Dietary Polyphenols in Age-Related Macular Degeneration: Protection against Oxidative Stress and Beyond

Abstract

Age-related macular degeneration (AMD) is a multifactorial disease of the retina featured by degeneration and loss of photoreceptors and retinal pigment epithelium (RPE) cells with oxidative stress playing a role in its pathology. Although systematic reviews do not support the protective role of diet rich in antioxidants against AMD, dietary polyphenols (DPs) have been reported to have beneficial effects on vision. Some of them, such as quercetin and cyanidin-3-glucoside, can directly scavenge reactive oxygen species (ROS) due to the presence of two hydroxyl groups in their B ring structure. Apart from direct ROS scavenging, DPs can lower oxidative stress in several other pathways. Many DPs induce NRF2 (nuclear factor, erythroid 2-like 2) activation and expression of phase II enzymes that are under transcriptional control of this factor. DPs can inhibit A2E photooxidation in RPE cells, which is a source of oxidative stress. Anti-inflammatory action of DPs in RPE cells is associated with regulation of various interleukins and signaling pathways, including IL-6/JAK2 (Janus kinase 2)/STAT3. Some DPs can improve impaired cellular waste clearance, including AMD-specific deficient phagocytosis of the Aβ42 peptide and autophagy.

Bioactive Compounds and Health-Promoting Properties of Pear (Pyrus communis L.) Fruits

“…In recent years, more and more attention has been paid to the impact of food on the human body. The development of chronic diseases, autoimmune and neurodegenerative diseases, metabolic diseases, and cancer is positively correlated with oxidative stress [ 1 ]. Oxidative stress, that is, the imbalance of antioxidants and prooxidants in favor of prooxidants, is caused by high levels of reactive oxygen species (ROS).…”

Bilberry anthocyanin-rich extract protects against retinal photooxidative damage via activation of HO-1 and inhibition of NF-κB

“…A2E also induces production of ROS in response to light exposure, which can lead to RPE cell apoptosis (Wang, Kim, et al, 2017). Therefore, enhancing the antioxidant defense system and inhibiting ROS production are crucial for sustaining the structure and function of retina (Pawlowska, Szczepanska, Koskela, Kaarniranta, & Blasiak, 2019;Xu, Sun, Li, & Sun, 2017). Bilberry ACNs can prevent the photooxidative damage from A2E in RPE cells, as well as protection against membrane permeabilization (Jang, Zhou, Nakanishi, & Sparrow, 2005).…”

Combination of green tea catechins, polysaccharides, and flavonols against urban fine dust particle-induced bronchial damage mediated by modulation of inflammation factors and airway cilia

“…Green tea is an important dietary product that contains antioxidative molecules with cytoprotective and anti-in ammatory activities that protect cells from oxidative stress-induced apoptosis [15,16,17]. Catechin compounds, such as (-)-epigallocatechin-3-gallate (EGCG), act as radical scavengers and metal-chelating agents and play roles in various cellular processes; for example, they exert neuroprotective functions, regulate blood pressure, and protect against cardiovascular disease [18,19,20]. Previous studies have reported the protective effects of plant extracts and phenolic compounds against oxidative stress and in ammation induced by FDPs [21,22,23,24], and we hypothesized that green tea components could exert potent protective effects against FDP-induced toxicity.…”