Molecular mechanism of Chuanxiong Rhizoma in treating coronary artery diseases

Objective: Most of the studies on the herb Chuanxiong Rhizoma (CR) have focused on the l-arginine-nitric oxide (NO) pathway, but the nitrate-nitrite-NO (NO₃ ^--NO₂ ^--NO) pathway was rarely investigated. Therefore, the aim of this study was to evaluate the effects and mechanisms of action of CR in coronary artery disease (CAD).

Methods: The NO₃ ^-, NO₂ ^- and NO levels were examined in the NO₃ ^--NO₂ ^--NO pathway. High-performance ion chromatography was used to quantify NO₃ ^- and NO₂ ^- levels. Then, NO was quantified using a multifunctional enzyme marker with a fluorescent probe. The tension of aortic rings was measured using a multi myograph system.

Results: High content of NO₃ ^- and low content of NO₂ ^- was found in CR, and which could potently convert NO₃ ^- to NO₂ ^- in the presence of endogenous reductase enzyme. Incubating human coronary artery endothelial cells (HCAECs) with CR-containing serum showed that CR significantly decreased the NO₃ ^- content and increased the levels of NO₂ ^- and NO in the cells under hypoxic conditions. In addition, CR significantly relaxed isolated aortic rings when the l-arginine -NO pathway was blocked. The optimal concentration of CR for relaxation was 200 mg/mL.

Conclusion: CR supplements large amounts of NO in cells and vessels to achieve relaxation via the NO₃ ^--NO₂ ^--NO pathway, thereby making up for the deficiency caused by the lack of NO after the l-arginine-NO pathway is suppressed. This study also supports the potential use of a traditional Chinese herb for future drug development.