Ethyl acetate fraction from Hibiscus sabdariffa L. attenuates diabetes-associated cognitive impairment in mice.

The ameliorating effects of the ethyl acetate fraction from Hibiscus sabdariffa L. (EFHS)2 against diabetes mellitus (DM)3 and DM-induced cognitive impairment were investigated on streptozotocin (STZ)4-induced DM mice. The EFHS groups showed improved hyperglycemia and glucose tolerance compared to the STZ group. Furthermore, their liver and kidney function and lipid metabolic imbalance in the blood serum were effectively recovered. The EFHS groups significantly ameliorated STZ-induced cognitive impairment in Y-maze, passive avoidance, and Morris water maze (MWM)5 tests. The EFHS groups showed significant improvement in the antioxidant and cholinergic systems of the brain tissue. In addition, EFHS had an excellent ameliorating effect on protein expression levels from the tau hyperphosphorylation pathways, such as phospho-c-Jun N-terminal kinases (p-JNK),6 phospho-tau (p-tau),7 and cleaved poly (ADP-ribose) polymerase (c-PARP).8 The main compounds of EFHS were identified as various phenolic compounds, including hibiscus acid, caffeoylquinic acid (CQA)9 isomers, and quercetin derivates. Therefore, EFHS containing various physiologically active materials can potentially be used for improving DM-induced cognitive impairment via its antioxidant activity, improvement of the cholinergic system, and hyperphosphorylation tau signaling.

Ginsenoside Re Ameliorates Brain Insulin Resistance and Cognitive Dysfunction in High Fat Diet-Induced C57BL/6 Mice.

The ameliorating effects of ginsenoside Re (G Re) on high fat diet (HFD)-induced insulin resistance in C57BL/6 mice were investigated to assess its physiological function. In the results of behavioral tests, G Re improved cognitive dysfunction in diabetic mice using Y-maze, passive avoidance, and Morris water maze tests. G Re also significantly recovered hyperglycemia and fasting blood glucose level. In the results of serum analysis, G Re decreased triglyceride (TG), total cholesterol (TCHO), low-density lipoprotein cholesterol (LDLC), glutamic-oxaloacetic transaminase (GOT), and glutamic-pyruvic transaminase (GPT) and increased the ratio of high-density lipoprotein cholesterol (HDLC). G Re regulated acetylcholine (ACh), acetylcholinesterase (AChE), malondialdehyde (MDA), superoxide dismutase (SOD), and oxidized glutathione (GSH)/total GSH by regulating the c-Jun N-terminal protein kinase (JNK) pathway. These findings suggest that G Re could be used to improve HFD-induced insulin resistance condition by ameliorating hyperglycemia via protecting the cholinergic and antioxidant systems in the mouse brains.

Antiamnesic Effect of Actinidia arguta Extract Intake in a Mouse Model of TMT-Induced Learning and Memory Dysfunction.

The antiamnesic effects of ethyl acetate fraction from Actinidia arguta (EFAA) on trimethyltin- (TMT-) induced memory impairment were investigated to find the possibility of functional food substances. EFAA showed a potent AChE inhibitory effect (IC50 = 53 µg/mL) and efficient neuroprotection against H2O2-induced oxidative stress. The administration of EFAA significantly decreased TMT-induced cognitive deficit in Y-maze, passive avoidance, and Morris water maze (MWM) tests. After the behavioral tests, the antioxidant activities were confirmed using mice brain tissues. EFAA not only showed the inhibition of AChE activity and the decline of malondialdehyde (MDA) level as a sign of lipid peroxidation but also presented the increase of the superoxide dismutase (SOD) level and the decrease of the oxidized glutathione (GSSG)/total glutathione (GSH + GSSG) ratio. Finally, the phenolics in EFAA were identified using liquid chromatography coupled with hybrid triple quadrupole-linear ion trap mass spectrometry, and four main phenolics, such as quinic acid, chlorogenic acid, caffeoyl hexose, and quercetin-3-glucoside, were identified. These results suggest that EFAA containing physiological phenolics might enhance drug-induced amnesia through AChE inhibition and neuroprotection.

Effect of Ginseng (Panax ginseng) Berry EtOAc Fraction on Cognitive Impairment in C57BL/6 Mice under High-Fat Diet Inducement.

High-fat diet-induced obesity leads to type 2 diabetes. Recently, there has been growing apprehension about diabetes-associated cognitive impairment (DACM). The effect of ginseng (Panax ginseng) berry ethyl acetate fraction (GBEF) on mice with high-fat diet-induced cognitive impairment was investigated to confirm its physiological function. C57BL/6 mice were fed a high-fat diet for 5 weeks and then a high-fat diet with GBEF (20 and 50 mg/kg of body weight) for 4 weeks. After three in vivo behavioral tests (Y-maze, passive avoidance, and Morris water maze tests), blood samples were collected from the postcaval vein for biochemical analysis, and whole brains were prepared for an ex vivo test. A method based on ultra-performance liquid chromatography (UPLC) accurate-mass quadrupole time-of-flight mass spectrometry (Q-TOF/MS) was used to determine major ginsenosides. GBEF decreased the fasting blood glucose levels of high-fat diet-induced diabetes mellitus (DM) mice and improved hyperglycemia. Cognitive behavior tests were examined after setting up the DM mice. The in vivo experiments showed that mice treated with GBEF exhibited more improved cognitive behavior than DM mice. In addition, GBEF effectively inhibited the acetylcholinesterase (AChE) activity and malondialdehyde (MDA) levels of DM mice brain tissues. Q-TOF UPLC/MS analyses of GBEF showed that ginsenoside Re was the major ginsenoside.

Ameliorating effects of ethyl acetate fraction from onion (Allium cepa L.) flesh and peel in mice following trimethyltin-induced learning and memory impairment.

The anti-amnesic effects of onion (Allium cepa L.) flesh (OF)1 and peel (OP)2 on trimethyltin (TMT)3-induced learning and memory dysfunction were investigated to confirm learning and memory function. The inhibitory effect against cellular acetylcholinesterase (AChE)4 showed that the EtOAc fraction of OP (EOP5, IC50 value=37.11µg/mL) was higher than the EtOAc fraction of OF (EOF6, IC50 value=433.34µg/mL). The cognitive effects in ICR mice were also evaluated using Y-maze, passive avoidance, and Morris water maze tests. After the behavioral tests, AChE activity (control=100%, TMT=128%, EOF 20=108%, EOP 10=104%, and EOP 20=98%), superoxide dismutase (SOD)7 activity, oxidized glutathione (GSSG)8/total glutathione (GSH)9 and malondialdehyde (MDA)10 production were examined. These results indicate that both EOF and EOP improved learning and memory function. The main compounds of the EOF and EOP were analyzed by Q-TOF UPLC/MS, and the results were as follows: The EOF (quercetin and quercetin-4'-glucoside) and the EOP (quercetin-4'-glucoside and isorhamnetin-4'-glucoside). Consequently, our results suggest that both EOF and EOP could be efficacious in improving cognitive function through AChE inhibition and antioxidant activity in mice brains.