Protective effect of 4',5-dihydroxy-3',6,7-trimethoxyflavone from Artemisia asiatica against Abeta-induced oxidative stress in PC12 cells

Anti-photoaging effects of canola meal extract on human dermal fibroblasts against UVB-induced oxidative stress

Canola meal, a by-product of canola oil processing, is a source of bioactive compounds that show antioxidant and skin anti-aging effects through upcycling (i.e., creative reuse). Here we describe the antioxidant and skin anti-aging effects of canola meal extract (CME) obtained by upcycling canola meal. The antioxidant capacity of CME is due in part to its antioxidative phenolics. Seven phenolics, including sinapine and sinapic acid, in CME were identified using ultra-high-performance liquid chromatography-Orbitrap mass spectrometry. Addition of CME (1000 μg/mL) to human dermal fibroblast neonatal cells  significantly (p < 0.05) reduced matrix metalloproteinase-12 production and increased pro-collagen Ι alpha 1 content in response to ultraviolet B-induced oxidative stress compared with cells without CME. These results suggest that CME can serve as a functional food ingredient with antioxidant capacity and anti-aging effects on the skin.

Phytochemistry and biological activity of Erigeron annuus (L.) Pers

Erigeron annuus L. is a flowering herb of North America, Europe, Asia and Russia. This plant is used as folk medicine in China for the cure of indigestion, enteritis, epidemic hepatitis, haematuria and diabetes. Phytochemical studies showed the presence of 170 bioactive compounds like coumarins, flavonoids, terpenoids, polyacetylenic compounds; γ-pyrone derivatives, sterols and various caffeoylquinic acids derived from the essential oil and organic extracts from its various parts such as aerial parts, roots, leaves, stems and flowers. The pharmacological studies demonstrated various extracts and the compounds of E. annuus to exhibit anti-fungal, anti-atherosclerosis, anti-inflammatory, antidiabetic, phytotoxic, cytoprotective, antiobesity and antioxidant activities. This article covers a critical compendious on geographical distribution, botanical description, phytochemistry, ethnomedicinal uses and pharmacological activities of E. annuus. However, further in-depth studies are needed to determine the medical uses of E. annuus and its chemical constituents, pharmacological activities and clinical applications.

Leaves of Cedrela sinensis Attenuate Chronic Unpredictable Mild Stress-Induced Depression-like Behavior via Regulation of Hormonal and Inflammatory Imbalance

This study aimed to evaluate the protective effects of ethyl acetate fraction from Cedrela sinensis (EFCS) against chronic unpredictable mild stress (CUMS)-induced behavioral dysfunction and stress response in C57BL/6 mice. The physiological compounds of EFCS were identified as rutin, isoquercitrin, ethyl gallate, quercitrin, kaempferol-3-O-rhamnoside, and ethyl digallate, using UPLC-Q-TOF/MS^E. To evaluate the neuroprotective effect of EFCS, H₂O₂^- and corticosterone-induced neuronal cell viability was conducted in human neuroblastoma MC-IXC cells. It was found that EFCS alleviated depression-like behavior by conducting the sucrose preference test (SPT), forced swimming test (FST), open field test (OFT), and tail suspension test (TST). EFCS inhibited mitochondrial dysfunction related to neuronal energy metabolism by regulating reactive oxygen species (ROS) levels, mitochondrial membrane potential (MMP), and ATP contents in brain tissue. In addition, the administration of EFCS regulated the stress hormones in serum. EFCS regulated stress-related indicators such as CRF, ACTH, CYP11B1, and BDNF. Moreover, EFCS downregulated the inflammatory responses and apoptosis proteins such as caspase-1, TNF-α, IL-1β, p-JNK, BAX, and p-tau in brain tissues. These results suggest that EFCS might be a potential natural plant material that alleviates CUMS-induced behavior disorder by regulating inflammation in brain tissue against CUMS-induced depression.

Effects of Ecklonia cava Extract on Neuronal Damage and Apoptosis in PC-12 Cells against Oxidative Stress

Marine algae (seaweed) encompass numerous groups of multicellular organisms with various shapes, sizes, and colors, and serve as important sources of natural bioactive substances. The brown alga Ecklonia cava Kjellman, an edible seaweed, contains many bioactives such as phlorotannins and fucoidans. Here, we evaluated the antioxidative, neuroprotective, and anti-apoptotic effects of E. cava extract (ECE), E. cava phlorotannin-rich extract (ECPE), and the phlorotannin dieckol on neuronal PC-12 cells. The antioxidant capacities of ECPE and ECE were 1,711.5 and 1,050.4 mg vitamin C equivalents/g in the ABTS assay and 704.0 and 474.6 mg vitamin C equivalents/g in the DPPH assay, respectively. The dieckol content of ECPE (58.99 mg/g) was approximately 60% higher than that of ECE (36.97 mg/g). Treatment of PC-12 cells with ECPE and ECE increased cell viability in a dose-dependent manner. Intracellular oxidative stress in PC-12 cells due to ECPE and ECE decreased dose-independently by up to 63% and 47%, respectively, compared with the stress control (323%). ECPE reduced the production of the pro-apoptotic proteins Bax and caspase-3 more effectively than ECE. Early and late apoptosis in PC-12 cells were more effectively decreased by ECPE than ECE treatments. From the results obtained in this study, we concluded that ECPE, which is rich in phlorotannins, including the marker compound dieckol, may be applied to the development of functional materials for improving cognition and memory.

Anti-Amnesic Effect of Walnut via the Regulation of BBB Function and Neuro-Inflammation in Aβ1-42-Induced Mice

This study was conducted to assess the protective effect of walnut (Juglans regia L.) extract on amyloid beta (Aβ)_1-42-induced institute of cancer research (ICR) mice. By conducting a Y-maze, passive avoidance, and Morris water maze tests with amyloidogenic mice, it was found that walnut extract ameliorated behavioral dysfunction and memory deficit. The walnut extract showed a protective effect on the antioxidant system and cholinergic system by regulating malondialdehyde (MDA) levels, superoxide dismutase (SOD) contents, reduced glutathione (GSH) contents, acetylcholine (ACh) levels, acetylcholinesterase (AChE) activity, and protein expression of AChE and choline acetyltransferase (ChAT). Furthermore, the walnut extract suppressed Aβ-induced abnormality of mitochondrial function by ameliorating reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and ATP contents. Finally, the walnut extract regulated the expression of zonula occludens-1 (ZO-1) and occludin concerned with blood–brain barrier (BBB) function, expression of tumor necrosis factor-alpha (TNF-α), tumor necrosis factor receptor 1 (TNFR1), phosphorylated c-Jun N-terminal kinase (p-JNK), phosphorylated nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor (p-IκB), cyclooxygenase-2 (COX-2), and interleukin 1 beta (IL-1β), related to neuroinflammation and the expression of phosphorylated protein kinase B (p-Akt), caspase-3, hyperphosphorylation of tau (p-tau), and heme oxygenase-1 (HO-1), associated with the Aβ-related Akt pathway.

Phenolic Profiles of Hardy Kiwifruits and Their Neuroprotective Effects on PC-12 and SH-SY5Y Cells against Oxidative Stress

Hardy kiwifruits (Actinidia arguta Planch.) have high amounts of antioxidants, including ascorbic acid (vitamin C) and phenolics. The anti-cholinesterase activity and neuroprotective effects of three different cultivars of hardy kiwifruits, cv. Mansu (A. arguta × A. deliciosa), cv. Haeyeon (A. arguta), and cv. Chiak (A. arguta), on PC-12 and SH-SY5Y cells were evaluated. Extraction of phenolics and vitamin C was carried out using 80% (v/v) aqueous ethanol and metaphosphoric acid assisted with homogenization, respectively. Hardy kiwifruit of cv. Mansu showed higher total phenolic, total flavonoid, and vitamin C contents and antioxidant capacity compared to the other tw°Cultivars of hardy kiwifruits, cv. Haeyeon and cv. Chiak. Analysis of high-performance liquid chromatography results revealed the presence of procyanidin B2, (?)-epicatechin, neochlorogenic acid, cryptochlorogenic acid, rutin, hyperoside, isoquercitrin, and astragalin in hardy kiwifruits. The three cultivars of hardy kiwifruits had a wide range of vitamin C content of 55.2?130.0 mg/100 g fresh weight. All three cultivars of hardy kiwifruits had protective effects on neuronal PC-12 and SHSY5Y cells exposed to hydrogen peroxide by increasing cell viability and reducing intracellular oxidative stress. Furthermore, the hardy kiwifruits inhibited acetylcholinesterase and butyrylcholinesterase. Collectively, these results suggest that hardy kiwifruits rich in antioxidants like phenolics and vitamin C have good potential as functional materials in neuroprotective applications.

Neuroprotective Effects of Phlorotannin-Rich Extract from Brown Seaweed Ecklonia cava on Neuronal PC-12 and SH-SY5Y Cells with Oxidative Stress

Neurodegenerative disorders in the elderly are characterized by gradual loss of memory and cognitive function. Oxidative stress caused by reactive oxygen species is associated with progressive neuronal cell damage and death in Alzheimer's disease, one of the most common neurodegenerative disorders. An edible brown seaweed, Ecklonia cava, contains a variety of biologically active compounds such as phlorotannins. In this study, we comparatively evaluated the total phenolic content, antioxidant capacity, and neuroprotective effects of the phlorotannin-rich extract from E. cava (PEEC). The total phenolic content of PEEC and dieckol was 810.8 mg gallic acid equivalents (GAE)/g and 996.6 mg GAE/g, respectively. Antioxidant capacity of PEEC was 1,233.8 mg vitamin C equivalents (VCE)/g and 392.1 mg VCE/g determined using ABTS and DPPH assays, respectively, while those of dieckol were 2,238.4 mg VCE/g and 817.7 mg VCE/g. High-performance liquid chromatography results revealed 48.08 ± 0.67 mg dieckol/g of PEEC. PEEC had neuroprotective effects in pheochromocytoma (PC-12) and human neuroblastoma (SH-SY5Y) cells against H₂O₂- and AAPH-induced oxidative damage, partly due to reduced intracellular oxidative stress. PEEC treatment inhibited acetylcholinesterase and butyrylcholinesterase in a dose-dependent manner. Taken together, these findings suggest that PEEC is a good source of antioxidants and neuroprotective materials.

Green Tea Seed Oil Suppressed Aβ1⁻42-Induced Behavioral and Cognitive Deficit via the Aβ-Related Akt Pathway

The aim of this study was to investigate the availability of seeds, one of the byproducts of green tea, and evaluate the physiological activity of seed oil. The ameliorating effect of green tea seed oil (GTO) was evaluated on H₂O₂-induced PC12 cells and amyloid beta (Aβ)_1–42-induced ICR mice. GTO showed improvement of cell viability and reduced reactive oxygen species (ROS) production in H₂O₂-induced PC12 cells by conducting the 2′,3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and 2′,7′-dichlorofluorescein diacetate (DCF-DA) analysis. Also, administration of GTO (50 and 100 mg/kg body weight) presented protective effects on behavioral and memory dysfunction by conducting Y-maze, passive avoidance, and Morris water maze tests in Aβ-induced ICR mice. GTO protected the antioxidant system by reducing malondialdehyde (MDA) levels, and by increasing superoxide dismutase (SOD) and reducing glutathione (GSH) contents. It significantly regulated the cholinergic system of acetylcholine (ACh) contents, acetylcholinesterase (AChE) activities, and AChE expression. Also, mitochondrial function was improved through the reduced production of ROS and damage of mitochondrial membrane potential (MMP) by regulating the Aβ-related c-Jun N-terminal kinase (JNK)/protein kinase B (Akt) and Akt/apoptosis pathways. This study suggested that GTO may have an ameliorating effect on cognitive dysfunction and neurotoxicity through various physiological activities.

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.

Novel Tacrine-Scutellarin Hybrids as Multipotent Anti-Alzheimer's Agents: Design, Synthesis and Biological Evaluation

A novel series of 6-chlorotacrine-scutellarin hybrids was designed, synthesized and the biological activity as potential anti-Alzheimer's agents was assessed. Their inhibitory activity towards human acetylcholinesterase (hAChE) and human butyrylcholinesterase (hBChE), antioxidant activity, ability to cross the blood-brain barrier (BBB) and hepatotoxic profile were evaluated in vitro. Among these compounds, hybrid K1383, bearing two methylene tether between two basic scaffolds, was found to be very potent hAChE inhibitor (IC50 = 1.63 nM). Unfortunately, none of the hybrids displayed any antioxidant activity (EC50 ≥ 500 μM). Preliminary data also suggests a comparable hepatotoxic profile with 6-Cl-THA (established on a HepG2 cell line). Kinetic studies performed on hAChE with the most active compound in the study, K1383, pointed out to a mixed, non-competitive enzyme inhibition. These findings were further corroborated by docking studies.

Natural products against Alzheimer's disease: Pharmaco-therapeutics and biotechnological interventions

Alzheimer's disease (AD) is a severe, chronic and progressive neurodegenerative disease associated with memory and cognition impairment ultimately leading to death. It is the commonest reason of dementia in elderly populations mostly affecting beyond the age of 65. The pathogenesis is indicated by accumulation of the amyloid-beta (Aβ) plaques and neurofibrillary tangles (NFT) in brain tissues and hyperphosphorylation of tau protein in neurons. The main cause is considered to be the formation of reactive oxygen species (ROS) due to oxidative stress. The current treatment provides only symptomatic relief by offering temporary palliative therapy which declines the rate of cognitive impairment associated with AD. Inhibition of the enzyme acetylcholinesterase (AChE) is considered as one of the major therapeutic strategies offering only symptomatic relief and moderate disease-modifying effect. Other non-cholinergic therapeutic approaches include antioxidant and vitamin therapy, stem cell therapy, hormonal therapy, use of antihypertensive or lipid-lowering medications and selective phosphodiesterase (PDE) inhibitors, inhibition of β-secretase and γ-secretase and Aβ aggregation, inhibition of tau hyperphosphorylation and intracellular NFT, use of nonsteroidal anti-inflammatory drugs (NSAIDs), transition metal chelators, insulin resistance drugs, etanercept, brain-derived neurotrophic factor (BDNF) etc. Medicinal plants have been reported for possible anti-AD activity in a number of preclinical and clinical trials. Ethnobotany, being popular in China and in the Far East and possibly less emphasized in Europe, plays a substantial role in the discovery of anti-AD agents from botanicals. Chinese Material Medica (CMM) involving Chinese medicinal plants has been used traditionally in China in the treatment of AD. Ayurveda has already provided numerous lead compounds in drug discovery and many of these are also undergoing clinical investigations. A number of medicinal plants either in their crude forms or as isolated compounds have exhibited to reduce the pathological features associated with AD. In this present review, an attempt has been made to elucidate the molecular mode of action of various plant extracts, phytochemicals and traditional herbal formulations investigated against AD as reported in various preclinical and clinical tests. Herbal synergism often found in polyherbal formulations were found effective to combat disease heterogeneity as found in complex pathogenesis of AD. Finally a note has been added to describe biotechnological improvement, genetic and genomic resources and mathematical and statistical techniques for empirical model building associated with anti-AD plant secondary metabolites and their source botanicals.

Lithospermum erythrorhizon extract protects keratinocytes and fibroblasts against oxidative stress

Oxidative stress damages dermal and epidermal cells and degrades extracellular matrix proteins, such as collagen, ultimately leading to skin aging. The present study evaluated the potential protective effect of the aqueous methanolic extract obtained from Lithospermum erythrorhizon (LE) against oxidative stress, induced by H2O2 and ultraviolet (UV) irradiation, on human keratinocyte (HaCaT) and human dermal fibroblast-neonatal (HDF-n) cells. Exposure of cells to H2O2 or UVB irradiation markedly increased oxidative stress and reduced cell viability. However, pretreatment of cells with the LE extract not only increased cell viability (up to 84.5%), but also significantly decreased oxidative stress. Further, the LE extract downregulated the expression of matrix metalloproteinase-1, an endopeptidase that degrades extracellular matrix collagen. In contrast, treatment with the LE extract did not affect the expression of procollagen type 1 in HDF-n cells exposed to UVA irradiation. Thirteen phenolic compounds, including derivatives of shikonin and caffeic acid, were identified by ultrahigh-performance liquid chromatography-electrospray ionization-tandem mass spectrometry. These results suggest that LE-derived extracts may protect oxidative-stress-induced skin aging by inhibiting degradation of skin collagen, and that this protection may derive at least in part from the antioxidant phenolics present in these extracts. Further studies are warranted to determine the potential utility of LE-derived extracts in both therapeutic and cosmetic applications.

2,4-Di-tert-butylphenol from sweet potato protects against oxidative stress in PC12 cells and in mice

In this study, the protective effect of sweet potato extract against hydrogen peroxide-induced oxidative stress and cytotoxicity on the pheochromocytoma cell line (PC12) was investigated. The active component of the sweet potato extract was purified and determined to be 2,4-di-tert-butylphenol. The antioxidant capacity of 2,4-di-tert-butylphenol was measured by using 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) radical. To examine the effects of 2,4-di-tert-butylphenol on amyloid-beta peptide (Aβ1₁₋₄₂)-induced learning and memory impairment in mice, in vivo behavioral tests were performed. Administration of 2,4-di-tert-butylphenol increased alternation behavior in mice injected with Aβ₁₋₄₂. These results suggest that sweet potato extract could be protective against Aβ-induced neurotoxicity, possibly due to the antioxidative capacity of its constituent, 2,4-di-tert-butylphenol.

Neurite outgrowth of PC12 cells by 4'-O-β-D-glucopyranosyl-3',4-dimethoxychalcone from Brassica rapa L. 'hidabeni' was enhanced by pretreatment with p38MAPK inhibitor

The cellular effects of eleven compounds including chalcone glycosides isolated from Brassica rapa L. 'hidabeni' and their synthetic derivatives were studied in rat pheochromocytoma PC12 cells. Of the compounds tested, 4'-O-β-D-glucopyranosyl-3',4-dimethoxychalcone (A2) significantly increased the levels of the phosphorylated forms of extracellular signal-regulated kinases 1/2 (ERK 1/2), p38 mitogen-activated protein kinase (p38MAPK), and stress-activated protein kinases/Jun amino-terminal kinases (JNK/SAPK), but it did not affect Akt. Nerve growth factor (NGF), a well-known neurotrophic factor, increased the levels of phosphorylated ERK1/2, JNK/SAPK, and Akt but not p38MAPK, which may mediate marked neurite outgrowth. Signals evoked by A2 shared common characteristics with those induced by NGF; therefore, we evaluated the neuritogenic activity of A2 and found it induced only weak neurite outgrowth. However, this effect was enhanced by pre-treatment with a p38MAPK inhibitor, suggesting that the phosphorylation of p38MAPK down-regulated neurite outgrowth. From the results of this study, it was found that A2 in combination with a p38MAPK inhibitor can induce NGF-like effects. Hence, a combination of chalcone glycosides containing A2 and a p38MAPK inhibitor increases the likelihood that chalcone glycosides could be put to practical use in the form of drugs or alternative medicines to maintain neural health.

Neurite Outgrowth in PC12 Cells Stimulated by Components from Dendranthema × grandiflorum cv. "Mottenohoka" Is Enhanced by Suppressing Phosphorylation of p38MAPK

Components from Dendranthema × grandiflorum cv. "Mottenohoka" that promote neurite outgrowth of PC12 cells were identified and the mechanism of neurite outgrowth stimulated by isolated components was studied. Components that promoted the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK 1/2) of PC12 cells were isolated. From various structural analyses, the active components were identified as acacetin and luteolin. The effects of acacetin or luteolin on PC12 cells were evaluated by electro-blotting and immunostaining. Slight neurite outgrowth in PC12 cells was observed within 2 days of culture after stimulation by luteolin or acacetin. However, NGF-stimulation induced remarkable neurite outgrowth in comparison. Neurite outgrowth by luteolin or acacetin was significantly enhanced by pretreatment with SB203580 (a p38MAPK inhibitor). The results of this study into the phosphorylation of ERK 1/2 and p38MAPK by flavonoids suggest that the inhibition of p38MAPK phosphorylation may effectively enhance neurite outgrowth.

Antiamnesic effects of ethyl acetate fraction from chestnut (Castanea crenata var. dulcis) inner skin on Aβ(25-35)-induced cognitive deficits in mice

To investigate neuronal cell protective effects of an ethyl acetate fraction from chestnut inner skin, in vitro assays, including 2',7'-dichlorofluorescein diacetate, 3-[4,5-dimethythiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT), and lactate dehydrogenase (LDH), were performed. Intracellular accumulation of reactive oxygen species resulting from hydrogen peroxide (H(2)O(2)) treatment of PC12 cells was significantly reduced when ethyl acetate fractions were present in the medium compared to PC12 cells treated with H(2)O(2) only. In a cell viability assay using MTT, the ethyl acetate fraction protected against H(2)O(2)-induced neurotoxicity, and inhibited LDH release into the medium. In addition, the ethyl acetate fraction improved in vivo cognitive ability against amyloid β-peptide (Aβ)-induced neuronal deficit. High-performance liquid chromatography analyses showed that gallic acid, catechin, and epicatechin were predominant phenolics in the ethyl acetate fraction. Consequently, the results suggest that chestnut inner skin, including above phenolics, could ameliorate Aβ-induced learning and memory deficiency, and be utilized as effective substances for neurodegenerative disorders, notably Alzheimer's disease.

3-(2,6-Dimethylphenyl)-2-Selenoxo-1,3-Thiazolidin-4-One Suppresses Hydrogen Peroxide–Induced Cytotoxicity on PC12 Cells Via Activation of MAPK

We newly synthesized organic selenium compounds (5-membered ring compounds) including 2-selenoxo-1,3-thiazolidin-4-ones (compounds A) and 3-alkoxy-4,5-dihydro-5-selenoxo- 1H-1,2,4-triazole-1-carboxylates (compounds B). To address whether these compounds show antioxidative effects, we also examined their superoxide radical (O2−)-scavenging effects. Moreover, we examined the effects of compound Aa on the activation of mitogen-activated protein kinase/extracellular signal-regulated protein kinases (MAPK/ERK1/2) and suppression of hydrogen peroxide-induced cytotoxicity in rat pheochromocytoma cells (PC12 cells). We evaluated the O2−-scavenging activities of the compounds by a chemiluminescence method, and activation of ERK1/2 in PC12 cells was evaluated by Western blot analysis. At 166 μmol/L, the O2−-scavenging activities were markedly different among compounds A and B. 3-(2,6-Dimethylphenyl)-2-selenoxo-1,3-thiazolidin-4-one (compound Aa) exhibited the strongest superoxide anion-scavenging activity among compounds A and B. The concentration necessary for 50% inhibition of the activity (IC50) of compound Aa was 25.9 μmol/L. Compound Aa activated ERK1/2 of the PC12 cell, as did ebselen, and suppressed hydrogen peroxide-induced cytotoxicity more potently than ebselen. In addition, the toxicity of compound Aa was less than that of ebselen. From these results, it is assumed that compound Aa is a candidate drug to prevent oxidative stress-induced cell death.

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

Background

Since oxidative stress has been implicated in a neurodegenerative disease such as Alzheimer's 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.

Methods

Antioxidant 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.

Results

This 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.

Conclusion

Erigeron annuus leaf extracts containing caffeic acid as an active compound have antioxidative and neuroprotective effects on neuronal cells.

Punica granatum protects against oxidative stress in PC12 cells and oxidative stress-induced Alzheimer's symptoms in mice

Alzheimer's disease (AD) is a progressive degenerative brain disorder that is characterized by neuronal loss, neurofibrillary tangles, and the abnormal deposition of senile plaque and amyloid β peptide (Aβ). The brains of AD patients are under intense oxidative stress. The overproduction of Aβ leads to Aβ-associated free radical oxidative stress. In this study, the antioxidative and neuronal protective effects of Punica granatum extract were investigated against oxidative stress-induced cytotoxicity in PC12 cells. The ethanol extracts of P. granatum protected PC12 cells from hydrogen peroxide (H₂O₂-induced oxidative stress. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction assays revealed a significant increase in cell viability when oxidatively stressed PC12 cells were treated with the P. granatum extract. To examine the effects of P. granatum on Aβ₁₋₄₂-induced learning and memory impairment in mice, in vivo behavioral tests were performed. Treatment with the extract of P. granatum increased step-through latency in mice injected with Aβ₁₋₄₂. The results of this study suggest that the ethanol extract of P. granatum mitigated H₂O₂-induced oxidative stress in PC12 cells. In addition, the extract inhibited neuronal cell death caused by Aβ-induced oxidative stress and Aβ-induced learning and memory deficiency.

Neuroprotective effect of caffeoylquinic acids from Artemisia princeps Pampanini against oxidative stress-induced toxicity in PC-12 cells

Phenolics in dry Artemisia princeps Pampanini, an herbal plant traditionally consumed as food ingredients in Korea was extracted, fractionated, and quantified as well as evaluated for its neuroprotection for PC-12 cells. Whole extract had 5,852 mg gallic acid equivalents/100 g of total phenolics and 6,274 mg and 9,698 mg vitamin C equivalents/100 g of antioxidant capacities assayed by DPPH and ABTS radicals, respectively. The fraction extracted with n-butanol had the highest levels of total phenolics and antioxidant capacity than the other fractions (n-hexane, chloroform, ethyl acetate, and water). Using a reversed-phase HPLC system, caffeoylquinic acid (CQA) and its derivatives such as 3-CQA, 4-CQA, 5-CQA, 1,5-diCQA, 3,4-diCQA, 3,5-diCQA, and 4,5-diCQA were isolated and quantified. The whole extract and its n-butanol fraction yielded 3,5-diCQA with the highest amount, which consisted of approximately 36.8% and 33.5%, respectively. The whole extract, the n-butanol fraction, and 3,5-diCQA showed neuroprotective effect on PC-12 cells under the insult of amyloid ß peptide in a dose-dependent manner. Treatments of the whole extract and the n-butanol fraction for PC-12 cells under oxidative stress increased approximately 1.6 and 2.4 times higher cell viability, compared with the control without treatments. For PC-12 cells treated with 3,5-diCQA, intracellular oxidative stress decreased by 51.3% and cell viability increased up to 2.8 times compared to the control with oxidative insult of amyloid ß peptide only. These results indicate that phenolics from A. princeps Pampanini alleviated the oxidative stress and enhanced the viability of PC-12 cells, suggesting that it may be applied as a dietary antineurodegenerative agent in functional foods.

Cirsilineol inhibits proliferation of cancer cells by inducing apoptosis via mitochondrial pathway

Cirsilineol (4′,5-dihydroxy-3′,6,7-trimethoxyflavone) is a compound isolated from the herb of Artemisia vestita Wall (Compositae). In this study, we aimed at examining the anti-proliferative activity of cirsilineol against multiple types of cancer cells and the underlying mechanisms. Cirsilineol significantly inhibited proliferation of Caov-3, Skov-3, PC3 and Hela cells in a concentration-dependent manner. The compound also dose-dependently induced apoptosis in Caov-3 cells, as determined by annexin V/propidium iodide staining. Besides, cirsilineol induced a remarkable change in mitochondrial membrane potential and caused release of cytochrome c to cytosol. Furthermore, the compound caused a marked activation of capase-3, caspase-9 and poly (ADP-ribose) polymerase (PARP). These results suggested that the induction of apoptosis via the mitochondrial pathway was involved in the anti-proliferative activity of cirsilineol against cancer cells.

Zeatin prevents amyloid beta-induced neurotoxicity and scopolamine-induced cognitive deficits

The antioxidative and protective effects of zeatin against amyloid beta-protein (Abeta)-induced neurotoxicity were investigated using PC12 cells. Zeatin showed antioxidative and cell protective effects against Abeta-induced neurotoxicity. In this study, we also evaluated the effect of zeatin on learning and memory capacity in vivo using ICR mice with amnesia induced by scopolamine (1 mg/kg of body weight). Zeatin, when administered to mice at 4.5 mg/kg of body weight, significantly ameliorated scopolamine-induced amnesia as measured in both the passive avoidance test and Y-maze test. Injecting mice with scopolamine impaired performance on the passive avoidance test (48 +/- 4.5% decrease) and on the Y-maze test (12 +/- 1.3% decrease). In contrast, mice treated with zeatin before scopolamine injections were protected from these changes (5-34% decrease in step-through latency; 1-4% decrease in alternation behavior). The present results suggest a possible chemopreventive role of zeatin in Alzheimer's disease.

Anti-inflammatory and immunosuppressive effect of flavones isolated from Artemisia vestita

AIM OF THE STUDY

Artemisia vestita is a common traditional Tibetan medicinal plant which has been used widely in China for treating various inflammatory diseases. Since little is known about its active components, the purpose of this study was to isolate and identify the immunosuppressive compounds from Artemisia vestita.

MATERIALS AND METHODS

A bioassay-guided isolation was performed with picryl chloride-induced contact hypersensitivity in mice. MTT assay and Flow cytometric analysis were used for determining Con A-induced lymphocyte proliferation and CD25 expression in T cells, respectively.

RESULTS

The ethanol extract of the Artemisia vestita was found to possess significant inhibitory activity against the picryl chloride-induced contact hypersensitivity in mice. Then 4 fractions were isolated by macroporous adsorption resin and one of these fractions (AV3), which showed the highest activity in in vivo test, was further subjected to column chromatography. Nine known flavones were isolated and identified as pectolinarigenin (1), jaceosidin (2), cirsilineol (3), cirsimaritin (4), hispidulin (5), quercetin (6), 6-methoxytricin (7), acacetin (8), and apigenin (9). The structures of the 9 flavones were elucidated by spectral techniques. All the compounds were evaluated for their inhibitory activity on the proliferation and activation of T cells in vitro. Among the 9 flavones, cirsilineol (3), 6-methoxytricin (7) and apigenin (9) significantly inhibited T cell proliferation and activation in the bioassays.

CONCLUSION

The result suggests that cirsilineol, 6-methoxytricin and apigenin are the major active components in Artemisia vestita.

Inhibition of microglial neurotoxicity by ethanol extract of Artemisia asiatica Nakai

Artemisia asiatica Nakai has been used for the treatment of infections and inflammatory disorders in traditional Oriental medicine. Previously, an ethanol extract of A. asiatica has been shown to exert antioxidative and antiinflammatory activities and to exhibit protective effects against experimentally induced damage in the gastrointestinal system, liver and pancreas. This study examined whether the ethanol extract of A. asiatica affects inflammatory activation of microglia in the central nervous system, and whether the antiinflammatory activity of A. asiatica is related to neuroprotective effects. The extract of A. asiatica inhibited inflammatory activation of mouse microglial cells as determined by the production of nitric oxide and the expression of inducible nitric oxide synthase and inflammatory cytokine. The extract also protected nerve growth factor-differentiated PC12 cells against microglial cytotoxicity, indicating that the ethanol extract of A. asiatica may be neuroprotective by inhibiting microglial neurotoxicity.

Effects of banana, orange, and apple on oxidative stress-induced neurotoxicity in PC12 cells

Banana, orange, and apple are the major fruits in Western and Asian diets. In order to find the effects of these fruits, neuron like PC12 cells were exposed to the extracts of these fruits before H(2)O(2) treatment. We found a significant viability of PC12 cells by the MTT reduction test, which indicated that the phenolics of banana, orange, and apple fruits prevented oxidative stress-induced neurotoxicity. Additional tests by lactate dehydrogenase and trypan blue exclusion assays showed that the extracts reduced oxidative stress-induced neuronal cell membrane damage. These results suggest that fresh apples, banana, and orange in our daily diet along with other fruits may protect neuron cells against oxidative stress-induced neurotoxicity and may play an important role in reducing the risk of neurodegenerative disorders such as Alzheimer's disease.

DA-9601, a standardized extract of Artemisia asiatica, blocks TNF-α-induced IL-8 and CCL20 production by inhibiting p38 kinase and NF-κB pathways in human gastric epithelial cells

AIM: To investigate whether, or how, DA-9601, which is a new gastroprotective agent, inhibits TNF-α-induced inflammatory signals in gastric epithelial AGS cells.

METHODS: Cell viability was determined by MTT assay. IL-8 and CCL20 promoter activities were determined by a luciferease reporter gene assay. NF-κB-dependent transcriptional activity was determined by I-κBα degradation, NF-κB p65 nuclear translocation and a luciferase activity assay. IL-8 and CCL20 gene expression and protein secretion were determined by RT-PCR and an enzyme-linked immunosorbent assay (ELISA). Total and phosphorylated forms of mitogen-activated protein kinases (MAPKs) were determined by Western blot.

RESULTS: Treatment of AGS cells with DA-9601 reduced TNF-α-induced IL-8 and CCL20 promoter activities, as well as their gene expression and protein release. TNF-α also induced NF-κB-dependent transcriptional activity in AGS cells. In contrast, in cells treated with DA-9601, TNF-α-induced NF-κB activity was significantly blocked. Although all three MAP kinase family members were phosphorylated in response to TNF-α, a selective inhibitor of p38 kinase SB203580 only could inhibit both NF-κB-dependent transcriptional activity and IL-8 and CCL20 production, suggesting a potential link between p38 kinase and NF-κB-dependent pathways in AGS cells. Interestingly, DA-9601 also selectively inhibited p38 kinase phosphorylation induced by TNF-α.

CONCLUSION: DA-9601 blocked TNF-α-mediated inflammatory signals by potentially modulating the p38 kinase pathway and/or a signal leading to NF-κB-dependent pathways in gastric epithelial cells.

Effects of oleamide on choline acetyltransferase and cognitive activities

We screened 50 Korean traditional natural plants to measure the activation effect on choline acetyltransferase and attenuation of scopolamine-induced amnesia. The methanolic extracts from Zizyphus jujuba among the tested 50 plants, showed the highest activatory effect (34.1%) on choline acetyltransferase in vitro. By sequential fractionation of Zizyphus jujuba, the active component was finally identified as cis-9-octadecenoamide (oleamide). After isolation, oleamide showed a 65% activation effect. Administration of oleamide (0.32%) to mice significantly reversed the scopolamine-induced memory and/or cognitive impairment in the passive avoidance test and Y-maze test. Injection of scopolamine to mice impaired performance on the passive avoidance test (31% decrease in step-through latency), and on the Y-maze test (16% decrease in alternation behavior). In contrast, mice treated with oleamide before scopolamine injection were protected from these changes (12-25% decrease in step-through latency; 1-10% decrease in alternation behavior). These results suggest that oleamide should be a useful chemo-preventive agent against Alzheimer's disease.

Nutritional approaches to combat oxidative stress in Alzheimer's disease

Alzheimer's disease (AD) brains are characterized by extensive oxidative stress. Additionally, large depositions of amyloid beta-peptide (Abeta) are observed, and many researchers opine that Abeta is central to the pathogenesis of AD. Our laboratory combined these two observations in a comprehensive model for neurodegeneration in AD brains centered around Abeta-induced oxidative stress. Given the oxidative stress in AD and its potentially important role in neurodegeneration, considerable research has been conducted on the use of antioxidants to slow or reverse the pathology and course of AD. One source of antioxidants is the diet. This review examines the literature of the effects of endogenous and exogenous, nutritionally-derived antioxidants in relation to AD. In particular, studies of glutathione and other SH-containing antioxidants, vitamins, and polyphenolic compounds and their use in AD and modulation of Abeta-induced oxidative stress and neurotoxicity are reviewed.

Inhibitory effects of the standardized extract (DA-9601) of Artemisia asiatica Nakai on phorbol ester-induced ornithine decarboxylase activity, papilloma formation, cyclooxygenase-2 expression, inducible nitric oxide synthase expression and nuclear transcription factor kappa B activation in mouse skin

Artemisia asiatica Nakai has been used in traditional Asian medicine for the treatment of inflammatory and other disorders. Previous studies have revealed that the formulated ethanol extract (DA-9601) of A. asiatica has pronounced antioxidative and antiinflammatory activities and exhibits cytoprotective effects against experimentally induced gastrointestinal, hepatic and pancreatic damage. In the present study, we assessed the inhibitory effect of DA-9601 on tumor promotion, which is closely linked to inflammatory tissue damage. As an initial approach to evaluating the possible antitumor-promoting potential of DA-9601, its effects on TPA-induced ear edema were examined in female ICR mice. Pretreatment of the inner surface of the mouse ear with DA-9601 30 min prior to topical application of TPA inhibited ear edema at 5 hr. TPA-stimulated expression of epidermal COX-2 and iNOS was also mitigated by topical application of the same extract. Moreover, DA-9601 abrogated the TPA-mediated activation of NF-kappa B/Rel and AP-1 in mouse epidermis. Suppression of epidermal NF-kappa B by DA-9601 appeared to be mediated in part through inhibition of I kappa B alpha degradation, thereby blocking the nuclear translocation of p65, the functional subunit of NF-kappa B. DA-9601 also significantly suppressed TPA-induced ODC activity and papilloma formation in mouse skin. Taken together, these findings suggest that DA-9601 derived from A. asiatica possesses potential chemopreventive activities.