Anti-hypertensive effect of Gastrodia elata Bl leaf extract in rats

Purpose: To investigate the probable antihypertensive effects of Gastrodia elata Bl. extract (GEBE) in renovascular hypertensive rats as well as the mechanism involved in blood pressure reduction.Methods: The two-kidney one-clip (2K1C) Goldblatt model of renovascular hypertension was used in Wistar rats. The 2K1C group rats were treated with captopril (40 mg/kg/day), low-dose GEBE (150 mg/kg/day) and high-dose of GEBE (300 mg/kg/day) for 6 weeks by intragastric administration. Systolic (SBP) and diastolic blood pressure (DBP) were measured by the tail-cuff method. Urine creatinine and urea levels of the rats were measured by enzyme-linked immunosorbent assay (ELISA). Superoxide dismutase (SOD) and malondialdehyde (MDA) levels were also evaluated.Results: In the captopril- and GEBE-treated groups, blood pressure decreased progressively over the course of the 6-week treatment period compared with that of the untreated (control) rats (p < 0.01). High-dose GEBE also significantly increased plasma SOD activity but decreased plasma MDA concentration (p < 0.05). Renal function improved following captopril and GEBE (300 mg/kg/day) treatment (p < 0.01).Conclusion: The results suggest that GEBE probably exerts an antihypertensive effect by inhibiting endothelin (ET)-converting enzyme and via its antioxidant activity.Keywords: Antihypertensive, Gastrodia elata, Goldblatt renovascular hypertension, Endothelin-1, Hypertrophy