Nature against Diabetic Retinopathy: A Review on Antiangiogenic, Antioxidant, and Anti-Inflammatory Phytochemicals

Abstract

Background and Purpose. Diabetes mellitus (DM), hyperglycemia, and hypertension can result in diabetic retinopathy (DR), which is a major cause of blindness on a global scale. Development of DR is associated with decreased endothelial cells, increased basal membrane thickness, permeation of the retinal blood barrier, and neovascularization in patients. The purpose of the present review is to provide an overview of the findings regarding applications of phytochemicals for DR treatment and could be a beneficial resource for further clinical studies and also a basis for pharmaceutical purposes for drug design. Materials and Methods. A narrative literature review was performed from electronic databases including Web of Science, PubMed, and Scopus to analyze the effects of different phytochemicals to prevent or treat oxidation, angiogenesis, and inflammation in diabetic retinopathy. The inclusion criteria were original studies, which included the effects of different phytochemicals on diabetic retinopathy. The exclusion criteria included studies other than original articles, studies which assessed the effects of phytochemicals on nondiabetic retinopathy, and studies which used phytochemical-rich extracts. Results and Conclusions. Studies have shown that increased levels of inflammatory cytokines, angiogenic, and oxidative stress factors are involved in the progression and pathogenesis of DR. Therefore, phytochemicals with their anti-inflammatory, antiangiogenic, and antioxidant properties can prevent DR progression and retinal damage through various cellular mechanisms. It is also shown that some phytochemicals can simultaneously affect the inflammation, oxidation, and angiogenesis in DR.

β-Asarone Alleviates High-Glucose-Induced Oxidative Damage via Inhibition of ROS Generation and Inactivation of the NF-κB/NLRP3 Inflammasome Pathway in Human Retinal Pigment Epithelial Cells

“…Excess ROS production due to hyperglycemia initiates oxidative stress and inflammatory responses, which are mechanisms involved in the pathogenesis of DR [3,7]. Antioxidants with antiinflammatory effects exert inhibitory effects on the onset and progression of DR [41][42][43]. β-asarone, a type of volatile oil, exerts multiple pharmacological effects, including antioxidant and anti-inflammatory effects [19,20,44].…”

The signaling pathways of traditional Chinese medicine in treating diabetic retinopathy

“…In addition, the expression levels of various inflammatory mediators such as tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1), and intercellular cell adhesion molecule-1 (ICAM-1) are increased under the stimulation of persistent hyperglycemia, which has been demonstrated in the vitreous cavity and serum of diabetic patients and various types of diabetic animal models. The anomalies of the aforementioned indicators usually do not appear alone because they influence each other on the basis of their own development; for example, TNF-α aggravates leukocyte adhesion and BRB breakdown, and ICAM-1 is closely related to leukocyte adhesion ( Li W. C. et al, 2020 ; Khazeei Tabari et al, 2022 ; Kovoor et al, 2022 ). It has been reported that many TCMs exhibit against retinal inflammation in diabetes ( Figure 2 ), and the signaling pathways involved are explained in the following paragraphs.…”