Effects of Red Raspberry Crude Extracts (RCE) on Biomarkers of Oxidative Stress and Inflammation in Human Umbilical Vein Endothelial Cell (HUVEC) Induced by Glucose

Oxidative stress and inflammation are known to play key roles in both pathogenesis and progression of diabetes mellitus (DM). The study was conducted to determine the effects of red raspberry (Rubus idaeus L.) crude extracts (RCE) on biomarkers of oxidative stress and inflammation that mimic hyperglycemia in DM in glucose-induced hyperglycemia in human umbilical vein endothelial cells (HUVECs). The results showed that the red raspberries contained polyphenols such as quercetin and flavonoids known to exert strong antioxidant capacity. An in vitro study showed that RCE can attenuate oxidative stress by significantly inhibiting reactive oxygen species (ROS) (p < 0.05) and lipid peroxidation (P < 0.05). However, at higher concentration (20 µg/mL), RCE acted as pro-oxidant and significantly decreased cell proliferation (p < 0.05). RCE interacted with molecular signaling pathways involved in oxidative stress and inflammation, and significantly up-regulated the expression of transcription factors Nrf2 and PPAR-γ in a non-dose-dependent manner. RCE also significantly down-regulated the expression of the pro-inflammatory transcription factor NF-kB and the inflammatory IL-6 in a dose-dependent manner.