Helminthostachys zeylanica alleviates hepatic steatosis and insulin resistance in diet-induced obese mice.

BACKGROUND: Obesity and its associated health conditions, type 2 diabetes mellitus (T2DM) and nonalcoholic fatty liver disease (NAFLD), are worldwide health problems. It has been shown that insulin resistance is associated with increased hepatic lipid and causes hepatic steatosis through a myriad of mechanisms, including inflammatory signaling. METHODS: Helminthostachys zeylanica (HZ) is used widely as a common herbal medicine to relieve fever symptoms and inflammatory diseases in Asia. In the present study, we evaluated whether HZ has therapeutic effects on obesity, NAFLD and insulin resistance. The protective effects of HZ extract were examined using free fatty acid-induced steatosis in human HuS-E/2 cells and a high-fat diet-induced NAFLD in mice. RESULTS: The major components of the HZ extract are ugonins J and K, confirmed by HPLC. Incubation of human hepatocytes, HuS-E/2 cells, with palmitate markedly increased lipid accumulation and treatment with the HZ extract significantly decreased lipid deposition and facilitated AMPK and ACC activation. After 12 weeks of a high-fat diet with HZ extract treatment, the HFD mice were protected from hyperlipidemia and hyperglycemia. HZ extract prevented body weight gain, adipose tissue expansion and adipocyte hypertrophy in the HFD mice. In addition, fat accumulation was reduced in mice livers. Moreover, the insulin sensitivity-associated index, which evaluates insulin function, was also significantly restored. CONCLUSIONS: These results suggest that HZ has a promising pharmacological effect on high-fat diet-induced obesity, hepatic steatosis and insulin resistance, which may have the potential for clinical application.

15,16-Dihydrotanshinone I from the Functional Food Salvia miltiorrhiza Exhibits Anticancer Activity in Human HL-60 Leukemia Cells: in Vitro and in Vivo Studies.

15,16-Dihydrotanshinone I (DHTS) is extracted from Salvia miltiorrhiza Bunge which is a functional food in Asia. In this study, we investigated the apoptotic effect of DHTS on the human acute myeloid leukemia (AML) type III HL-60 cell line. We found that treatment with 1.5 µg/mL DHTS increased proapoptotic Bax and Bad protein expressions and activated caspases-3, -8, and -9, thus leading to poly ADP ribose polymerase (PARP) cleavage and resulting in cell apoptosis. DHTS induced sustained c-Jun N-terminal kinase (JNK) phosphorylation and Fas ligand (FasL) expression. The anti-Fas blocking antibody reversed the DHTS-induced cell death, and the JNK-specific inhibitor, SP600125, inhibited DHTS-induced caspase-3, -8, -9, and PARP cleavage. In a xenograft nude mice model, 25 mg/kg DHTS showed a great effect in attenuating HL-60 tumor growth. Taken together, these results suggest that DHTS can induce HL-60 cell apoptosis in vitro and inhibit HL-60 cell growth in vivo; the underlying mechanisms might be mediated through activation of the JNK and FasL signal pathways.

N-Hydroxycinnamide derivatives of osthole inhibit cell migration and invasion by suppressing Smad2 and Akt pathways in human colorectal adenocarcinoma cells.

WJ1376-1 and WJ1398-1 are new synthetic compounds developed based on the structure of the Chinese herbal medicine osthole. Previously, we reported that WJ1376-1 and WJ1398-1 can induce cell-cycle arrest by activating ATR kinase (ataxia telangiectasia and rad3 related kinase) and inhibiting the phosphorylation of Aurora A kinase. In this study, we determined that WJ1376-1 and WJ1398-1 strongly inhibited the migration and invasion in human colorectal cancer cells at concentrations as low as 1µM. In the transforming growth factor (TGF)-ß-induced epithelial-mesenchymal transition model, WJ1376-1 and WJ1398-1 potently downregulated the transcription factor Snail1, the mesenchymal protein vimentin, and matrix metalloprotease-9, but upregulated the epithelial protein E-cadherin. WJ1376-1 and WJ1398-1 also inhibited the TGF-ß-induced phosphorylation of Smad2 and of Akt at Ser 473, and the nuclear translocation of Smad2 was substantially lower in WJ1376-1- and WJ1398-1-treated cells than it was in control cells. In transient transfection experiments, we observed that WJ1376-1 and WJ1398-1 strongly inhibited TGF-ß-stimulated activity of a Smad reporter. Finally, WJ1376-1 and WJ1398-1 blocked TGF-ß-induced phosphorylation of the TGF-ß Type I receptor (TGF-ßRI). These results suggest that WJ1376-1 and WJ1398-1 inhibit cell migration and invasion by suppressing TGF-ßRI phosphorylation and subsequently hindering both Smad2 and phosphatidylinositol 3-kinase/Akt signaling pathways.

A Taiwanese Propolis Derivative Induces Apoptosis through Inducing Endoplasmic Reticular Stress and Activating Transcription Factor-3 in Human Hepatoma Cells.

Activating transcription factor-(ATF-) 3, a stress-inducible transcription factor, is rapidly upregulated under various stress conditions and plays an important role in inducing cancer cell apoptosis. NBM-TP-007-GS-002 (GS-002) is a Taiwanese propolin G (PPG) derivative. In this study, we examined the antitumor effects of GS-002 in human hepatoma Hep3B and HepG2 cells in vitro. First, we found that GS-002 significantly inhibited cell proliferation and induced cell apoptosis in dose-dependent manners. Several main apoptotic indicators were found in GS-002-treated cells, such as the cleaved forms of caspase-3, caspase-9, and poly(ADP-ribose) polymerase (PARP). GS-002 also induced endoplasmic reticular (ER) stress as evidenced by increases in ER stress-responsive proteins including glucose-regulated protein 78 (GRP78), growth arrest- and DNA damage-inducible gene 153 (GADD153), phosphorylated eukaryotic initiation factor 2 α (eIF2 α ), phosphorylated protein endoplasmic-reticular-resident kinase (PERK), and ATF-3. The induction of ATF-3 expression was mediated by mitogen-activated protein kinase (MAPK) signaling pathways in GS-002-treated cells. Furthermore, we found that GS-002 induced more cell apoptosis in ATF-3-overexpressing cells. These results suggest that the induction of apoptosis by the propolis derivative, GS-002, is partially mediated through ER stress and ATF-3-dependent pathways, and GS-002 has the potential for development as an antitumor drug.

15,16-Dihydrotanshinone I-induced apoptosis in human colorectal cancer cells: involvement of ATF3.

15,16-Dihydrotanshinone I (DHTS) is a component of the traditional Chinese medicinal plant Salvia miltiorrhiza Bunge. In this study, DHTS at as low as 2.5 µg/ml concentration significantly inhibited proliferation of human benign (SW480) and malignant (SW620) colorectal cancer cells, as shown by 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-diphenytetrazoliumromide (MTT) and flow cytometric analysis. Activating transcription factor (ATF)-3, a basic leucine zipper-type transcription factor, was found to be predominantly up-regulated in DHTS-treated SW480 and SW620 cells. The up-regulation of ATF3 was blocked by a c-JUN N-terminal kinase (JNK) or p38 inhibitor. Overexpression of ATF3 resulted in a significant augmentation of DHTS-induced apoptosis of SW480 cells, but resistance to DHTS-induced apoptosis of SW620 cells. These results suggest that DHTS has a strong therapeutic or preventive potential against cancer. In addition, ATF3 has a dual role in DHTS-induced apoptosis, depending on the degree of malignancy of colorectal cancer.

Cytotoxicity of (-)-vitisin B in human leukemia cells.

Vitis thunbergii var. taiwaniana (VTT) is an indigenous Taiwanese wild grape and is used as a folk medicine in Taiwan. VTT is rich in polyphenols, especially quercetin and resveratrol derivatives, which were demonstrated to exhibit inhibitory activities against carcinogenesis and prevent some neurodegenerative diseases. (-)-Vitisin B is one of the resveratrol tetramers extracted from VTT. In this study, we investigated the mechanisms of (-)-vitisin B on the induction of apoptosis in human HL-60 promyelocytic leukemia cells. First, (-)-vitisin B significantly inhibited cell proliferation through inducing cell apoptosis. This effect appeared to occur in a time- and dose-dependent manner. Cell-cycle distribution was also examined, and we found that (-)-vitisin B significantly induced a sub-G1 population in a dose-dependent manner. In addition, (-)-vitisin B exhibited stronger inhibitory effects on cell proliferation than resveratrol. Second, (-)-vitisin B dose dependently induced apoptosis-related protein expressions, such as the cleavage form of caspase-3, caspase-8, caspase-9, poly(ADP ribose) polymerase, and the proapoptotic Bax protein. Third, (-)-vitisin B treatment also resulted in increases in c-Jun N-terminal kinase (JNK) phosphorylation and Fas ligand (FasL) expression. Moreover, the (-)-vitisin B-induced FasL expression and caspase-3 activation could be reversed by a JNK inhibitor. These results suggest that (-)-vitisin B-induced apoptosis of leukemia cells might be mediated through activation of JNK and Fas death-signal transduction.

NBM-HD-1: A Novel Histone Deacetylase Inhibitor with Anticancer Activity.

HDAC inhibitors (HDACis) have been developed as promising anticancer agents in recent years. In this study, we synthesized and characterized a novel HDACi, termed NBM-HD-1. This agent was derived from the semisynthesis of propolin G, isolated from Taiwanese green propolis (TGP), and was shown to be a potent suppressor of tumor cell growth in human breast cancer cells (MCF-7 and MDA-MB-231) and rat glioma cells (C6), with an IC(50) ranging from 8.5 to 10.3 µM. Western blot demonstrated that levels of p21((Waf1/Cip1)), gelsolin, Ac-histone 4, and Ac-tubulin markedly increased after treatment of cancer cells with NBM-HD-1. After NBM-HD-1 treatment for 1-4 h, p-PTEN and p-AKT levels were markedly decreased. Furthermore, we also found the anticancer activities of NBM-HD-1 in regulating cell cycle regulators. Treatment with NBM-HD-1, p21((Waf1/Cip1)) gene expression had markedly increased while cyclin B1 and D1 gene expressions had markedly decreased. On the other hand, we found that NBM-HD-1 increased the expressions of tumor-suppressor gene p53 in a dose-dependent manner. Finally, we showed that NBM-HD-1 exhibited potent antitumor activity in a xenograft model. In conclusion, this study demonstrated that this compound, NBM-HD-1, is a novel and potent HDACi with anticancer activity in vitro and in vivo.

Osthole enhances glucose uptake through activation of AMP-activated protein kinase in skeletal muscle cells.

AMP-activated protein kinase (AMPK) is an energy sensor that regulates cellular metabolism. Activation of AMPK in skeletal muscles, the liver, and adipose tissues results in a favorable metabolic milieu for preventing and treating type 2 diabetes, i.e., decreased levels of circulating glucose, plasma lipids, and ectopic fat accumulation and enhanced insulin sensitivity. Osthole was extracted from a Chinese herbal medicine, and we found that it had glucose lowering activity in our previous study. However, the detailed glucose lowering mechanisms of osthole are still unclear. In this study, we used skeletal muscle cells to examine the underlying molecular mechanisms of osthole's glucose lowering activity. A Western blot analysis revealed that osthole significantly induced phosphorylation of AMPK and acetyl-CoA carboxylase (ACC). Next, we found that osthole significantly increased the level of translocation of glucose transporter 4 (GLUT4) to plasma membranes and glucose uptake in a dose-dependent manner. Osthole-induced glucose uptake was reversed by treatment with Compound C, an AMPK inhibitor, suggesting that osthole-induced glucose uptake was mediated in an AMPK-dependent manner. The increase in the AMP:ATP ratio was involved in osthole's activation of AMPK. Finally, we found that osthole counteracted hyperglycemia in mice with streptozotocin-induced diabetes. These results suggest that the increase in the AMP:ATP ratio by osthole triggered activation of the AMPK signaling pathway and led to increases in plasma membrane GLUT4 content and glucose uptake level. Therefore, osthole might have potential as an antidiabetic agent for treating diabetes.

An in vitro hyperbaric oxygen system for evaluation of free radical damage and protection by catechins on hemorheological parameters.

Free radicals play a critical role in causing hemorheologic abnormality which is highly correlated with cardiovascular disease and stroke. In this study, we established an in vitro model to evaluate the influence of free radical attacks on hemorheological parameters. A well-sealed chamber with hyperbaric oxygen was used to simulate an environment of free radical attacks. Hemorheological parameters, including whole blood viscosity, erythrocyte membrane lipid peroxidation, and erythrocyte deformability, were investigated. We then used the in vitro model to evaluate the anti-free radical effects of some well-known catechin antioxidants, such as epigallocatechin gallate (EGCG), (-)-epicatechin 3-gallate (ECG), and (-)-epigallocatechin (EGC) on abnormal hemorheological parameters induced by hyperbaric oxygen. The results show that an increase in oxygen partial pressure (1.0, 1.5, 2.0 and 2.5 atm) and exposure time (4, 8, 12 and 16 h) resulted in elevated free radical formation and viscosity of whole blood, enhanced lipid peroxidation in erythrocyte membranes, but decreased erythrocyte deformability. In addition, EGCG, ECG, and EGC (0.1, 0.5 and 1.0 µM) effectively ameliorated hemorheologic abnormality and enhanced erythrocyte deformability. Therefore, this study has provided an in vitro hyperbaric oxygen model to rapidly screen or assess the efficacy of functional foods and drugs in the prevention or improvement of hemorheologic abnormality.

15,16-Dihydrotanshinone I, a Compound of Salvia miltiorrhiza Bunge, Induces Apoptosis through Inducing Endoplasmic Reticular Stress in Human Prostate Carcinoma Cells.

5,16-dihydrotanshinone I (DHTS) is extracted from Salvia miltiorrhiza Bunge (tanshen root) and was found to be the most effective compound of tanshen extracts against breast cancer cells in our previous studies. However, whether DHTS can induce apoptosis through an endoplasmic reticular (ER) stress pathway was examined herein. In this study, we found that DHTS significantly inhibited the proliferation of human prostate DU145 carcinoma cells and induced apoptosis. DHTS was able to induce ER stress as evidenced by the upregulation of glucose regulation protein 78 (GRP78/Bip) and CAAT/enhancer binding protein homologous protein/growth arrest- and DNA damage-inducible gene 153 (CHOP/GADD153), as well as increases in phosphorylated eukaryotic initiation factor 2α (eIF2α), c-jun N-terminal kinase (JNK), and X-box-binding protein 1 (XBP1) mRNA splicing forms. DHTS treatment also caused significant accumulation of polyubiquitinated proteins and hypoxia-inducible factor (HIF)-1α, indicating that DHTS might be a proteasome inhibitor that is known to induce ER stress or enhance apoptosis caused by the classic ER stress-dependent mechanism. Moreover, DHTS-induced apoptosis was reversed by salubrinal, an ER stress inhibitor. Results suggest that DHTS can induce apoptosis of prostate carcinoma cells via induction of ER stress and/or inhibition of proteasome activity, and may have therapeutic potential for prostate cancer patients.

Neuroprotective activity of Vitis thunbergii var. taiwaniana extracts in vitro and in vivo.

Vitis thunbergii var. taiwaniana (VTT) is a wild grape native to Taiwan, where it has been used as a folk medicine. In this study, we found that the branch and leaf ethanol extracts of VTT significantly inhibited the inducible nitric oxide (NO) synthase protein expression and NO production in BV2 microglia. Using primary neuronal cells, kainic acid (KA) significantly increased hydrogen peroxide production in a dose-dependent manner. All four ethanol extracts of VTT significantly decreased hydrogen peroxide production. However, only root and branch ethanol extracts were able to prevent the neuronal cell death induced by KA in vitro. In the animal study, administration of all four plant part extracts of VTT delayed the onset of seizure and decreased the hippocampus neuronal cell loss, and the neuroprotective activity could be ranked as follows: branch approximately leaf > root > trunk. The results suggest that VTT extracts have a potential to prevent neurodegeneration through the antioxidative activity by their ability to inhibit NO and hydrogen peroxide production.

Acteoside and 6-O-acetylacteoside downregulate cell adhesion molecules induced by IL-1beta through inhibition of ERK and JNK in human vascular endothelial cells.

Acteoside, an active phenylethanoid glycoside of many medicinal plants and bitter tea, displays anti-inflammatory properties in vitro. However, it is unclear whether acteoside and similar compounds may inhibit the expression of cell adhesion molecules (CAMs), which plays a role in the pathogenesis of atherosclerosis and inflammation. Here, we found that acteoside, isoacteoside, and 6-O-acetylacteoside inhibited IL-1beta-activated expression of intercellular CAM-1 (ICAM-1) and vascular CAM-1 (VCAM-1) in human umbilical vein endothelial cells (HUVECs); the inhibitory potency was as follows: 6-O-acetylacteoside > acteoside > isoacteoside. Acteoside and 6-O-acetylacteoside also dose-dependently inhibited VCAM-1 gene promoter activity in IL-1beta-activated HUVECs. The inhibition of acteoside and 6-O-acetylacteoside on IL-1beta-activated expression of CAMs was manifested by decreased phosphorylation of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK). These results indicate that acteoside and 6-O-acetylacteoside may exert anti-inflammatory activities in vascular endothelium by inhibiting the expression of CAMs, primarily through decreased phosphorylation of ERK and JNK.

Magnolol inhibits human glioblastoma cell proliferation through upregulation of p21/Cip1.

Previously, we demonstrated that magnolol isolated from the bark of Magnolia officinalis has anticancer activity in colon, hepatoma, and leukemia cell lines. In this study, we show that magnolol concentration dependently (0-40 microM) decreased the cell number in a cultured human glioblastoma cancer cell line (U373) and arrested the cells at the G0/G1 phase of the cell cycle. Magnolol treatment decreased the protein levels of cyclins A and D1 and increased p21/Cip1, but not cyclins B and D3, cyclin-dependent kinase (CDK)2, CDK4, CDC25C, Weel, p27/Kip1, and p53. The CDK2-p21/Cip1 complex was increased, and the CDK2 kinase activity was decreased in the magnolol-treated U373. Pretreatment of U373 with p21/Cip1 specific antisense oligodeoxynucleotide prevented the magnolol-induced increase of p21/Cip1 protein levels and the decrease of DNA synthesis. Magnolol at a concentration of 100 microM induced DNA fragmentation in U373. Our findings suggest the potential applications of magnolol in the treatment of human brain cancers.

The effect of caffeic acid phenethyl ester on the functions of human monocyte-derived dendritic cells.

BACKGROUND: Propolis, an ancient herbal medicine, has been reported the beneficial effect both in asthma patients and murine model of asthma, but the mechanism was not clearly understood. In this study, the effect of caffeic acid phenethyl ester (CAPE), the most extensively studied components in propolis, on the functions of human monocyte-derived dendritic cells (MoDCs) was investigated. RESULTS: CAPE significantly inhibited IL-12 p40, IL-12 p70, IL-10 protein expression in mature healthy human MoDCs stimulated by lipopolysaccharides (LPS) and IL-12 p40, IL-10, IP-10 stimulated by crude mite extract. CAPE significantly inhibited IL-10 and IP-10 but not IL-12 expression in allergic patients' MoDCs stimulated by crude mite extract. In contrast, the upregulation of costimulatory molecules in mature MoDCs was not suppressed by CAPE. Further, the antigen presenting ability of DCs was not inhibited by CAPE. CAPE inhibited IkappaBalpha phosphorylation and NF-kappaB activation but not mitogen-activated protein kinase (MAPK) family phosphorylation in human MoDCs. CONCLUSION: These results indicated that CAPE inhibited cytokine and chemokine production by MoDCs which might be related to the NF-kappaB signaling pathway. This study provided a new insight into the mechanism of CAPE in immune response and the rationale for propolis in the treatment of asthma and other allergic disorders.

Liposome encapsulation reduces cantharidin toxicity.

Several reports have demonstrated that cantharidin is a strong anticancer compound in vitro; however, its in vivo usefulness is often limited due to its high systemic toxicity. In this study, we encapsulated cantharidin into pegylated liposomes and studied its activity against human breast cancer MCF-7 cells in vitro and its systemic toxicity in mice. Another two methods were also used to reduce the dosage of cantharidin, including labeling liposomal cantharidin with octreotide and exposing cells to hyperbaric oxygen. The cytotoxic activity of pegylated liposomal cantharidin was drastically reduced compared with free cantharidin in vitro. Octreotide-labeled pegylated liposomal cantharidin induced cell death by specifically targeting somatostatin receptors in MCF-7 cells. Cell death was augmented with a low dose of cantharidin under hyperbaric oxygen. Liposomal cantharidin had significantly less systemic toxicity than free cantharidin in vivo and also exhibited a high efficacy against antitumor growth in nude mice. These results suggest that the systemic toxicity of cantharidin can be mitigated by liposome encapsulation; however, that did not decrease its antitumor activity.

Taiwanofungus camphoratus activates peroxisome proliferator-activated receptors and induces hypotriglyceride in hypercholesterolemic rats.

Taiwanofungus camphoratus (T. camphoratus), a fungus and a Taiwan-specific, well-known traditional Chinese medicine, has long been used to treat diarrhea, hypertension, itchy skin, and liver cancer. To gain a large amount of T. camphoratus, several culture techniques have been developed, including solid-state culture and liquid-state fermentation. Peroxisome proliferator-activated receptor gamma (PPARgamma) has been described as a hypoglycemic agent that increases insulin sensitivity in peripheral tissues and results in reduced blood glucose, insulin, and triglyceride levels in insulin-resistant animals and in type-2 (non-insulin-dependent) diabetic patients. In this study, we investigate the possibility that T. camphoratus might activate PPARgamma in vitro and hypolipidemic activity in vivo. The results show that an aqueous extract of the wild fruiting bodies of T. camphoratus was able to increase the PPARgamma activity in cells transfected with the PPARgamma expression plasmid and the AOx-TK reporter plasmid. Based on the cell experiment, we examined the hypolipidemic effect of wild fruiting bodies (WFT) and a solid-state culture (SST) of T. camphoratus on SD rats fed on a high-cholesterol (HC) diet. The results show that WFT significantly decreased the serum triglyceride level, but could not affect the cholesterol level. SST only slightly decreased the serum triglyceride level. In addition, both WFT and SST significantly decreased the serum alanine transaminase (ALT) level and protected against the liver damage induced by the HC diet from the results of a histological examination. These results suggest that T. camphoratus might contain PPARgamma ligands and result in a hypotriglyceridemic effect, and that it also exhibits a liver protective activity.

Comparative anti-inflammatory characterization of wild fruiting body, liquid-state fermentation, and solid-state culture of Taiwanofungus camphoratus in microglia and the mechanism of its action.

Taiwanofungus camphoratus (syn. Antrodia camphorata), a medicinal mushroom in Taiwan, is reputed to provide several therapeutic benefits, but the wild fruiting body is very rare. In this study, we used Taiwanofungus camphoratus extracts from wild fruiting bodies and two types of artificial cultivation (solid-state culture and liquid-state fermentation) to examine their anti-inflammatory effects in microglia cells and their possible roles in protection against neurodegenerative diseases. First, EOC13.31 microglia was treated with various kinds of Taiwanofungus camphoratus extracts and lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma) to evaluate the iNOS expression. Western blot and RT-PCR analysis showed that among the various kinds of extracts from wild fruiting bodies, methanol extracts were the most potent inhibitors of iNOS expression. Secondly, the potency of methanol extracts could be ranked as follows: extracts of wild fruiting body>solid-state culture>liquid-state fermentation. To clarify the mechanisms involved, methanol extracts from fruiting body were found to inhibit the phosphorylation of extracellular signal-regulated protein kinases (ERK), c-Jun NH2-terminal protein kinases (JNK) and signal transducer and activator of transcription-1 (STAT-1) induced by LPS/IFN-gamma. Methanol extracts from fruiting body also inhibited NF-kappaB activation through the prevention of inhibitor kappaB (IkappaB) degradation. Moreover, methanol extracts from wild fruiting body inhibited both the iNOS and cyclooxygenase-2 (COX-2) expression induced by beta-amyloid in microglia in a dose-dependent manner. In an animal model, we confirmed that methanol extracts from fruiting bodies were able to suppress ear edema, indicating that they have anti-inflammatory activity in vivo. These results suggest that Taiwanofungus camphoratus exhibits an anti-inflammatory activity that might contribute to the prevention of neurodegenerative diseases.

Suppression of endotoxin-induced proinflammatory responses by citrus pectin through blocking LPS signaling pathways.

Pectin is composed of complex polysaccharides rich in galactoside residues, and it is most abundant in citrus fruits. Pectin and modified pectin have been found to exhibit anti-mutagenic activity and inhibit cancer metastasis and proliferation, with no evidence of toxicity or other serious side effects. In this study, we investigated the inhibitory effect of pectin at different degrees of esterification (DEs) on the expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in lipopolysaccharide (LPS)-activated macrophages. Western blot and RT-PCR analyses demonstrated that 30% esterified pectin (DE30), DE60 pectin, and DE90 pectin significantly inhibited the protein and mRNA expressions of iNOS and COX-2 in LPS-activated macrophages, and DE90 pectin was the most-potent inhibitor. To clarify the mechanisms involved, DE90 pectin was found to inhibit the phosphorylation of MAPKs and IKK kinase activity. In addition, DE90 pectin inhibited the activation of NF-kappaB and AP-1 by electrophoretic mobility shift assay and transient transfection experiments. Finally, we found that DE90 pectin could bind with LPS, and might result in decreased binding of LPS to its receptor. These results suggest that modulation of iNOS and COX-2 expressions by dietary pectin may be important in cancer chemoprevention and anti-inflammation.

Isovitexin suppresses lipopolysaccharide-mediated inducible nitric oxide synthase through inhibition of NF-kappa B in mouse macrophages.

Isovitexin exhibits potent antioxidant activities. In this study, the activity of nitric oxide synthase (iNOS) in lipopolysaccharide (LPS)-activated RAW264.7 macrophages after incubation with isovitexin was investigated. Isovitexin was able to reduce the production of hydrogen peroxide induced by LPS in mouse macrophage RAW264.7 cells. The cells incubated with isovitexin had markedly reduced LPS-stimulated NO production with an IC (50) value of 58.5 microM. The expression of iNOS was also inhibited when the cells were treated with isovitexin. A transient transfection experiment showed that isovitexin suppressed the iNOS promoter and NF-kappaB-dependent transcriptional activities. It was also found to inhibit IKK kinase activity and prevent the degradation of IkappaBalpha in activated RAW264.7 cells. Additionally, Western blotting analysis revealed that isovitexin prevented the translocation of NF-kappaB from the cytoplasm to the nucleus. Our results indicate that its ROS scavenger and IKK inhibitory activities also contribute to the suppression of ROS-mediated NF-kappaB activity. These results suggest that isovitexin, a food phytochemical contained in dietary rice products, might have biological significance.

Protective effects of Ginkgo biloba extract on the ethanol-induced gastric ulcer in rats.

AIM: To evaluate the preventive effect of Ginkgo biloba extract (GbE) on ethanol-induced gastric mucosal injuries in rats. METHODS: Female Wistar albino rats were used for the studies. We randomly divided the rats for each study into five subgroups: normal control, experimental control, and three experimental groups. The gastric ulcers were induced by instilling 1 mL 50% ethanol into the stomach. We gave GbE 8.75, 17.5, 26.25 mg/kg intravenously to the experimental groups respectively 30 min prior to the ulcerative challenge. We removed the stomachs 45 min later. The gastric ulcers, gastric mucus and the content of non-protein sulfhydryl groups (NP-SH), malondialdehyde (MDA), c-Jun kinase (JNK) activity in gastric mucosa were evaluated. The amount of gastric juice and its acidity were also measured. RESULTS: The findings of our study are as follows: (1) GbE pretreatment was found to provide a dose-dependent protection against the ethanol-induced gastric ulcers in rats; (2) the GbE pretreatment afforded a dose-dependent inhibition of ethanol-induced depletion of stomach wall mucus, NP-SH contents and increase in the lipid peroxidation (increase MDA) in gastric tissue; (3) gastric ulcer induced by ethanol produced an increase in JNK activity in gastric mucosa which also significantly inhibited by pretreatment with GbE; and (4) GbE alone had no inhibitory effect on gastric secretion in pylorus-ligated rats. CONCLUSION: The finding of this study showed that GbE significantly inhibited the ethanol-induced gastric lesions in rats. We suggest that the preventive effect of GbE may be mediated through: (1) inhibition of lipid peroxidation; (2) preservation of gastric mucus and NP-SH; and (3) blockade of cell apoptosis.