Danggui Buxue Tang, Chinese Herbal Decoction Containing Astragali Radix and Angelicae Sinensis Radix, Induces Production of Nitric Oxide in Endothelial Cells: Signaling Mediated by Phosphorylation of Endothelial Nitric Oxide Synthase

Abstract

Danggui Buxue Tang, an ancient Chinese herbal decoction containing Astragali Radix and Angelicae Sinensis Radix at the weight ratio of 5:1, is used to mitigate menopausal syndromes in women. The pharmacological properties of Danggui Buxue Tang have been illustrated in bone development, blood enhancement, and immune stimulation. Here, we extended the possible pharmacological role of Danggui Buxue Tang in cardiovascular function. In cultured human umbilical vein endothelial cells, the application of Danggui Buxue Tang induced the release of nitric oxide and the phosphorylation of endothelial nitric oxide synthase and Akt kinase in time- and dose-dependent manners. The robust activation of nitric oxide signaling, however, required the boiling of Astragali Radix and Angelicae Sinensis Radix together, i.e., as Danggui Buxue Tang instead of other herbal extracts. The Danggui Buxue Tang-induced phosphorylation of endothelial nitric oxide synthase and Akt kinase in human umbilical vein endothelial cells were fully blocked by treatment with an endothelial nitric oxide synthase inhibitor (L-NAME), a PI3K/Akt inhibitor (LY294002), and a Ca(2+) chelator (BAPTA-AM). In parallel, the blockage of endothelial nitric oxide synthase and Akt activation subsequently fully abolished the Danggui Buxue Tang-induced nitric oxide production.