Epicatechin Prevents Methamphetamine-Induced Neuronal Cell Death via Inhibition of ER Stress

Methamphetamine (METH) acts strongly on the nervous system and damages neurons and is known to cause neurodegenerative diseases such as Alzheimer's and Parkinson's. Flavonoids, polyphenolic compounds present in green tea, red wine and several fruits exhibit antioxidant properties that protect neurons from oxidative damage and promote neuronal survival. Especially, epicatechin (EC) is a powerful flavonoid with antibacterial, antiviral, antitumor and antimutagenic effects as well as antioxidant effects. We therefore investigated whether EC could prevent METH-induced neurotoxicity using HT22 hippocampal neuronal cells. EC reduced METH-induced cell death of HT22 cells. In addition, we observed that EC abrogated the activation of ERK, p38 and inhibited the expression of CHOP and DR4. EC also reduced METH-induced ROS accumulation and MMP. These results suggest that EC may protect HT22 hippocampal neurons against METH-induced cell death by reducing ER stress and mitochondrial damage.

Anti-inflammatory Effect of Dactyloquinone B and Cyclospongiaquinone-1 Mixture in RAW264.7 Macrophage and ICR Mice

Sesquiterpene-quinone is a class of secondary metabolites frequently encountered from marine sponge. The present study was designed to examine the anti-inflammatory action of sponge-derived dactyloquinone B (DQB) and cyclospongiaquinone-1 (CSQ1) mixture using lipopolysaccharide (LPS)-induced inflammatory responses. We measured the production of nitric oxide (NO), tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), and interleukin-6 (IL-6) and expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein. TNF-alpha, IL-1beta, and IL-6 production, which increased by treatment with LPS, were significantly inhibited by DQB and CSQ1 mixture. It also decreased the production of NO production, and iNOS and COX-2 expression. Furthermore, it reduced 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced ear edema of ICR mice. These results demonstrate that sesquiterpene-quinone, DQB and CSQ1 mixture, might serve as a chemical pipeline for the development of anti-inflammatory agent.

Sulfuretin protects against cytokine-induced beta-cell damage and prevents streptozotocin-induced diabetes

NF-kappaB activation has been implicated as a key signaling mechanism for pancreatic beta-cell damage. Sulfuretin is one of the main flavonoids produced by Rhus verniciflua, which is reported to inhibit the inflammatory response by suppressing the NF-kappaB pathway. Therefore, we isolated sulfuretin from Rhus verniciflua and evaluated if sulfuretin could inhibit cytokine- or streptozotocin-induced beta-cell damage. Rat insulinoma RINm5F cells and isolated rat islets were treated with IL-1beta and IFN-gamma to induce cytotoxicity. Incubation of cells and islets with sulfuretin resulted in a significant reduction of cytokine-induced NF-kappaB activation and its downstream events, iNOS expression, and nitric oxide production. The cytotoxic effects of cytokines were completely abolished when cells or islets were pretreated with sulfuretin. The protective effect of sulfuretin was further demonstrated by normal insulin secretion of cytokine-treated islets in response to glucose. Treatment of mice with streptozotocin resulted in hyperglycemia and hypoinsulinemia, which was further evidenced by immunohistochemical staining of islets. However, the diabetogenic effects of streptozotocin were completely prevented when mice were pretreated with sulfuretin. The anti-diabetogenic effects of sulfuretin were also mediated by suppression of NF-kappaB activation. Collectively, these results indicate that sulfuretin may have therapeutic value in preventing beta-cell damage.

In vitro and in vivo Antibacterial Activities of Cinnamomum cassia Extracts Against Helicobacter pylori / 한국실험동물학회지

Infection with Helicobacter pylori (H. pylori) is strongly associated with duodenal and gastric ulcers. Substantial epidemiological data has revealed that high rates of H. pylori infection might be related to high rates of gastric cancer and gastric adenocarcinoma. In this study, a medicinal herbal plant, Cinnamomum cassia, was examined and screened for anti-H. pylori activity. Seventy percent ethanol was used for herbal extraction. For anti-H. pylori activity screening, inhibitory zone tests as an in vitro assay and in vivo study using a Mongolian gerbil (Meriones unguiculatus) model were performed. Also, the safety of herbal compounds was evaluated by animal study. As a result of inhibitory zone test, Cinnamomum cassia extract demonstrated strong anti-H. pylori activities. Also, as results of in vivo animal studies, Cinnamomum cassia demonstrated strong therapeutic effects against H. pylori infection according to the criteria of histological examination and rapid urease test. As results of the safety study, after 28 days treatment of the Cinnamomum cassia extract, the animals were not detected any grossly and histological changes. These results demonstrate that it can be successfully cured against H. pylori infection and protected from H. pylori-induced pathology with Cinnamomum cassia. It could be a promising native herb treatment for patients with gastric complaints including gastric ulcer caused by H. pylori.

Antibacterial Activity of Sanguisorba officinalis against Helicobacter pylori / 한국실험동물학회지

In this study, a medicinal herbal plant, Sanguisorba officinalis, was examined and screened for anti-Helicobacter pylori (H. pylori) activity. Seventy percent ethanol was used for herbal extraction. For anti-H. pylori activity screening, inhibitory zone tests as an in vitro assay and in vivo study using a Mongolian gerbil (Meriones unguiculatus) model were performed. Also, the safety of herbal compounds was evaluated by animal study. As a result of inhibitory zone test, Sanguisorba officinalis extract demonstrated strong anti-H. pylori activities. Also, as results of in vivo animal studies, Sanguisorba officinalis extract demonstrated strong therapeutic effects against H. pylori infection according to the criteria of histological examination and rapid urease test. As results of the safety study, after 28 days treatment of the Sanguisorba officinalis extract, the animals were not detected any grossly and histological changes. These results demonstrate that it can be successfully cured against H. pylori infection and protected from H. pylori-induced pathology with Sanguisorba officinalis extract. It could be a promising candidate herb treatment for patients with gastric complaints including gastric ulcer caused by H. pylori.

Antibacterial Activity of Sanguisorba officinalis against Helicobacter pylori / 한국실험동물학회지

In this study, a medicinal herbal plant, Sanguisorba officinalis, was examined and screened for anti-Helicobacter pylori (H. pylori) activity. Seventy percent ethanol was used for herbal extraction. For anti-H. pylori activity screening, inhibitory zone tests as an in vitro assay and in vivo study using a Mongolian gerbil (Meriones unguiculatus) model were performed. Also, the safety of herbal compounds was evaluated by animal study. As a result of inhibitory zone test, Sanguisorba officinalis extract demonstrated strong anti-H. pylori activities. Also, as results of in vivo animal studies, Sanguisorba officinalis extract demonstrated strong therapeutic effects against H. pylori infection according to the criteria of histological examination and rapid urease test. As results of the safety study, after 28 days treatment of the Sanguisorba officinalis extract, the animals were not detected any grossly and histological changes. These results demonstrate that it can be successfully cured against H. pylori infection and protected from H. pylori-induced pathology with Sanguisorba officinalis extract. It could be a promising candidate herb treatment for patients with gastric complaints including gastric ulcer caused by H. pylori.

Roles of heme oxygenase-1 in curcumin-induced growth inhibition in rat smooth muscle cells

In vascular smooth muscle cells (VSMCs), induction of the heme oxygenase-1 (HO-1) confers vascular protection against cellular proliferation mainly via its up-regulation of the cyclin-dependent kinase inhibitor p21(WAF1/CIP1) that is involved in negative regulation of cellular proliferation. In the present study, we investigated whether the phytochemical curcumin and its metabolite tetrahydrocurcumin could induce HO-1 expression and growth inhibition in rat VSMCs and, if so, whether their antiproliferative effect could be mediated via HO-1 expression. At non-toxic concentrations, curcumin possessing two Michael-reaction acceptors induced HO-1 expression by activating antioxidant response element (ARE) through translocation of the nuclear transcription factor E2-related factor-2 (Nrf2) into the nucleus and also inhibited VSMC growth triggered by 5% FBS in a dose-dependent manner. In contrast, tetrahydrocurcumin lacking Michael-reaction acceptor showed no effect on HO-1 expression, ARE activation and VSMC growth inhibition. The antiproliferative effect of curcumin in VSMCs was accompanied by the increased expression of p21(WAF1/CIP1). Inhibition of VSMC growth and expression of p21(WAF1/CIP1) by curcumin were partially, but not completely, abolished when the cells were co- incubated with the HO inhibitor tin protoporphyrin. In human aortic smooth muscle cells (HASMCs), curcumin also inhibited growth triggered by TNF-alpha and increased p21(WAF1/CIP1) expression via HO-1-dependent manner. Our findings suggest that curcumin has an ability to induce HO-1 expression, presumably through Nrf2-dependent ARE activation, in rat VSMCs and HASMCs, and provide evidence that the antiproliferative effect of curcumin is considerably linked to its ability to induce HO-1 expression.

Comparative effects of curcuminoids on endothelial heme oxygenase-1 expression: ortho-methoxy groups are essential to enhance heme oxygenase activity and protection

Recently, it has been reported that curcumin, which is known as a potent antioxidant, acts as a non-stressful and non-cytotoxic inducer of the cytoprotective heme oxygenase (HO)-1. In this study, naturally occurring curcuminoids, such as pure curcumin, demethoxycurcumin (DMC) and bis-demethoxycurcumin (BDMC), were compared for their potential ability to modulate HO-1 expression and cytoprotective activity in human endothelial cells. All three curcuminoids could induce HO-1 expression and HO activity with differential levels. The rank order of HO activity was curcumin, DMC and BDMC. In comparison with endothelial protection against H2O2-induced cellular injury, cytoprotective capacity was found to be highest with curcumin, followed by DMC and BDMC. Interestingly, cytoprotective effects afforded by curcuminoids were considerably associated with their abilities to enhance HO activity. Considering that the main difference among the three curcuminoids is the number of methoxy groups (none for BDMC, one for DMC, and two for curcumin), the presence of methoxy groups in the ortho position on the aromatic ring was suggested to be essential to enhance HO-1 expression and cytoprotection in human endothelial cells. Our results may be useful in designing more efficacious HO-1 inducers which could be considered as promising pharmacological agents in the development of therapeutic approaches for the prevention or treatment of endothelial diseases caused by oxidative damages.