Phloretin induces apoptosis of human esophageal cancer via a mitochondria-dependent pathway

Therapeutic Potential and Pharmaceutical Development of a Multitargeted Flavonoid Phloretin

Phloretin is a flavonoid of the dihydrogen chalcone class, present abundantly in apples and strawberries. The beneficial effects of phloretin are mainly associated with its potent antioxidant properties. Phloretin modulates several signaling pathways and molecular mechanisms to exhibit therapeutic benefits against various diseases including cancers, diabetes, liver injury, kidney injury, encephalomyelitis, ulcerative colitis, asthma, arthritis, and cognitive impairment. It ameliorates the complications associated with diabetes such as cardiomyopathy, hypertension, depression, memory impairment, delayed wound healing, and peripheral neuropathy. It is effective against various microbial infections including Salmonella typhimurium, Listeria monocytogenes, Mycobacterium tuberculosis, Escherichia coli, Candida albicans and methicillin-resistant Staphylococcus aureus. Considering the therapeutic benefits, it generated interest for the pharmaceutical development. However, poor oral bioavailability is the major drawback. Therefore, efforts have been undertaken to enhance its bioavailability by modifying physicochemical properties and molecular structure, and developing nanoformulations. In the present review, we discussed the pharmacological actions, underlying mechanisms and molecular targets of phloretin. Moreover, the review provides insights into physicochemical and pharmacokinetic characteristics, and approaches to promote the pharmaceutical development of phloretin for its therapeutic applications in the future. Although convincing experimental data are reported, human studies are not available. In order to ascertain its safety, further preclinical studies are needed to encourage its pharmaceutical and clinical development.

Dihydrochalcones as antitumor agents

Dihydrochalcones are a class of secondary metabolites, possessing several biological properties such as antitumor, antioxidant, antibacterial, antidiabetic, estrogenic, anti-inflammatory, antithrombotic, antiviral, neuroprotective and immunomodulator properties; therefore, they are currently considered promising candidates in the drug discovery process. This review intend to debate their pharmacological actions with a particular attention to their antitumor activity against a panel of cancer cell-lines and to the description of the inhibition mechanisms of cell proliferation such as the regulation of angiogenesis, apoptosis, etc etc.

Onco-Preventive and Chemo-Protective Effects of Apple Bioactive Compounds

Cancer is one of the leading causes of death globally. Epidemiological studies have strongly linked a diet high in fruits to a lower incidence of cancer. Furthermore, extensive research shows that secondary plant metabolites known as phytochemicals, which are commonly found in fruits, have onco-preventive and chemo-protective effects. Apple is a commonly consumed fruit worldwide that is available all year round and is a rich source of phytochemicals. In this review, we summarize the association of apple consumption with cancer incidence based on findings from epidemiological and cohort studies. We further provide a comprehensive review of the main phytochemical patterns observed in apples and their bioavailability after consumption. Finally, we report on the latest findings from in vitro and in vivo studies highlighting some of the key molecular mechanisms targeted by apple phytochemicals in relation to inhibiting multiple 'hallmarks of cancer' that are important in the progression of cancer.

Natural Products Targeting the Mitochondria in Cancers

There are abundant sources of anticancer drugs in nature that have a broad prospect in anticancer drug discovery. Natural compounds, with biological activities extracted from plants and marine and microbial metabolites, have significant antitumor effects, but their mechanisms are various. In addition to providing energy to cells, mitochondria are involved in processes, such as cell differentiation, cell signaling, and cell apoptosis, and they have the ability to regulate cell growth and cell cycle. Summing up recent data on how natural products regulate mitochondria is valuable for the development of anticancer drugs. This review focuses on natural products that have shown antitumor effects via regulating mitochondria. The search was done in PubMed, Web of Science, and Google Scholar databases, over a 5-year period, between 2015 and 2020, with a keyword search that focused on natural products, natural compounds, phytomedicine, Chinese medicine, antitumor, and mitochondria. Many natural products have been studied to have antitumor effects on different cells and can be further processed into useful drugs to treat cancer. In the process of searching for valuable new drugs, natural products such as terpenoids, flavonoids, saponins, alkaloids, coumarins, and quinones cover the broad space.

Dermatological applications of the flavonoid phloretin

Botanical molecules are known to have the ability to counteract ultraviolet radiation-induced skin damage. The interest in the development of natural compound-based products for the prevention of solar ultraviolet radiation-induced skin photoaging, melasma, and photocarcinogenesis has been increasing. Recently, the flavonoid phloretin has attracted the attention of researchers in the dermatological field for application in cosmetics and therapeutics. In addition to its antioxidant activity, phloretin has been shown to have properties such as anti-aging and depigmenting effects. In this study, we review the dermatological treatments with phloretin for conditions such as melasma, photoaging, acne, and melanoma. Phloretin has been shown to inhibit elastase and matrix metalloproteinase-1 activity, to reduce cellular tyrosinase activity and melanin content, and induce apoptosis in B16 mouse melanoma 4A5 cells. An in vivo study showed that phloretin, applied topically to the dorsal skin of mice, suppressed the 12-O-tetradecanoylphorbol 13-acetate-induced expression of COX-2, a critical molecular target of many chemopreventive, as well as anti-inflammatory agents. Phloretin can penetrate the skin; nevertheless, its penetration profile in different skin layers has not yet been evaluated. Despite its health benefits, phloretin application has been limited because of its photoinstability and poor aqueous solubility, among other limitations. Therefore, we reviewed the recent advances in pharmaceutical applications such as the use of nanotechnology, in order to improve the cutaneous availability of phloretin. In this review, we also focus on the oral application, product development challenges, and recent progress and future research directions on phloretin.

Stable Isotope Tracing Metabolomics to Investigate the Metabolic Activity of Bioactive Compounds for Cancer Prevention and Treatment

A major hallmark of cancer is the metabolic reprogramming of cancer cells to fuel tumor growth and proliferation. Various plant-derived bioactive compounds efficiently target the metabolic vulnerabilities of cancer cells and exhibit potential as emerging therapeutic agents. Due to their safety and common use as dietary components, they are also ideal for cancer prevention. However, to render their use as efficient as possible, the mechanism of action of these phytochemicals needs to be well characterized. Stable isotope tracing is an essential technology to study the molecular mechanisms by which nutraceuticals modulate and target cancer metabolism. The use of positionally labeled tracers as exogenous nutrients and the monitoring of their downstream metabolites labeling patterns enable the analysis of the specific metabolic pathway activity, via the relative production and consumption of the labeled metabolites. Although stable isotope tracing metabolomics is a powerful tool to investigate the molecular activity of bioactive compounds as well as to design synergistic nutraceutical combinations, this methodology is still underutilized. This review aims to investigate the research efforts and potentials surrounding the use of stable isotope tracing metabolomics to examine the metabolic alterations mediated by bioactive compounds in cancer.

Decrypting the Molecular Mechanistic Pathways Delineating the Chemotherapeutic Potential of Ruthenium-Phloretin Complex in Colon Carcinoma Correlated with the Oxidative Status and Increased Apoptotic Events

To explore fresh strategies in colorectal cancer (CRC) chemotherapy, we evaluated the capability of the ruthenium-phloretin complex in exterminating colon cancer by effectively addressing multiple apoptotic mechanisms on HT-29 cancer cells together with an animal model of colorectal cancer activated by 1,2-dimethylhydrazine and dextran sulfate sodium. Our current approach offers tangible evidence of the application of the ruthenium-phloretin complex in future chemotherapy. The complex triggers intrinsic apoptosis triggered by p53 and modulates the Akt/mTOR pathway along with other inflammatory biomarkers. The ruthenium-phloretin complex has been synthesized and successfully characterized by numerous spectroscopic methodologies accompanied by DPPH, FRAP, and ABTS assays assessing its antioxidant potential. Studies conducted in human cell lines revealed that the complex improved levels of p53 and caspase-3 while diminishing the activities of VEGF and mTOR, triggers apoptosis, and induces fragmentation of DNA in the HT-29 cells. Toxicity studies were conducted to identify the therapeutic doses of the novel complex in animal models. The outcomes of the in vivo report suggest that the complex was beneficial in repressing multiplicity of aberrant crypt foci as well as hyperplastic lesions and also promoted increased levels of CAT, SOD, and glutathione. In addition, the ruthenium-phloretin complex was able to control cell proliferation and boosted apoptotic outbursts in cancer cells associated with the increase in cellular response towards Bax while diminishing responses towards Bcl-2, NF-κB, and MMP-9. Our observations from the experiments deliver testament that the ruthenium-phloretin complex has the potential to act as a promising chemotherapeutic agent in colorectal cancer because it can affect the growth of ACF and hyperplastic abrasions in the colon tissues by evoking cell death.

Association between obesity and breast cancer: Molecular bases and the effect of flavonoids in signaling pathways

Obesity is an abnormal or excessive accumulation of fat that leads to different health problems, such as cancer, where the adipocytes promote the proliferation, migration, and invasion of cancer cells, especially in the breast, where the epithelial cells are immersed in a fatty environment, and the interactions between these two types of cells involve, not only adipokines but also local pro-inflammatory mechanisms and hypoxic processes generating anti-apoptotic signals, which are a common result in leptin signaling. The expression of the Vascular Endothelial Growth Factor (VEGF) and cyclin D1, results in the decrease in phosphorylation of AMPK, increasing the activity of the aromatase enzyme; alternatively, the adiponectin activates AMPK to reduce inflammation. Nevertheless, alterations of the JAK/STAT pathways contribute to mammary carcinogenesis, while the PI3K/AKT/mTOR pathway controls most of the cancer's characteristics such as the cell cycle, survival, differentiation, proliferation, motility, metabolism, and genetic stability. Therefore, the purpose of the present review is, through the accumulated scientific evidence, to find the concordance between the signaling pathways involved among obesity and breast cancer, which can be modulated by using flavonoids.

Dihydrochalcones: Methods of Acquisition and Pharmacological Properties-A First Systematic Review

Dihydrochalcones are a class of secondary metabolites, for which demand in biological and pharmacological applications is still growing. They posses several health-endorsing properties and, therefore, are promising candidates for further research and development. However, low content of dihydrochalcones in plants along with their low solubility and bioavailability restrict the development of these compounds as clinical therapeutics. Therefore, chemomicrobial and enzymatic modifications are required to expand their application. This review aims at analyzing and summarizing the methods of obtaining dihydrochalcones and of presenting their pharmacological actions that have been described in the literature to support potential future development of this group of compounds as novel therapeutic drugs. We have also performed an evaluation of the available literature on beneficial effects of dihydrochalcones with potent antioxidant activity and multifactorial pharmacological effects, including antidiabetic, antitumor, lipometabolism regulating, antioxidant, anti-inflammatory, antibacterial, antiviral, and immunomodulatory ones. In addition, we provide useful information on their properties, sources, and usefulness in medicinal chemistry.

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.

Dynamic influence of Rhein lysinate on HeLa cells

In a previous study, it was demonstrated that Rhein lysinate (RHL) inhibited HeLa cell proliferation via a specific mechanism. The aim of the present study was to clarify the mechanism of RHL by investigating its effect on mitochondrial damage and cell apoptosis. The results indicated that RHL inhibited cell growth and proliferation in HeLa cells. HeLa cells treated with RHL developed extensive vacuolization in a dose- and time-dependent manner. Ultrastructure analysis using transmission electron microscopy revealed that the vacuoles observed were damaged mitochondria and endoplasmic reticulum. The effects of RHL on mitochondria were further confirmed by a decrease in mitochondrial membrane potential and increased generation of reactive oxygen species. The mitochondrial proteome was analyzed, and the results demonstrated that the expression of the cytoskeletal protein keratin and dermal papilla derived protein 12 (associated with the oxidation-reduction process), which are associated with mitochondrial structure and function, were decreased compared with the untreated control group. Hoechst staining, flow cytometry and western blotting also revealed that apoptosis was induced at 24 h following RHL treatment. These results confirm that RHL toxicity in HeLa cells is a dynamic process. Vacuolar degeneration appeared in HeLa cells treated with 160 µmol/l RHL during the first 6 h and with the extension of RHL treatment, cell apoptosis was presented at ~24 h in HeLa cells.

Anticancer Activity of Phloretin Against Human Gastric Cancer Cell Lines Involves Apoptosis, Cell Cycle Arrest, and Inhibition of Cell Invasion and JNK Signalling Pathway

BACKGROUND Gastric cancer is one of most commonly diagnosed cancers and causes significant mortality worldwide. In this study, the antiproliferative and anticancer effects of Phloretin were evaluated against gastric cancer cell lines. MATERIAL AND METHODS MTT assay was used to assess the proliferation rate of gastric cancer cells. DAPI and annexin V/PI were used for detection of apoptotic cell death. Cell invasion was investigated by Transwell assays and the expression of the proteins was estimated by immunoblotting. RESULTS The results revealed that Phloretin exerts anticancer effects on all the gastric cancer cell lines used in this study. However, the anticancer effects were more significant (p<0.05) on the AGS cell line. Further, the effect of Phloretin on the viability of normal GES-1 cells was minimal. Apoptosis assays showed that Phloretin triggers apoptotic cell death in AGS gastric cancer cells. Phloretin could also cause the arrest of the AGS gastric cancer cells in the G2/M phase of the cell cycle and suppress their ability to migrate. Western blotting analysis revealed that Phloretin significantly decreased the expression of p-JNK and p-38. However, comparatively lower effects were observed on the expression of JNK and P38. CONCLUSIONS We showed that Phloretin is an important molecule for the treatment of gastric cancer.