Lespedeza cuneata protects the endothelial dysfunction via eNOS phosphorylation of PI3K/Akt signaling pathway in HUVECs

Background: Lespedeza cuneata G.Don (LCE), which belongs to the genus Lespedeza (Leguminosae), is a traditional oriental medicine known to prevent diabetes and cardiovascular diseases. However, no scientific studies about the effectiveness of LCE, their responsible bioactive constituents, and its mechanisms against endothelial dysfunction have been performed. Purpose: This study was performed to investigate the role of LCE and its chemical components in ameliorating endothelial dysfunction. Methods: The production of nitric oxide (NO) was evaluated after LCE treatment in HUVECs. Cell viability was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reagent. Western blot analysis was performed to determine the protein expression of endothelial nitric oxide synthase (eNOS) and protein kinase B (PKB, also known as Akt) in human umbilical vein endothelial cells (HUVECs). Results: Pretreatment with L-NAME and LY294002 significantly decreased the LCE-induced NO production, as well as eNOS and Akt phosphorylation. beta-Sitosterol and beta-Sitosterol 6'-linolenoyl-3-O-beta-D glucopyranoside are the bioactive constituents increase NO production as well as eNOS phosphorylation. Conclusion: Our findings suggest that LCE increase NO production via eNOS phosphorylation of PI3K/Akt signaling pathway.