Improvement of memory in mice and increase of hippocampal excitability in rats by ginsenoside Rg1's metabolites ginsenoside Rh1 and protopanaxatriol.
Ginsenoside Rg1 has been reported to improve cognitive function in many memory-impaired animal models. However, little is known about the bioactivity of its metabolites in the central nervous system in vivo. In the present study, we employed the step through test and electrophysiological approach to investigate the effects of ginsenoside Rg1's primary metabolite ginsenoside Rh1 and end metabolite protopanaxatriol (Ppt) on learning and memory as well as hippocampal excitability. The behavioral study showed that both ginsenoside Rh1 and Ppt significantly ameliorated memory-impaired models induced by scopolamine in mice. Consistently, the electrophysiological work revealed that ginsenoside Rh1 and Ppt as well as their precursor ginsenoside Rg1 all increased hippocampal excitability in the dentate gyrus of anesthetized rats. These results demonstrated that both ginsenoside Rh1 and Ppt had similar but more potent actions than ginsenoside Rg1 in improving memory and hippocampal excitability, suggesting the role of ginsenoside's sugar moieties in biological activities is not as necessary as traditionally considered.
Center for Drug Evaluation, State Food and Drug Administration, Haidian District, Beijing, China.
Yu-Zhu
YZ
Wang
Ji
J
Chen
Shi-Feng
SF
Chu
Yong-Sheng
YS
Wang
Xiao-Ying
XY
Wang
Nai-Hong
NH
Chen
Jun-Tian
JT
Zhang
D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D004567:Electrodes, Implanted; D004594:Electrophysiology; D005071:Evoked Potentials / Q000187:drug effects; D036145:Ginsenosides / Q000378:metabolism* / Q000494:pharmacology*; D006624:Hippocampus / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism; D007276:Injections, Intraventricular; D007858:Learning / Q000187:drug effects; D008297:Male; D008568:Memory / Q000187:drug effects*; D051379:Mice; D010147:Pain Measurement / Q000187:drug effects; D017288:Pain Threshold / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000187:drug effects; D012502:Sapogenins / Q000494:pharmacology*; D053719:Tandem Mass Spectrometry
D036145:Ginsenosides; D012502:Sapogenins; C081552:protopanaxatriol; C425564:ginsenoside Rh1; C035054:ginsenoside Rg1