Original Paper Pharmacology	Planta Med 2006; 72: 126-131 DOI: 10.1055/s-2005-873197
© Georg Thieme Verlag KG Stuttgart · New York
Influence of Ginsenoside Rh1 and F1 on Human Cytochrome P450 Enzymes
Yong Liu1, 2, Hong Ma3, Jiang-Wei Zhang1, 2, Mai-Cun Deng1, 2, Ling Yang1
1 Laboratory of Pharmaceutical Resource Discovery, Dalian Institute of Chemical Physics, The Chinese Academy of Sciences, Dalian, P. R. China 2 Graduate School of the Chinese Academy of Sciences, Dalian, P. R. China 3 College of Life Sciences, Liaoning Normal University, Liaoning, P. R. China

Abstract

For an oral herbal medicine, the components that can enter the systemic circulation may be the really effective components. In the present study, the effects on the human cytochrome P450 activities of ginsenoside Rb₁ and two hydrolysis products of 20(S)-protopanaxatriol ginsenosides in humans, namely ginsenoside Rh₁ and F₁, which may reach the systemic circulation after oral administration of ginseng extract, were evaluated. Our results showed that Rb₁ exhibited no marked effects on the activities of human cytochrome P450, whereas Rh₁ and F₁ exhibited competitive inhibition of the activity of CYP3A4 with K_i values of 57.7 ± 9.6 μM and 67.8 ± 16.2 μM, respectively. F₁ also exhibited a weaker inhibition of the activity of CYP2D6. Rh₁ exhibited a weak stimulation rather than an inhibition of the activity of CYP2E1. The degradation of ginsenosides in the gastrointestinal tract may play an important role in the ginseng-associated drug-drug interactions, but the effects might be not due to Rh₁ and F₁.

Key words

Ginsenoside - hydrolysis products - systemic circulation - cytochrome P450