6-Shogaol, a ginger product, modulates neuroinflammation: a new approach to neuroprotection

A New Neolignan Derivative, Balanophonin Isolated from Firmiana simplex Delays the Progress of Neuronal Cell Death by Inhibiting Microglial Activation

Excessive activation of microglia causes the continuous production of neurotoxic mediators, which further causes neuron degeneration. Therefore, inhibition of microglial activation is a possible target for the treatment of neurodegenerative disorders. Balanophonin, a natural neolignoid from Firmiana simplex, has been reported to have anti-inflammatory and anti-cancer effects. In this study, we aimed to evaluate the anti-neuroinflammatory effects and mechanism of balanophonin in lipopolysaccharide (LPS)-stimulated BV2 microglia cells. BV2 microglia cells were stimulated with LPS in the presence or absence of balanophonin. The results indicated that balanophonin reduced not only the LPS-mediated TLR4 activation but also the production of inflammatory mediators, such as nitric oxide (NO), prostaglandin E2 (PGE2), Interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α), in BV2 cells. Balanophonin also inhibited LPS-induced inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX2) protein expression and mitogen activated protein kinases (MAPKs), including extracellular signal-regulated kinase (ERK1/2), c-Jun N-terminal kinase (JNK), and p38 MAPK. Interestingly, it also inhibited neuronal cell death resulting from LPS-activated microglia by regulating cleaved caspase-3 and poly ADP ribose polymerase (PARP) cleavage in N2a cells. In conclusion, our data indicated that balanophonin may delay the progression of neuronal cell death by inhibiting microglial activation.

Neuroprotective and Anti-Inflammatory Activities of Allyl Isothiocyanate through Attenuation of JNK/NF-κB/TNF-α Signaling

Allyl isothiocyanate (AITC), present in Wasabia japonica (wasabi), is an aliphatic isothiocyanate derived from the precursor sinigrin, which is a glucosinolate present in vegetables of the Brassica family. Traditionally, it has been used to treat rheumatic arthralgia, blood circulation, and pain. This study focuses on its anti-apoptotic activity through the regulation of lipopolysaccharide (LPS)-induced neuroinflammation. Furthermore, we assessed its neuroprotective efficacy, which it achieves through the upregulation of nerve growth factor (NGF) production. Pretreatment with AITC significantly inhibited inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression, decreased tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), prostaglandin E2 (PGE2), and nitric oxide (NO) production in activated microglia, and increased the nerve growth factor (NGF) and neurite outgrowth in neuroblastoma cells. AITC inhibited the nuclear factor (NF-κB-mediated transcription by modulating mitogen activated protein kinase (MAPK) signaling, particularly downregulating c-Jun N-terminal kinase (JNK) phosphorylation, which was followed by a reduction in the TNF-α expression in activated microglia. This promising effect of AITC in controlling JNK/NF-κB/TNF-α cross-linking maintains the Bcl-2 gene family and protects neuroblastoma cells from activated microglia-induced toxicity. These findings provide novel insights into the anti-neuroinflammatory effects of AITC on microglial cells, which may have clinical significance in neurodegeneration.

6-shogaol, a neuroactive compound of ginger (jahe gajah) induced neuritogenic activity via NGF responsive pathways in PC-12 cells

BACKGROUND

Ginger is a popular spice and food preservative. The rhizomes of the common ginger have been used as traditional medicine to treat various ailments. 6-Shogaol, a pungent compound isolated from the rhizomes of jahe gajah (Zingiber officinale var officinale) has shown numerous pharmacological activities, including neuroprotective and anti-neuroinflammatory activities. The aim of this study was to investigate the potential of 6-shogaol to mimic the neuritogenic activity of nerve growth factor (NGF) in rat pheochromocytoma (PC-12) cells.

METHODS

The cytotoxic effect of 6-shogaol was determined by 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The neuritogenic activity was assessed by neurite outgrowth stimulation assay while the concentration of extracellular NGF in cell culture supernatant was assessed by enzyme-linked immunosorbent assay (ELISA). Involvement of cellular signaling pathways, mitogen-activated protein kinase kinase/extracellular signal-regulated kinase1/2 (MEK/ERK1/2) and phosphoinositide-3-kinase/protein kinase B (PI3K/AKT) in 6-shogaol-stimulated neuritogenesis were examined by using specific pharmacological inhibitors.

RESULTS

6-Shogaol (500 ng/ml) induced neuritogenesis that was comparable to NGF (50 ng/ml) and was not cytotoxic towards PC-12 cells. 6-Shogaol induced low level of NGF biosynthesis in PC-12 cells, showing that 6-shogaol stimulated neuritogenesis possibly by inducing NGF biosynthesis, and also acting as a substitute for NGF (NGF mimic) in PC-12 cells. The inhibitors of Trk receptor (K252a), MEK/ERK1/2 (U0126 and PD98059) and PI3K/AKT (LY294002) attenuated the neuritogenic activity of both NGF and 6-shogaol, respectively.

CONCLUSIONS

The present findings demonstrated that 6-shogaol induced neuritogenic activity in PC-12 cells via the activation MEK/ERK1/2 and PI3K/AKT signaling pathways. This study suggests that 6-shogaol could act as an NGF mimic, which may be beneficial for preventive and therapeutic uses in neurodegenerative diseases.

Protective effects of gingerol on streptozotocin-induced sporadic Alzheimer's disease: emphasis on inhibition of β-amyloid, COX-2, alpha-, beta - secretases and APH1a

Gingerol is a major dietary compound that occurs in several plants belonging to the Zingiberaceae family. In the current study, the protective effect of gingerol on STZ-induced sporadic Alzheimer's disease (SAD) was determined. Gingerol was isolated from the seeds of Aframomum melegueta K. Schum and tested at doses of 10 and 20 mg/kgbwt for its possible effect on the SAD model in mice, using celecoxib (30 mg/kg bwt) as a reference standard. The curative effects of gingerol were assessed through measurement of β-amyloid (Aβ-42), α-, β- secretases, APH1a and COX-2 levels. In addition, improvement in the cognitive deficit in mice after treatment was confirmed using the water maze and Y-maze with intra-maze cues. Gingerol improved the cognitive and behavioral impairment and AD-like pathology in streptozotocin model mice. These beneficial effects occurred with an increase in α-secretase activity and a decrease in cerebral Aβ-42, β- secretase, APH1a activity and COX-2-linked neuro-inflammation.

Equol, a Dietary Daidzein Gut Metabolite Attenuates Microglial Activation and Potentiates Neuroprotection In Vitro

Estrogen deficiency has been well characterized in inflammatory disorders including neuroinflammation. Daidzein, a dietary alternative phytoestrogen found in soy (Glycine max) as primary isoflavones, possess anti-inflammatory activity, but the effect of its active metabolite Equol (7-hydroxy-3-(4′-hydroxyphenyl)-chroman) has not been well established. In this study, we investigated the anti-neuroinflammatory and neuroprotective effect of Equol in vitro. To evaluate the potential effects of Equol, three major types of central nervous system (CNS) cells, including microglia (BV-2), astrocytes (C6), and neurons (N2a), were used. Effects of Equol on the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX-2), Mitogen activated protein kinase (MAPK) signaling proteins, and apoptosis-related proteins were measured by western blot analysis. Equol inhibited the lipopolysaccharide (LPS)-induced TLR4 activation, MAPK activation, NF-kB-mediated transcription of inflammatory mediators, production of nitric oxide (NO), release of prostaglandin E2 (PGE-2), secretion of tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6), in Lipopolysaccharide (LPS)-activated murine microglia cells. Additionally, Equol protects neurons from neuroinflammatory injury mediated by LPS-activated microglia through downregulation of neuronal apoptosis, increased neurite outgrowth in N2a cell and neurotrophins like nerve growth factor (NGF) production through astrocytes further supporting its neuroprotective potential. These findings provide novel insight into the anti-neuroinflammatory effects of Equol on microglial cells, which may have clinical significance in cases of neurodegeneration.

Sortilin-related receptor 1 interacts with amyloid precursor protein and is activated by 6-shogaol, leading to inhibition of the amyloidogenic pathway

Sortilin-related receptor 1 (SORL1) is a neuronal sorting protein that reduces amyloid precursor protein (APP) trafficking to secretases that generate amyloid beta (Aβ). Although 6-shogaol, a constituent of ginger, has been reported to have anti-inflammatory and anti-oxidant effects on neuronal cells, research regarding the activation of SORL1 has not yet been reported. Here, we aimed to investigate whether 6-shogaol contributes to the increases in SORL1 that are related to Alzheimer's disease (AD). To clarify the effect of 6-shogaol as a possible activator of SORL1, we used SORL1 siRNA as a blockade of SORL1 in hippocampal neuronal cells (HT22). We found that SORL1 siRNA treatment naturally inhibited SORL1 and led to increases in β-secretase APP cleaving enzyme (BACE), secreted APP-β (sAPPβ) and Aβ. In contrast, 6-shogaol-mediated activation of SORL1 significantly downregulated BACE, sAPPβ, and Aβ in both in vitro HT22 cells and in vivo APPSw/PS1-dE9 Tg mice. Therefore, SORL1 activation by 6-shogaol provides neuronal cell survival through the inhibition of Aβ production. These results indicate that 6-shogaol should be regarded as an SORL1 activator and a potential preventive agent for the treatment of AD.

Possible Role of Common Spices as a Preventive and Therapeutic Agent for Alzheimer's Disease

For centuries, spices have been consumed as food additives or medicinal agents. However, there is increasing evidence indicating the plant-based foods in regular diet may lower the risk of neurodegenerative diseases including Alzheimer disease. Spices, as one of the most commonly used plant-based food additives may provide more than just flavors, but as agents that may prevent or even halt neurodegenerative processes associated with aging. In this article, we review the role and application of five commonly used dietary spices including saffron turmeric, pepper family, zingiber, and cinnamon. Besides suppressing inflammatory pathways, these spices may act as antioxidant and inhibit acetyl cholinesterase and amyloid β aggregation. We summarized how spice-derived nutraceuticals mediate such different effects and what their molecular targets might be. Finally, some directions for future research are briefly discussed.

Modulation of Inflammatory Response to Implanted Biomaterials Using Natural Compounds

Tissue engineering offers a promising strategy to restore injuries resulting from trauma, infection, tumor resection, or other diseases. In spite of significant progress, the field faces a significant bottleneck; the critical need to understand and exploit the interdependencies of tissue healing, angiogenesis, and inflammation. Inherently, the balance of these interacting processes is affected by a number of injury site conditions that represent a departure from physiological environment, including reduced pH, increased concentration of free radicals, hypoglycemia, and hypoxia. Efforts to harness the potential of immune response as a therapeutic strategy to promote tissue repair have led to identification of natural compounds with significant anti-inflammatory properties. This article provides a concise review of the body's inflammatory response to biomaterials and describes the role of oxygen as a physiological cue in this process. We proceed to highlight the potential of natural compounds to mediate inflammatory response and improve host-graft integration. Herein, we discuss the use of natural compounds to map signaling molecules and checkpoints that regulate the cross-linkage of immune response and skeletal repair.

6-Shogaol, an active compound of ginger, alleviates allergic dermatitis-like skin lesions via cytokine inhibition by activating the Nrf2 pathway

Allergic dermatitis (AD) clinically presents with skin erythematous plaques, eruption, and elevated serum IgE, and T helper cell type 2 and 1 (Th2 and Th1) cytokine levels. 6-Shogaol [1-(4-hydroxy-methoxyphenyl)-4-decen-one], a pungent compound isolated from ginger, has shown anti-inflammatory effects, but its inhibitory effects on AD are unknown. The aim of this study was to examine whether 6-shogaol inhibits AD-like skin lesions and their underlying mechanism in vivo and in vitro. An AD-like response was induced by tumor necrosis factor-α (TNF-α)+IFN-γ in human keratinocytes or by 2,4-dinitrochlorobenzene (DNCB) in mice. In vivo, 6-shogaol inhibited the development of DNCB-induced AD-like skin lesions and scratching behavior, and showed significant reduction in Th2/1-mediated inflammatory cytokines, IgE, TNF-α, IFN-γ, thymus and activation-regulated chemokine, IL-1, 4, 12, and 13, cyclooxygenase-2, and nitric oxide synthase levels. In vitro, 6-shogaol inhibited reactive oxygen species (ROS) and mitogen-activated protein kinases (MAPKs) signaling, and increased the levels of total glutathione, heme oxygenase-1, and quinone 1 via nuclear factor erythroid 2 related factor 2 (Nrf2) activation. 6-Shogaol can alleviate AD-like skin lesions by inhibiting immune mediators via regulating the ROS/MAPKs/Nrf2 signaling pathway, and may be an effective alternative therapy for AD.

Changes in antioxidant and antibacterial activities as well as phytochemical constituents associated with ginger storage and polyphenol oxidase activity

Background

Herbal materials should be stored at optimal conditions in order to retain their nutritional quality. Proper storage has a significant impact on the quality of the herbs and spices.

Methods

The effects of storage temperature (5 and 15 °C) and time (4 and 8 months) on the phytochemical constituents associated with the antioxidant and antibacterial activities of ginger varieties (Halia bentong and Halia bara) were evaluated to determine the optimal storage conditions for ginger rhizomes. Total flavonoid content (TFC) and Total phenolic content (TPC) were measured using the spectrophotometric method. Individual phenolic acids and flavonoids, 6-gingerol and 6-shogaol were identified by ultra-high performance liquid chromatography. Ferric reducing antioxidant potential (FRAP) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays were used for evaluation of antioxidant activities. An antibacterial property of ginger varieties was evaluated using well diffusion method.

Results

Dry matter, TPC, TFC and individual phenolics and flavonoids content, 6-gingerol and 6-shogaol content noticeably decreased at 5 and 15 °C during the storage times from 4 to 8 months. Highest content of flavonoids, phenolic acids, 6-gingerol, and 6-shogaol was observed in fresh samples followed by rhizomes stored at 5 °C for 4 months. Storage at 15 °C for 4 months reduced the phytochemical content significantly. Cinnamic acid and tannic acid were not detected in those variety stored at 15 °C for 4 and 8 months. Polyphenol oxidase (PPO) activity was associated significantly with storage time and temperature. Highest and lowest PPO activity was observed in stored and fresh rhizomes respectively. Antioxidant and antimicrobial activities gradually declined with the increase of storage temperature (from 5 to 15 °C) and duration (from 4 to 8 months) in both the varieties. Freshly harvested Halia bara variety had higher antioxidant and antibacterial activity compared to the Halia bentong variety.

Conclusions

Halia bara exhibited valuable phytochemical content and antioxidant and antibacterial activities at higher levels compared to that exhibited by Halia bentong rhizomes. In general, storage of Malaysian ginger varieties at temperature of 5 °C is recommended and the storage time should be not more than 4 months. This storage condition will provide greater stability to the concentration of the phytochemical constituents more similar to the fresh material. 

Identification of Neuroactive Constituents of the Ethyl Acetate Fraction from Cyperi Rhizoma Using Bioactivity-Guided Fractionation

Cyperi Rhizoma (CR), the rhizome of Cyperus rotundus L., exhibits neuroprotective effects in in vitro and in vivo models of neuronal diseases. Nevertheless, no study has aimed at finding the neuroactive constituent(s) of CR. In this study, we identified active compounds in a CR extract (CRE) using bioactivity-guided fractionation. We first compared the anti-oxidative and neuroprotective activities of four fractions and the CRE total extract. Only the ethyl acetate (EA) fraction revealed strong activity, and further isolation from the bioactive EA fraction yielded nine constituents: scirpusin A (1), scirpusin B (2), luteolin (3), 6′-acetyl-3,6-diferuloylsucrose (4), 4′,6′ diacetyl-3,6-diferuloylsucrose (5), p-coumaric acid (6), ferulic acid (7), pinellic acid (8), and fulgidic acid (9). The activities of constituents 1–9 were assessed in terms of anti-oxidative, neuroprotective, anti-inflammatory, and anti-amyloid-β activities. Constituents 1, 2, and 3 exhibited strong activities; constituents 1 and 2 were characterized for the first time in this study. These results provide evidence for the value of CRE as a source of multi-functional neuroprotectants, and constituents 1 and 2 may represent new candidates for further development in therapeutic use against neurodegenerative diseases.

Phytochemicals in Ischemic Stroke

Stroke is the second foremost cause of mortality worldwide and a major cause of long-term disability. Due to changes in lifestyle and an aging population, the incidence of stroke continues to increase and stroke mortality predicted to exceed 12 % by the year 2030. However, the development of pharmacological treatments for stroke has failed to progress much in over 20 years since the introduction of the thrombolytic drug, recombinant tissue plasminogen activator. These alarming circumstances caused many research groups to search for alternative treatments in the form of neuroprotectants. Here, we consider the potential use of phytochemicals in the treatment of stroke. Their historical use in traditional medicine and their excellent safety profile make phytochemicals attractive for the development of therapeutics in human diseases. Emerging findings suggest that some phytochemicals have the ability to target multiple pathophysiological processes involved in stroke including oxidative stress, inflammation and apoptotic cell death. Furthermore, epidemiological studies suggest that the consumption of plant sources rich in phytochemicals may reduce stroke risk, and so reinforce the possibility of developing preventative or neuroprotectant therapies for stroke. In this review, we describe results of preclinical studies that demonstrate beneficial effects of phytochemicals in experimental models relevant to stroke pathogenesis, and we consider their possible mechanisms of action.

Advances of wogonin, an extract from Scutellaria baicalensis, for the treatment of multiple tumors

As the major bioactive compound of Scutellaria baicalensis that has been approved to be effective as an anti-inflammatory and antiviral inhibitor in cardiovascular diseases, wogonin (WG) showed potent and promising antitumor effects both in vitro and in vivo. It has been proved that WG has the ability to inhibit the growth of tumor cells, induce apoptosis, and suppress angiogenesis. The molecular mechanisms involve reactive oxygen species, Ca²⁺, NF-κB, tumor necrosis factor-related apoptosis-inducing ligand, and tumor necrosis factor-alpha. Furthermore, the synergistic effect of WG with 5-fluorouracil, etoposide, and adriamycin to enhance chemotherapy and reverse drug resistance has also been confirmed. In this review, we summarize the advances in recent years on the antitumor effect of WG on multiple tumors; in addition, we also present information regarding the synergistic and chemosensitizing effects of WG with other drugs to illustrate its potential use in the clinic.

[6]-Shogaol, a dietary phenolic compound, induces oxidative stress mediated mitochondrial dependant apoptosis through activation of proapoptotic factors in Hep-2 cells

Ginger (Zingiber officinale) is a well-known herb used in ethnomedicine. [6]-shogaol, a phenolic nature is a major constituent of ginger. In this study, we investigated the anticancer activity of [6]-shogaol in Laryngeal cancer (Hep-2) cells. We demonstrated the effects of [6]-shogaol on the cell growth and apoptosis in Hep-2 cells were analyzed by the generation of reactive oxygen species (ROS), the level of mitochondrial membrane potential (ΔYm), DNA damage and apoptotic morphological changes were analyzed by AO/EtBr, AO and Hoechst staining. Further, apoptotic protein expressions were analyzed by western blot analysis. Our results indicated that [6]-shogaol induces apoptosis as evidenced by loss of cell viability, enhanced ROS, lipid peroxidation results in altered mitochondrial membrane potential, increased DNA damage in Hep-2 cells. Further, the prooxidant role of [6]-shogaol inhibit Bcl-2 expression with the simultaneous up-regulation of Bax, Cytochrome c, Caspase-9 and -3 protein expressions were observed in Hep-2 cells. Thus, [6]-shogaol induces apoptosis in Hep-2 cells through inducing oxidative damage and modulate apoptotic marker expressions. Therefore, [6]-shogaol might be used as a therapeutic agent for the treatment of laryngeal cancer.

Pilot clinical study of the effects of ginger root extract on eicosanoids in colonic mucosa of subjects at increased risk for colorectal cancer

Colorectal cancer (CRC) remains a significant cause of mortality. Inhibitors of cyclooxygenase (COX) and thus prostaglandin E2, are promising CRC preventives, but have significant toxicities. Ginger has been shown to inhibit COX, to decrease the incidence and multiplicity of adenomas, and decrease PGE2 concentrations in subjects at normal risk for CRC. This study was conducted to determine the effects of 2.0 g/d of ginger given orally on the levels of PGE2, leukotriene B4 (LTB4), 13-hydroxy-octadecadienoic acids, and 5-, 12-, & 15-hydroxyeicosatetraenoic acid, in the colonic mucosa of subjects at increased risk for CRC. We randomized 20 subjects to 2.0 g/d ginger or placebo for 28 d. At baseline and Day 28, a flexible sigmoidoscopy was used to obtain colon biopsies. A liquid chromatography mass spectrometry method was used to determine eicosanoid levels in the biopsies, and levels were expressed per amount of protein or free arachidonic acid (AA). There was a significant decrease in AA between baseline and Day 28 (P = 0.05) and significant increase in LTB4 (P = 0.04) when normalized to protein, in subjects treated with ginger versus placebo. No other changes in eicosanoids were observed. There was no difference between the groups in total adverse events (AE; P = 0.06). Ginger lacks the ability to decrease eicosanoid levels in people at increased risk for CRC. Ginger did appear to be both tolerable and safe; and could have chemopreventive effects through other mechanisms. Further investigation should focus on other markers of CRC risk in those at increased CRC risk.

Gingerols and shogaols: Important nutraceutical principles from ginger

Gingerols are the major pungent compounds present in the rhizomes of ginger (Zingiber officinale Roscoe) and are renowned for their contribution to human health and nutrition. Medicinal properties of ginger, including the alleviation of nausea, arthritis and pain, have been associated with the gingerols. Gingerol analogues are thermally labile and easily undergo dehydration reactions to form the corresponding shogaols, which impart the characteristic pungent taste to dried ginger. Both gingerols and shogaols exhibit a host of biological activities, ranging from anticancer, anti-oxidant, antimicrobial, anti-inflammatory and anti-allergic to various central nervous system activities. Shogaols are important biomarkers used for the quality control of many ginger-containing products, due to their diverse biological activities. In this review, a large body of available knowledge on the biosynthesis, chemical synthesis and pharmacological activities, as well as on the structure-activity relationships of various gingerols and shogaols, have been collated, coherently summarised and discussed. The manuscript highlights convincing evidence indicating that these phenolic compounds could serve as important lead molecules for the development of therapeutic agents to treat various life-threatening human diseases, particularly cancer. Inclusion of ginger or ginger extracts in nutraceutical formulations could provide valuable protection against diabetes, cardiac and hepatic disorders.

Activation of Nrf2 target enzymes conferring protection against oxidative stress in PC12 cells by ginger principal constituent 6-shogaol

Natural compounds containing phenoxyl groups and/or Michael acceptor units appear to possess antioxidant and cytoprotective properties. The ginger principal constituent 6-shogaol (6-S) represents one of such compounds. In this study, we reported that 6-S efficiently scavenges various free radicals in vitro, and displays remarkable cytoprotection against oxidative stress-induced cell damage in the neuron-like rat pheochromocytoma cell line, PC12 cells. Pretreatment of PC12 cells with 6-S significantly upregulates a series of phase II antioxidant molecules, such as glutathione, heme oxygenase 1, NAD(P)H: quinone oxidoreductase 1, thioredoxin reductase 1, and thioredoxin 1. A mechanistic study revealed that 6-S enhanced the translocation of Nrf2 from the cytosol to the nucleus and knockdown of Nrf2 abolished such protection, indicating that this cytoprotection is mediated by the activation of the transcription factor Nrf2. Another ginger constituent 6-gingerol (6-G), having a similar structure of 6-S but lacking the alpha,beta-unsaturated ketone structure (Michael acceptor moiety), failed to shelter PC12 cells from oxidative stress. Our results demonstrate that 6-S is a novel small molecule activator of Nrf2 in PC12 cells, and suggest that 6-S might be a potential candidate for the prevention of oxidative stress-mediated neurodegenerative disorders.

Optimization protocol for the extraction of 6-gingerol and 6-shogaol from Zingiber officinale var. rubrum Theilade and improving antioxidant and anticancer activity using response surface methodology

BACKGROUND

Analysis and extraction of plant matrices are important processes for the development, modernization, and quality control of herbal formulations. Response surface methodology is a collection of statistical and mathematical techniques that are used to optimize the range of variables in various experimental processes to reduce the number of experimental runs, cost , and time, compared to other methods.

METHODS

Response surface methodology was applied for optimizing reflux extraction conditions for achieving high 6-gingerol and 6-shogaol contents, and high antioxidant activity in Zingiber officinale var. rubrum Theilade . The two-factor central composite design was employed to determine the effects of two independent variables, namely extraction temperature (X1: 50-80 °C) and time (X2: 2-4 h), on the properties of the extracts. The 6-gingerol and 6-shogaol contents were measured using ultra-performance liquid chromatography. The antioxidant activity of the rhizome extracts was determined by means of the 1,1-diphenyl-2-picrylhydrazyl assay. Anticancer activity of optimized extracts against HeLa cancer cell lines was measured using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay.

RESULTS

Increasing the extraction temperature and time induced significant response of the variables. The optimum extraction condition for all responses was at 76.9 °C for 3.4 h. Under the optimum condition, the corresponding predicted response values for 6-gingerol, 6-shogaol, and the antioxidant activity were 2.89 mg/g DW, 1.85 mg/g DW, and 84.3%, respectively. 6-gingerol and 6-shogaol were extracted under optimized condition to check the viability of the models. The values were 2.92 and 1.88 mg/g DW, and 84.0% for 6-gingerol, 6-shogaol, and the antioxidant activity respectively. The experimental values agreed with those predicted, thus indicating suitability of the models employed and the success of RSM in optimizing the extraction condition. With optimizing of reflux extraction anticancer activity of extracts against HeLa cancer cells enhanced about 16.8%. The half inhibition concentration (IC50) value of optimized and unoptimized extract was found at concentration of 20.9 and 38.4 μg/mL respectively. Optimized extract showed more distinct anticancer activities against HeLa cancer cells in a concentration of 40 μg/mL (P < 0.01) without toxicity to normal cells.

CONCLUSIONS

The results indicated that the pharmaceutical quality of ginger could be improved significantly by optimizing of extraction process using response surface methodology.

Ginger and Zingerone Ameliorate Lipopolysaccharide-Induced Acute Systemic Inflammation in Mice, Assessed by Nuclear Factor-κB Bioluminescent Imaging

Ginger is a commonly used spice in cooking. In this study, we comprehensively evaluated the anti-inflammatory activities of ginger and its component zingerone in lipopolysaccharide (LPS)-induced acute systemic inflammation in mice via nuclear factor-κB (NF-κB) bioluminescent imaging. Ginger and zingerone significantly suppressed LPS-induced NF-κB activities in cells in a dose-dependent manner, and the maximal inhibition (84.5% ± 3.5% and 96.2% ± 0.6%) was observed at 100 μg/mL ginger and zingerone, respectively. Moreover, dietary ginger and zingerone significantly reduced LPS-induced proinflammatory cytokine production in sera by 62.9% ± 18.2% and 81.3% ± 6.2%, respectively, and NF-κB bioluminescent signals in whole body by 26.9% ± 14.3% and 38.5% ± 6.2%, respectively. In addition, ginger and zingerone suppressed LPS-induced NF-κB-driven luminescent intensities in most organs, and the maximal inhibition by ginger and zingerone was observed in small intestine. Immunohistochemical staining further showed that ginger and zingerone decreased interleukin-1β (IL-1β)-, CD11b-, and p65-positive areas in jejunum. In conclusion, our findings suggested that ginger and zingerone were likely to be broad-spectrum anti-inflammatory agents in most organs that suppressed the activation of NF-κB, the production of IL-1β, and the infiltration of inflammatory cells in mice.

Phytochemicals that regulate neurodegenerative disease by targeting neurotrophins: a comprehensive review

Alzheimer's disease (AD), characterized by progressive dementia and deterioration of cognitive function, is an unsolved social and medical problem. Age, nutrition, and toxins are the most common causes of AD. However, currently no credible treatment is available for AD. Traditional herbs and phytochemicals may delay its onset and slow its progression and also allow recovery by targeting multiple pathological causes by antioxidative, anti-inflammatory, and antiamyloidogenic properties. They also regulate mitochondrial stress, apoptotic factors, free radical scavenging system, and neurotrophic factors. Neurotrophins such as BDNF, NGF, NT3, and NT4/5 play a vital role in neuronal and nonneuronal responses to AD. Neurotrophins depletion accelerates the progression of AD and therefore, replacing such neurotrophins may be a potential treatment for neurodegenerative disease. Here, we review the phytochemicals that mediate the signaling pathways involved in neuroprotection specifically neurotrophin-mediated activation of Trk receptors and members of p75(NTR) superfamily. We focus on representative phenolic derivatives, iridoid glycosides, terpenoids, alkaloids, and steroidal saponins as regulators of neurotrophin-mediated neuroprotection. Although these phytochemicals have attracted attention owing to their in vitro neurotrophin potentiating activity, their in vivo and clinical efficacy trials has yet to be established. Therefore, further research is necessary to prove the neuroprotective effects in preclinical models and in humans.

Anticholinesterase and antioxidant investigations of crude extracts, subsequent fractions, saponins and flavonoids of atriplex laciniata L.: potential effectiveness in Alzheimer's and other neurological disorders

Background

Atriplex laciniata L. was investigated for phenolic, flavonoid contents, antioxidant, anticholinesterase activities, in an attempt to explore its effectiveness in Alzheimer’s and other neurological disorders. Plant crude methanolic extract (Al.MeF), subsequent fractions; n-hexane (Al.HxF), chloroform (Al.CfF), ethyl acetate (Al.EaF), aqueous (Al.WtF), Saponins (Al.SPF) and Flavonoids (Al.FLVF) were investigated for DPPH, ABTS and H₂O₂ free radical scavenging activities. Further these extracts were subjected to acetylcholinesterase (AChE) & butyrylcholinesterase (BChE) inhibitory activities using Ellman’s assay. Phenolic and Flavonoid contents were determined and expressed in mg Gallic acid GAE/g and Rutin RTE/g of samples respectively.

Results

In DPPH free radicals scavenging assay, Al.FLVF, Al.SPF and Al.MeF showed highest activity causing 89.41 ± 0.55, 83.37 ± 0.34 and 83.37 ± 0.34% inhibition of free radicals respectively at 1 mg/mL concentration. IC₅₀ for these fractions were 33, 83 and 82 μg/mL respectively. Similarly, plant extracts showed high ABTS scavenging potential, i.e. Al.FLVF (90.34 ± 0.55), Al.CfF (83.42 ± 0.57), Al.MeF (81.49 ± 0.60) with IC₅₀ of 30, 190 and 70 μg/ml respectively. further, H₂O₂ percent scavenging was highly appraised in Al.FLVF (91.29 ± 0.53, IC₅₀ 75), Al.SPF (85.35 ± 0.61, IC₅₀ 70) and Al.EaF (83.48 ± 0.67, IC₅₀ 270 μg/mL). All fractions exhibited concentration dependent AChE inhibitory activity as; Al.FLVF, 88.31 ± 0.57 (IC₅₀ 70 μg/mL), Al.SPF, 84.36 ± 0.64 (IC₅₀ 90 μg/mL), Al.MeF, 78.65 ± 0.70 (IC₅₀ 280 μg/mL), Al.EaF, 77.45 ± 0.46 (IC₅₀ 270 μg/mL) and Al.WtF 72.44 ± 0.58 (IC₅₀ 263 μg/mL) at 1 mg/mL. Likewise the percent BChE inhibitory activity was most obvious in Al.FLVF 85.46 ± 0.62 (IC₅₀ 100 μg/mL), Al.CfF 83.49 ± 0.46 (IC₅₀ 160 μg/mL), Al.MeF 82.68 ± 0.60 (IC₅₀ 220 μg/mL) and Al.SPF 80.37 ± 0.54 (IC₅₀ 120 μg/mL).

Conclusions

These results stipulate that A. laciniata is enriched with phenolic and flavonoid contents that possess significant antioxidant and anticholinestrase effects. This provide pharmacological basis for the presence of compounds that may be effective in Alzheimer’s and other neurological disorders.

Neuroprotective effect of 6-paradol in focal cerebral ischemia involves the attenuation of neuroinflammatory responses in activated microglia

Paradols are non-pungent and biotransformed metabolites of shogaols and reduce inflammatory responses as well as oxidative stress as shogaols. Recently, shogaol has been noted to possess therapeutic potential against several central nervous system (CNS) disorders, including cerebral ischemia, by reducing neuroinflammation in microglia. Therefore, paradol could be used to improve neuroinflammation-associated CNS disorders. Here, we synthesized paradol derivatives (2- to 10-paradols). Through the initial screening for anti-inflammatory activities using lipopolysaccharide (LPS)-stimulated BV2 microglia, 6-paradol was chosen to be the most effective compound without cytotoxicity. Pretreatment with 6-paradol reduced neuroinflammatory responses in LPS-stimulated BV2 microglia by a concentration-dependent manner, which includes reduced NO production by inhibiting iNOS upregulation and lowered secretion of proinflammatory cytokines (IL-6 and TNF-α). To pursue whether the beneficial in vitro effects of 6-paradol leads towards in vivo therapeutic effects on transient focal cerebral ischemia characterized by neuroinflammation, we employed middle cerebral artery occlusion (MCAO)/reperfusion (M/R). Administration of 6-paradol immediately after reperfusion significantly reduced brain damage in M/R-challenged mice as assessed by brain infarction, neurological deficit, and neural cell survival and death. Furthermore, as observed in cultured microglia, 6-paradol administration markedly reduced neuroinflammation in M/R-challenged brains by attenuating microglial activation and reducing the number of cells expressing iNOS and TNF-α, both of which are known to be produced in microglia following M/R challenge. Collectively, this study provides evidences that 6-paradol effectively protects brain after cerebral ischemia, likely by attenuating neuroinflammation in microglia, suggesting it as a potential therapeutic agent to treat cerebral ischemia.

Chemical profiling and quantification of Gua-Lou-Gui-Zhi decoction by high performance liquid chromatography/quadrupole-time-of-flight mass spectrometry and ultra-performance liquid chromatography/triple quadrupole mass spectrometry

Gua-Lou-Gui-Zhi decoction (GLGZD) is a classical formula of traditional Chinese medicine, which has been commonly used to treat dysfunction after stroke, epilepsy and spinal cord injury. In this study, a systematic method was established for chemical profiling and quantification analysis of the major constituents in GLGZD. For qualitative analysis, a method of high performance liquid chromatography/quadrupole time-of-flight mass spectrometry (Q-TOF MS) was developed. 106 compounds, including monoterpene glycosides, galloyl glucoses, phenolic acids, flavonoids, gingerols and triterpene saponins were identified or tentatively presumed by comparison with reference standards or literature data. According to the qualitative results, a new quantitative analysis method of ultra-performance liquid chromatography/triple quadrupole mass spectrometry (QqQ-MS) was established. 24 representative compounds were simultaneously detected in 10 batches of GLGZD samples in 7.5 min. The calibration curves for all analytes showed good linearity (r>0.9959) within the test ranges. The LODs and the LOQs were less than 30.6 and 70.9 ng/mL, respectively. The RSDs of intra- and inter-day precision, repeatability and stability were below 3.64%, 4.85%, 4.84% and 3.87%, respectively. The overall recoveries ranged from 94.94% to 103.66%, with the RSDs within 5.12%. This study established a high sensitive and efficient method for the integrating quality control, including identification and quantification of Chinese medicinal preparation.

Ginger extracts influence the expression of IL-27 and IL-33 in the central nervous system in experimental autoimmune encephalomyelitis and ameliorates the clinical symptoms of disease

The immunomodulatory effects of the IL-27 and IL-33 and the anti-inflammatory effects of ginger have been reported in some studies. The aim was to evaluate the effects of the ginger extract on the expression of IL-27 and IL-33 in a model of experimental autoimmune encephalomyelitis (EAE). In PBS-treated EAE mice the expression of IL-27 P28 was significantly lower whereas the expression of IL-33 was significantly higher than unimmunized control mice. In 200 and 300 mg/kg ginger-treated EAE groups the expression of IL-27 P28 and IL-27 EBI3 was significantly higher whereas the expression of IL-33 was significantly lower than PBS-treated EAE mice. The EAE clinical symptoms and the pathological scores were significantly lower in ginger-treated EAE groups. These results showed that the ginger extract modulates the expression of the IL-27 and IL-33 in the spinal cord of EAE mice and ameliorates the clinical symptoms of disease.

Ginger components as new leads for the design and development of novel multi-targeted anti-Alzheimer's drugs: a computational investigation

Ginger (Zingiber officinale), despite being a common dietary adjunct that contributes to the taste and flavor of foods, is well known to contain a number of potentially bioactive phytochemicals having valuable medicinal properties. Although recent studies have emphasized their benefits in Alzheimer's disease, limited information is available on the possible mechanism by which it renders anti-Alzheimer activity. Therefore, the present study seeks to employ molecular docking studies to investigate the binding interactions between active ginger components and various anti-Alzheimer drug targets. Lamarckian genetic algorithm methodology was employed for docking of 12 ligands with 13 different target proteins using AutoDock 4.2 program. Docking protocol was validated by re-docking of all native co-crystallized ligands into their original binding cavities exhibiting a strong correlation coefficient value (r (2)=0.931) between experimentally reported and docking predicted activities. This value suggests that the approach could be a promising computational tool to aid optimization of lead compounds obtained from ginger. Analysis of binding energy, predicted inhibition constant, and hydrophobic/hydrophilic interactions of ligands with target receptors revealed acetylcholinesterase as most promising, while c-Jun N-terminal kinase was recognized as the least favorable anti-Alzheimer's drug target. Common structural requirements include hydrogen bond donor/acceptor area, hydrophobic domain, carbon spacer, and distal hydrophobic domain flanked by hydrogen bond donor/acceptor moieties. In addition, drug-likeness score and molecular properties responsible for a good pharmacokinetic profile were calculated by Osiris property explorer and Molinspiration online toolkit, respectively. None of the compounds violated Lipinski's rule of five, making them potentially promising drug candidates for the treatment of Alzheimer's disease.

6-Shogaol, an active constituent of ginger, attenuates neuroinflammation and cognitive deficits in animal models of dementia

Recently, increased attention has been directed towards medicinal extracts as potential new drug candidates for dementia. Ginger has long been used as an important ingredient in cooking and traditional herbal medicine. In particular, ginger has been known to have disease-modifying effects in Alzheimer's disease (AD). However, there is no evidence of which constituents of ginger exhibit therapeutic effects against AD. A growing number of experimental studies suggest that 6-shogaol, a bioactive component of ginger, may play an important role as a memory-enhancing and anti-oxidant agent against neurological diseases. 6-Shogaol has also recently been shown to have anti-neuroinflammatory effects in lipopolysaccharide (LPS)-treated astrocytes and animal models of Parkinson's disease, LPS-induced inflammation and transient global ischemia. However, it is still unknown whether 6-shogaol has anti-inflammatory effects against oligomeric forms of the Aβ (AβO) in animal brains. Furthermore, the effects of 6-shogaol against memory impairment in dementia models are also yet to be investigated. In this study, we found that administration of 6-shogaol significantly reduced microgliosis and astrogliosis in intrahippocampal AβO-injected mice, ameliorated AβO and scopolamine-induced memory impairment, and elevated NGF levels and pre- and post-synaptic marker in the hippocampus. All these results suggest that 6-shogaol may play a role in inhibiting glial cell activation and reducing memory impairment in animal models of dementia.

Daphnetin attenuates microglial activation and proinflammatory factor production via multiple signaling pathways

Daphnetin, a natural coumarin derivative, is known to display anti-inflammatory properties and has been used to treat inflammatory diseases. A novel finding suggested that daphnetin might have a neuroprotective effect in stressed mice, leading us to explore its role in the microglial inflammatory response, as well as its underlying mechanism of action. We found that the production of pro-inflammatory mediators, including interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), induced by lipopolysaccharide (LPS) or β-amyloid (Aβ) was significantly suppressed by daphnetin in a dose-dependent manner in BV2 microglia. Also, daphnetin inhibited LPS-induced nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression and NO formation by microglia. Mechanistically, daphnetin blunted the transcriptional activity of nuclear factor-kappa B (NF-κB), which was associated with the down-regulation of the phosphorylation and nuclear translocation of RelA/p65. Inhibitors of kappa B (IκB) phosphorylation and degradation were also affected by daphnetin, which was likely due to the reduced activation of IκB kinase (IKK). Additionally, LPS-induced activation of mitogen-activated protein kinases (MAPKs), such as extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 MAPK, were, to a varying extent, altered by daphnetin. Finally, daphnetin blocked phosphatidylinositol-3 kinase (PI-3K)/protein kinase B (Akt) signaling in LPS-activated microglia, which appeared to at least partially account for the reduction in NF-κB transcriptional activity. Thus, daphnetin inhibited microglial activation and proinflammatory responses by modulating a series of intracellular signaling pathways, including IKK/IκB, MAPKs and PI-3K/Akt.

Herbal medicines for ischemic stroke: combating inflammation as therapeutic targets

Stroke is a debilitating disease for which limited therapeutic approaches are available currently. Thus, there is an urgent need for developing novel therapies for stroke. Astrocytes, endothelial cells and pericytes constitute a neurovascular network for metabolic requirement of neurons. During ischemic stroke, these cells contribute to post-ischemic inflammation at multiple stages of ischemic cascades. Upon ischemia onset, activated resident microglia and astrocytes, and infiltrated immune cells release multiple inflammation factors including cytokines, chemokines, enzymes, free radicals and other small molecules, not only inducing brain damage but affecting brain repair. Recent progress indicates that anti-inflammation is an important therapeutic strategy for stroke. Given a long history with direct experience in the treatment of human subjects, Traditional Chinese Medicine and its related natural compounds are recognized as important sources for drug discovery. Last decade, a great progress has been made to identify active compounds from herbal medicines with the properties of modulating post-ischemic inflammation for neuroprotection. Herein, we discuss the inflammatory pathway in early stage and secondary response to injured tissues after stroke from initial artery occlusion to brain repair, and review the active ingredients from natural products with anti-inflammation and neuroprotection effects as therapeutic agents for ischemic stroke. Further studies on the post-ischemic inflammatory mechanisms and corresponding drug candidates from herbal medicine may lead to the development of novel therapeutic strategies in stroke treatment.

Standardized ethyl acetate fraction from the roots of Brassica rapa attenuates the experimental arthritis by down regulating inflammatory responses and inhibiting NF-κB activation

This study was undertaken to investigate the anti-arthritic potential of a standardized ethyl acetate fraction from the roots of Brassica rapa (EABR) and to explore the molecular mechanisms in adjuvant-induced arthritic rats and macrophages. In AIA-induced arthritic rats, EABR significantly reduced paw swelling, an arthritic index, serum rheumatoid factor, and tissue expression ratio of RANKL/OPG versus vehicle-administered group. This was found to be well correlated with significant suppressions in productions of PGE2, NO, and pro-inflammatory cytokines and in activations of NF-κB in AIA-induced paw tissues and LPS-induced macrophages. EABR attenuated NF-κB activation by reducing the nuclear translocation and phosphorylation of the p65 NF-κB, which were accompanied by parallel reductions in the degradation and phosphorylation of IκBα after blocking the phosphorylation mediated IKK activation. The findings suggest EABR exerts its anti-arthritic and anti-inflammatory properties via NF-κB inactivation in vitro and in vivo, and that EABR is a potential therapeutic for the treatment of arthritis and inflammation-associated disorders.

Neuroprotective effects of Gua Lou Gui Zhi decoction against glutamate-induced apoptosis in BV-2 cells

Gua Lou Gui Zhi decoction (GLGZD), a traditional Chinese medicine consisting of different herbal medicines, has been used for centuries in the treatment of muscular spasticity following stroke, epilepsy or spinal cord injury. However, the precise mechanisms involved remain poorly understood. In the present study, we investigated the neuroprotective effects of GLGZD on glutamate-induced apoptosis in cultured BV-2 cells, as well as the underlying mechanisms. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was applied to assess the viability of the cells. An Annexin V/propidium iodide (PI) assay was utilized to analyze cellular apoptosis. Mitochondrial membrane potential (MMP) was evaluated by flow cytometry and laser scanning confocal microscopy. The gene and protein expression of the apoptosis-related genes, Bcl-2 and Bax, was analyzed by RT-PCR and western blot analysis, respectively. Furthermore, the expression of cleaved caspase-3 protein was detected by immunofluorescence. Glutamate treatment induced the loss of BV-2 cell viability, which was associated with an increase in the apoptotic rate, as well as an increase in the Bax/Bcl-2 ratio and the extracellular levels of cleaved caspase-3. Treatment with GLGZD significantly reversed these phenotypes, with its maximum protective effects observed at the concentration of 1,000 µg/ml. These results indicate that GLGZD protects BV-2 cells from glutamate-induced cytotoxicity. These protective effects may be ascribed to its anti-apoptotic activities, in part, associated with the decrease in the Bax/Bcl-2 ratio and caspase-3 expression, as well as with the stability of high mitochondrial membrane potential.

Anti-neuroinflammatory capacity of fresh ginger is attributed mainly to 10-gingerol

Despite the anti-neuroinflammatory capacity of ginger, the corresponding active constituents are unclear. This study analyzed the composition of fresh ginger ethanolic extract by using LC-MS. Inhibitory activities of fresh ginger extract and seven gingerol-related compounds on the neuro-inflammation were also evaluated by using a lipopolysaccharide (LPS)-activated BV2 microglia culture model. Except for zingerone and 6-gingerol, other gingerols and shogaols at a concentration of 20 μM inhibited the production of nitric oxide, IL-1β, IL-6 and TNF-α as well as their mRNA levels in LPS-activated BV2 microglia. Blocking NF-κB activation was the underlying mechanism responsible for inhibiting the proinflammatory gene expression. Increasing the alkyl chain length enhanced the anti-neuroinflammatory capacity of gingerols yet, conversely, attenuated those of shogaols. 6-Gingerol was the most abundant compound in the fresh ginger extract, followed by 10-gingerol. Furthermore, fresh ginger extract exhibited a significant anti-neuroinflammatory capacity, which was largely owing to 10-gingerol, but not 6-gingerol.

Recent advances in psychoneuroimmunology relevant to schizophrenia therapeutics

PURPOSE OF REVIEW

Immunological understanding of neurological and cognitive alterations of schizophrenia has made a significant breakthrough in unfolding the pathophysiological mechanisms of schizophrenia, at least in a group of patients. Such psychoneuroimmunological aberrations essentially argue for an alternative treatment approach based on immunomodulation in schizophrenia.

RECENT FINDINGS

Recent findings in schizophrenia have shown exaggerated immuno-inflammatory responses due to persistent systemic inflammation and neuroinflammation involving microglia activation. The existing antipsychotic drugs have shown substantial benefits in the control of positive symptoms, but they have not demonstrated adequate immuno-dampening effects specifically and effectively. However, a group of emerging nonsteroidal as well as other anti-inflammatory drugs currently being used as an adjunct therapy seem to exhibit increased target specificity and effectiveness in reducing symptom severity to some extent.

SUMMARY

The anti-inflammatory drugs that have been shown to reduce the levels of pro-inflammatory mediators and inhibit microglia activation have paved the way for better outcomes of schizophrenia treatment. However, many of the currently tested anti-inflammatory drugs often lack methodological robustness. The identification of novel target(s) that will integrate the processes evoked by various risk determinants into a common signalling pathway is urgently required, and this may take immunomodulation into a new therapeutic domain in schizophrenia.

6-Shogaol, an active compound of ginger, protects dopaminergic neurons in Parkinson's disease models via anti-neuroinflammation

AIM

6-Shogaol [1-(4-hydroxy-methoxyphenyl)-4-decen-one], a pungent compound isolated from ginger, has shown various neurobiological and anti-inflammatory effects. The aim of this study was to examine the effects of 6-shogaol on neuroinflammatory-induced damage of dopaminergic (DA) neurons in Parkinson's disease (PD) models.

METHODS

Cultured rat mesencephalic cells were treated with 6-shogaol (0.001 and 0.01 μmol/L) for 1 h, then with MPP(+)(10 μmol/L) for another 23 h. The levels of TNF-α and NO in medium were analyzed spectrophotometrically. C57/BL mice were administered 6-shogaol (10 mg·kg(-1)·d(-1), po) for 3 d, and then MPTP (30 mg/kg, ip) for 5 d. Seven days after the last MPTP injection, behavioral testings were performed. The levels of tyrosine hydroxylase (TH) and macrophage antigen (MAC)-1 were determined with immunohistochemistry. The expression of iNOS and COX-2 was measured using RT PCR.

RESULTS

In MPP(+)-treated rat mesencephalic cultures, 6-shogaol significantly increased the number of TH-IR neurons and suppressed TNF-α and NO levels. In C57/BL mice, treatment with 6-shogaol reversed MPTP-induced changes in motor coordination and bradykinesia. Furthermore, 6-shogaol reversed MPTP-induced reductions in TH-positive cell number in the substantia nigra pars compacta (SNpc) and TH-IR fiber intensity in stratum (ST). Moreover, 6-shogaol significantly inhibited the MPTP-induced microglial activation and increases in the levels of TNF-α, NO, iNOS, and COX-2 in both SNpc and ST.

CONCLUSION

6-Shogaol exerts neuroprotective effects on DA neurons in in vitro and in vivo PD models.

6-Shogaol inhibits breast and colon cancer cell proliferation through activation of peroxisomal proliferator activated receptor γ (PPARγ)

6-Shogaol has been shown to possess many antitumor properties including inhibition of cancer cell growth, inhibition of cancer metastasis, induction of apoptosis in cancer cells and induction of cancer cell differentiation. Despite its prominent antitumor effects, the direct molecular target of 6-shogaol has remained elusive. To identify the direct targets of 6-shogaol, a comprehensive antitumor profile of 6-shogaol (NSC752389) was tested in the NCI-60 cell line in an in vitro screen. The results show that 6-shogaol is COMPARE negative suggesting that it functions via a mechanism of action distinct from existing classes of therapeutic agents. Further analysis using microarray gene profiling and Connectivity Map analysis showed that MCF-7 cells treated with 6-shogaol display gene expression signatures characteristic of peroxisome proliferator activated receptor γ (PPARγ) agonists, suggesting that 6-shogaol may activate the PPARγ signaling pathway for its antitumor effects. Indeed, treatment of MCF-7 and HT29 cells with 6-shogaol induced PPARγ transcriptional activity, suppressed NFκB activity, and induced apoptosis in breast and colon cancer cells in a PPARγ-dependent manner. Furthermore, 6-shogaol is capable of binding to PPARγ with a binding affinity comparable to 15-delta prostaglandin J2, a natural ligand for PPARγ. Together, our findings suggest that the antitumor effects of 6-shogaol are mediated through activation of PPARγ and imply that activation of PPARγ might be beneficial for breast and colon cancer treatment.

Epithelial transient receptor potential ankyrin 1 (TRPA1)-dependent adrenomedullin upregulates blood flow in rat small intestine

The functional roles of transient receptor potential (TRP) channels in the gastrointestinal tract have garnered considerable attention in recent years. We previously reported that daikenchuto (TU-100), a traditional Japanese herbal medicine, increased intestinal blood flow (IBF) via adrenomedullin (ADM) release from intestinal epithelial (IE) cells (Kono T et al. J Crohns Colitis 4: 161-170, 2010). TU-100 contains multiple TRP activators. In the present study, therefore, we examined the involvement of TRP channels in the ADM-mediated vasodilatatory effect of TU-100. Rats were treated intraduodenally with the TRP vanilloid type 1 (TRPV1) agonist capsaicin (CAP), the TRP ankyrin 1 (TRPA1) agonist allyl-isothiocyanate (AITC), or TU-100, and jejunum IBF was evaluated using laser-Doppler blood flowmetry. All three compounds resulted in vasodilatation, and the vasodilatory effect of TU-100 was abolished by a TRPA1 antagonist but not by a TRPV1 antagonist. Vasodilatation induced by AITC and TU-100 was abrogated by anti-ADM antibody treatment. RT-PCR and flow cytometry revealed that an IEC-6 cell line originated from the small intestine and purified IE cells expressed ADM and TRPA1 but not TRPV1. AITC increased ADM release in IEC cells remarkably, while CAP had no effect. TU-100 and its ingredient 6-shogaol (6SG) increased ADM release dose-dependently, and the effects were abrogated by a TRPA1 antagonist. 6SG showed similar TRPA1-dependent vasodilatation in vivo. These results indicate that TRPA1 in IE cells may play an important role in controlling bowel microcirculation via ADM release. Epithelial TRPA1 appears to be a promising target for the development of novel strategies for the treatment of various gastrointestinal disorders.

Molecular mechanism underlying anti-inflammatory and anti-allergic activities of phytochemicals: an update

The resort worldwide to edible medicinal plants for medical care has increased significantly during the last few years. Currently, there is a renewed interest in the search for new phytochemicals that could be developed as useful anti-inflammatory and anti-allergic agents to reduce the risk of many diseases. The activation of nuclear transcription factor-kappa B (NF-κB) has now been linked to a variety of inflammatory diseases, while data from numerous studies underline the importance of phytochemicals in inhibiting the pathway that activates this transcription factor. Moreover, the incidence of type I allergic disorders has been increasing worldwide, particularly, the hypersensitivity to food. Thus, a good number of plant products with anti-inflammatory and anti-allergic activity have been documented, but very few of these compounds have reached clinical use and there is scant scientific evidence that could explain their mode of action. Therefore, this paper intends to review the most salient recent reports on the anti-inflammatory and anti-allergic properties of phytochemicals and the molecular mechanisms underlying these properties.