6-Shogaol suppressed lipopolysaccharide-induced up-expression of iNOS and COX-2 in murine macrophages

Glutathione conjugation attenuates biological activities of 6-dehydroshogaol from ginger

6-Dehydroshogaol (6-DHSG) is a bioactive α,β-unsaturated carbonyl compound isolated from fresh ginger with anti-inflammatory and phase II enzyme inducing activities. Here we describe the glutathione (GSH)-dependent metabolism and the effect of this metabolic transformation on the biological activities of 6-DHSG. Compared with other ginger compounds, such as 6-gingerol and 6-shogaol, 6-DHSG showed the most potent anti-inflammatory effect in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. The biological activities of 6-DHSG were attenuated by sulfhydryl antioxidants such as glutathione (GSH) or N-acetyl cysteine (NAC), but not ascorbic acid (ASC). 6-DHSG was metabolised by GSH to form a GSH conjugate (GS-6-DHSG) in RAW 264.7 cells, via a potential mechanism involving the catalytic activity of glutathione-S-transferase (GST). GS-6-DHSG showed reduced biological activities compared with 6-DHSG in multiple biological assays. Together, these results indicate that GSH conjugation attenuates the biological activities of 6-DHSG and other α,β-unsaturated carbonyl compounds.

Dried Ginger (Zingiber officinalis) Inhibits Inflammation in a Lipopolysaccharide-Induced Mouse Model

Objectives. Ginger rhizomes have a long history of human use, especially with regards to their anti-inflammatory properties. However, the mechanisms by which ginger acts on lipopolysaccharide-(LPS-)induced inflammation have not yet been identified. We investigated the anti-inflammatory effects of dried Zingiber officinalis (DZO) on LPS-induced hepatic injury. Methods. ICR mice were given a DZO water extract (100, 1000 mg/kg) orally for three consecutive days. On the third day, they were administered by LPS intraperitoneally. To investigate the anti-inflammatory effects of DZO, histological, cytokine expression, and protein factor analyses were performed. Results. Oral administration of DZO significantly reduced pathological changes in the liver and proinflammatory cytokines including interferon-(IFN-)γ and interleukin-(IL-)6 in the serum. In addition, DZO inhibited LPS-induced NF-κB activation by preventing degradation of the IκB-α, as well as the phosphorylation of ERK1/2, SAPK/JNK, and p38 MAPKs. These were associated with a decrease in the expression of inducible nitric oxide synthase (iNOS) and cyclooxyenase-2 (COX-2). Conclusions. Our data provide evidence for the hepatoprotective mechanisms of DZO as an anti-inflammatory effect. Furthermore, use of DZO to treat could provide therapeutic benefits in clinical settings.

[6]-Shogaol inhibits the production of proinflammatory cytokines via regulation of NF-κB and phosphorylation of JNK in HMC-1 cells

[6]-Shogaol is a major bioactive component of Zingiber officinale. Although [6]-shogaol has a number of pharmacological activities including antipyretic, analgesic, antitussive and anti-inflammatory effects, the specific mechanisms of its anti-allergic effects have not been studied. In this study, we present the effects of [6]-shogaol on mast cell-mediated allergic reactions in vivo and in vitro. Sprague-Dawley rats received intradermal injections of anti-DNP IgE was injected into dorsal skin sites. After 48 h, [6]-shogaol was administered orally 1 h prior to challenge with DNP-HSA in saline containing 4% Evans blue through the dorsal vein of the penis. In addition, rat peritoneal mast cells (RPMCs) were cultured and purified to investigate histamine release. In vitro, we evaluated the regulatory effects of [6]-shogaol on the level of inflammatory mediators in phorbol 12-myristate 13-acetate plus calcium ionomycin A23187-stimulated human mast cells (HMC-1). [6]-Shogaol reduced the passive cutaneous anaphylaxis reaction compared to the control group, and histamine release decreased significantly following the treatment of RPMCs with [6]-shogaol. In HMC-1 cells, [6]-shogaol inhibited the production of TNF-α, IL-6 and IL-8, as well as the activation of nuclear factor-κB (NF-κB) and phosphorylation of JNK in compound 48/80-induced HMC-1 cells. [6]-shogaol inhibited mast cell-mediated allergic reactions by inhibiting the release of histamine and the production of proinflammatory cytokines with the involvement of regulation of NF-κB and phosphorylation of JNK.

Characterization of thiol-conjugated metabolites of ginger components shogaols in mouse and human urine and modulation of the glutathione levels in cancer cells by [6]-shogaol

SCOPE

Shogaols, a series of major constituents in dried ginger with the most abundant being [6]-, [8]-, and [10]-shogaols, show much higher anticancer potencies than gingerols. Previously, we reported the mercapturic acid pathway as a major metabolic route for [6]-shogaol in mice. However, it is still unclear how the side chain length affects the metabolism of shogaols and how shogaols are metabolized in humans.

METHODS AND RESULTS

We first investigate the metabolism of [10]-shogaol in mouse urine, and then investigate the biotransformation of shogaols in human urine. Our results show that eight major thiol-conjugated metabolites of [10]-shogaol were detected in mouse urine, while six major thiol-conjugated metabolites of [6]-shogaol, two thiol-conjugated metabolites of [8]-shogaol, and two thiol-conjugated metabolites of [10]-shogaol were detected in urine collected from human after drinking ginger tea, using LC/ESI-MS/MS. Our results clearly indicate the mercapturic acid pathway is a major metabolic route for [10]-shogaol in mice and for shogaols in human. Furthermore, we also investigated the regulation of glutathione (GSH) by [6]-shogaol in human colon cancer cells HCT-116. Our results show [6]-shogaol, after initially depleting glutathione levels, can subsequently restore and increase GSH levels over time.

CONCLUSION

Shogaols are metabolized extensively in mouse and human to form thiol-conjugated metabolites and GSH might play an important role in the cancer-preventive activity of ginger.

6-Shogaol Protects against Oxidized LDL-Induced Endothelial Injruries by Inhibiting Oxidized LDL-Evoked LOX-1 Signaling

Endothelial dysfunction and oxLDL are believed to be early and critical events in atherogenesis. 6-Shogaol is the major bioactive compound present in Zingiber officinale and possesses the anti-atherosclerotic effect. However, the mechanisms remain poorly understood. The goal of this study was to investigate the effects of 6-shogaol on oxLDL-induced Human umbilical vein endothelial cells (HUVECs) injuries and its possible molecular mechanisms. Hence, we studied the effects of 6-shogaol on cell apoptosis, cellular reactive oxygen species (ROS), NF-κB activation, Bcl-2 expression, and caspase -3, -8, -9 activities. In addition, E-selectin, MCP-1, and ICAM-1 were determined by ELISA. Our study show that oxLDL increased LOX-1 expression, ROS levels, NF-κB, caspases-9 and -3 activation and decreased Bcl-2 expression in HUVECs. These alterations were attenuated by 6-shogaol. Cotreatment with 6-shogaol and siRNA of LOX-1 synergistically reduced oxLDL-induced caspases -9, -3 activities and cell apoptosis. Overexpression of LOX-1 attenuated the protection by 6-shogaol and suppressed the effects of 6-shogaol on oxLDL-induced oxidative stress. In addition, oxLDL enhanced the activation of NF-κB and expression of adhesion molecules. Pretreatment with 6-shogaol, however, exerted significant cytoprotective effects in all events. Our data indicate that 6-shogaol might be a potential natural antiapoptotic agent for the treatment of atherosclerosis.

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.

In vitro antioxidant and anti-inflammatory activities of 1-dehydro-[6]-gingerdione, 6-shogaol, 6-dehydroshogaol and hexahydrocurcumin

Hexahydrocurcumin, 1-dehydro-[6]-gingerdione, 6-dehydroshogaol and 6-shogaol were evaluated for their antioxidant and anti-inflammatory activities in the present study. The relative antioxidant potencies of ginger compounds decreased in similar order of 1-dehydro-[6]-gingerdione, hexahydrocurcumin>6-shogaol>6-dehydroshogaol in both 1,1-diphenyl-2-picyrlhydrazyl (DPPH) radical-scavenging and trolox equivalent antioxidant capacity (TEAC) assays. All tested compounds could attenuate lipopolysaccharide (LPS)-elicited increase of prostaglandin E2 (PGE(2)) in murine macrophages (RAW 264.7) in a concentration-dependent manner but hexahydrocurcumin of 7μM and 6-shogaol of 7μM. The strongest inhibitory effect was observed for 6-dehydroshogaol and 6-shogaol at 14μM with the inhibition of 53.3% and 48.9%, respectively. Furthermore, both 6-dehydroshogaol and 1-dehydro-[6]-gingerdione significantly suppressed the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins in a concentration-dependent fashion. These results contribute to our theoretical understanding of the potential beneficial effects of consuming ginger as a food and/or dietary supplement.

Identification of phase II metabolites of thiol-conjugated [6]-shogaol in mouse urine using high-performance liquid chromatography tandem mass spectrometry

Ginger is frequently consumed as a spice and has numerous medicinal properties. Extensive research has characterized the anti-inflammatory, antioxidant, and antitumor activities of ginger. Previously, we reported the mercapturic acid pathway as a major metabolic route of [6]-shogaol in mice and the thiol conjugates of [6]-shogaol existed in the glucuronidated and sulfated forms in mouse urine. However, their structures are still unknown. In the present study, we further investigated the phase II metabolism of thiol-conjugated [6]-shogaol in mouse urine, in which we identified sixteen phase II metabolites of thiol-conjugated [6]-shogaol: 5-cysteinyl-[6]-shogaol glucuronide (9), 5-N-acetylcysteinyl-[6]-shogaol glucuronide (10), 5-cysteinylglycinyl-[6]-shogaol glucuronide (11), 5-methylthio-[6]-shogaol glucuronide (12), 5-cysteinyl-M6 glucuronide (13 and 14), 5-cysteinyl-M6 sulfate (15 and 16), 5-N-acetylcysteinyl-M6 glucuronide (17 and 18), 5-cysteinylglycinyl-M6 glucuronide (19 and 20), 5-cysteinylglycinyl-M6 sulfate (21 and 22), and 5-methylthio-M6 glucuronide (23 and 24) using liquid chromatography/electrospray ionization tandem mass spectrometry. The structures of these metabolites were confirmed by analyzing their MS(n) (n=1-4) spectra as well as comparing with the tandem mass spectra of authentic standards. To the best of our knowledge, this is the first report involving identification of phase II urinary metabolites of [6]-shogaol in mice.

1-Dehydro-[10]-gingerdione from ginger inhibits IKKβ activity for NF-κB activation and suppresses NF-κB-regulated expression of inflammatory genes

BACKGROUND AND PURPOSE

Pungent constituents of ginger (Zingiber officinale) have beneficial effects on inflammatory pain and arthritic swelling. However, the molecular basis for these pharmacological properties is only partially understood. Here, we investigated the molecular target of 1-dehydro-[10]-gingerdione (D10G), one of the pungent constituents of ginger, that mediates its suppression of NF-κB-regulated expression of inflammatory genes linked to toll-like receptor (TLR)-mediated innate immunity.

EXPERIMENTAL APPROACH

RAW 264.7 macrophages or primary macrophages-derived from bone marrows of C57BL/6 or C3H/HeJ mice were stimulated with the TLR4 agonist LPS in the presence of D10G. Catalytic activity of inhibitory κB (IκB) kinase β (IKKβ) was determined by a kinase assay and immunoblot analysis, and the expression of inflammatory genes by RT-PCR analysis and a promoter-dependent reporter assay.

KEY RESULTS

D10G directly inhibited the catalytic activity of cell-free IKKβ. Moreover, D10G irreversibly inhibited cytoplasmic IKKβ-catalysed IκBα phosphorylation in macrophages activated by TLR agonists or TNF-α, and also IKKβ vector-elicited NF-κB transcriptional activity in these cells. These effects of D10G were abolished by substitution of the Cys(179) with Ala in the activation loop of IKKβ, indicating a direct interacting site of D10G. This mechanism was shown to mediate D10G-induced disruption of NF-κB activation in LPS-stimulated macrophages and the suppression of NF-κB-regulated gene expression of inducible NOS, COX-2 and IL-6.

CONCLUSION AND IMPLICATIONS

This study demonstrates that IKKβ is a molecular target of D10G involved in the suppression of NF-κB-regulated gene expression in LPS-activated macrophages; this suggests D10G has therapeutic potential in NF-κB-associated inflammation and autoimmune disorders.

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

Inflammatory processes in the central nervous system play an important role in a number of neurodegenerative diseases mediated by microglial activation, which results in neuronal cell death. Microglia act in immune surveillance and host defense while resting. When activated, they can be deleterious to neurons, even resulting in neurodegeneration. Therefore, the inhibition of microglial activation is considered a useful strategy in searching for neuroprotective agents. In this study, we investigated the effects of 6-shogaol, a pungent agent from Zingiber officinale Roscoe, on microglia activation in BV-2 and primary microglial cell cultures. 6-Shogaol significantly inhibited the release of nitric oxide (NO) and the expression of inducible nitric oxide synthase (iNOS) induced by lipopolysaccharide (LPS). The effect was better than that of 6-gingerol, wogonin, or N-monomethyl-l-arginine, agents previously reported to inhibit nitric oxide. 6-Shogaol exerted its anti-inflammatory effects by inhibiting the production of prostaglandin E(2) (PGE(2)) and proinflammatory cytokines, such as interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), and by downregulating cyclooxygenase-2 (COX-2), p38 mitogen-activated protein kinase (MAPK), and nuclear factor kappa B (NF-κB) expression. In addition, 6-shogaol suppressed the microglial activation induced by LPS both in primary cortical neuron-glia culture and in an in vivo neuroinflammatory model. Moreover, 6-shogaol showed significant neuroprotective effects in vivo in transient global ischemia via the inhibition of microglia. These results suggest that 6-shogaol is an effective therapeutic agent for treating neurodegenerative diseases.

Inhibition of LPS binding to MD-2 co-receptor for suppressing TLR4-mediated expression of inflammatory cytokine by 1-dehydro-10-gingerdione from dietary ginger

Myeloid differentiation protein 2 (MD-2) is a co-receptor of toll-like receptor 4 (TLR4) for innate immunity. Here, we delineated a new mechanism of 1-dehydro-10-gingerdione (1D10G), one of pungent isolates from ginger (Zingiber officinale), in the suppression of lipopolysaccharide (LPS)-induced gene expression of inflammatory cytokines. 1D10G inhibited LPS binding to MD-2 with higher affinity than gingerol and shogaol from dietary ginger. Moreover, 1D10G down-regulated TLR4-mediated expression of nuclear factor-κB (NF-κB) or activating protein 1 (AP1)-target genes such as tumor necrosis factor α (TNF-α) and interleukin-1β, as well as those of interferon (IFN) regulatory factor 3 (IRF3)-target IFN-β gene and IFN-γ inducible protein 10 (IP-10) in LPS-activated macrophages. Taken together, MD-2 is a molecular target in the anti-inflammatory action of 1D10G.

Attenuation of liver pro-inflammatory responses by Zingiber officinale via inhibition of NF-kappa B activation in high-fat diet-fed rats

The aim of this study was to investigate whether treatment with a ginger (Zingiber officinale) extract of high-fat diet (HFD)-fed rats suppresses Nuclear factor-kappa B (NF-κB)-driven hepatic inflammation and to subsequently explore the molecular mechanisms in vitro. Adult male Sprague-Dawley rats were treated with an ethanolic extract of Zingiber officinale (400 mg/kg) along with a HFD for 6 weeks. Hepatic cytokine mRNA levels, cytokine protein levels and NF-κB activation were measured by real-time PCR, Western blot and an NF-κB nuclear translocation assay, respectively. In vitro, cell culture studies were carried out in human hepatocyte (HuH-7) cells by treatment with Zingiber officinale (100 μg/mL) for 24 hr prior to interleukin-1β (IL-1β, 8 ng/mL)-induced inflammation. We showed that Zingiber officinale treatment decreased cytokine gene TNFα and IL-6 expression in HFD-fed rats, which was associated with suppression of NF-κB activation. In vitro, Zingiber officinale treatment decreased NF-κB-target inflammatory gene expression of IL-6, IL-8 and serum amyloid A1 (SAA1), while it suppressed NF-κB activity, IκBα degradation and IκB kinase (IKK) activity. In conclusion, Zingiber officinale suppressed markers of hepatic inflammation in HFD-fed rats, as demonstrated by decreased hepatic cytokine gene expression and decreased NF-κB activation. The study demonstrates that the anti-inflammatory effect of Zingiber officinale occurs at least in part through the NF-κB signalling pathway.

Synbiotic (probiotic and ginger extract) loaded floating beads: a novel therapeutic option in an experimental paradigm of gastric ulcer

OBJECTIVE

This study investigated the use of a bioactive phytochemical, namely ginger extract (GE), for its antioxidant and antiulcer effects, and also for supporting probiotic growth and activity. Use of probiotics is limited in therapy because of their transience and inability to survive the adverse physiological conditions of the gastrointestinal tract. Packaging probiotics in a suitably designed pharmaceutical system with GE may facilitate their establishment in the stomach mucosa.

METHODS

A probiotic (Lactobacillus acidophilus) and GE were simultaneously and individually encapsulated/immobilized in alginate floating beads. The developed system was evaluated for diameter, buoyancy, entrapment, porosity, in-vitro viability/release and pharmacodynamics in a cold restraint stress induced gastric ulcer model in rats.

KEY FINDING

The developed floating beads stayed in the stomach for more than 10 h and both agents were released slowly and over a prolonged period from these beads. Significant and promising results were obtained for the combination (synbiotic) system in terms of ulcer index, mucus secretion, oxidative stress and histopathological parameters, as compared with the individual agents. The developed system could completely revert the damage induced in ulcerated stomachs at physiological (ulcer index and mucus secretion), biochemical (oxidative stress) and histological levels.

CONCLUSION

This study establishes that suitable packaging of GE and Lactobacillus acidophilus together in floating beads can help exploit their prospects as therapeutic curative agents rather than potential preventive agents.

4-Shogaol, an active constituent of dietary ginger, inhibits metastasis of MDA-MB-231 human breast adenocarcinoma cells by decreasing the repression of NF-κB/Snail on RKIP

4-Shogaol is one of the phytoconstituents isolated from dried red ginger, which is commercially available to consumers. Some active constituents from ginger have been found to have anti-inflammatory and antioxidant effects, but studies on 4-shogaol have been relatively rare. This is the first report describing the antimetastasis activities of 4-shogaol and the possible mechanisms. This study determined that 4-shogaol inhibits the migration and invasion of MDA-MB-231 and causes mesenchymal-epithelial transition (MET). In addition, 4-shogaol suppresses the activation of NF-κB and cell migration and invasion induced by TNF-α. Furthermore, 4-shogaol has been shown to inhibit the phosphorylation of IκB and the translocation of NF-κB/Snail in MDA-MB-231. This study shows that RKIP, an inhibitory molecule of IKK, is up-regulated after 4-shogaol treatment and prolongs the inhibitory effects of 4-shogaol. Inhibition of RKIP by shRNA transfection significantly decreases the inhibitory effect of 4-shogaol on the NF-κB/Snail pathway, together with cell migration and invasion, whereas overexpression of Snail suppresses 4-shogaol-mediated metastasis inhibition and E-cadherin upregulation. Finally, the animal model revealed that 4-shogaol effectively inhibits metastasis of MDA-MB-231 in mice. This study demonstrates that 4-shogaol may be a novel anticancer agent for the the treatment of metastasis in breast cancer.

Shogaols at proapoptotic concentrations induce G(2)/M arrest and aberrant mitotic cell death associated with tubulin aggregation

Shogaols have been previously reported to induce cancer cell death via multiple mechanisms, among which one analog 6-shogaol has been reported to cause microtubule damage through specific reaction with sulfhydryl groups in tubulin. In this study, a series of shogaols with different side chain lengths (4-, 6-, 8- and 10-shogaol) was synthesized and evaluated for antiproliferative activity in HCT 116 colon carcinoma and SH-SY5Y neuroblastoma cells. 4- and 6-shogaol were identified as lead compounds possessing the strongest antiproliferative activity. In the soft agar assay, the lead shogaols displayed dose-dependent inhibition on cancer cell colony formation under anchorage-independent conditions. Using HCT 116 as the selected cancer cell line, the molecular events linking shogaols-induced G(2)/M cell cycle arrest to apoptosis characterized by caspase 3 and PARP cleavage were investigated. At sublethal concentrations, the halt at G(2)/M phase was alleviated along time and cells survived. Conversely, proapoptotic concentrations of 4- and 6-shogaol induced irreversible G(2)/M arrest that was at least in part associated with down-regulation of cell cycle checkpoint proteins cdk1, cyclin B and cdc25C, as well as spindle assembly checkpoint proteins mad2, cdc20 and survivin. A dose- and time-dependent accumulation of insoluble tubulin in the insoluble fractions of cell lysates provided evidence that G(2) checkpoint failure led to disruption of microtubule turnover. In summary, our results conclude that shogaols cause apoptosis by inducing aberrant mitosis at least through the attenuation of cell cycle and spindle assembly checkpoint proteins.

Development and evaluation of a gastro-retentive delivery system for improved antiulcer activity of ginger extract (Zingiber officinale)

Aim was to develop and optimize multiunit gastro-retentive floating beads (FBs) intended for localized and prolonged release of ginger for treating gastric ulcers. Protective effect of ginger extract (GE) against ulcer is well documented, but therapeutic use is compromised due to poor bioavailability and physicochemical properties. GE was only slightly soluble (3.19 ± 0.38 mg/ml) in simulated gastric fluid (SGF; pH 1.2). The solubility decreased in water to 0.69 ± 0.03 mg/ml and further by 26% in the presence of calcium carbonate (0.5% w/v). We prepared FBs of GE using calcium carbonate and sodium alginate in different proportions. Beads were evaluated for diameter, buoyancy, entrapment, and porosity. In vitro dissolution showed a Fickian release with a cumulative release of >80% at 24 h. Preclinical evaluation was done in cold-restraint stress induced gastric ulcers, in albino rats, in terms of (i) ulcer index, hemorrhagic streaks (l), mucus content, (ii) oxido-nitrosative stress, and (iii) histopathology. GE loaded FBs (200 mg/kg) were significantly better than free GE and better/equivalent to cimetidine (10 mg/kg). The system was evaluated for therapeutic effect (curative), i.e. after the induction of ulcers. Most of the natural phytochemical or antioxidants show pretreatment effectiveness. We, however, developed and established GE FBs for sustained curative effect.

Preparation of the monomers of gingerols and 6-shogaol by flash high speed counter-current chromatography

The flash high speed counter-current chromatographic (FHSCCC) separation of gingerols and 6-shogaol was performed on a HSCCC instrument equipped with a 1200-ml column (5 mm tubing i.d.) at a flow rate of 25 ml/min. The performance met the FHSCCC feature that the flow rate of mobile phase (ml) is equal to or greater than the square of the diameter of the column tubing (mm). The separation employed the upper phase of stationary phase of the n-hexane-ethyl acetate-methanol-water (3:2:2:3, v/v) as the stationary phase. A stepwise elution was performed by eluting with the lower phase of n-hexane-ethyl acetate-methanol-water (3:2:2:3, v/v) for first 90 min and the lower phase of the n-hexane-ethyl acetate-methanol-water (3:2:6:5, v/v) for the second 90 min. In each separation 5 g of the ethyl acetate extract of rhizomes of ginger was loaded, yielding 1.96 g of 6-gingerol (98.3%), 0.33 g of 8-gingerol (97.8%), 0.64 g of 6-shogaol (98.8%) and 0.57 g of 10-gingerol (98.2%). The separation can be expected to scale up to industrial separation.

Bioactive phytochemicals of leaf essential oils of Cinnamomum osmophloeum prevent lipopolysaccharide/D-galactosamine (LPS/D-GalN)-induced acute hepatitis in mice

The purpose of this study was to investigate the bioactive phytochemicals of leaf essential oils of Cinnamomum osmophloeum on lipopolysaccharide/D-galactosamine (LPS/D-GalN)-induced acute hepatitis. The results revealed that post-treatment with 100 μmol/kg trans-cinnamaldehyde, (-)-aromadendrene, T-cadinol, or α-cadinol significantly decreased the aspartate aminotransferase (AST), alanine aminotransferase (ALT), tumor necrosis factor-α (TNF-α), and interleukin 6 (IL-6) levels in serum. Moreover, both T-cadinol and α-cadinol treatments decreased the expressions of cleaved caspase-3 and cleaved poly-ADP ribose polymerase (PARP) in the liver tissues when compared with the LPS/D-GalN group. Liver histopathology also showed that silymarin, trans-cinnamaldehyde, (-)-aromadendrene, T-cadinol, or α-cadinol significantly reduced the incidence of liver lesions induced by LPS/D-GalN. These results suggest that the above phytochemicals exhibit potent hepatoprotection against LPS/D-GalN-induced liver damage in mice, and their hepatoprotective effects may be due to the modulation of anti-inflammatory activities.

Ginger suppresses phthalate ester-induced airway remodeling

This study has two novel findings: it is not only the first to demonstrate inflammatory cytokines, which are produced by the bronchial epithelium after exposure to phthalate esters and contribute to airway remodeling by increasing human bronchial smooth muscle cells (BSMC) migration and proliferation, but it is also the first to reveal that ginger reverses phthalate ester-mediated airway remodeling. Human bronchial epithelial cell lines BEAS-2B and HBE135-E6E7 (HBE) were treated with butylbenzyl phthalate (BBP), bis(2-ethylhexyl) phthalate (BEHP), dibutyl phthalate (DBP), and diethyl phthalate (DEP), and the conditioned medium (CM) was harvested and then added to BSMC. Cultures of BSMC with BBP-, BEHP-, DBP-, and DEP-BEAS-2B-CM and DEP-HBE-CM increased BSMC proliferation and migration, which are major features in asthma remodeling. Exposure of BEAS-2B and HBE to DBP caused epithelial cells to produce inflammatory cytokines IL-8 and RANTES, which subsequently induced BSMC proliferation and migration. Depleting both IL-8 and RANTES completely reversed the effect of DBP-BEAS-2B-CM and DBP-HBE-CM-mediated BSMC proliferation and migration, suggesting this effect is a synergistic influence of IL-8 and RANTES. Moreover, [6]-shogaol, [6]-gingerol, [8]-gingerol, and [10]-gingerol, which are major bioactive compounds present in Zingiber officinale , suppress phthalate ester-mediated airway remodeling. This study suggests that ginger is capable of preventing phthalate ester-associated asthma.

Ginger (Zingiber officinale Roscoe) elicits antinociceptive properties and potentiates morphine-induced analgesia in the rat radiant heat tail-flick test

Ginger (Zingiber officinale Roscoe), a well-known spice plant, has been used traditionally in the treatment of a wide variety of ailments. It has been shown that ginger is a calcium channel blocker; however, its influence on morphine analgesic effects has not been elucidated. We examined the effect of ginger root extract on nociceptive threshold and morphine-induced analgesia in male Wistar rats. To determine the effect of ginger on morphine analgesia, ginger extract (200, 400, and 600 mg/kg i.p.) was injected before a subeffective dose of morphine (2.5 mg/kg i.p.). The radiant heat tail-flick test was used to assess the nociceptive threshold before and at different times after drug administration. Our results showed that ginger extract elicited a significant antinociceptive effect. In addition, in groups that received both morphine and ginger, the observed analgesia was higher than that in groups treated with either morphine or ginger extract alone. Thus, the data indicate that ginger extract has a beneficial influence on morphine analgesia and can be an efficacious adjunct for pain management.

6-Shogaol, an active constituent of ginger, inhibits breast cancer cell invasion by reducing matrix metalloproteinase-9 expression via blockade of nuclear factor-κB activation

BACKGROUND AND PURPOSE

Shogaols are reported to possess anti-inflammatory and anticancer activities. However, the antimetastatic potential of shogaols remains unexplored. This study was performed to assess the effects of shogaols against breast cancer cell invasion and to investigate the underlying mechanisms.

EXPERIMENTAL APPROACH

The anti-invasive effect of a series of shogaols was initially evaluated on MDA-MB-231 breast cancer cells using the matrigel invasion assay. The suppressive effects of 6-shogaol on phorbol 12-myristate 13-acetate (PMA)-induced matrix metalloproteinase-9 (MMP-9) gelatinolytic activity and nuclear factor-κB (NF-κB) activation were further determined.

KEY RESULTS

Shogaols (6-, 8- and 10-shogaol) inhibited PMA-stimulated MDA-MB-231 cell invasion with an accompanying decrease in MMP-9 secretion. 6-Shogaol was identified to display the greatest anti-invasive effect in association with a dose-dependent reduction in MMP-9 gene activation, protein expression and secretion. The NF-κB transcriptional activity was decreased by 6-shogaol; an effect mediated by inhibition of IκB phosphorylation and degradation that subsequently led to suppression of NF-κB p65 phosphorylation and nuclear translocation. In addition, 6-shogaol was found to inhibit JNK activation with no resulting reduction in activator protein-1 transcriptional activity. By using specific inhibitors, it was demonstrated that ERK and NF-κB signalling, but not JNK and p38 signalling, were involved in PMA-stimulated MMP-9 activation.

CONCLUSIONS AND IMPLICATIONS

6-Shogaol is a potent inhibitor of MDA-MB-231 cell invasion, and the molecular mechanism involves at least in part the down-regulation of MMP-9 transcription by targeting the NF-κB activation cascade. This class of naturally occurring small molecules thus have potential for clinical use as antimetastatic treatments.

Profiling of the compounds absorbed in human plasma and urine after oral administration of a traditional Japanese (kampo) medicine, daikenchuto

Daikenchuto (DKT), a pharmaceutical-grade traditional Japanese (Kampo) medicine, has been widely used for the treatment of various gastrointestinal disorders including postoperative ileus and has been integrated into the modern medical care system in Japan as a prescription drug. DKT is a multiherbal medicine consisting of Japanese pepper (zanthoxylum fruit), processed ginger, and ginseng with maltose as an additive. Despite substantial research on the pharmacological activities of DKT and its ingredients, the lack of studies on absorption, distribution, metabolism, and excretion of DKT has made it difficult to obtain a consistent picture of its mechanism of action. In the present study, we constructed an analysis procedure consisting of seven conditions of liquid chromatography and mass spectrometric analysis, which enabled the identification of 44 ingredients of DKT component herbs. We investigated the plasma and urine profiles of these ingredients 0.5 to 8 h after oral administration of 15.0 g of DKT in four healthy volunteers. The results indicated that 1) hydroxy-α-sanshool and [6]-shogaol, the prominent peaks in plasma derived from Japanese pepper and ginger, respectively, were detected at 0.5 h and thereafter decreased throughout the sampling period; 2) ginsenoside Rb(1), a prominent peak derived from ginseng, increased gradually during the sampling period; 3) glucuronide conjugates of hydroxy-sanshools, shogaols, and gingerols were detected in plasma and urine; and 4) no obvious differences between samples from the two male and the two female individuals were observed. These results provide a strong basis for future studies on pharmacokinetics and pharmacology of DKT.

Anti-invasion effects of 6-shogaol and 6-gingerol, two active components in ginger, on human hepatocarcinoma cells

SCOPE

Hepatocellular carcinoma is the most common type of liver cancer and is highly metastatic. Metastasis is considered to be the major cause of death in cancer patients. Ginger is a natural dietary rhizome with anti-oxidative, anti-inflammatory, and anti-carcinogenic activities. The aims of this study were to evaluate the anti-invasion activity of 6-shogaol and 6-gingerol, two compounds found in ginger, on hepatoma cells.

METHODS AND RESULTS

The migratory and invasive abilities of phorbol 12-myristate 13-acetate (PMA)-treated HepG2 and PMA-untreated Hep3B cells were both reduced in a dose-dependent manner by treatment with 6-shogaol and 6-gingerol. Upon incubation of PMA-treated HepG2 cells and PMA-untreated Hep3B cells with 6-shogaol and 6-gingerol, matrix metalloproteinase (MMP)-9 activity decreased, whereas the expression of tissue inhibitor metalloproteinase protein (TIMP)-1 increased in both cell types. Additionally, urokinase-type plasminogen activator activity was dose-dependently decreased in Hep3B cells after incubation with 6-shogaol for 24 h. Analysis with semi-quantitative reverse transcription-PCR showed that the regulation of MMP-9 by 6-shogaol and 6-gingerol and the regulation of TIMP-1 by 6-shogaol in Hep3B cells may on the transcriptional level.

CONCLUSIONS

These results suggest that 6-shogaol and 6-gingerol might both exert anti-invasive activity against hepatoma cells through regulation of MMP-9 and TIMP-1 and that 6-shogaol could further regulate urokinase-type plasminogen activity.

Effect of [6]-shogaol on cytosolic Ca2+ levels and proliferation in human oral cancer cells (OC2)

The effect of [6]-shogaol (1) on cytosolic free Ca(2+) concentrations ([Ca(2+)](i)) and viability has not been explored previously in oral epithelial cells. The present study has examined whether 1 alters [Ca(2+)](i) and viability in OC2 human oral cancer cells. Compound 1 at concentrations > or = 5 microM increased [Ca(2+)](i) in a concentration-dependent manner with a 50% effective concentration (EC(50)) value of 65 microM. The Ca(2+) signal was reduced substantially by removing extracellular Ca(2+). In a Ca(2+)-free medium, the 1-induced [Ca(2+)](i) elevation was mostly attenuated by depleting stored Ca(2+) with thapsigargin (an endoplasmic reticulum Ca(2+) pump inhibitor). The [Ca(2+)](i) signal was inhibited by La(3+) but not by L-type Ca(2+) channel blockers. The elevation of [Ca(2+)](i) caused by 1 in a Ca(2+)-containing medium was not affected by modulation of protein kinase C activity, but was inhibited by 82% with the phospholipase A2 inhibitor aristolochic acid I (20 microM). U73122, a selective inhibitor of phospholipase C, abolished 1-induced [Ca(2+)](i) release. At concentrations of 5-100 microM, 1 killed cells in a concentration-dependent manner. These findings suggest that [6]-shogaol induces a significant rise in [Ca(2+)](i) in oral cancer OC2 cells by causing stored Ca(2+) release from the thapsigargin-sensitive endoplasmic reticulum pool in an inositol 1,4,5-trisphosphate-dependent manner and by inducing Ca(2+) influx via a phospholipase A2- and La(3+)-sensitive pathway.

Molecular targets of [6]-gingerol: Its potential roles in cancer chemoprevention

A wide variety of phenolic compounds derived from spices possess potent antioxidant, anti-inflammatory, antimutagenic, and anticarcinogenic activities. [6]-gingerol (1-[4'-hydroxy-3'-methoxyphenyl]-5-hydroxy-3-decanone) is the major pungent principle of ginger, with numerous pharmacological properties including antioxidant, anti-inflammation, and antitumor promoting properties. It could decrease inducible nitric oxide synthase (iNOS) and tumor necrosis factor alpha (TNF-alpha) expression through suppression of I-kappaB alpha (IkappaBalpha) phosphorylation, nuclear factor kappa B (NF-kappaB) nuclear translocation. Other antiproliferative mechanisms of [6]-gingerol include the release of Cytochrome c, Caspases activation, and increase in apoptotic protease-activating factor-1 (Apaf-1) as mechanism of apoptosis induction. Taken together, the chemopreventive potentials of [6]-gingerol present a promising future alternative to therapeutic agents that are expensive, toxic, and might even be carcinogenic.

Induction of apoptosis by [8]-shogaol via reactive oxygen species generation, glutathione depletion, and caspase activation in human leukemia cells

Ginger, the rhizome of Zingiber officinale , is a traditional medicine with a carminative effect and antinausea, anti-inflammatory, and anticarcinogenic properties. This study examined the growth inhibitory effects of [8]-shogaol, one of the pungent phenolic compounds in ginger, on human leukemia HL-60 cells. It demonstrated that [8]-shogaol was able to induce apoptosis in a time- and concentration-dependent manner. Treatment with [8]-shogaol caused a rapid loss of mitochondrial transmembrane potential, stimulation of reactive oxygen species (ROS) production, release of mitochondrial cytochrome c into cytosol, and subsequent induction of procaspase-9 and procaspase-3 processing. Taken together, these results suggest for the first time that ROS production and depletion of glutathione that contributed to [8]-shogaol-induced apoptosis in HL-60 cells.

6-Shogaol inhibits monosodium urate crystal-induced inflammation--an in vivo and in vitro study

Gout is a rheumatic disease that is manifestated by an intense inflammation secondary to monosodium urate crystal deposition in joints. In the present study, we assessed the effect of 6-shogaol (isolated active principle from ginger) on monosodium urate crystal-induced inflammation in mice; an experimental model for gouty arthritis and compared it with that of the non-steroidal anti-inflammatory drug, indomethacin. Paw volume and levels/activities of lysosomal enzymes, lipid peroxidation, anti-oxidant status and inflammatory mediator TNF-alpha were determined in control and monosodium urate crystal-induced mice. The levels of beta-glucuronidase and lactate dehydrogenase were also measured in monosodium urate crystal-incubated polymorphonuclear leucocytes (PMNL) in vitro. The levels of lysosomal enzymes, lipid peroxidation, and inflammatory mediator tumour necrosis factor-alpha and paw volume were increased significantly and the activities of anti-oxidant status were in turn decreased in monosodium urate crystal-induced mice, whereas these changes were reverted to near normal levels upon 6-shogaol administration. In vitro, 6-shogaol reduced the level of beta-glucuronidase and lactate dehydrogenase in monosodium urate crystal-incubated polymorphonuclear leucocytes in concentration dependent manner when compared to control cells. The present results clearly indicated that 6-shogaol exerted a strong anti-inflammatory effect and can be regarded as useful tool for the treatment of acute gouty arthritis.

Increased growth inhibitory effects on human cancer cells and anti-inflammatory potency of shogaols from Zingiber officinale relative to gingerols

Ginger, the rhizome of the plant Zingiber officinale , has received extensive attention because of its antioxidant, anti-inflammatory, and antitumor activities. Most researchers have considered gingerols as the active principles and have paid little attention to shogaols, the dehydration products of corresponding gingerols during storage or thermal processing. In this study, we have purified and identified eight major components, including three major gingerols and corresponding shogaols, from ginger extract and compared their anticarcinogenic and anti-inflammatory activities. Our results showed that shogaols ([6], [8], and [10]) had much stronger growth inhibitory effects than gingerols ([6], [8], and [10]) on H-1299 human lung cancer cells and HCT-116 human colon cancer cells, especially when comparing [6]-shogaol with [6]-gingerol (IC50 of approximately 8 versus approximately 150 microM). In addition, we found that [6]-shogaol had much stronger inhibitory effects on arachidonic acid release and nitric oxide (NO) synthesis than [6]-gingerol.

Modulation of inflammatory genes by natural dietary bioactive compounds

Several epidemiologic studies have shown that chronic inflammation predisposes individuals to various types of cancer. Many cancers arise from sites of infection, chronic irritation, and inflammation. Conversely, an oncogenic change induces an inflammatory microenvironment that promotes the development of tumors. Natural bioactive compounds in dietary plant products including fruits, vegetables, grains, legumes, tea, and wine are claimed to help prevent cancer, degenerative diseases, and chronic and acute inflammation. Modern methods in cell and molecular biology allow us to understand the interactions of different natural bioactive compounds with basic mechanisms of inflammatory response. The molecular pathways of this cancer-related inflammation are now unraveled. Natural bioactive compounds exert anti-inflammatory activity by modulating pro-inflammatory gene expressions have shown promising chemopreventive activity. This review summarizes current knowledge on natural bioactive compounds that act through the signaling pathways and modulate inflammatory gene expressions, thus providing evidence for these substances in cancer chemopreventive action.