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Abstract In the water maze test, oral administration with 1,2-dilynoleoyl-sn-glycero-3-phosphocholine (DLPhtCho)(5 mg/kg) alone or DLPhtCho (5 mg/kg) plus 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPhtCho)(5 mg/kg) significantly shortened the prolonged acquisition latency for rats intraperitoneally injected with scopolamine, with more efficient effect than (POPhtCho)(5 mg/kg) alone, arachidonic acid (AA)(5 mg/kg) alone, docosahexaenoic acid (DHA)(5 mg/kg) alone, or 1-palmitoyl-2-linoleil-sn-glycero-3-phosphoserine (PLPhtSer)(5 mg/kg) alone. POPhtCho (5 mg/kg) alone or DLPhtCho (5 mg/kg) plus POPhtCho (5 mg/kg) also significantly shortened the prolonged retention latency for rats intraperitoneally injected with scopolamine, but otherwise no significant effect was obtained with DLPhtCho (5 mg/kg) alone, AA (5 mg/kg) alone, DHA (5 mg/kg) alone, or PLPhtSer (5 mg/kg) alone. Oral co-administration with DLPhtCho (5 mg/kg) and POPhtCho (5 mg/kg) significantly shortened the acquisition latency for rats untreated with scopolamine as compared with the latency for administration with polyethylene glycol (PEG), DLPhtCho alone at doses of 5 and 10 mg/kg, or POPhtCho alone at doses of 5 and 10 mg/kg, while no efficient effect on the retention latency was obtained. To assess the effect of DLPhtCho and POPhtCho on cognitive functions for humans, Mini Mental State Examination (MMSE) test was performed in subjects with cognitive disorders (the average MMSE score, 15). Oral co-intake with DLPhtCho (50 mg) and POPhtCho (45 mg) once after breakfast everyday raised the score to over 20, corresponding to normal cognitive functions, throughout 5 months after intake, and the increase in the score was significantly greater than that for oral intake with DLPhtCho (100 mg/day) alone or POPhtCho (90 mg/kg) alone. Taken together, the results of the present study show that co-intake with DLPhtCho and POPhtCho could enhance learning and memory ability and improve cognitive disorders for both the animals and humans with a promising efficacy.

Abstract Background Accumulating evidence has pointed that a variety of lipids could exert their beneficial actions against dementia including Alzheimer disease and age-related cognitive decline via diverse signaling pathways. Endoplasmic reticulum (ER) stress-induced neuronal apoptosis, on the other hand, is a critical factor for pathogenesis of neurodegenerative diseases such as Alzheimer disease and Parkinson disease, senile dementia, and ischemic neuronal damage. The present study examined the effects of 1,2-dilinoleoyl-sn-glycero-3-phosphoethanolamine (DLPhtEtn), a phospholipid, on ER stress-induced neuronal death and age-related cognitive disorders. Methods PC-12 cell viability was assayed before and after treatment with amyloid-β1-40 peptide or thapsigargin in the presence and absence of DLPhtEtn. A series of behavioral tests were performed for senescence-accelerated mouse-prone 8 (SAMP8) mice after 7-month oral administration with polyethylene glycol (PEG) or DLPhtEtn and then, the number of hippocampal neurons was counted. Results Amyloid-β1-40 peptide or thapsigargin is capable of causing ER stress-induced apoptosis. DLPhtEtn (30 μM) significantly inhibited PC-12 cell death induced by amyloid-β1-40 peptide or thapsigargin. In the water maze test, oral administration with DLPhtEtn (1 mg/kg) for 7 months (three times a week) significantly shortened the prolonged retention latency for SAMP8 mice. In contrast, DLPhtEtn had no effect on the acquisition and retention latencies in both the open field test and the passive avoidance test for SAMP8 mice. Oral administration with DLPhtEtn (1 mg/kg) for 7 months prevented a decrease in the number of hippocampal neurons for SAMP8 mice. Conclusion The results of the present study show that DLPhtEtn ameliorates age-related spatial memory decline without affecting motor activities or fear memory, possibly by protecting hippocampal neuronal death. DLPhtEtn, thus, might exert its beneficial action against senile dementia and neurodegenerative diseases such as Alzheimer disease.