Essential Oil from Fructus Alpiniae Zerumbet Protects Human Umbilical Vein Endothelial Cells In Vitro from Injury Induced by High Glucose Levels by Suppressing Nuclear Transcription Factor-Kappa B Signaling.

BACKGROUND In China, the essential oil of the fruit, Fructus Alpiniae zerumbet (FAZ), is used to treat cardiovascular diseases. Recent in vitro studies have shown that the essential oil of FAZ (EOFAZ) can protect endothelial cells from injury. Because of the prevalence of diabetes mellitus and its effects on the cardiovascular system, the aim of this study was to investigate the mechanism of the effects of EOFAZ on human umbilical vein endothelial cells (HUVECs) treated with high levels of glucose in vitro. MATERIAL AND METHODS The lactate dehydrogenase (LDH) leakage assay was used to detect HUVEC injury. Tumor necrosis factor-alpha (TNF-α), interleukin-8 (IL-8), and nuclear transcription factor-kappa B (NF-κB) p65 subunit DNA-binding activity was detected. The expression of NF-κB pathway-associated proteins, intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) was studied by Western blotting. The cellular location of NF-κB in HUVECs was evaluated using immunofluorescence. RESULTS Cell viability and LDH leakage assays showed that high glucose-induced HUVEC injury was reduced by EOFAZ. High glucose-induced secretion of IL-8, TNF-α, ICAM-1, and VCAM-1 was reduced, and translocation of the p65 subunit of NF-κB to the endothelial cell nucleus was inhibited by EOFAZ. Western blotting confirmed that EOFAZ blocked the activation of NF-κB induced by high glucose levels. EOFAZ reduced high glucose-induced p65/DNA binding to inhibit NF-κB activation. CONCLUSIONS The findings of this in vitro study showed that treatment of HUVECs with EOFAZ had a protective role against the effects of high glucose levels via the NF-κB signaling pathway.