Pharmacodynamic components and molecular mechanism of Gastrodia elata Blume in treating hypertension: absorbed components, network pharmacology analysis, molecular docking and in vivo experimental verification.

Ethnopharmacological Relevance: Rhizome of Gastrodia elata Blume (RGE) is a valuable traditional Chinese Medicine (TCM) in the clinical practice. The Compendium of Materia Medica records that RGE has the effect of flatting liver wind out. It has sedative, analgesic, hypnotic, anticonvulsant, anti-hypertensive, anti-myocardial ischemia, anti-arrhythmic and anti-platelet aggregation effects. RGE is often used to relieve and treat vertigo, headache, hypertension, convulsions, and epilepsy in TCM clinic for thousands of years. Accumulated evidences have suggested that hypertension disease is related to the renin-angiotensin-aldosterone system (RAAS) disturbance. However, the potential pharmacodynamic components and anti-hypertensive mechanisms of RGE are unclear now.

Aim Of The Study: The active component and mechanism of RGE in treating hypertension were elucidated to strengthen the quality control and development of anti-hypertensive drugs.

Materials And Methods: The anti-hypertensive active components of RGE were analyzed by multi-dimensional qualitative analysis method including ethanol extract, in-vitro intestinal absorption, in-vivo plasma. The ultra high performance liquid chromatography-mass spectrometry (UPLC-Q-Exactive MS/MS) analysis technology was adopted to identify these components. Network pharmacology was applied to predicted anti-hypertensive active components, target proteins and pathways. Molecular docking was used to evaluate the potential molecular binding modes between 68 components and nine proteins. Spontaneously hypertensive rats (SHR) model was adopted to evaluate the activity of reducing systolic and diastolic blood pressure (SBP and DBP). Levels of renin, angiotcnsin II (Ang II) and aldosterone (ALD) in serum were determined by Elisa kit. Immunohistochemical were adopted to compare the changes of Ang II receptor 1 (AT1R) protein levels in SHR model and RGE groups.

Results: The multi-dimensional components qualitative analysis method of RGE was established. The results showed that 79, 70 and 30 components were identified in RGE ethanol extract, in-vitro intestinal absorption and in-vivo plasma, respectively. These components were mainly parishins, nucleosides, amino acids, phenolic acids, flavonoids, organic acids, et al. Network pharmacology results showed that anti-hypertensive active components were nucleosides and organic acids. It was speculated that RGE could exert its anti-hypertensive effect by regulating aldosterone-regulated sodium reabsorption, renin-angiotensin system pathways and related target proteins. Molecular docking results showed that 21 components including parishins, nucleosides and phenolic acids were potential active components of anti-hypertensive. Taking together, parishin A, B, E, C, D, adenosine, N-(4-hydroxybenzyl) adenosine, guanosine, ferulic acid were the main anti-hypertensive active components of RGE. Pharmacodynamic results showed that RGE (0.7 g·kg) at low dosage could reduce SBP and DBP of SHR in vivo. Meanwhile, RGE (1.4 g·kg) markedly reduced the contents of renin, angiotcnsin II and ALD (p < 0.05) of SHR. Immunohistochemical data demonstrated that RGE (0.7 g·kg) could downregulate the protein expression of AT1R. In general, RGE can significantly reduce blood pressure of SHR by regulating RAAS.

Conclusion: The multi-dimensional components qualitative analysis combining network pharmacology and molecular docking technology provide a new perspective for discovering potential anti-hypertensive components of RGE. RGE possess anti-hypertensive activity by regulating multiple targets of RAAS. Thus, it has the potential to develop into the novel raw material of anti-hypertensive drugs.