX)-2 selective inhibitor, was conjugated with hyaluronic acid (HA), and the HA-nimesulide conjugates were expected to increase the solubility and biocompatibility for alleviating the DES in the benzalkonium chloride (BAC)-induced goblet cell-loss dry eye model. The therapeutic efficacy of HA-nimesulide was assessed using fluorescein staining, goblet cell density by conjunctival impression cytology, and histology and immunohistochemistry of corneal tissues. Compared to commercial artificial tears and Restasis®, the HA-nimesulide conjugates could promote goblet cell recovery and enhance the regeneration of the corneal epithelium. Importantly, immunofluorescent staining studies demonstrated that the HA-nimesulide conjugates could decrease the number of infiltrating CD11b-positive cells after two weeks of topical application. In the anti-inflammatory test, the HA-nimesulide conjugates could inhibit the production of pro-inflammatory cytokines and prostaglandin E2 (PGE2) in the lipopolysaccharide (LPS)-stimulated Raw 264.7 cell model. In conclusion, we demonstrated that HA-nimesulide conjugates had anti-inflammatory activity, and promoted goblet cell recovery and corneal epithelium regeneration when used as topical eye drops; accordingly, the HA-nimesulide conjugates could potentially be effective for the treatment of DES.

Metabolomics Insights of the Immunomodulatory Activities of Phlorizin and Phloretin on Human THP-1 Macrophages

Dihydrochalcones, phlorizin (PZ) and its aglycone phloretin (PT), have evidenced immunomodulatory effects through several mechanisms. However, the differential metabolic signatures that lead to these properties are largely unknown. Since macrophages play an important role in the immune response, our study aimed to characterise human THP-1 macrophages under PZ and PT exposure. A multiplatform-based untargeted metabolomics approach was used to reveal metabolites associated with the anti-inflammatory mechanisms triggered by the dihydrochalcones in LPS-stimulated macrophages, for the first time. Results showed differential phenotypic response in macrophages for all treatments. Dihydrochalcone treatment in LPS-stimulated macrophages mimics the response under normal conditions, suggesting inhibition of LPS response. Antagonistic effects of dihydrochalcones against LPS was mainly observed in glycerophospholipid and sphingolipid metabolism besides promoting amino acid biosynthesis. Moreover, PT showed greater metabolic activity than PZ. Overall, the findings of this study yielded knowledge about the mechanisms of action PZ and PT at metabolic level in modulating inflammatory response in human cells.

Dietary Supplementation of Apple Phlorizin Attenuates the Redox State Related to Gut Microbiota Homeostasis in C57BL/6J Mice Fed with a High-Fat Diet

We explored the effects of dietary supplementation with phlorizin on redox state-related gut microbiota homeostasis in an obesity mouse model. Mice (C57BL/6J) were grouped as follows for 12 weeks: normal chow diet group (NCD), high-fat and cholesterol diet group (HFD), and treatment groups fed with HFD along with three levels of phlorizin. Phlorizin alleviated the hyperlipidemia and redox status and increased the total ccal SCFA content (1.88 ± 0.25 mg/g). Additionally, phlorizin regulated gene expression related to lipid metabolism, redox status, and cecum barrier and rebuilt gut microbiota homeostasis. After interference by antibiotics, the total phloretin content in the feces was decreased about 4-fold, and most of the health-promoting effects were abolished, indicating that phlorizin might be susceptible to microbial biotransformation and that microecology is indispensable for maintaining the redox state capacities of phlorizin. Phlorizin treatment could be an advantageous option for improving HFD-related obesity and redox states related to gut microbiota homeostasis.

Phloretin protects against cardiac damage and remodeling via restoring SIRT1 and anti-inflammatory effects in the streptozotocin-induced diabetic mouse model

Diabetic cardiomyopathy increases the risk of heart failure independent of coronary artery disease and hypertension. Phloretin (PHL) shows anti-inflammatory effects in macrophages. In this study, we explored the protective effects of PHL on high glucose (HG)-induced injury in diabetic cardiomyopathy in vivo and in vitro. Using streptozotocin-induced diabetic mouse model and incubating cardiac cells line under a HG environment, PHL were evaluated of the activities of anti-inflammation and anti-fibrosis. In the study, PHL treatment ameliorated cardiomyocyte inflammation injury, and reduced fibrosis in vivo and in vitro. PHL also improved cardiac biochemical criterions after 8 weeks of induction of diabetes in C57BL/6 mice. Molecular docking results indicated that silent information regulator 2 homolog 1 (SIRT1) bound to PHL directly and that SIRT1 expression was upregulated in the PHL-treated group in HG-induced H9C2 cells. Protective effect of PHL was been eliminated in silence SIRT1 H9C2 cells. Taken together, these results suggested that PHL suppressed HG-induced cardiomyocyte injury via restoring SIRT1 expression.

Apple Flavonols Mitigate Adipocyte Inflammation and Promote Angiogenic Factors in LPS- and Cobalt Chloride-Stimulated Adipocytes, in Part by a Peroxisome Proliferator-Activated Receptor-γ-Dependent Mechanism

Adipose tissue (AT) expansion induces local hypoxia, a key contributor to the chronic low-grade inflammation that drives obesity-associated disease. Apple flavonols phloretin (PT) and phlorizin (PZ) are suggested anti-inflammatory molecules but their effectiveness in obese AT is inadequately understood. Using in vitro models designed to reproduce the obese AT microenvironment, 3T3-L1 adipocytes were cultured for 24 h with PT or PZ (100 μM) concurrent with the inflammatory stimulus lipopolysaccharide (LPS; 10 ng/mL) and/or the hypoxia mimetic cobalt chloride (CoCl₂; 100 μM). Within each condition, PT was more potent than PZ and its effects were partially mediated by peroxisome proliferator-activated receptor (PPAR)-γ (p < 0.05), as tested using the PPAR-γ antagonist bisphenol A diglycidyl ether (BADGE). In LPS-, CoCl₂-, or LPS + CoCl₂-stimulated adipocytes, PT reduced mRNA expression and/or secreted protein levels of inflammatory and macrophage chemotactic adipokines, and increased that of anti-inflammatory and angiogenic adipokines, which was consistent with reduced mRNA expression of M1 polarization markers and increased M2 markers in RAW 264.7 macrophages cultured in media collected from LPS + CoCl₂-simulated adipocytes (p < 0.05). Further, within LPS + CoCl₂-stimulated adipocytes, PT reduced reactive oxygen species accumulation, nuclear factor-κB activation, and apoptotic protein expression (p < 0.05). Overall, apple flavonols attenuate critical aspects of the obese AT phenotype.

Phloridzin docosahexaenoate, a novel fatty acid ester of a plant polyphenol, inhibits mammary carcinoma cell metastasis

Triple-negative breast cancer (TNBC) tends to recur and metastasize following initial chemotherapy, which presents a treatment challenge. Here, we detail the anti-metastatic activity of phloridzin docosahexaenoate (PZ-DHA), synthesized from the natural polyphenol, phloridzin, and the ω-3 fatty acid, docosahexaenoic acid. Sub-cytotoxic PZ-DHA suppressed the migration of MDA-MB-231, SUM149, and 4T1 cells, as well as invasion by MDA-MB-231 and 4T1 cells. Sub-cytotoxic PZ-DHA also inhibited MDA-MB-231 expression of matrix metalloproteinase 2, and expression of epithelial-to-mesenchymal transition-associated transcription factors by MDA-MB-231 and SUM149 cells. Transforming growth factor-β-induced Rho GTPase signaling in MDA-MB-231 cells and non-malignant MCF-10A mammary epithelial cells was suppressed by sub-cytotoxic PZ-DHA, which also inhibited Akt/phosphoinositide 3-kinase and extracellular signal-regulated kinase 1 and 2 signaling in MDA-MB-231 cells. Finally, intraperitoneal administration of PZ-DHA suppressed the metastasis of 4T1 and GFP-transfected MDA-MB-231 cells from the mammary fat pad to the lungs of BALB/c and NOD-SCID female mice, respectively, which was unrelated to any inhibition of primary tumor growth. There was no evidence of toxicity as PZ-DHA treatment did not affect liver or kidney function. We conclude that PZ-DHA might prevent or inhibit the progression of TNBC.

In vivo anti-inflammatory activity and UPLC-MS/MS profiling of the peels and pulps of Cucumis melo var. cantalupensis and Cucumis melo var. reticulatus

ETHNOPHARMACOLOGICAL RELEVANCE

Cucumis melo var. cantalupensis and Cucumis melo var. reticulatus are the most famous varieties of netted muskmelon or cantaloupe in Egypt. Cantaloupe has a great reputation as an anti-inflammatory drug for hot inflammation of liver, cough, eczema, and kidney disorders such as ulcers in the urinary tract, and our objective was to confirm this use scientifically.

MATERIALS AND METHODS

Inflammation was induced in adult male Sprague Dawley rats by subcutaneous injection of 0.05 ml of carrageenan (1% solution in saline) into the plantar surface of the right hind paw 30 min after oral pretreatment of the rats with 95% ethanolic extracts of Cucumis melo var. cantalupensis peels (CCP) and pulps (CCU) and Cucumis melo var. reticulatus peels (CRP) and pulps (CRU) at doses of 25 and 50 mg/kg. Indomethacin (10 mg/kg) was used as a standard drug. The effect of the tested samples was measured on the oedema volume, as well as PGE-2, TNF-α, IL-6 and IL-1β levels. Metabolic profiling of the extracts was performed using UPLC-MS/MS analysis.

RESULTS

Pretreatment of rats with the ethanol extract of the pulps and peels of the two varieties at doses of 25 and 50 mg/kg significantly inhibited the carrageenan-induced increase in the oedema volume of the rat paws after 3 h, except for the low dose of the French cantaloupe pulp. CRP at 50 mg/kg caused the most significant reductions in both TNF-α (P < 0.05) and IL-1β (P < 0.001) levels, while CCP caused the most significant reductions in PGE-2 and IL-6 (P < 0.05) levels. Increases in PGE-2, TNF-α, IL-6 and IL-1β levels were also significantly prevented by indomethacin (10 mg/kg). UPLC-MS/MS facilitated the identification of 44 phenolic compounds, including phenolic acids and flavonoids.

CONCLUSION

This is the first report of the chemical and biological study of the peels of Cucumis melo var. cantalupensis and Cucumis melo var. reticulatus.

Antioxidant capacity and hepatoprotective activity of myristic acid acylated derivative of phloridzin

The antioxidant activities in vitro and hepatoprotective effects against carbon tetrachloride (CCl₄) induced acute liver injury in vivo of myristic acid acylated derivative of phloridzin (PZM) were investigated. The PZM was obtained by enzymatic acylation of myristic acid and phloridzin (PZ). The antioxidant capability of PZM in vitro was evaluated by the ferric reducing antioxidant power assay (FRAP), 2,2'-Azinobis- 3-ethylbenzthiazoline-6-sulphonate (ABTS⁺·) and 2,2-diphenyl-1-picrylhydrazyl (DPPH·) radical scavenging assay. Mice were intragastrically treated with control or PZM (20, 40, and 80 mg/kg) for 5 days and intra-peritoneal injection with CCl₄. The enzymatic acylated synthesis of myristic acid and phloridzin was region-selective taken place on 6″-OH of phloridzin glycoside moiety and achieved 93% yield. PZM had a significantly higher total antioxidant ability, same scavenging ABTS⁺· ability and weaker scavenging DPPH· ability when compared to the parent PZ. The of aminotransferase serum activity and malondialdehyde hepatic activity were elevated (P < 0.015) after treatment with CCl₄, while the related liver enzymatic activities and glutathione concentration were lower. These changes were enhanced by PZM. Further studies showed that PZM reduced the interleukin-6 expression and stimulated liver regeneration caused by CCl₄. PZM attained good antioxidant capacity in vitro and had excellent hepatoprotective effects in vivo and better bioactivity compared to the parent phloridzin. The significance of hepatoprotective effect of phloridzin derivative against CCl₄-induced hepatotoxicity in mice is an important and new finding.

Biochemical Basis of Anti-Cancer-Effects of Phloretin-A Natural Dihydrochalcone

Apple is a rich source of bioactive phytochemicals that help improve health by preventing and/or curing many disease processes, including cancer. One of the apple polyphenols is phloretin [2′,4′,6′-Trihydroxy-3-(4-hydroxyphenyl)-propiophenone], which has been widely investigated for its antioxidant, anti-inflammatory and anti-cancer activities in a wide array of preclinical studies. The efficacy of phloretin in suppressing xenograft tumor growth in athymic nude mice implanted with a variety of human cancer cells, and the ability of the compound to interfere with cancer cells signaling, have made it a promising candidate for anti-cancer drug development. Mechanistically, phloretin has been reported to arrest the growth of tumor cells by blocking cyclins and cyclin-dependent kinases and induce apoptosis by activating mitochondria-mediated cell death. The blockade of the glycolytic pathway via downregulation of GLUT2 mRNA and proteins, and the inhibition of tumor cells migration, also corroborates the anti-cancer effects of phloretin. This review sheds light on the molecular targets of phloretin as a potential anti-cancer and anti-inflammatory natural agent.

Novel Docosahexaenoic Acid Ester of Phloridzin Inhibits Proliferation and Triggers Apoptosis in an In Vitro Model of Skin Cancer

Skin cancer is among the most common cancer types accompanied by rapidly increasing incidence rates, thus making the development of more efficient therapeutic approaches a necessity. Recent studies have revealed the potential role of decosahexaenoic acid ester of phloridzin (PZDHA) in suppressing proliferation of liver, breast, and blood cancer cell lines. In the present study, we investigated the cytotoxic potential of PZDHA in an in vitro model of skin cancer consisting of melanoma (A375), epidermoid carcinoma (A431), and non-tumorigenic (HaCaT) cell lines. Decosahexaenoic acid ester of phloridzin led to increased cytotoxicity in all cell lines as revealed by cell viability assays. However, growth inhibition and induction of both apoptosis and necrosis was more evident in melanoma (A375) and epidermoid carcinoma (A431) cells, whereas non-tumorigenic keratinocytes (HaCaT) appeared to be more resistant as detected by flow cytometry. More specifically, PZDHA-induced cell cycle growth arrest at the G2/M phase in A375 and A431 cells in contrast to HaCaT cells, which were growth arrested at the G0/G1 phase. Elevated intracellular generation of reactive oxygen species ROS was detected in all cell lines. Overall, our findings support the potential of PZDHA as a novel therapeutic means against human skin cancer.

Phloretin attenuates mucus hypersecretion and airway inflammation induced by cigarette smoke

BACKGROUNDS

Cigarette smoke (CS)-induced airway mucus hypersecretion and inflammation are the prominent features of chronic obstructive pulmonary disease (COPD). As an anti-inflammatory flavonoid, phloretin was found to be involved in various inflammatory disorders such as sepsis. In this study, the effects of phloretin on CS-induced airway mucin secretion and inflammation were investigated in vivo and in vitro.

METHODS

Phloretin dissolved in 1% DMSO was daily injected intraperitoneally to mice, which were then exposed to CS for four weeks. Mouse lung histologic changes were evaluated, the expression of mucin 5ac (MUC5AC) was measured, bronchoalveolar lavage fluid (BALF) total cells, neutrophils, and macrophages were counted. BALF and lung levels of tumor necrosis factor-alpha and interleukin-1 beta (IL-1β) were quantified. Moreover, the effects of phloretin on cigarette smoke extract (CSE)-induced expression of MUC5AC and IL-1β were investigated in NCI-H292 cells. Then, to explore the potential mechanisms, the signaling molecules including epidermal growth factor receptor (EGFR), extracellular signal-regulated kinase (ERK) and P38 were evaluated.

RESULTS

Phloretin pretreatment dramatically suppressed the mucins secretion, inflammatory cell infiltration and inflammatory cytokine release in mouse lungs induced by CS, and it also suppressed CSE-induced expression of MUC5AC and IL-1β in NCI-H292 bronchial epithelial cells. Furthermore, western blot showed that phloretin attenuated the activation of EGFR, ERK and P38 both in vivo and in vitro.

CONCLUSIONS

This study highlights the protective effect of phloretin on CS-related airway mucus hypersecretion and inflammation, where EGFR, ERK and P38 might be involved. These findings suggest that phloretin could be a potential therapeutic drug for COPD.

THP-1 and human peripheral blood mononuclear cell-derived macrophages differ in their capacity to polarize in vitro

Macrophages (Mφ) undergo activation to pro-inflammatory (M1) or anti-inflammatory (M2) phenotypes in response to pathophysiologic stimuli and dysregulation of the M1-M2 balance is often associated with diseases. Therefore, studying mechanisms of macrophage polarization may reveal new drug targets. Human Mφ polarization is generally studied in primary monocyte-derived Mφ (PBMC Mφ) and THP-1-derived Mφ (THP-1 Mφ). We compared the polarization profile of THP-1 Mφ with that of PBMC Mφ to assess the alternative use of THP-1 for polarization studies. Cellular morphology, the expression profiles of 18 genes and 4 cell surface proteins, and phagocytosis capacity for apoptotic cells and S. aureus bioparticles were compared between these Mφ, activated towards M1, M2a, or M2c subsets by stimulation with LPS/IFNγ, IL-4, or IL-10, respectively, for 6h, 24h and 48h. The Mφ types are unique in morphology and basal expression of polarization marker genes, particularly CCL22, in a pre-polarized state, and were differentially sensitive to polarization stimuli. Generally, M1 markers were instantly induced and gradually decreased, while M2 markers were markedly expressed at a later time. Expression profiles of M1 markers were similar between the polarized Mφ types, but M2a cell surface markers demonstrated an IL-4-dependent upregulation only in PBMC Mφ. Polarized THP-1 Mφ but not PBMC Mφ showed distinctive phagocytic capacity for apoptotic cells and bacterial antigens, respectively. In conclusion, our data suggest that THP-1 may be useful for performing studies involving phagocytosis and M1 polarization, rather than M2 polarization.

Insulin Sensitivity-Enhancing Activity of Phlorizin Is Associated with Lipopolysaccharide Decrease and Gut Microbiota Changes in Obese and Type 2 Diabetes (db/db) Mice

Phlorizin exists in a number of fruits and foods and exhibits many bioactivities. The mechanism of its antidiabetic effect has been known as it can competitively inhibit sodium-glucose symporters (SGLTs). However, phlorizin has a wide range of two-phase metabolism in systemic circulation and shows poor oral bioavailability. An alternative mechanism may involve gut microbiota in intestine. Sixteen obese mice with type 2 diabetes (db/db) and eight age-matched control mice (db/+) were divided into three groups: diabetic group treated with phlorizin (DMT group), vehicle-treated diabetic group (DM group), and normal control group (CC group). Phlorizin was given in normal saline solution by intragastric administration for 10 weeks. After the last treatment course, body weight, energy intake, serum lipopolysaccharides (LPS), insulin resistance, and fecal short-chain fatty acids (SCFAs) were compared. 16S rRNA gene denaturing gradient gel electrophoresis (DGGE) and quantitative PCR were used to determine the changes in microbiome composition. Coadministration of phlorizin significantly prevented metabolic syndrome by decreasing weight gain, energy intake, serum lipopolysaccharides, and insulin resistance, and the fecal level of total SCFAs was dramatically increased, especially butyric acid. DGGE and quantitative PCR demonstrated that phlorizin coadministration increased the gut microbial diversity and the growth of Akkermansia muciniphila and Prevotella. Meanwhile, the gut microbiota structure of db/db mice after phlorizin treatment was improved and approached the normal group. The mechanism of the hypoglycemic action of phlorizin is associated with LPS decrease and gut microbiota changes; briefly, it acts in the intestine to modify gut microbial community structure, resulting in lower LPS load in the host and higher SCFAs producing beneficial bacteria.

Dietary Phytochemicals: Natural Swords Combating Inflammation and Oxidation-Mediated Degenerative Diseases

Cumulatively, degenerative disease is one of the most fatal groups of diseases, and it contributes to the mortality and poor quality of life in the world while increasing the economic burden of the sufferers. Oxidative stress and inflammation are the major pathogenic causes of degenerative diseases such as rheumatoid arthritis (RA), diabetes mellitus (DM), and cardiovascular disease (CVD). Although a number of synthetic medications are used to treat these diseases, none of the current regimens are completely safe. Phytochemicals (polyphenols, carotenoids, anthocyanins, alkaloids, glycosides, saponins, and terpenes) from natural products such as dietary fruits, vegetables, and spices are potential sources of alternative medications to attenuate the oxidative stress and inflammation associated with degenerative diseases. Based on in vitro, in vivo, and clinical trials, some of these active compounds have shown good promise for development into novel agents for treating RA, DM, and CVD by targeting oxidative stress and inflammation. In this review, phytochemicals from natural products with the potential of ameliorating degenerative disease involving the bone, metabolism, and the heart are described.

Docosahexaenoic acid-acylated phloridzin, a novel polyphenol fatty acid ester derivative, is cytotoxic to breast cancer cells

Docosahexaenoic acid-acylated phloridzin (PZ-DHA), a novel polyphenol fatty acid ester derivative, was synthesized through a regioselective acylation reaction with the aim of increasing the bioactivity of phloridzin (PZ) and docosahexaenoic acid (DHA). In this study, PZ-DHA's cytotoxic activity was explored using in vitro and in vivo models of mammary carcinoma. PZ-DHA was selectively cytotoxic for mammary carcinoma (MDA-MB-231, MDA-MB-468, 4T1, MCF-7 and T-47D) cells compared to non-malignant human mammary epithelial cells (HMEC and MCF-10A) and fibroblasts by MTS assay and Annexin-V-FLUOS/propidium iodide staining. Flow cytometric analysis of Oregon Green 488- and Ki-67-stained MDA-MB-231 cells showed antiproliferative activity of PZ-DHA at a subcytotoxic concentration. PZ-DHA also arrested MDA-MB-231 cell division at the G2/M phase and down-regulated expression of cyclin B1 and cyclin-dependent kinase 1 (CDK1). PZ-DHA-induced apoptosis in MDA-MB-231 cells was confirmed by caspase 3/7 activation in a luminescence assay and DNA fragmentation by TUNEL staining. Moreover, MDA-MB-231 xenograft growth in non-obese diabetic severe combined immunodeficient mice was suppressed by intra-tumoral administration of PZ-DHA. This study shows that PZ-DHA is selectively cytotoxic to breast cancer cells in vitro and in vivo, suggesting that further investigations of PZ-DHA are warranted as a potential treatment for breast cancer.

Novel long chain fatty acid derivatives of quercetin-3-O-glucoside reduce cytotoxicity induced by cigarette smoke toxicants in human fetal lung fibroblasts

Smoking has become a global health concern due to its association with many disease conditions, such as chronic obstructive pulmonary disease (COPD), cardiovascular diseases (CVD) and cancer. Flavonoids are plant polyphenolic compounds, studied extensively for their antioxidant, anti-inflammatory, and anti-carcinogenic properties. Quercetin-3-O-glucoside (Q3G) is a flavonoid which is widely found in plants. Six novel long chain fatty acid [stearic acid, oleic acid, linoleic acid, α-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] derivatives of Q3G were evaluated for their potential in protecting human lung fibroblasts against cytotoxicity induced by selected cigarette smoke toxicants: 4-(methylnitrosoamino)-1-(3-pyridinyl)-1-butanone (NNK), benzo-α-pyrene (BaP), nicotine and chromium (Cr[VI]). Nicotine and Cr[VI] induced toxicity in fibroblasts and reduced the percentage of viable cells, while BaP and NNK did not affect cell viability. The fatty acid derivatives of Q3G provided protection against nicotine- and Cr[VI]-induced cell death and membrane lipid peroxidation. Based on the evaluation of inflammatory markers of cyclooxygenase-2 (COX-2) and prostaglandin E2 (PGE2), the fatty acid derivatives of Q3G were found to be effective in lowering the inflammatory response. Overall, these novel fatty acid esters of Q3G warrant further investigation as potential cytoprotective agents.

Long Chain Fatty Acid Esters of Quercetin-3-O-glucoside Attenuate H₂O₂-induced Acute Cytotoxicity in Human Lung Fibroblasts and Primary Hepatocytes

Cellular oxidative stress causes detrimental effects to macromolecules, such as lipids, nucleic acids and proteins, leading to many pathological conditions. Quercetin-3-O-glucoside (Q3G), a glycosylated derivative of quercetin (Q), is a natural polyphenolic compound known to possess antioxidant activity. The hydrophilic/lipophilic nature of an antioxidant molecule is considered as an important factor governing the accessibility to the active sites of oxidative damages in vivo. Six long chain fatty acid esters of Q3G were evaluated with comparison to Q and Q3G, for their cytoprotective activity under H₂O₂-induced oxidative stress using cell culture model systems through cell viability, lipid peroxidation and fluorescence microscopy studies. Pre-incubation of α-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) esters of Q3G exhibited significantly (p ≤ 0.05) greater cell viability in both human lung fibroblast (WI-38) and human primary hepatocytes upon exposure to H₂O₂ insult when compared to the control. Cytoprotection due to oleic acid and linoleic acid esters of Q3G was observed only in human primary hepatocytes. All the derivatives, Q3G and quercetin showed ability to significantly (p ≤ 0.05) lower production of lipid hydroperoxides under induced oxidative stress, compared to the control. However, ALA and DHA esters of Q3G resulted in significantly lower lipid hydroperoxidation than Q and Q3G. Based on fluorescence microscopy study, H₂O₂-induced apoptosis was attenuated by the fatty acid derivatives of Q3G. The fatty acid derivatives of Q3G possess better cytoprotective effect than Q3G against H₂O₂-induced cytotoxicity in vitro and the concentration should be selected to avoid cytotoxicity.

Phloretin-induced cytoprotective effects on mammalian cells: A mechanistic view and future directions

Phloretin (C15 H14 O5 ), a dihydrochalcone flavonoid, is mainly found in fruit, leaves, and roots of apple tree. Phloretin exerts antioxidant, anti-inflammatory, and anti-tumor activities in mammalian cells through mechanisms that have been partially elucidated throughout the years. Phloretin bioavailability is well known in humans, but still remains to be better studied in experimental animals, such as mouse and rat. The focus of the present review is to gather information regarding the mechanisms involved in the phloretin-elicited effects in different in vitro and in vivo experimental models. Several manuscripts were analyzed and data raised by authors were described and discussed here in a mechanistic manner. Comparisons between the effects elicited by phloretin and phloridzin were made whenever possible, as well as with other polyphenols, clarifying questions about the use of phloretin as a potential therapeutic agent. Toxicological aspects associated to phloretin exposure were also discussed here. Furthermore, a special section containing future directions was created as a suggestive guide towards the elucidation of phloretin-related actions in mammalian cells and tissues.