The effect of Korean red ginseng extracts with escalating levels of ginsenoside Rg3 on blood pressure in individuals with high normal blood pressure or hypertension

Many animal and aortic ring studies show that Korean red ginseng (KRG) can improve vascular tone. This effect is mediated by a group of steroidal saponins in KRG called ginsenosides. Of the KRG ginsenosides, Rg3 is the most potent vasodilator. Thus, it is of interest to determine in humans if KRG extracts with increasing levels of just Rg3 can cause dose dependent reductions in blood pressure (BP). After a 12-hour fast on 4 separate days, 10 drug-treated subjects with hypertension and 3 drug-naı¨ve subjects with high-normal BP (7 females/6 males; mean±SD: age = 57±10 years; systolic BP/diastolic BP = 135±8/85±5 mm Hg) randomly consumed 500mg of placebo (0mg Rg3), KRG-1 (0.27mg Rg3), KRG-2 (0.81mg Rg3) or KRG-3 (2.43mg Rg3) in identical capsules at time 0-min in a 4-period crossover study. Drug-treated individuals refrained from taking antihypertensive agents on test days. At time 60-min, a 360-calorie liquid meal replacement (Ensure) was consumed. BP was measured with ambulatory BP monitors (Accutracker II, SunTech) every 5 min for 20 min before time 0-min (the mean of this represented baseline BP) and every 15 minutes for 180 min after the consumption of placebo or KRG. At time 135-min, the change in diastolic BP relative to baseline differed (p=0.02) between placebo and KRG-2 (-1.6±9.5 and -8.9±7.8 mm Hg, respectively); as well, at time 135 min the change in systolic BP relative to baseline differed (p=0.06) between placebo and KRG-2 (+2.7±11 and -4.3±9.2 mm Hg, respectively). Consumption of the other KRG treatments showed no significant effect on BP. Only the KRG extract that contained 0.84mg of Rg3 (medium dose in this study) caused an acute reduction in BP; levels of Rg3 beyond this point appear to have no further effect on BP. Overall, this study demonstrates that selectively increasing the level of ginsenoside Rg3 in KRG extracts can yield profound acute reductions in BP.