Control of hypertension in rats using volatile components of leaves of Taxus chinensis var. mairei

Ethnopharmacological relevanceThe leaves of Taxus chinensis var. mairei (Taxaceae) is used traditionally to fill pillows in some rural areas of China. Its volatile substances have been speculated to be capable of improving sleep quality, making blood pressure stable, and having diuretic capacity as recorded in Ancient Chinese Materia Medica. Using animal models and new technologies, we confirmed the hypotensive potential of volatile components from leaves of Taxus chinensis var. mairei (VCLT).Materials and methodsVCLT was obtained by supercritical CO2 extraction equipment from Taxus chinensis var. mairei fresh leaves. Hypertensive rats were pre-induced by intraperitoneal (i,p.) injection of Nω-Nitro-l-Ariginine (l-NNA) for 15 days (15 mg/kg, twice a day), then divided into 5 groups and subjected to the following treatments. l-NNA group (group 1) receiving l-NNA alone (15 mg/kg, i.p., twice per day for 6 weeks); in addition to receiving l-NNA same as group 1, Hydrochlorothiazide (HDZ) group (group 2) receiving HDZ (orally administration, 5 mg/kg, once per day for 6 weeks); VCLT groups (groups 3-5), including VCLT1, VCLT2, VCLT3. The VCLT rats were housed in an enclosed cage (2 rats/0.064 m3). VCLT was mixed well and sprayed on fresh leaves surface of Taxus chinensis var. mairei (100 ml/kg) with three dosages: 167 g/kg (VCLT1), 233 g/kg (VCLT2) and 333 g/kg (VCLT3), respectively. Systolic Blood Pressure (SBP), plasma nitric oxide (NO), plasma angiotensin II, postprandial blood glucose, fasting blood glucose and blood lipids were determined.ResultsVCLT prevented the increase of SBP and plasma angiotensin II in l-NNA treated rats. Although VCLT does not significantly reduce blood triglycerides (TG), high-density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C), it decreases total cholesterol (TC) while increasing plasma NO levels in a dose-dependent manner.ConclusionVCLT can be used as a natural and supplementary reagents for the treatment of hypertension.