Antihypertensive activities of extracts from tissue cultures of Vitis thunbergii var. taiwaniana

Vitis thunbergii var. taiwaniana (VTT), the wild grape, is an endemic plant in Taiwan which has long been used as a folk medicine. Two ethanolic extracts (EE), including shoots (S) and root parts (R), from each plant growth regulator-treated VTT tissue culture (TC) plantlets, including TC1 (treated with IAA), TC2 (treated with IBA), TC3 (as the control), and TC4 (treated with NAA), were used to test the angiotensin converting enzyme (ACE) inhibitory activities. It was found that EE of R and S parts from four VTT-TC plantlets exhibited ACE inhibitory activities and the TC-R had better ones. The EE of whole plantlet exhibited dose-dependently ACE inhibitory activities (expressed as IC 50), and the orders were TC1 (98.67 μg/ mL) > TC3 (99.04 μg/mL) > TC4 (102.46 μg/mL) > TC2 (132.05 μg/mL). The hot water extracts (HWE) of TC1-A and HWE-TC1-B exhibited dose-dependently ACE inhibitory activities and the IC 50 were 29.51 and 32.79 μg/mL, respectively. For short-term antihypertensive activity of EE-TC1-R in vivo, the spontaneously hypertensive rats (SHRs) were fed by a single oral adminisration (20 mg/Kg of SHR), and the changes of systolic blood pressure (SBP) and diastolic blood pressure (DBP) during 24-h were measured. It was found that EE showed antihypertensive activities and the higherst lowering effects was reached at 4 th-h after being orally administered and the reductions of SBP and DBP were 16.9 and 17.7 mmHg, respectively. It can also be noted that the SBP reduction could last over 24-h. For long-term antihypertensive activity of EE-TC1-R in vivo, SHRs were fed orally once a day for four weeks (30 mg/Kg of SHR), and the changes of systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured weekly. It was found that the reductions of SBP, but not DBP, were 12.45, 17.13, and 10.05 mmHg, respectively, at the 2 nd, 3 rd, and 4 th-week and showed significantly different (P