Effects of Red Ginseng upon Vascular Endothelial Function in Patients with Essential Hypertension

American Journal of Chinese Medicine, Spring, 2000 by Jidong Sung, Ki-Hoon Han, Joo-Hee Zo, Hwa-Jin Park, Cheol-Ho Kim, Byung-Hee Oh

Abstract: This study is to estimate the effect of Korean red ginseng on vascular endothelial cell dysfunction in patients with hypertension. Seventeen patients with hypertension who were divided into ginseng-treated (7) and non-treated (10) groups and 10 normotensive subjects were included. To assess the function of the vascular endothelial cell, changes of forearm blood flow to infusion of acetylcholine, sodium nitroprusside and bradykinin in incremental doses were measured by venous occlusion plethysmography. In the ginseng-treated hypertensive group, forearm blood flows at the highest dose of acetylcholine and bradykinin were significantly higher than those of the non-treated hypertensive group and were not different from those of the control group. In the case of sodium nitroprusside infusion, no significant differences were observed between the control, non-treated and treated groups. In conclusion, Korean red ginseng can improve the vascular endothelial dysfunction in patients with hypertension possibly through increasing synthesis of nitric oxide.

Hypertension is one of the independent risk factors of atherosclerosis and the predisposing factors of thromboembolic cerebrovascular disease, ischemic heart disease such as angina pectoris, myocardial infarction, and peripheral vascular obstructive disease (Management Committee, 1980; Medical Research Council Working Party, 1985; MDFP, 1984; IPPPSH, 1985). Before the development of overt atherosclerotic lesion under hypertensive condition, the functional abnormality of vascular endothelium develops and it reportedly causes dysregulation of blood flow by impairing local physiologic response to vasoactive substances and reducing vasodilatory reserve (Furchgott et al., 1980; Furchgott et al., 1983; Zeiher et al., 1991; Vita et al., 1990). The functional role of nitric oxide in maintaining vascular vasodilatory reserve has been extensively studied and the synthesis and release of nitric oxide in response to vasoactive substances has been shown to be impaired in the presence of hypertension, atherosclerosis or hyperlipidemia (Palmer et al., 1988; Fujii et al., 1992; Moncada et al., 1991; editorial, 1991; Star et al., 1993; Moncada et al., 1993; Lowenstein et al., 1994). The dysfunction of vascular endothelium precedes hypertrophic change of vascular wall in atherosclerosis (Palmer et al., 1987), suggesting endothelial dysfunction might be an antecedent factor of atherosclerotic change.

Reports have been made recently on the pharmacological effects of Korean red ginseng and its extracts on vascular tone, which showed that Korean red ginseng could enhance endothelium-dependent vasodilatory reserve in ex vivo experimental model using rabbit or mouse (Kim et al., 1992; Kang et al., 1995; Kim et al., 1994). However, the effect of Korean red ginseng on vascular endothelium has not been studied in an in vivo human study.

In this study, we estimated the vasodilatory reserve of hypertensive patients with and without administration of Korean red ginseng by measuring the forearm blood flow using vein occlusion plethysmography (Kiowski, 1991; Linder et al., 1990) and we report that Korean red ginseng can significantly improve endothelial dysfunction in patients with essential hypertension.

Subject and Method

Subject

Twenty patients diagnosed with essential hypertension were enrolled in this study. After washout of antihypertensive medication for 4 weeks, all subjects showed mild to moderate hypertension ([is greater than] 140/90 mmHg and diastolic blood pressures lower than 110 mmHg). Twenty-four-hour ambulatory blood pressure monitoring was done in all subjects to exclude white coat hypertension. Twenty hypertensive patients were randomized into either red ginseng treated group or non-treated group. Ten healthy volunteers were also enrolled.

Informed consents were obtained from all subjects before enrollment. Exclusion criteria were as follows: 1) Age under 18 or over 70, 2) being pregnant or planning pregnancy, 3) secondary hypertension, 4) malignant or accelerated hypertension, 5) nephrotic syndrome, 6) history of stroke within 3 months, 7) history of acute myocardial infarction or unstable angina within 3 months, 8) congestive heart failure, 9) renal dysfunction of more than moderate degree (serum creatinine [is greater than] 150 [micro]mol/L), 10) hepatic dysfunction (AST/ALT more than two-fold of normal value), 11) dementia, 12) alcoholics or other drug abusers, 13) inability to maintain medication during the study period, 14) failure to obtain informed consent

Among the 10 treated patients, two did not consent to plethysmographic examination and examination was impossible in one patient due to failure of arterial cannulation. Plethysmography and evaluation of endothelial function was successfully done in the remaining 7 patients. The study was completed in the non-treated hypertensive group and the normal control group, with 10 patients each.

All subjects had no evidence of ischemic heart disease or atherosclerosis. The possibility of secondary hypertension and coexisting diseases was ruled out by history taking, physical examination, electrocardiography, chest X-ray, and blood chemistry. Table 1 shows age, sex, blood pressure, serum creatinine, and total cholesterol and blood glucose of the subjects, duration of ginseng treatment, fundus findings and blood chemistry of the ginseng-treated hypertensive group.