Effects and mechanism of total phenols of Magnolia officinalis combined with Maijunan Tablets on blood pressure of spontaneous hypertensive rats

Abstract

ObjectiveMaijunan (MJA) Tablets is a protected variety of traditional Chinese medicine (TCM) consisted of Pueraria lobata, hydrochlorothiazide (HTCZ), Uncaria rhynchophylla (366:1:980) and excipient. In the present work, MJA was consisted of the total flavones of P. lobata, HCTZ and total alkaloids of U. rhynchophylla (40:11:75). The combination of MJA and the total phenols of Magnolia officinalis (M-MJA) was consisted of the total flavones of P. lobata, the total phenols of M. officinalis, HCTZ and the total alkaloids of U. rhynchophylla (40:40:11:75). The aim of this work was to examine the effect and mechanism of M-MJA on the blood pressure of spontaneous hypertensive rats (SHRs). MethodsAdult male SHRs were randomly divided into control group, MJA group (180 mg/kg·d), and the M-MJA group (218 mg/kg·d) (n = 5). SHRs were orally administered with M-MJA and MJA respectively once a day for 8 weeks, the blood pressure of SHRs was measured every two weeks, and the biochemical indicators related to blood pressures were detected at the last dosing. ResultsAfter oral administration of M-MJA to SHRs once a day for 8 weeks, the systolic and diastolic blood pressures of SHRs were deceased significantly. M-MJA affected renin-angiotensin-aldosterone system by decreasing the levels of Ren, Ang II and ALD, affected the endothelial function by decreasing the levels of ET-1 and 20-HETE, and increasing the level of eNOS, affected the oxidative stress by increasing the protein expression of Nrf2 and the activities of HO-1 and GSH-Px, and decreasing the protein expression of CYP2E1 and CYP4A, as well as the content of MDA. ConclusionThese results indicated that M-MJA could regulate the renin-angiotensin-aldosterone system, improve endothelial function, and inhibit CYP4A activity to reduce the production of 20-HETE, alleviate the oxidative stress disorder of the visceral organs, and eventually exert antihypertensive effect. Additionally, the anti-oxidant ability, regulating the renin-angiotensin-aldosterone system and improving endothelial function of M-MJA are more powerful than that of MJA, suggesting that M-MJA may have a better anti-hypertensive effect than MJA.