Preventive effects of Rosa rugosa root extract on advanced glycation end product-induced endothelial dysfunction

Rosa rugosa has traditionally been used as a folk remedy for diabetes. The objective of this study was therefore to demonstrate the inhibition of endothelial dysfunction activities through antioxidants and the anti-glycation of Rosa rugosa roots. Dried roots of Rosa rugosa were boiled in methanol for three hours, evaporated and lyophilized with a freeze-dryer. The methanolic extract of Rosa rugosa roots (RRE) was tested for antioxidant activities by measuring total polyphenol (TP) content, flavonoid content, 1,1-diphenyl-2- picrylhydrazyl free radical-scavenging activity (DPPH) assay, and ferric-reducing antioxidant power (FRAP) assay. The total TP content, flavonoid content, FRAP value, and DPPH-SC₅₀ are 345.2 μg gallic acid equivalents/mg dry matter (DM), 128.1 μg quercetin equivalents/mg DM, 2.2 mM FeSO₄/mg DM and 34.2 μg DM/mL, respectively. Treatment of RRE significantly lowered fluorescent formation due to advanced glycation reaction. In addition, reactive oxygen species (ROS) scavenging assay, monocyte adherent assay and transendothelial electrical resistance (TEER) assay were performed to investigate the possibility that RRE improves endothelial dysfunction-induced diabetic complications. The adhesion of THP-1 to treated HUVEC with RRE (100 μg/mL; 33% and 500 μg/mL; 75%) was significantly reduced compared to HUVEC stimulated by glyceraldehydes-AGEs (advanced glycation end product). The TEER value (88 Ω·cm²) of stimulated HUVEC by glyceraldehydes-AGEs was reduced compared to non-stimulation (113 Ω·cm²). However, normalization with RRE increased endothelial permeability in a dose-dependent manner (100 μg/mL; 102 Ω·cm² and 500 μg/mL; 106 Ω·cm ²). Thus, these results suggest that Rosa rugosa roots could be a novel candidate for the prevention of diabetic complications through antioxidants and inhibition of advanced glycation end product formation.