Korean red ginseng rootlets decrease acute postprandial glycemia: results from sequential preparation- and dose-finding studies.
BACKGROUND
Fractionation of a ginseng source to produce differences in the ginsenoside profile might influence its effect on postprandial glycemia. To explore this possibility and identify an efficacious ginseng for a longterm study, we conducted a preparation-finding study of different Korean red ginseng (KRG) root fractions followed by a dose-finding study of the most efficacious fraction.


METHODS
A double-blind, randomized, within-subject design was used in both studies. In the preparation-finding study, 7 healthy subjects (sex: 3m:4f, age: 32 +/- 4 y, BMI: 24 +/- 2 kg/m2) received 6 g placebo and KRG-rootlets, -body, and -H2O extract 40 min before a 50 g-OGTT with finger-prick blood samples at -40-, 0-, 15-, 30-, 45-, 60-, 90-, 120-min. In the dose-finding study, 12 healthy subjects (sex: 9M,3F, age: 29 +/- 3 y, BMI: 22.5 +/- 1 kg/m2) received 0 g (placebo), 2 g, 4 g, and 6 g of the most efficacious root fraction following the same protocol. Ginsenosides were analyzed using HPLC-UV.


RESULTS
In the preparation-finding study, a wide variation in the ginsenoside profiles was achieved across the 3 KRG fractions. This variation coincided with differential effects. The main effects of KRG-rootlets (p = 0.050) and time (p < 0.001) and their interaction (p < 0.1) were significant. This was reflected in a 29% reduction in area under the curve (AUC) by KRG-rootlets compared with placebo (p = 0.052). Conversely, neither KRG-H2O extract nor KRG-body affected glycemia. Stepwise-multiple regression models identified Rg1 as the sole predictor of mean- and AUC postprandial blood glucose. In the dose-finding study, KRG-rootlets were tested as the most efficacious fraction. A significant effect of KRG-rootlets treatment (mean of 3 doses) but not dose was found. The mean of 3 doses decreased AUC by 17% compared with placebo (p = 0.057).


CONCLUSIONS
Together the studies indicate 2 g KRG-rootlets is sufficient to achieve reproducible reductions in postprandial glycemia. But the longterm sustainability of KRG selected using this approach remains to be tested.
Sievenpiper
John L
JL
Department of nutritional sciences, Faculty of Medicine, University of Toronto, Canada.
Sung
Mi-Kyung
MK
Di Buono
Marco
M
Seung-Lee
Kwang
K
Nam
Ki Yeul
KY
Arnason
John T
JT
Leiter
Lawrence A
LA
Vuksan
Vladimir
V
D000328:Adult; D001786:Blood Glucose / Q000032:analysis*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D005502:Food; D036145:Ginsenosides / Q000008:administration & dosage / Q000032:analysis; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage*; D007723:Korea; D008297:Male; D005894:Panax / Q000737:chemistry*; D010919:Placebos; D010936:Plant Extracts / Q000008:administration & dosage*; D018517:Plant Roots / Q000737:chemistry*
D001786:Blood Glucose; D036145:Ginsenosides; D007004:Hypoglycemic Agents; D010919:Placebos; D010936:Plant Extracts