Effect of American ginseng (Panax quinquefolius L.) on arterial stiffn in subjects with type-2 diabetes and concomitant hypertension

Ethnopharmacological relevance: 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. Therefore, this study evaluates the effect of American ginseng (AG) on arterial stiffness, as measured by augmentation index (AI), and blood pressure (BP), in type 2 diabetes patients with concomitant hypertension.

Materials and methods: Using a double-blind, placebo-controlled, parallel design, each participant was randomized to either the selected AG extract or placebo at daily dose of 3 g for 12 weeks as an adjunct to their usual antihypertensive and anti-diabetic therapy (diet and/or medications). AI and BP 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:6379.3 years, BP: 145710.8/8478.0 mmHg, HbA1c: 7.071.3%, fasting blood glucose (FBG): 8.172.3 mmol/L) completed the study. Compared to placebo, 3 g of AG significantly lowered radial AI by 5.3% (P¼0.041) and systolic BP by 11.7% (Po0.001) at 12 weeks. No effect was observed with diastolic BP.

Conclusions: Addition of AG extract to conventional therapy in diabetes with concomitant hypertension improved arterial stiffness and attenuated systolic BP, thus warrants further investigation on long-term endothelial parameters before recommended as an adjunct treatment.