lignans and Eye-Diseases

Diabetes mellitus is a chronic metabolic disease characterized by disturbances in carbohydrate, protein, and lipid metabolism, often accompanied by oxidative stress. Diabetes treatment is a complicated process in which, in addition to the standard pharmacological action, it is necessary to append a comprehensive approach. Introducing the aspect of non-pharmacological treatment of diabetes allows one to alleviate its many adverse complications. Therefore, it seems important to look for substances that, when included in the daily diet, can improve diabetic parameters. Magnolol, a polyphenolic compound found in magnolia bark, is known for its health-promoting activities and multidirectional beneficial effects on the body. Accordingly, the goal of this review is to systematize the available scientific literature on its beneficial effects on type 2 diabetes and its complications. Taking the above into consideration, the article collects data on the favorable effects of magnolol on parameters related to glycemia, lipid metabolism, or oxidative stress in the course of diabetes. After careful analysis of many scientific articles, it can be concluded that this lignan is a promising agent supporting the conventional therapies with antidiabetic drugs in order to manage diabetes and diabetes-related diseases.

Topics: Animals; Biphenyl Compounds; Blood Glucose; Diabetes Complications; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Eye Diseases; Homeostasis; Humans; Hypoglycemic Agents; Inflammation; Lignans; Lipid Metabolism; Magnolia; Mice; Oxidative Stress; Plant Bark; Polyphenols; Treatment Outcome

Topics: Angiogenesis Inhibitors; Animals; Anti-Inflammatory Agents; Chorioallantoic Membrane; Disease Models, Animal; Drug Discovery; Electroretinography; Eye Diseases; Inflammation; Intraocular Pressure; Intravitreal Injections; Lignans; Male; Rats; Rats, Wistar; Retinal Pigment Epithelium; Safety; Treatment Outcome; Uveitis

Pathological activation of the hypoxia-inducible-factor (HIF) pathway leading to expression of pro-angiogenic genes, such as vascular endothelial growth factor (VEGF), is the fundamental cause of neovascularization in ocular ischemic diseases and cancers. We have shown that pure honokiol inhibits the HIF pathway and hypoxia-mediated expression of pro-angiogenic genes in a number of cancer and retinal pigment epithelial (RPE) cell lines. The crude extracts, containing honokiol, from Magnolia plants have been used for thousands of years in the traditional oriental medicine for a number of health benefits. We have recently demonstrated that daily intraperitoneal injection of honokiol starting at postnatal day (P) 12 in an oxygen induced retinopathy mouse model significantly reduced retinal neovascularization at P17. Here, we evaluate the mechanism of HIF inhibition by honokiol in RPE cells. Using chromatin immunoprecipitation experiments, we demonstrate that honokiol inhibits binding of HIF to hypoxia-response elements present on VEGF promoter. We further show using a number of in vitro angiogenesis assays that, in addition to anti-HIF effect, honokiol manifests potent anti-angiogenic effect on human retinal micro vascular endothelial cells. Our results suggest that honokiol possesses potent anti-HIF and anti-angiogenic properties. These properties of honokiol make it an ideal therapeutic agent for the treatment of ocular neovascular diseases and solid tumors.

Topics: Angiogenesis Inhibitors; Biphenyl Compounds; Cell Line; Cell Movement; Cell Proliferation; Endothelium, Vascular; Eye Diseases; HeLa Cells; Humans; Hypoxia-Inducible Factor 1; Lignans; Luciferases; Neovascularization, Pathologic; Retinal Pigment Epithelium