Effect of American ginseng on arterial stiffness in subjects with well-controlled type-2 diabetes and concomitant hypertension

Background: Substantial pre-clinical and some clinical data are available showing that Asian ginseng (Panax ginseng C.A Meyer) varieties or its particular ginsenosides exert a vasodilatating effect, thus may modulate vascular function. However, the clinical evidence for American ginseng (Panax quinquefolius L.) is scarce. Objective: This study explores the effect of American ginseng (AG) treatment on peripheral blood pressure (BP) and arterial stiffness, as measured by augmentation index (AI), in subjects with well-controlled type 2 diabetes and concomitant hypertension. Methods: Using a double-blind, randomized, placebo-controlled design, each participant received either the selected AG root preparation (10% extract) or placebo at the dose of 500 mg/meal = 3 g/day for 12 weeks as an adjunct to their usual antihypertensive and anti-diabetic therapy (diet and/or medications). BP and AI were measured by applanation tonometry at baseline and after 12 weeks of treatment. Results: A total of 64 individuals with well-controlled essential hypertension and type 2 diabetes (gender: 22 M: 42 F, age: 63, 1 ± 9, 27 years, systolic/diastolic BP: 145, 4 ± 10, 81/ 84, 8 ± 8, 03 mmHg, HbA1c: 7, 0 ± 1, 31 %, FPG: 8, 1 ± 2, 31 mmol/L) completed the study. Compared to placebo, 3 g of AG significantly lowered radial AI by 5.25% (P=0.041) and systolic BP by 11.72% (P< 0.001) (Figure 1), and no significant effect was observed with diastolic BP (Table 1 and Table 2). Conclusions: The present study was the first to demonstrate that AG can generate favourable effects on pulse wave reflection and systolic BP. The selected AG treatment showed convincing preliminary long-term clinical efficacy when administered as an adjunct to usual antihypertensive and antidiabetic therapy. This study supports the results seen with other ginseng species in both preclinical and clinical studies and warrants potential clinical application.