Dratanguticumides G and H, two new glucosides from Dracocephalum tanguticum Maxim relax vessels via NO pathway

Abstract Hypertension is one of the major sources of global incidence of cardiovascular diseases and one of the leading causes of global morbidity and mortality. It is necessary to search for natural products which have not adverse effects like many synthetic drugs as potential development agents for treating hypertension. Dracocephalum tanguticum Maxim, a perennial herb for Tibetan medicine in China, is widely used for the treatment of many diseases. In the present study, two new glucosides, Dratanguticumide G (1) and Dratanguticumide H (2), and seven known compounds (3-9) were isolated from D. tanguticum. The new structures were elucidated by spectroscopic data and the known ones were identified by comparison with spectroscopic data, physical and chemical data of reported references. The vasodilatory effects and the underlying mechanisms of the components of D. tanguticum on rat aortic rings were investigated. The result showed that the new compounds exhibited significant endothelium-dependent vasodilatory effects on the aortic rings, and the NO-dependent pathway and PI3K/AKT pathway might play a pivotal role in the vasodilatory effect, as did five of known compounds. Our findings firstly showed that some natural compounds of 95% ethanol extract of D. tanguticum had significant vasodilatory effects and could be the potential development agents for treating hypertension.