The ethanolic extract of the Eclipta prostrata L. ameliorates the cognitive impairment in mice induced by scopolamine.
BACKGROUND
Eclipta prostrata L. (Asteraceae) has been prescribed for whole body nourishment and nervine tonic in Asia. However, the effects of E. prostrata in learning and memory have not been fully explored.


OBJECTIVE
To scientifically elucidate the effects of E. prostrata on cognitive functions, we examined whether E. prostrata could ameliorate a cholinergic blockade-induced memory impairment, and we also investigated the effects of E. prostrata on the synaptic plasticity in the hippocampus.


METHODS
Memory impairment was induced by scopolamine, a cholinergic muscarinic receptor antagonist. The anti-amnesic effects of the ethanolic extract of Eclipta prostrata L. (EEEP) were measured in mice by the passive avoidance, Y-maze and Morris water maze tasks. To test the effects of EEEP on synaptic plasticity, we measured long-term potentiation (LTP) in the hippocampus. We also studied several signaling molecules related to learning and memory, such as phosphorylated protein kinase B (Akt) or phosphorylated glycogen synthase kinase-3β (GSK-3β).


RESULTS
In the passive avoidance task, EEEP (50 or 100mg/kg, p.o.) significantly ameliorated the shortened step-through latency induced by scopolamine. EEEP (100mg/kg, p.o.) also showed significant increase in alternation behavior during the Y-maze task. In the Morris water maze task, scopolamine-induced a decrease in both the swimming time within the target zone and the number of crossings where the platform had been placed were significantly reversed by EEEP (50 or 100mg/kg, p.o.). Moreover, EEEP (100μg/ml) significantly enhanced hippocampal LTP without affecting basal synaptic transmission. The administration of EEEP (100mg/kg) increased the phosphorylation levels of Akt and GSK-3β in the hippocampal region.


CONCLUSIONS
These results suggest that EEEP has memory-ameliorating activity against scopolamine-induced cognitive impairment and facilitates LTP in the hippocampus. This could be, at least in part, mediated by the activation of the Akt-GSK-3β signaling pathway.
Department of Oriental Pharmaceutical Science, College of Pharmacy, Kyung Hee University, Seoul 130-701, Republic of Korea; East-West Medical Research Institute, Kyung Hee University Medical Center, Seoul 130-701, Republic of Korea.
Won Yong
WY
Jung
Department of Life and Nanopharmaceutical Science, Kyung Hee University, Seoul 130-701, Republic of Korea.
Haneul
H
Kim
Department of Oriental Pharmaceutical Science, College of Pharmacy, Kyung Hee University, Seoul 130-701, Republic of Korea.
Ho Jae
HJ
Park
Department of Life and Nanopharmaceutical Science, Kyung Hee University, Seoul 130-701, Republic of Korea.
Se Jin
SJ
Jeon
Department of Medicinal Biotechnology, College of Health Sciences, Dong-A University, Busan 604-714, Republic of Korea.
Hye Jin
HJ
Park
East-West Medical Research Institute, Kyung Hee University Medical Center, Seoul 130-701, Republic of Korea.
Hyuck Jai
HJ
Choi
East-West Medical Research Institute, Kyung Hee University Medical Center, Seoul 130-701, Republic of Korea.
Nam Jae
NJ
Kim
Department of Life and Nanopharmaceutical Science, Kyung Hee University, Seoul 130-701, Republic of Korea.
Dae Sik
DS
Jang
Department of Medicinal Biotechnology, College of Health Sciences, Dong-A University, Busan 604-714, Republic of Korea; Institute of Convergence Bio-Health, Dong-A University, Busan 604-714, Republic of Korea. Electronic address: mose79@dau.ac.kr.
Dong Hyun
DH
Kim
Department of Oriental Pharmaceutical Science, College of Pharmacy, Kyung Hee University, Seoul 130-701, Republic of Korea; Department of Life and Nanopharmaceutical Science, Kyung Hee University, Seoul 130-701, Republic of Korea. Electronic address: jhryu63@khu.ac.kr.
Jong Hoon
JH
Ryu
D000647:Amnesia / Q000139:chemically induced / Q000503:physiopathology / Q000517:prevention & control* / Q000523:psychology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D003071:Cognition / Q000187:drug effects*; D003072:Cognition Disorders / Q000139:chemically induced / Q000503:physiopathology / Q000517:prevention & control* / Q000523:psychology; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D036601:Eclipta / Q000737:chemistry*; D000431:Ethanol / Q000737:chemistry*; D000071679:Glycogen Synthase Kinase 3 beta / Q000378:metabolism; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D017774:Long-Term Potentiation / Q000187:drug effects; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D008568:Memory / Q000187:drug effects*; D008813:Mice, Inbred ICR; D009043:Motor Activity / Q000187:drug effects; D018697:Nootropic Agents / Q000302:isolation & purification / Q000494:pharmacology*; D010766:Phosphorylation; D008517:Phytotherapy; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D010946:Plants, Medicinal; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011930:Reaction Time / Q000187:drug effects; D012601:Scopolamine; D015398:Signal Transduction / Q000187:drug effects; D012997:Solvents / Q000737:chemistry*
D018697:Nootropic Agents; D010936:Plant Extracts; D012997:Solvents; D000431:Ethanol; D012601:Scopolamine; D000071679:Glycogen Synthase Kinase 3 beta; C000605507:Gsk3b protein, mouse; D051057:Proto-Oncogene Proteins c-akt
Eclipta prostrata l.; Glycogen synthase kinase 3β; Learning and memory; Long-term potentiation; Protein kinase b