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- Title
Effects of Ginsenosides and Their Metabolites on Voltagedependent Ca<sup>2+</sup> Channel Subtypes.
- Authors
Jun-Ho Lee; Sang Min Jeong; Jong-Hoon Kim; Byung-Hwan Lee; In-Soo Yoon; Joon-Hee Lee; Sun-Hye Choi; Sang-Mok Lee; Yong-Sun Park; Jung-Ha Lee; Sung Soo Kim; Hyoung-Chun Kim; Boo-Yong Lee; Seung-Yeol Nah
- Abstract
In previous reports we demonstrated that ginsenosides, active ingredients of Panax ginseng, affect some subsets of voltage-dependent Ca2+ channels in neuronal cells expressed in Xenopus laevis oocytes. However, the major component(s) of ginseng that affect cloned Ca2+ channel subtypes such as α1C (L)-, α1B (N)-, α1A (P/Q)-, α1E (R)- and α1G (T) have not been identified. Here, we used the two-microelectrode voltage clamp technique to characterize the effects of ginsenosides and ginsenoside metabolites on Ba2+ currents (IBa) in Xenopus oocytes expressing five different Ca2+ channel subtypes. Exposure to ginseng total saponins (GTS) induced voltage-dependent, dose-dependent and reversible inhibition of the five channel subtypes, with particularly strong inhibition of the α1G-type. Of the various ginsenosides, Rb1, Rc, Re, Rf, Rg1, Rg3, and Rh2, ginsenoside Rg3 also inhibited all five channel subtypes and ginsenoside Rh2 had most effect on the α1C- and α1E-type Ca2+ channels. Compound K (CK), a protopanaxadiol ginsenoside metabolite, strongly inhibited only the α1G-type of Ca2+ channel, whereas M4, a protopanaxatriol ginsenoside metabolite, had almost no effect on any of the channels. Rg3, Rh2, and CK shifted the steady-state activation curves but not the inactivation curves in the depolarizing direction in the α1B- and α1A-types. These results reveal that Rg3, Rh2 and CK are the major inhibitors of Ca2+ channels in Panax ginseng, and that they show some Ca2+ channel selectivity.
- Publication
Molecules & Cells (Springer Nature), 2006, Vol 21, Issue 1, p52
- ISSN
1016-8478
- Publication type
Article
- DOI
10.1016/s1016-8478(23)12902-5