Decreasing, Null and Increasing Effects of Eight Popular Types of Ginseng on Acute Postprandial Glycemic Indices in Healthy Humans: The Role of Ginsenosides

Abstract

Background: It is unclear whether other ginseng sources can replicate the glycemic-lowering efficacy observed previously with American ginseng and whether ginsenosides are mediators. We assessed the effect of eight popular ginseng types on postprandial plasma glucose (PG) and insulin (PI) indices, linking effects to ginsenoside profiles.

Methods: Using a double-blind, randomized, multiple-crossover design, 12 healthy participants (gender: 6M:6F, age: 34 ± 3 y, BMI: 25.8 ± 1.2 kg/m²) received 10 3g treatments: American, American-wild, Asian, Asian-red, Vietnamese-wild, Siberian, Japanese-rhizome, and Sanchi ginsengs and two placebos. Each treatment was given 40-minutes before a 75g-oral-glucose-tolerance-test (75g-OGTT) with blood drawn at −40, 0, 15, 30, 45, 60, 90, 120-minutes. HPLC-UV analysis quantified seven principal ginsenosides.

Results: Two-factor analysis showed the main effects of ginseng-type and time were significant for PG and PI, with an interaction for PG (p < 0.05). Subsequent one-factor analysis showed an effect of ginseng-type on 90-min-PG and 90-min-PI (p < 0.05). This was reflected in effects on peak-PG, area under the curve (AUC)-PG and AUC-PI (p < 0.05). But the effect on 90-min-PI and AUC-PI were significant (p < 0.05) only in overweight participants (BMI > 25 kg/m², n = 6). Planned comparisons with placebo showed a tendency for American ginseng and Vietnamese ginseng to lower 90-min-PG (p < 0.06), while Asian ginseng raised peak-PG and AUC-PG, American-wild ginseng raised 120-min-PG, and Siberian ginseng raised 90-min-PG, 120-min-PG, and AUC-PG (p < 0.05). Stepwise-multiple-regression assessed the protopanaxadiol:protopanaxatriol (PPD:PPT)-ginsenoside ratio as the sole predictor (p < 0.05) for 90-min-PG (β = −0.43, r² = 0.072), AUC-PG (β = −0.25, r² = 0.06), 90-min-PI (β = −0.26, r² = 0.065), AUC-PI (β = −0.20, r² = 0.04).

Conclusions: Ginseng has variable glycemic effects, in which the PPD:PPT-ginsenoside ratio might be involved. But the low variance explained suggests the involvement of other unmeasured ginsenoside or non-ginsenoside components.

• complementary and alternative medicine
• ginseng
• ginsenosides
• acute
• postprandial
• OGTT
• glucose
• insulin secretion
• insulin sensitivity

The funding for this study was provided by a Grant for Applied Research and Education from the Canadian Diabetes Association. JLS was in receipt of an Ontario Graduate Scholarship during the conduct of this work. The placebo and ginseng batches used in the study were generously donated by The Korean Ginseng Cooperative Federation, Korean Institute of Ginseng and Tobacco, Seoul, Korea (Asian, Asian-red, and Sanchi ginsengs), Chai-Na-Ta Corp, Langlay, BC (American ginseng and placebo), and Professor Kazou Yamasaki from Hiroshima University (Japanese-rhizome and Vietnamese-wild ginsengs). We thank Denise Lamure for excellent technical assistance in the handling and processing of blood samples and Jeremy Quan at the Banting and Best Diabetes Centre Core Laboratory for prompt and expert analyses.

Partial findings from this study were presented at the Federation of American Societies for Experimental Biology (FASEB) conference held in New Orleans, LA from April 20–24, 2002 [51] and the 20^th International Symposium on Diabetes and Nutrition held in Samos, Greece from June 27–29, 2002 [52].

Notes

Dr. Vuksan has received research and travel funding from Chai-Na-Ta Corp., Langley, BC; MuscleTech Research and Development Incorporated, Mississauga, ON; the Ontario Ginseng Growers Association, Simcoe, ON; Ginseng Growers of Canada, Simcoe, ON; Ontario Ministry of Agriculture, Toronto, ON, the Korean Ministry of Agriculture, Soeul, South Korea; and BioSapogen Inc, Seoul, South Korea