Uk Lee

Neuroprotective and anti-oxidant effects of caffeic acid isolated from Erigeron annuus leaf

BackgroundSince oxidative stress has been implicated in a neurodegenerative disease such as Alzheimers disease (AD), natural antioxidants are promising candidates of chemopreventive agents. This study examines antioxidant and neuronal cell protective effects of various fractions of the methanolic extract of Erigeron annuus leaf and identifies active compounds of the extract.MethodsAntioxidant activities of the fractions from Erigeron annuus leaf were examined with [2,2-azino-bis(3-ethylbenz thiazoline-6-sulfonic acid diammonium salt)] (ABTS) and ferric reducing antioxidant power (FRAP) assays. Neuroprotective effect of caffeic acid under oxidative stress induced by H2O2 was investigated with [3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide] (MTT) and lactate dehydrogenase (LDH) assays.ResultsThis study demonstrated that butanol fraction had the highest antioxidant activity among all solvent fractions from methanolic extract E. annuus leaf. Butanol fraction had the highest total phenolic contents (396.49 mg of GAE/g). Caffeic acid, an isolated active compound from butanol fraction, showed dose-dependent in vitro antioxidant activity. Moreover, neuronal cell protection against oxidative stress induced cytotoxicity was also demonstrated.ConclusionErigeron annuus leaf extracts containing caffeic acid as an active compound have antioxidative and neuroprotective effects on neuronal cells.

Reversal of Trimethyltin-Induced Learning and Memory Deficits by 3,5-Dicaffeoylquinic Acid

The antiamnesic effect of 3,5-dicaffeoylquinic acid (3,5-diCQA) as the main phenolic compound in Artemisia argyi H. extract on cognitive dysfunction induced by trimethyltin (TMT) (7.1 μg/kg of body weight; intraperitoneal injection) was investigated in order to assess its ameliorating function in mice. In several behavioral tests, namely, the Y-maze, passive avoidance, and Morris water maze (MWM) test, 3,5-diCQA significantly ameliorated learning and memory deficits. After the behavioral tests, brain tissues from the mice were analyzed to characterize the basis of the neuroprotective effect. Acetylcholine (ACh) levels increased, whereas the activity of acetylcholinesterase (AChE) decreased upon administration of 3,5-diCQA. In addition, 3,5-diCQA effectively protected against an increase in malondialdehyde (MDA) content, an increase in the oxidized glutathione (GSH) ratio, and a decline of total superoxide dismutase (SOD) level. 3,5-diCQA may prevent neuronal apoptosis through the protection of mitochondrial activities and the repression of apoptotic signaling molecules such as p-Akt, BAX, and p-tau (Ser 404).

Anti-amnesic effect of Dendropanax morbifera via JNK signaling pathway on cognitive dysfunction in high-fat diet-induced diabetic mice

The ameliorating effects of the ethyl acetate fraction from Dendropanax morbifera (EFDM) on cognitive impairment in high-fat diet (HFD)-induced diabetic mice were examined by measuring its possible pharmacological activities. Administration of EFDM (20 and 50mg/kg body weight) in HFD-induced diabetic mice significantly improved glucose tolerance status in the intraperitoneal glucose tolerance test (IPGTT). In animal experiments using Y-maze, passive avoidance and Morris water maze tests, the cognitive and behavioral disorders in HFD-induced diabetic mice were considerably recovered by regulating cholinergic systems, including acetylcholine (ACh) levels and acetylcholinesterase (AChE) inhibition, and antioxidant systems, including superoxide dismutase (SOD), glutathione (GSH), oxidized GSH, and malondialdehyde (MDA) levels. Furthermore, HFD-induced abnormal activity of mitochondria were also significantly protected by the improvement of the c-Jun N-terminal protein kinase (JNK) signaling pathway with phosphorylated JNK (p-JNK), phosphorylated insulin receptor substrate (p-IRS), serine/threonine protein kinase (Akt), phosphorylated Akt (p-Akt), and phosphorylated tau (p-tau). Finally, rutin, orientin, isoorientin, and luteolin-7-O-rutinoside as the main phenolics of EFDM were identified using ultra-performance liquid chromatography/quadrupole time of flight tandem mass spectrometry (UPLC-QTOF/MS(2)). These findings suggest that EFDM may have an effect as a multiple preventive substances to reduce diabetes-associated cognitive dysfunction.

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.

Change in the Chemical Composition of Chestnuts (Castanea crenata) from Different Periods

Compositional changes of the Korean chestnut (Castanea crenata) including Daebo, Tsukuba, Tanzawa and Okkwang were investigated in order to characterize them from different periods (immature, mature and storage period). Proximate compositions of mature cultivars were higher than that of the immature cultivars. Between minerals, K (263.0- 420.6 mg/100 g) and P (45.8-69.6 mg/100 g) of Tanzawa were highest, and they gradually increased during storage. Tsukuba, in mature period, showed the highest contents of total essential amino acids and glutamic acids as savory amino acids. Major fatty acids were palmitic acid and linolenic acid in four cultivars. In addition, linoleic acids, as ω-6 fatty acids, were increased during the storage period. Tanzawa, in the mature period, presented the highest levels of sucrose, however, tsukuba, in the storage period, showed relatively higher free sugar content than others. β-Carotene, as a provitamin A, of Tsukuba in the mature period was highly detected among them, and vitamin C of Tsukuba and Tanzawa was more plentiful than others.

Inhibitory effects of chestnut inner skin extracts on melanogenesis

Antioxidant capacities (ABTS radical scavenging assay and ferric reducing/antioxidant power assay), mushroom tyrosinase inhibitory effect, and α-melanocyte stimulating hormone (α-MSH) induced melanogenesis inhibitory effect of 60% methanol extracts and ethylacetate fractions from chestnut inner skin in B16F10 cells were investigated to inspect whitening effect. Above research showed that 60% methanol extracts and ethylacetate fractions from chestnut inner skin resulted in a dose-dependent manner on in vitro antioxidant effects. Especially, the ethylacetate fractions inhibited enzyme activity of mushroom tyrosinases with an IC50 value of 160 μg/mL. Ethylacetate fractions from chestnut inner skin also decreased cellular melanin synthesis in B16F10 melanoma cells. Expression of tyrosinase showed that ethylacetate fractions from chestnut inner skin significantly decreased cellular melanogenesis. Consequently, these results suggest that chestnut inner skin extracts can be considered for a whitening agent of human skin.

Antiamnesic Effect of Broccoli (Brassica oleracea var. italica) Leaves on Amyloid Beta (Aβ)1-42-Induced Learning and Memory Impairment.

To examine the antiamnesic effects of broccoli (Brassica oleracea var. italica) leaves, we performed in vitro and in vivo tests on amyloid beta (Aβ)-induced neurotoxicity. The chloroform fraction from broccoli leaves (CBL) showed a remarkable neuronal cell-protective effect and an inhibition against acetylcholinesterase (AChE). The ameliorating effect of CBL on Aβ1-42-induced learning and memory impairment was evaluated by Y-maze, passive avoidance, and Morris water maze tests. The results indicated improving cognitive function in the CBL group. After the behavioral tests, antioxidant effects were detected by superoxide dismutase (SOD), oxidized glutathione (GSH)/total GSH, and malondialdehyde (MDA) assays, and inhibition against AChE was also presented in the brain. Finally, oxo-dihydroxy-octadecenoic acid (oxo-DHODE) and trihydroxy-octadecenoic acid (THODE) as main compounds were identified by quadrupole time-of-flight ultraperformance liquid chromatography (Q-TOF UPLC-MS) analysis. Therefore, our studies suggest that CBL could be used as a natural resource for ameliorating Aβ1-42-induced learning and memory impairment.

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.

Antioxidant and Neuronal Cell Protective Effects of Columbia Arabica Coffee with Different Roasting Conditions

In vitro antioxidant activities and neuronal cell protective effects of ethanol extract from roasted coffee beans were investigated. Colombia arabica coffee (Coffea arabica) green beans were roasted to give medium (230°C, 10 min), city (230°C, 12 min) and french (230°C, 15 min) coffee beans. Total phenolics in raw green beans, medium, city and french-roasted beans were 8.81±0.05, 9.77±0.03, 9.92±0.04 and 7.76±0.01 mg of GAE/g, respectively. The content of 5-O-caffeoylquinic acid, the predominant phenolic, was detected higher in medium-roasted beans than others. In addition, we found that extracts from medium-roasted beans particularly showed the highest in vitro antioxidant activity on ABTS radical scavenging activity and FRAP assays. To determine cell viability using the MTT assay, extracts from medium-roasted beans showed higher protection against H2O2-induced neurotoxicity than others. Lactate dehydrogenase (LDH) leakage was also inhibited by the extracts due to prevention of lipid peroxidation using the malondialdehyde (MDA) assay from mouse whole brain homogenates. These data suggest that the medium-roasting condition to making tasty coffee from Columbia arabica green beans may be more helpful to human health by providing the most physiological phenolics, including 5-O-caffeoylquinic acids.

Ethyl Acetate Fraction from Persimmon (Diospyros kaki) Ameliorates Cerebral Neuronal Loss and Cognitive Deficit via the JNK/Akt Pathway in TMT-Induced Mice

This study was conducted to assess the antioxidant capacity and protective effect of the ethyl acetate fraction from persimmon (Diospyros kaki) (EFDK) on H2O2-induced hippocampal HT22 cells and trimethyltin chloride (TMT)-induced Institute of Cancer Research (ICR) mice. EFDK had high antioxidant activities and neuroprotective effects in HT22 cells. EFDK ameliorated behavioral and memory deficits in Y-maze, passive avoidance and Morris water maze tests. Also, EFDK restored the antioxidant system by regulating malondialdehyde (MDA), superoxide dismutase (SOD) and reduced gluthathione (GSH), and the cholinergic system by controlling the acetylcholine (ACh) level and acetylcholinesterase (AChE) activity and expression. EFDK enhanced mitochondrial function by regulating reactive oxygen species (ROS) production, mitochondrial membrane potential (MMP), and adenosine triphosphate (ATP). Ultimately, EFDK regulated the c-Jun N-terminal kinase (JNK)/protein kinase B (Akt) pathway and apoptotic pathway by suppressing the expression of tumor necrosis factor-alpha (TNF-α), phosphorylated insulin receptor substrate 1 (IRS-1pSer), phosphorylated JNK (p-JNK), phosphorylated tau (p-tau), phosphorylated nuclear factor kappa-light-chain-enhancer of activated B cells (p-NF-κB), Bcl-2-associated X protein (BAX) and cytosolic cytochrome c, and increasing the expression of phosphorylated Akt (p-Akt) and mitochondrial cytochrome c. This study suggested that EFDK had antioxidant activity and a neuroprotective effect, and ameliorated cognitive abnormalities in TMT-induced mice by regulating the JNK/Akt and apoptotic pathway.