Enhanced Cognitive Effects of Demethoxycurcumin, a Natural Derivative of Curcumin on Scopolamine-Induced Memory Impairment in Mice.

In the present study, we examined the ameliorating effects of demethoxycurcumin (DMC) on memory impairment induced by scopolamine using passive avoidance and Morris water maze tests in mice. Moreover, to determine the neurobiological effects underlying the ameliorating effects of the DMC, choline acetyltransferase (ChAT) immunoreactivity was evaluated in mice exposed to scopolamine. Our results demonstrated that chronic oral administration (28 days) of DMC (10 mg/kg) improved scopolamine-induced learning impairment in the passive avoidance task and memory impairment in the Morris water maze. Moreover, Choline acetyltransferase (ChAT) activity in the DMC-treated group was significantly increased to 33.03% compared with the control group. Our present finding suggests that DMC ameliorates memory impairments induced by scopolamine treatment through reversing the reduction of hippocampal ChAT expression in mice.

Memory-enhancing effects of Ishige foliacea extract: In vitro and in vivo study.

Ishige foliacea is used as a functional food in East-Asian countries. We evaluated the memory-enhancing effect of an ethanol extract of I. foliacea (EEI) using in vitro and in vivo models. In vitro acetylcholinesterase and ß-secretase inhibitory activities, antioxidant properties, and neuroprotective effects against human neuronal cell death by H2 O2 and ß-amyloid (Aß) were investigated. We explored the memory-enhancing effect and its underlying mechanism in a mouse model of scopolamine (SCO)-induced memory deficits. EEI showed free radical scavenging and acetylcholinesterase and ß-secretase inhibition activities. Additionally, EEI significantly decreased neuronal cell death induced by H2 O2 or Aß in human neuroblastoma SH-SY5Y cells. In behavior tests, SCO-induced memory deficits was improved by EEI administration. EEI increased the protein expression of brain-derived neurotrophic factor (BDNF) and tropomyosin receptor kinase B (TrkB) and phosphorylated extracellular signal-regulated kinase, which are related to synaptic plasticity in the hippocampus. EEI may ameliorate memory deficits and prevent neurodegenerative disorders. PRACTICAL APPLICATIONS: As the population ages, dementia, a neurodegenerative disease, is becoming an important problem. Various Alzheimer's drugs have been developed based on the disease mechanism, but alternative treatments are required because of the low bioavailability and hepatotoxicity of current medications. Ishige foliacea is a type of brown algae containing various bioactive substances. Phlorotannins, known as brown algae polyphenols, have been studied for their various functionalities such as, anticancer, anti-obesity, antioxidant, and sleep improvement effects, and have attracted attention as raw materials for developing new natural products. We found that the EEI mitigates SCO-induced damage by protecting neurons from oxidative stress-induced cell damage, controlling synthesis mechanisms of the causative agents of AD, and activating BDNF-TrkB-ERK signaling to promote memory function in the hippocampus. The results of this study can serve as a foundation for further research. Additionally, I. foliacea may be useful for treating and improving AD.