Sasa quelpaertensis Leaf Extract Ameliorates Dyslipidemia, Insulin Resistance, and Hepatic Lipid Accumulation in High-Fructose-Diet-Fed Rats.

BACKGROUND: Increased dietary fructose consumption is closely associated with lipid and glucose metabolic disorders. Sasa quelpaertensis Nakai possesses various health-promoting properties, but there has been no research on its protective effect against fructose-induced metabolic dysfunction. In this study, we investigated the effects of S. quelpaertensis leaf extract (SQE) on metabolic dysfunction in high-fructose-diet-fed rats. METHODS: Animals were fed a 46% carbohydrate diet, a 60% high-fructose diet, or a 60% high-fructose diet with SQE (500 mg/kg of body weight (BW)/day) in drinking water for 16 weeks. Serum biochemical parameters were measured and the effects of SQE on hepatic histology, protein expression, and transcriptome profiles were investigated. RESULTS: SQE improved dyslipidemia and insulin resistance induced in high-fructose-diet-fed rats. SQE ameliorated the lipid accumulation and inflammatory response in liver tissues by modulating the expressions of key proteins related to lipid metabolism and antioxidant response. SQE significantly enriched the genes related to the metabolic pathway, namely, the tumor necrosis factor (TNF) signaling pathway and the PI3K-Akt signaling pathway. CONCLUSIONS: SQE could effectively prevent dyslipidemia, insulin resistance, and hepatic lipid accumulation by regulation of metabolism-related gene expressions, suggesting its role as a functional ingredient to prevent lifestyle-related metabolic disorders.

Effects of p-coumaric acid on microRNA expression profiles in SNU-16 human gastric cancer cells.

BACKGROUND: p-Coumaric acid (p-CA), a phenolic compound abundantly found in edible plants, was found to induce apoptosis in SNU-16 gastric cancer cells. However, the effects of p-CA on the microRNA expression pattern in SNU-16 cells have not been reported. OBJECTIVES: The primary objective of this study was to investigate microRNA expression profiles in p-CA-treated SNU-16 cells. METHODS: SNU-16 cells were treated with 1.5 mM p-CA for 48 h. High-throughput RNA sequencing was performed. The accuracy and validity of the RNA sequencing results were tested by real-time PCR. Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed using the differentially expressed microRNAs (DEMs). RESULTS: Thirty-two DEMs were identified between p-CA-treated and control cells, 9 of which were upregulated, and 23 downregulated. GO and KEGG pathway analyses of the target genes indicated that these genes were involved in a variety of biological functions and several cancer-related pathways. The miRNA interactive network analysis identified hsa-miR-125a-5p, hsa-miR-30a-5p, and hsa-miR-7-5p as the major nodes. CONCLUSIONS: Our findings indicated that p-CA exerted its anticancer effects in SNU-16 gastric cancer cells by modulating the expression of certain microRNAs, providing a better understanding of the anticancer properties of p-CA in gastric cancer cells.

Involvement of Estrogen and Its Receptors in Morphological Changes in the Eyes of the Japanese Eel, Anguilla japonica, in the Process of Artificially-Induced Maturation.

During the long migration from river habitats to the spawning ground, the Japanese eel undergoes sexual maturation. This spawning migration occurs concurrently with morphological changes, such as increases in eye size; however, the mechanisms by which sex steroids and their receptors influence these changes in peripheral tissues remain unclear. The aim of this study was to investigate changes in the eyes of female Japanese eels during sexual maturation, and our research focused on estrogen receptor (ER)α and ERß transcripts. During ovarian development, the gonadosomatic index increased and yolk-laden oocytes developed rapidly. These changes occurred in conjunction with a steady increase in plasma levels of estradiol-17ß (E2). Concomitant increases in transcript levels of ERα and ERß in eye, brain, pituitary, and ovary were also observed. Fluorescence in-situ hybridization analyses revealed that ERα and ERß transcripts were present in the choriocapillary layer and photoreceptor layer of the eyes, and the analysis also revealed that their signals in these layers became stronger in mature females compared to those observed in immature females, suggesting that under the influence of gonadotropins, morphological changes in the eyes are regulated by E2 through the activation of its receptors. In conclusion, E2 plays a crucial role in physiological adaptations that occur in peripheral tissues during the spawning migration.

Tangeretin Improves Glucose Uptake in a Coculture of Hypertrophic Adipocytes and Macrophages by Attenuating Inflammatory Changes.

Obesity is characterized by a state of chronic low-grade inflammation and insulin resistance, which are aggravated by the interaction between hypertrophic adipocytes and macrophages. In this study, we investigated the effects of tangeretin on inflammatory changes and glucose uptake in a coculture of hypertrophic adipocytes and macrophages. Tangeretin decreased nitric oxide production and the expression of interleukin (IL)-6, IL-1ß, tumor necrosis factor-α, inducible nitric oxide synthase, and cyclooxygenase-2 in a coculture of 3T3-L1 adipocytes and RAW 264.7 cells. Tangeretin also increased glucose uptake in the coculture system, but did not affect the phosphorylation of insulin receptor substrate (IRS) and Akt. These results suggest that tangeretin improves insulin resistance by attenuating obesity-induced inflammation in adipose tissue.

Sasa quelpaertensis Leaf Extract Inhibits Colon Cancer by Regulating Cancer Cell Stemness in Vitro and in Vivo.

A rare subpopulation of cancer cells, termed cancer stem cells (CSCs), may be responsible for tumor relapse and resistance to conventional chemotherapy. The development of a non-toxic, natural treatment for the elimination of CSCs is considered a strategy for cancer treatment with minimal side effects. In the present study, the potential for Sasa quelpaertensis leaf extract (SQE) and its two bioactive compounds, tricin and p-coumaric acid, to exert anti-CSC effects by suppressing cancer stemness characteristics were evaluated in colon cancer cells. CD133+CD44+ cells were isolated from HT29 and HCT116 cell lines using flow-activated cell sorting (FACs). SQE treatment was found to significantly suppress the self-renewal capacity of both cell lines. SQE treatment was also associated with the down-regulation of ß-catenin and phosphorylated GSK3ß, while significantly enhancing cell differentiation by up-regulating CK20 expression and blocking the expression of several stem cell markers, including DLK1, Notch1, and Sox-2. In vivo, SQE supplementation suppressed tumor growth in a xenograft model by down-regulating stem cell markers and ß-catenin as well as HIF-1α signaling. Compared with two bioactive compounds of SQE, SQE exhibited the most effective anti-CSC properties. Taken together, these results provide evidence that SQE inhibits colon cancer by regulating the characteristics of CSCs.

Tangeretin triggers melanogenesis through the activation of melanogenic signaling proteins and sustained extracellular signal- regulated kinase in B16/F10 murine melanoma cells.

In order to test the effectiveness of tangeretin at ameliorating melanoma and melanoma-associated depigmentation, western blotting was used to assess the melanin content of treated melanoma cells. Tangeretin, a 4',5,6,7,8-pentamethoxyflavone, was found to trigger intracellular melanin production in a concentration-dependent manner in B16/F10 murine melanoma cells. Melanin content increased 1.74-fold in response to treatment with 25 µM of tangeretin, compared to that in non-treated cells. Examination of melanogenic protein expression showed that tyrosinase, tyrosinase-related protein (TRP)-1, and extracellular signal-regulated kinase (ERK) 1/2 levels increased in a dose-dependent manner. Furthermore, the expression of cyclic adenosine monophosphate response element binding protein (CREB) and microphthalmia transcription factor (MITF) was increased by tangeretin in 1 h and 4 h, respectively. Tangeretin- upregulated melanogenesis was suppressed by ERK 1/2 inhibitor and not by ERK1 inhibitor. These results suggest that tangeretin has therapeutic potential for melanoma and melanoma-associated depigmentation because it can induce hyperpigmentation through the activation of melanogenic signaling proteins and initiation of sustained ERK2 expression.

Sinensetin enhances adipogenesis and lipolysis by increasing cyclic adenosine monophosphate levels in 3T3-L1 adipocytes.

Sinensetin is a rare polymethoxylated flavone (PMF) found in certain citrus fruits. In this study, we investigated the effects of sinensetin on lipid metabolism in 3T3-L1 cells. Sinensetin promoted adipogenesis in 3T3-L1 preadipocytes growing in incomplete differentiation medium, which did not contain 3-isobutyl-1-methylxanthine. Sinensetin up-regulated expression of the adipogenic transcription factors peroxisome proliferator-activated receptor γ, CCAAT/enhancer-binding protein (C/EBP) α, and sterol regulatory element-binding protein 1c. It also potentiated expression of C/EBPß and activation of cAMP-responsive element-binding protein. Sinensetin enhanced activation of protein kinase A and increased intracellular cAMP levels in 3T3-L1 preadipocytes. In mature 3T3-L1 adipocytes, sinensetin stimulated lipolysis via a cAMP pathway. Taken together, these results suggest that sinensetin enhances adipogenesis and lipolysis by increasing cAMP levels in adipocytes.

Intestinal anti-inflammatory activity of Sasa quelpaertensis leaf extract by suppressing lipopolysaccharide-stimulated inflammatory mediators in intestinal epithelial Caco-2 cells co-cultured with RAW 264.7 macrophage cells.

BACKGROUND/OBJECTIVES: Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, involves chronic inflammation of the gastrointestinal tract. Previously, Sasa quelpaertensis leaves have been shown to mediate anti-inflammation and anti-cancer effects, although it remains unclear whether Sasa leaves are able to attenuate inflammation-related intestinal diseases. Therefore, the aim of this study was to investigate the anti-inflammatory effects of Sasa quelpaertensis leaf extract (SQE) using an in vitro co-culture model of the intestinal epithelial environment. MATERIALS/METHODS: An in vitro co-culture system was established that consisted of intestinal epithelial Caco-2 cells and RAW 264.7 macrophages. Treatment with lipopolysaccharide (LPS) was used to induce inflammation. RESULTS: Treatment with SQE significantly suppressed the secretion of LPS-induced nitric oxide (NO), prostaglandin E2 (PGE2), IL-6, and IL-1ß in co-cultured RAW 264.7 macrophages. In addition, expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, and tumor necrosis factor (TNF)-α were down-regulated in response to inhibition of IκBα phosphorylation by SQE. Compared with two bioactive compounds that have previously been identified in SQE, tricin and P-coumaric acid, SQE exhibited the most effective anti-inflammatory properties. CONCLUSIONS: SQE exhibited intestinal anti-inflammatory activity by inhibiting various inflammatory mediators mediated through nuclear transcription factor kappa-B (NF-kB) activation. Thus, SQE has the potential to ameliorate inflammation-related diseases, including IBD, by limiting excessive production of pro-inflammatory mediators.

Sasa quelpaertensis leaf extract suppresses dextran sulfate sodium-induced colitis in mice by inhibiting the proinflammatory mediators and mitogen-activated protein kinase phosphorylation.

Sasa quelpaertensis leaves exert anti-inflammatory and anticarcinogenic effects, although it remains unclear whether these leaves can suppress inflammation-related intestinal diseases. This study hypothesized that Sasa quelpaertensis leaf extract (SQE) exerts a protective effect against inflammation in a dextran sulfate sodium (DSS)-induced colitis mouse model. Therefore, colon tissues of DSS-induced colitis mice that were treated with SQE were assayed for levels of proinflammatory markers, mitogen-activated protein kinase signaling, and activation of nuclear factor κB. For this purpose, mice were pretreated with SQE (100 mg/kg or 300 mg/kg body weight) by gavage for a 2-week period. Mice then received either SQE or sulfasalazine (100 mg/kg body weight) with 2.5% DSS in drinking water for 7 days twice daily and 7 days of tap water ad libitum between DSS treatment. Treatment with SQE was found to attenuate the severity of DSS-induced colitis, as assessed by disease activity index scores, shrinkage of colon length, and histopathologic changes. SQE reduced DSS-induced proliferation in distal colon tissues. It also significantly suppressed levels of tumor necrosis factor-α in serum and colon tissues, nitric oxide synthase, cyclooxygenase, and levels of phosphorylated c-Jun N-terminal kinases, p38, extracellular-signal-regulated kinases 1/2, and IκBα in colon tissues. To our knowledge, this is the first study to demonstrate that SQE supplementation can exert an anti-inflammatory effect on experimental chronic colitis.

Combination of Sasa quelpaertensis Nakai leaf extract and cisplatin suppresses the cancer stemness and invasion of human lung cancer cells.

Lung cancer is the leading cause of cancer death worldwide, and most chemotherapeutic drugs have limited success in treating this disease. Furthermore, some drugs show undesirable side effects due to the enrichment of cancer stem cells (CSCs) that are present, leading to resistance to conventional chemotherapy and tumor relapse. CSCs possess self-renewal characteristics, aggressive tumor initiating activity, and ability to facilitate tumor metastasis. Therefore, development of nontoxic agents that can potentiate chemotherapy and eliminate CSCs would be highly desirable. In the present study, we investigated whether Sasa quelpaertensis leaf extracts (SQE) and cisplatin (CIS), individually or in combination, would exert anti-CSC and antimetastatic effect in H1299 and A549 human lung cancer cells. Following these treatments, cell growth, phosphorylation of phosphoinositide-3 kinase, and activation of the mammalian target of rapamycin were inhibited. Decreased serial sphere formation, clonogenicity, and expression of major stem cell markers, such as CD44 and SOX-2, in CD44(+) cancer stem cells were also observed. In addition, inhibition of cell migration and invasion in both cell lines as well as inhibition of matrix metalloproteinase-2 activity and expression were detected. Importantly, the anticancer stemness and antimetastasis effects in each of these assays were greater for the combined treatment with SQE and CIS than with each treatment individually. In conclusion, the data suggest that SQE alone, or in combination with CIS, represents a promising therapeutic strategy for eliminating cancer stemness and cell invasion potential of CSCs, thereby treating and preventing metastatic lung cancer cells.

Sasa quelpaertensis leaf extract improves high fat diet-induced lipid abnormalities and regulation of lipid metabolism genes in rats.

Sasa quelpaertensis is a bamboo leaf that is only grown on Jeju Island in South Korea. It is used as a bamboo tea that is consumed for therapeutic purposes, particularly for its anti-diabetic, diuretic, and anti-inflammatory effects. This study investigated the effect of S. quelpaertensis leaf extract (SQE) on high fat-induced lipid abnormalities and regulation of lipid metabolism-related gene expressions in rats. SQE supplementation significantly decreased the levels of plasma triglycerides, total cholesterol, and low-density lipoprotein cholesterol as well as the atherogenic index. SQE restored levels of plasma high-density lipoprotein cholesterol, which were lowered by a high fat diet. Plasma and cardiac resistin levels were also significantly decreased by SQE supplementation. In adipose tissue, mRNA levels of CAAT/enhancer-binding protein ß (C/EBPß) were suppressed in the SQE group. SQE supplementation decreased the accumulation of lipid droplets, inflammatory cell infiltrations, levels of triglycerides, and total lipids in the liver and effectively down-regulated expression of sterol regulatory element binding protein-1 (SREBP-1), fatty acid synthetase (FAS), and uncoupling protein 2 (UCP-2). These results suggest that SQE may be a potential treatment for high fat-related disorders by improving lipid profiles and modulating lipid metabolism.

Sasa quelpaertensis and p-coumaric acid attenuate oleic acid-induced lipid accumulation in HepG2 cells.

In this study, we examined the effects of Jeju dwarf bamboo (Sasa quelpaertensis Nakai) extract (JBE) and p-coumaric acid (CA) on oleic acid (OA)-induced lipid accumulation in HepG2 cells. JBE and CA increased the phosphorylation of AMP-activated protein kinase (AMPK), and acetyl-CoA carboxylase (ACC) and the expression of carnitine palmitoyl transferase 1a (CPT1a) in OA-treated HepG2 cells. Additionally, these compounds decreased sterol regulatory element-binding protein-1c (SREBP-1c), fatty acid synthase (FAS), and OA-induced lipid accumulation, suggesting that JBE and CA modulate lipid metabolism in HepG2 cells via the AMPK activation pathway.

p-Coumaric acid modulates glucose and lipid metabolism via AMP-activated protein kinase in L6 skeletal muscle cells.

p-Coumaric acid (3-[4-hydroxyphenyl]-2-propenoic acid) is a ubiquitous plant metabolite with antioxidant, anti-inflammatory, and anticancer properties. In this study, we examined whether p-coumaric acid modulates glucose and lipid metabolism via AMP-activated protein kinase (AMPK) in L6 skeletal muscle cells. p-Coumaric acid increased the phosphorylation of AMPK in a dose-dependent manner in differentiated L6 skeletal muscle cells. It also increased the phosphorylation of acetyl-CoA carboxylase (ACC) and the expression of CPT-1 mRNA and PPARα, suggesting that it promotes the ß-oxidation of fatty acids. Also, it suppressed oleic acid-induced triglyceride accumulation, and enhanced 2-NBDG uptake in differentiated L6 muscle cells. Pretreatment with compound C inhibited AMPK activation, reduced ACC phosphorylation and 2-NBDG uptake, and increased triglyceride accumulation. However, p-coumaric acid counterbalanced the inhibitory effects of compound C. Taken together, these results suggest that p-coumaric acid modulates glucose and lipid metabolism via AMPK activation in L6 skeletal muscle cells and that it has potentially beneficial effects in improving or treating metabolic disorders.

Sinensetin attenuates LPS-induced inflammation by regulating the protein level of IκB-α.

Sinensetin is one of the polymethoxyflavones (PMFs) having five methoxy groups on the basic benzo-γ-pyrone skeleton with a carbonyl group at the C(4) position. We investigated in this study the anti-inflammatory activity of sinensetin in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Sinensetin showed anti-inflammatory activity by regulating the protein level of inhibitor κB-α (IκB-α).

Immature Citrus sunki peel extract exhibits antiobesity effects by ß-oxidation and lipolysis in high-fat diet-induced obese mice.

The peel of Citrus sunki HORT. ex TANAKA has been widely used in traditional Asian medicine for the treatment of many diseases, including indigestion and bronchial asthma. In this study, we investigated the antiobesity activity of immature C. sunki peel extract (designated CSE) using high-fat diet (HFD)-induced obese C57BL/6 mice and mature 3T3-L1 adipocytes. In the animal study, body weight gain, adipose tissue weight, serum total cholesterol, and triglyceride in the CSE-administered group decreased significantly compared to the HFD group. Also, CSE supplementation reduced serum levels of glutamic pyruvic transaminase, glutamic oxaloacetic transaminase, and lactate dehydrogenase. Moreover, it significantly decreased the accumulation of fatty droplets in liver tissue, suggesting a protective effect against HFD-induced hepatic steatosis. Dietary supplementation with CSE reversed the HFD-induced decrease in the phosphorylation levels of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC), which are related to fatty acid ß-oxidation, in the epididymal adipose tissue. Also, CSE increased AMPK and ACC phosphorylation in mature 3T3-L1 adipocytes. CSE also enhanced lipolysis by phosphorylation of cAMP-dependent protein kinase (PKA) and hormone-sensitive lipase (HSL) in mature 3T3-L1 adipocytes. These results suggest that CSE had an antiobesity effect via elevated ß-oxidation and lipolysis in adipose tissue.

Molecular characterization and expression analysis of Cathepsin B and L cysteine proteases from rock bream (Oplegnathus fasciatus).

Cathepsins are lysosomal cysteine proteases of the papain family that play an important role in intracellular protein degradation and turn over within the lysosomal system. In the present study, full-length sequences of cathepsin B (RbCathepsin B) and L (RbCathepsin L) were identified after transcriptome sequencing of rock bream Oplegnathus fasciatus mixed tissue cDNA. Cathepsin B was composed of 330 amino acid residues with 36 kDa predicted molecular mass. RbCathepsin L contained 336 amino acid residues encoding for a 38 kDa predicted molecular mass protein. The sequencing analysis results showed that both cathepsin B and L contain the characteristic papain family cysteine protease signature and active sites for the eukaryotic thiol proteases of cysteine, asparagine and histidine. In addition, RbCathepsin L contained EF hand Ca(2+) binding and cathepsin propeptide inhibitor domains. The rock bream cathepsin B and L showed the highest amino acid identity of 90 and 95% to Lutjanus argentimaculatus cathepsin B and Lates calcarifer cathepsin L, respectively. By phylogenetic analysis, cathepsin B and L exhibited a high degree of evolutionary relationship to respective cathepsin family members of the papain superfamily. Quantitative real-time RT-PCR analysis results confirmed that the expression of cathepsin B and L genes was constitutive in all examined tissues isolated from un-induced rock bream. Moreover, activation of RbCathepsin B and L mRNA was observed in both lipopolysaccharide (LPS) and Edwardsiella tarda challenged liver and blood cells, indicating a role of immune response in rock bream.

Anti-neuroinflammatory activity of nobiletin on suppression of microglial activation.

A growing body of evidence suggests that nobiletin (5,6,7,8,3',4'-hexamethoxy flavone) from the peel of citrus fruits, enhances the damaged cognitive function in disease animal models. However, the neuroprotective mechanism has not been clearly elucidated. Since nobiletin has shown anti-inflammatory effects in several tissues, we investigated whether nobiletin suppresses excessive microglial activation implicated in neurotoxicity in lipopolysaccharide (LPS)-stimulated BV-2 microglia cell culture models. Release of nitric oxide (NO), the major inflammatory mediator in microglia, was markedly suppressed in a dose-dependent manner following nobiletin treatment (1-50 µM) in LPS-stimulated BV-2 microglia cells. The inhibitory effect of nobiletin was similar to that of minocycline, a well-known microglial inactivator. Nobiletin significantly inhibited the release of the pro-inflammatory cytokine tumor necrosis factor (TNF-α) and interleukin-1ß (IL-1ß). LPS-induced phosphorylations of extracellular signal-regulated kinase (ERK), c-Jun NH(2)-terminal kinase (JNK), and p38 mitogen-activated protein kinases (MAPKs) were also significantly inhibited by nobiletin treatment. In addition, nobiletin markedly inhibited the LPS-induced pro-inflammatory transcription factor nuclear factor κB (NF-κB) signaling pathway by suppressing nuclear NF-κB translocation from the cytoplasm and subsequent expression of NF-κB in the nucleus. Taken together, these results may contribute to further exploration of the therapeutic potential and molecular mechanism of nobiletin in relation to neuroinflammation and neurodegenerative diseases.

Fermented guava leaf extract inhibits LPS-induced COX-2 and iNOS expression in Mouse macrophage cells by inhibition of transcription factor NF-kappaB.

The goal of this study was to elucidate the antiinflammatory activities of Psidium guajava L. (guava) leaf. To improve the functionality of guava leaf, it was fermented with Phellinus linteus mycelia, Lactobacillus plantarum and Saccharomyces cerevisiae. The ethanol extract from fermented guava leaf inhibited lipopolysaccharide (LPS)-induced nitric oxide (NO) and prostaglandin E(2) (PGE(2)) production. Western blot analysis showed that fermented guava leaf extract decreased LPS-induced inducible nitric oxide synthase (iNOS) and the cyclooxygenase-2 (COX-2) protein level in RAW 264.7 cells. To investigate the mechanism involved, the study examined the effect of fermented guava leaf extract on LPS-induced nuclear factor-kappaB (NF-kappaB) activation. Fermented guava leaf extract significantly inhibited LPS-induced NF-kappaB transcriptional activity. Immunochemical analysis revealed that fermented guava leaf extract suppressed LPS-induced degradation of I-kappaBalpha. Taken together, the data indicate that fermented guava leaf extract is involved in the inhibition of iNOS and COX-2 via the down-regulation of NF-kappaB pathway, revealing a partial molecular basis for the antiinflammatory properties of fermented guava leaf extract.

Involvement of extracellular signal-regulated kinase in nobiletin-induced melanogenesis in murine B16/F10 melanoma cells.

Nobiletin contributes to pharmacological activities such as anti-cancer and anti-inflammatory effects, but little is known about its effect on melanogenesis. In this study, we found that nobiletin increased melanin content and tyrosinase activity in murine B16/F10 melanoma cells. Furthermore, inhibition of the extracellular signal-regulated kinase (ERK) pathway with U0216 resulted in inhibition of nobiletin-induced melanin synthesis and tyrosinase expression.

Nobiletin from citrus fruit peel inhibits the DNA-binding activity of NF-kappaB and ROS production in LPS-activated RAW 264.7 cells.

Post-treatment with nobiletin (5,6,7,8,3',4'-hexamethoxy flavone), which was purified from the fruit peel of Citrus sunki Hort. ex Tanaka, at concentration 6-50 microM significantly suppressed NF-kappaB transcriptional activation, NO and PGE(2) production, and iNOS and COX-2 protein expression in lipopolysaccharide (LPS)-activated RAW 264.7 cells. Nobiletin inhibited neither LPS-induced phosphorylation/degradation of inhibitory kappaB-alpha nor LPS-induced nuclear translocation of NF-kappaB. However, it interrupted the DNA-binding activity of activated NF-kappaB. As reactive oxygen species (ROS) are also known to regulate the activation of NF-kappaB, we tested the effect of nobiletin on LPS-induced ROS generation. Nobiletin significantly inhibited LPS-induced intracellular ROS production in RAW 264.7 cells. These results suggest that nobiletin may exert an anti-inflammatory effect through the interruption of NF-kappaB DNA-binding activity and the suppression of ROS generation.