The memory-enhancing effects of Euphoria longan fruit extract in mice.
OBJECTIVE
The fruit of Euphoria longan (Lour.) Steud. (Sapindaceae) is sweet and edible. Dried Euphoria longan fruit is prescribed as a tonic and for the treatment of forgetfulness, insomnia, or palpitations caused by fright in traditional Chinese medicine. The effects of aqueous extract of Euphoria longan fruit (ELE) on learning and memory and their underlying mechanisms were investigated.


METHODS
Aqueous extract of Euphoria longan fruit (ELE) was administered to ICR mice for 14 days. Piracetam was used as a positive control for its known memory-enhancing effects. Memory performances were assessed using the passive avoidance task. The expressions of phosphorylated extracellular signal-regulated kinase (pERK) 1/2, phosphorylated cAMP response element binding protein (pCREB), brain-derived neurotrophic factor (BDNF), doublecortin (DCX) and the incorporation of 5-bromo-2-deoxyuridine (BrdU) in hippocampal dentate gyrus and CA1 regions were investigated using immunohistochemical methods.


RESULTS
The step-through latency in the ELE-treated group was significantly increased compared with that in the vehicle-treated controls (P<0.05) in the passive avoidance task. Piracetam-treated group also showed enhanced cognitive performaces in the passive avoidance task. Immunohistochemical studies revealed that the number of cells immunopositive for BDNF, pCREB, or pERK 1/2 was significantly increased in the hippocampal dentate gyrus and CA1 regions after ELE treatment for 14 days (P<0.05). DCX and BrdU immunostaining also revealed that ELE significantly enhanced immature neuronal survival, but not neuronal cell proliferation in the subgranular zone of the dentate gyrus.


CONCLUSIONS
The present results suggest that subchronic administration of aqueous extract of Euphoria longan fruit enhances learning and memory, and that its beneficial effects are mediated, in part, by BDNF expression and immature neuronal survival.
Park
Se Jin
SJ
Department of Life and Nanopharmaceutical Science, Kyung Hee University, Hoeki-dong, Dongdaemoon-Ku, Seoul 130-701, Republic of Korea.
Park
Dong Hyun
DH
Kim
Dong Hyun
DH
Lee
Seungjoo
S
Yoon
Byung Hoon
BH
Jung
Won Yong
WY
Lee
Kyung Tae
KT
Cheong
Jae Hoon
JH
Ryu
Jong Hoon
JH
D000818:Animals; D001362:Avoidance Learning; D019208:Brain-Derived Neurotrophic Factor / Q000494:pharmacology; D001973:Bromodeoxyuridine / Q000378:metabolism; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D000089622:Doublecortin Domain Proteins; D000089662:Doublecortin Protein; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006624:Hippocampus / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D007150:Immunohistochemistry; D008568:Memory / Q000187:drug effects*; D051379:Mice; D008813:Mice, Inbred ICR; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009479:Neuropeptides / Q000378:metabolism; D010766:Phosphorylation; D010936:Plant Extracts / Q000494:pharmacology*; D029631:Sapindaceae / Q000737:chemistry*
D019208:Brain-Derived Neurotrophic Factor; D017362:Cyclic AMP Response Element-Binding Protein; C000714847:Dcx protein, mouse; D000089622:Doublecortin Domain Proteins; D000089662:Doublecortin Protein; D008869:Microtubule-Associated Proteins; D009479:Neuropeptides; D010936:Plant Extracts; D048049:Extracellular Signal-Regulated MAP Kinases; D001973:Bromodeoxyuridine