Effects Of Arctigenin Research Articles

Effects of Arctigenin in Proliferation, Migration, and Invasion of Nasopharyngeal Carcinoma 5-8F Cells.

Nasopharyngeal carcinoma (NPC) is a malignant tumor of the nasopharynx. Here, we aimed to understand better the molecular basis for arctigenin (ARG)'s ability to promote NPC 5- 8F cell invasion. We tested the effects of several doses of ARG on 5-8F cells that had been cultured in vitro. We estimated the metabolic activity of cells by The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) tetrazolium assay. We examined the influence on cell invasion, and migration using Transwell Evaluation. Real-time polymerase chain reaction analysis was used to determine the relative amounts of epidermal growth factor receptor (EGFR), Janus kinase 2 (JAK2) , and transcriptional activator 3 (STAT 3) mRNA expression. Using western blotting, we looked at the level of phosphorylation of specific proteins like EGFR, phosphorylated EGFR, JAK2, and STAT 3. Our findings revealed that ARG inhibited NPC 5-8F cell development in a dose-and time-dependent manner. The invasiveness and mobility of 5-8F cells were significantly suppressed when ARG was overexpressed in a tumor development model. Expression levels of EGFR, JAK2, and STAT 3 mRNA were considerably low in the experimental group. As a consequence of being treated with ARG, lower levels of EGFR, p-EGFR, p-JAK2, and p-STAT3 expression were observed. These results suggest that ARG may prevent NPC 5-8F cells from proliferating, migrating, and invading other tissues. There are a few potential molecular pathways, two of which are the inhibition of EGFR phosphorylation and the reduction of levels of phospho-JAK2 and phospho-STAT3.

Arctigenin Prevents Retinal Edema in a Murine Retinal Vein Occlusion Model.

Macular edema causes vision loss in patients with retinal vein occlusion (RVO) and diabetic macular edema (DME). The intravitreal injection of anti-vascular endothelial growth factor (VEGF) agents is used for treatment; however, this therapy is invasive, and recurrence occurs in some cases. The establishment of a non-invasive treatment would help to solve these problems. Here, we focused on arctigenin, a lignan polyphenol found in burdock sprout, and has effects on inflammatory and microcirculatory when taken orally. We hypothesized that oral intake of arctigenin could be effective against retinal edema in RVO and DME. In this study, the degree of retinal edema by measuring the total retinal thickness using optical coherence tomography (OCT) and the thickness of the inner nuclear layer (INL) by hematoxylin-eosin (H&E) staining were investigated. Oral administration of arctigenin ameliorated retinal edema in an RVO murine model by inhibiting the decrease in occludin and vascular endothelial (VE)-cadherin. Moreover, in retinas with edema, arctigenin suppressed the induction of VEGF, tumor necrosis factor α (TNFα), and matrix metallopeptidase 9 (MMP9). Next, the effects of arctigenin on barrier function were assessed in human retinal microvascular endothelial cells (HRMECs) by measuring the trans-endothelial electrical resistance (TEER) and conducting fluorescein isothiocyanate (FITC)-dextran permeability assays. Arctigenin showed a protective effect against VEGF-induced barrier dysfunction. In addition, arctigenin inhibited the TNFα-mediated activation of the nuclear factor-kappaB (NF-κB)/p38 mitogen-activated protein kinase (MAPK) pathway. These results suggested that oral administration of arctigenin has beneficial effects on retinal edema by inhibiting vascular hyperpermeability in endothelial cells.

Ameliorative Effects of Arctigenin on Pulmonary Fibrosis Induced by Bleomycin via the Antioxidant Activity

In this study, we evaluated the in vivo effect of arctigenin (ATG) on bleomycin-induced pulmonary fibrosis in mice and assessed the role of antioxidant activity. Hematoxylin and eosin (H&E) staining, the results of Masson's trichrome, and Sirius red staining showed that bleomycin induced obvious pathological changes and collagen deposition in the lung tissue of mice, which were effectively inhibited by ATG. Specifically, based on immunohistochemistry and western blot results, ATG inhibited the expression of fibrosis markers, such as collagen, fibronectin, and α-SMA. Moreover, ATG regulated reactive oxygen species (ROS), superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione (GSH) in the lung tissue of pulmonary fibrosis mice and reduced the pressure of oxidative stress. ATG also regulated the TGF-β-induced expression of p-Akt, confirming that ATG can inhibit fibrosis through antioxidant activity modulation.

Arctigenin attenuates paraquat-induced human lung epithelial A549 cell injury by suppressing ROS/p38 mitogen-activated protein kinases-mediated apoptosis.

Paraquat (PQ)-induced acute lung injury (ALI) and pulmonary fibrosis are common diseases with high mortality but without effective antidotes in emergency medicine. Our previous study has proved that arctigenin suppressed pulmonary fibrosis induced by PQ. We wondered whether arctigenin could also have a protective effect on PQ-induced ALI. A PQ-induced A549 cell injury model was used, and the effect of arctigenin was determined by a cell counting kit-8 (CCK-8) cell viability assay. In addition, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labelling (TUNEL) staining assays and mitochondrial membrane potential assays were performed to evaluate the level of cell apoptosis. The generation of reactive oxygen species (ROS) was reflected by dihydroethidium (DHE) staining and a 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) assay. Moreover, immunoblotting studies were used to assess the expression of mitogen-activated protein kinases (MAPKs) and p38 MAPK. Arctigenin attenuated PQ-induced inhibition of A549 cell viability in a dose-dependent manner. Arctigenin also significantly reduced PQ-induced A549 cell apoptosis, as reflected by the TUNEL assay and mitochondrial membrane potential assay, which may result from suppressed ROS/p38 MAPK signaling because we found that arctigenin dramatically suppressed ROS generation and p38 MAPK phosphorylation. Arctigenin could attenuate PQ-induced lung epithelial A549 cell injury in vitro by suppressing ROS/p38 MAPK-mediated cell apoptosis, and arctigenin might be considered a potential candidate drug for PQ-induced ALI.

Arctigenin Exerts Neuroprotective Effect by Ameliorating Cortical Activities in Experimental Autoimmune Encephalomyelitis In Vivo.

Multiple sclerosis (MS) is a chronic disease in the central nervous system (CNS), characterized by inflammatory cells that invade into the brain and the spinal cord. Among a bulk of different MS models, the most widely used and best understood rodent model is experimental autoimmune encephalomyelitis (EAE). Arctigenin, a botanical extract from Arctium lappa, is reported to exhibit pharmacological properties, including anti-inflammation and neuroprotection. However, the effects of arctigenin on neural activity attacked by inflammation in MS are still unclear. Here, we use two-photon calcium imaging to observe the activity of somatosensory cortex neurons in awake EAE mice in vivo and found added hyperactive cells, calcium influx, network connectivity, and synchronization, mainly at preclinical stage of EAE model. Besides, more silent cells and decreased calcium influx and reduced network synchronization accompanied by a compensatory rise in functional connectivity are found at the remission stage. Arctigenin treatment not only restricts inordinate individually neural spiking, calcium influx, and network activity at preclinical stage but also restores neuronal activity and communication at remission stage. In addition, we confirm that the frequency of AMPA receptor-mediated spontaneous excitatory postsynaptic current (sEPSC) is also increased at preclinical stage and can be blunted by arctigenin. These findings suggest that excitotoxicity characterized by calcium influx is involved in EAE at preclinical stage. What is more, arctigenin exerts neuroprotective effect by limiting hyperactivity at preclinical stage and ameliorates EAE symptoms, indicating that arctigenin could be a potential therapeutic drug for neuroprotection in MS-related neuropsychological disorders.

Improved Method for Obtaining of Arctigenin from Arctium Lappa L. and its Antiproliferative Effect on Human Hepatocarcinoma HepG2 Cells

Background: Arctigenin is a lignan found in Arctium lappa L. (Asteraceae) that displays anti-inflammatory activities. Previous studies showed that the crude extract of A. Lappa has antitumor activity in human liver carcinoma, lung and stomach cancer cells. The aim of this study was to obtain arctigenin from A. lappa L., as well as to evaluate its antiproliferative effects in cells of liver carcinoma (HepG2) and fibroblasts (NIH/3T3). Methods: Arctigenin was obtained from the hydrolysis of arctiin, which was isolated from the crude extract of A. lappa. The effects of arctigenin and arctiin on HepG2 cell viability and cell adhesion were analyzed by MTT method. Adhesion assay was also carried out to evaluate the antitumor activity. Results: Our results showed that the analytical process to obtain arctigenin was fast and easy. In vitro experiments showed that arctigenin (107-269 μM) decreased HepG2 cells viability and did not cause cytotoxicity on NIH/3T3 cells. Arctigenin (27-269 μM) demonstrated anti-adhesion in HepG2 cells in a concentration-dependent manner, when compared with control. Conclusion: These results suggest a promising pharmacological activity for arctigenin as an antiproliferative compound.

Anti‑metastatic effects of arctigenin are regulated by MAPK/AP‑1 signaling in 4T‑1 mouse breast cancer cells.

Arctigenin is a natural lignan that is found in burdock with anti‑viral, ‑oxidative, ‑inflammatory and anti‑tumor activities. In the current study, the effect of arctigenin on metastatic potential was examined in 4T‑1 mouse triple‑negative breast cancer cells. The results indicated that arctigenin inhibited cell motility and invasiveness, which was determined using wound healing and transwell invasion assays. Arctigenin suppressed matrix metalloprotease‑9(MMP‑9) activity via gelatin zymography, and protein expression of cyclooxygenase‑2(COX‑2) and MMP‑3. Furthermore, arctigenin attenuated the mRNA expression of metastatic factors, including MMP‑9, MMP‑3 and COX‑2. Based on these results, the effect of arctigenin on the mitogen‑activated protein kinase (MAPK)/activating protein‑1(AP‑1) signaling pathway was assessed in an attempt to identify the regulatory mechanism responsible for its anti‑metastatic effects. Arctigenin was demonstrated to inhibit the phosphorylation of extracellular signal‑regulated protein kinase(ERK) and c‑Jun N‑terminal kinase(JNK), and the nuclear translocations of the AP‑1 subunits, c‑Jun and c‑Fos. In summary, the present study demonstrated that in 4T‑1 mouse triple‑negative breast cancer cells the anti‑metastatic effect of arctigenin is mediated by the inhibition of MMP‑9 activity and by the inhibition of the metastasis‑enhancing factors MMP‑9, MMP‑3 and COX‑2, due to the suppression of the MAPK/AP‑1 signaling pathway. The results of the current study demonstrated that arctigenin exhibits a potential for preventing cell migration and invasion in triple negative breast cancer.

Abstract 5253: Arctigenin inhibits prostate tumor growth in vitro and in vivo in obese state

Abstract Arctigenin is a novel anti-inflammatory lignan derived mainly from the seeds of Arctium lappa which is an herb widely used in traditional Chinese medicine to treat inflammation related diseases. We previously demonstrated that arctigenin strongly inhibited prostate tumor cell growth in cell culture and mouse models in non-obese state. The present study investigated the tumor inhibitory effect of arctigenin in obese state. An in vitro obese setting was created by co-culture of mouse adipocytes 3T3-L1 with androgen-sensitive LAPC-4 and LNCaP prostate cancer cells. An ELISA analysis of 3T3-L1 conditioned medium revealed that three cytokines/growth factors were prominently secreted by 3T3-L1 cells, including IGF-1, VEGF, and MCP-1, and the sensitivity of prostate cancer cells to arctigenin was decreased in the obese state. However, arctigenin at a moderate concentration (10 µM) significantly inhibited the proliferation of both LAPC-4 and LNCaP cell by 40-50% at 96h in the co-culture system. Male severe combined immunodeficiency (SCID) mice was implanted subcutaneously with LAPC-4 xenograft tumors to confirm the tumor-inhibitory effect of arctigenin in vivo. Mice were fed high-fat diet containing 45% energy from fat, and treated with arctigenin at 50mg/kg b.w. orally or vehicle control for 6 weeks (n=10 per group). The tumor growth in arctigenin group was significantly inhibited by 40% compared to control, along with decreased blood concentrations of several cytokines including IGF-1, VEGF, and MCP-1. Immunohistochemistry analysis is ongoing to determine the molecular changes involved in tumor cell proliferation and apoptosis in response to arctigenin treatment. This study provides a promising natural compound to enhance chemoprevention of prostate cancer especially in obese patients. These results warrant future clinical trial studies to confirm the anti-carcinogenic effect of arctigenin in humans. Citation Format: Piwen Wang, Tanya Diaz, Susanne Henning, Jaydutt Vadgama. Arctigenin inhibits prostate tumor growth in vitro and in vivo in obese state [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5253. doi:10.1158/1538-7445.AM2017-5253

Abstract 2626A: A lignan compound arctigenin inhibits prostate tumor growth in vitro and in vivo

Abstract Arctigenin is a novel anti-inflammatory lignan derived mainly from the seeds of Arctium lappa, an herb widely used in traditional Chinese medicine to treat inflammation related diseases such as cough, cold and swelling of throat. The present study was designed to investigate whether arctigenin is a potent inhibitor of prostate cancer using both in vitro and xenograft mouse models. The treatments with arctigenin at lower doses (< 2μM) for 48h dose-dependently inhibited the proliferation of two androgen-sensitive prostate cancer cell lines, LNCaP and LAPC-4, by 40-50% compared to control. There was no cytotoxicity observed in normal prostate epithelial PrEC cells with arctigenin doses up to 10μM. An intervention study was then conducted in severe combined immunodeficiency (SCID) mice to confirm the tumor-inhibitory effect of arctigenin in vivo. Male SCID mice (n = 10 per group) were inoculated with 5×10⁁5 LAPC-4 cells subcutaneously. One week later when tumors were palpable the intervention started. Mice were administered with arctigenin at 50mg/kg (LD) or 100mg/kg (HD) or vehicle control daily for 6 weeks by oral gavage. After 4 weeks of intervention the tumor growth was significantly inhibited by both of the arctigenin doses. After 6 weeks of intervention, the tumor volumes were reduced by 48% (LD arctigenin) and 67% (HD arctigenin) compared to control. There was no significant difference in food or water consumption or body weight among groups. An ELISA assay of growth factors demonstrates that arctigenin treatments significantly decreased the concentrations of VEGF, EGF, NGF-β, TNF-α, and FGF-β in tumor tissues compared to control. Western blot analysis revealed a significantly reduced expression of galectin-4 in tumor tissues by arctigenin treatment. Previous studies have shown that strong expression of galectin-4 can be induced in different types of cancer, associated with tumor growth and progression. A microRNA PCR array assay was performed to measure the tumor concentrations of 84 microRNAs involved in prostate cancer development and progression. A panel of microRNAs including miR-126 and miR-135 were identified to be responsive to arctigenin treatment. Further mechanistic investigation using tissue microarray assay is ongoing to measure the protein markers of proliferation and apoptosis in tumor tissues. This study provides a promising non-toxic agent to enhance chemoprevention of prostate cancer. These results warrant future clinical trial studies to confirm the anti-carcinogenic effect of arctigenin in humans. Citation Format: Piwen Wang, Susanne M. Henning, Jaydutt V. Vadgama. A lignan compound arctigenin inhibits prostate tumor growth in vitro and in vivo. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2626A.

Arctigenin Suppress Th17 Cells and Ameliorates Experimental Autoimmune Encephalomyelitis Through AMPK and PPAR-γ/ROR-γt Signaling.

Arctigenin is a herb compound extract from Arctium lappa and is reported to exhibit pharmacological properties, including neuronal protection and antidiabetic, antitumor, and antioxidant properties. However, the effects of arctigenin on autoimmune inflammatory diseases of the CNS, multiple sclerosis (MS), and its animal model experimental autoimmune encephalomyelitis (EAE) are still unclear. In this study, we demonstrated that arctigenin-treated mice are resistant to EAE; the clinical scores of arctigenin-treated mice are significantly reduced. Histochemical assays of spinal cord sections also showed that arctigenin reduces inflammation and demyelination in mice with EAE. Furthermore, the Th1 and Th17 cells in peripheral immune organs are inhibited by arctigenin in vivo. In addition, the Th1 cytokine IFN-γ and transcription factor T-bet, as well as the Th17 cytokines IL-17A, IL-17F, and transcription factor ROR-γt are significantly suppressed upon arctigenin treatment in vitro and in vivo. Interestedly, Th17 cells are obviously inhibited in CNS of mice with EAE, while Th1 cells do not significantly change. Besides, arctigenin significantly restrains the differentiation of Th17 cells. We further demonstrate that arctigenin activates AMPK and inhibits phosphorylated p38, in addition, upregulates PPAR-γ, and finally suppresses ROR-γt. These findings suggest that arctigenin may have anti-inflammatory and immunosuppressive properties via inhibiting Th17 cells, indicating that it could be a potential therapeutic drug for multiple sclerosis or other autoimmune inflammatory diseases.

Whitening Effects of Arctigenin Extracted from the Arctii Fructus

Whitening Effects of Arctigenin Extracted from the Arctii Fructus

Protective effect of arctigenin in GK rats combined with hypertension macroangiopathy

To study the protective effect of Arctigenin in goto-kakizaki (GK) rats combined with hypertension macroangiopathy. Six-week-old GK rats were divided randomly according to blood glucose level into four groups: the model group and low, middle and high dose arctigenin groups (12.5, 25, 50 mg x kg(-1)), with Wistar rats as the normal group. All of GK rats were given high-glucose and high-fat diet. After 16 weeks, GK rats were orally administrated with 10 mg x kg(-1) x d(-1) N-Ω-nitro-L-arginine methyl ester for eight weeks. During the modeling, all of arctigenin groups were orally administrated with different dose of arctigenin twice a day; The model group and the normal group were given solvents. At the beginning, mid-term and end of the experiment, blood glucose was measured. At the end of the experiment, efforts were made to detect blood pressure, collect abdominal aortic blood after anesthesia, fix thoracic aorta after bloodletting to make paraffin sections, observe morphological characteristics and detect the expression of VEGF by immunohistochemistry. According to the results, the blood glucose rose in all GK rats, with no significant difference between the drug group and the model group. At the end of the experiment, the blood pressure significantly increased in GK rats, indicating that Arctigenin could notably reduce the blood pressure in GK rats in a dose-dependent manner. The blood routine test showed increases in both the total white blood cell count and differential blood count, MPV and PDW, abnormal blood platelet parameters and decrease in PLT in GK rats, suggesting that Arctigenin could remarkably reduce the total white blood cell count and differential blood count, MPV and PDW. The thoracic aortic morphological observation revealed obvious endangium lesions in GK rats, demonstrating that Arctigenin could ameliorate the lesion extent. VEGF immumohistochemical staining showed a higher VEGF expression in the model group but lower expression in Arctigenin groups. In conclusion, Arctigenin had a protective effect on aorta in GK rats. Its mechanism may be related to blood pressure lowering, anti-inflammation, improvement in blood platelet function and reduction of VEGF expression.

The effects of arctigenin on human rheumatoid arthritis fibroblast-like synoviocytes

Context: Rheumatoid arthritis fibroblast-like synoviocytes (RAFLSs) play an important role in the initiation and progression of RA, which are resistant to apoptosis and proliferate in an anchorage-independent manner.Objective: The effects of arctigenin on the proliferation and apoptosis of RAFLSs were explored.Materials and methods: Arctigenin (0–160 µM) was used to treat RAFLSs for 48 h. Cell viability and apoptosis were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide assay and annexin V/propidium iodide staining. Western blot analysis was performed to detect the changes in apoptosis-related genes.Results and discussion: Arctigenin decreased cell viability by 23, 30, and 38% at the dose of 10, 20, and 30 µM, respectively. The half maximal inhibitory concentration (IC50) of arctignein on RAFLSs was about 38 µM. Moreover, 9, 15, and 21% of RAFLSs are induced apoptosis by 10, 20, and 30 µM of arctigenin. The apoptotic response was due to the loss of mitochondrial membrane potential, coupled with the release of cytochrome C into cytoplasm, the up-regulation of pro-apoptotic protein, Bax, and down-regulation of antiapoptotic protein, B cell lymphoma 2 (Bcl-2). The activation of mitochondrial pathway in arctigenin-treated RAFLSs induced the cleavage of caspase-9, caspase-3, and poly (ADP-ribose) polymerase (PARP). Additionally, arctigenin inhibited the nuclear translocation of p65, decreased the degradation of inhibitor of kappa B alpha (IκBα), and attenuated the phosphorylation of Akt.Conclusion: Our results reveal that arctigenin inhibits cell proliferation and induces mitochondrial apoptosis of RAFLSs, which is associated with the modulation of NF-κB and Akt signaling pathways.

Effect of arctigenin on apoptosis of mouse erythroleukemia FBL-3 cells and its mechanism

Objective To investigate the effect of arctigenin on the apoptosis of FBL-3 cells and its mechanisms. Methods The mouse erythroleukemia FBL-3 cells were taken as subjects. The untreated FBL-3 parental cells were taken as the control group, and the FBL-3 cells treated with 20 mg/L arctigenin for 24 h were taken as the experimental group. The effects of arctigenin on the apoptosis of the mouse erythroleukemia FBL-3 cells were determined by agarose gel electrophoresis and flow cytometry assay. The changes of apoptosis-related genes were analyzed by reverse transcriptase-polymerase chain reaction(RT-PCR). Results The agarose gel electrophoresis results revealed that the DNA ladder was displayed in the experimental group compared to the control group. The flow cytometry data demonstrated that the apoptosis number of FBL-3 cells in the experimental group was markedly increased compared to that in the control group (t=60.681, P=0.000). The RT-PCR assay results suggested that the expressions of Bcl-2 and IAP-1 gene were down-regulated in the experimental group compared to the control group (t=14.732, 29.702, all P=0.000), while the expressions of Bax and Smac gene were up-regulated(t=6.721, 8.499; P=0.003, 0.001), but the expression of Bcl-XL did not change(t=0.209, P=0.844). Conclusions Arctigenin can induce the apoptosis of the mouse erythrolenkemia FBL-3 cells. Apoptosis of the mouse erythrolenkemia FBL-3 cells induced by arctigenin may be correlated to the down-regulation of Bcl-2 and IAP-1 and up-regulation of Bax as well as Smac. Key words: Arctigenin; Leukemia; Apoptosis; Anti-apoptosis gene; Pro-apoptosis gene

Arctigenin suppresses receptor activator of nuclear factor κB ligand (RANKL)-mediated osteoclast differentiation in bone marrow-derived macrophages

Osteoclasts, multinucleated bone-resorbing cells, are closely associated with bone diseases such as rheumatoid arthritis and osteoporosis. Osteoclasts are derived from hematopoietic precursor cells, and their differentiation is mediated by two cytokines, including macrophage colony stimulating factor and receptor activator of nuclear factor κB ligand (RANKL). Previous studies have shown that arctigenin exhibits an anti-inflammatory effect. However, the effect of arctigenin on osteoclast differentiation is yet to be elucidated. In this study, we found that arctigenin inhibited RANKL-mediated osteoclast differentiation in bone marrow macrophages in a dose-dependent manner and suppressed RANKL-mediated bone resorption. Additionally, the expression of typical marker proteins, such as NFATc1, c-Fos, TRAF6, c-Src, and cathepsin K, were significantly inhibited. Arctigenin inhibited the phosphorylation of Erk1/2, but not p38 and JNK, in a dose-dependent manner. Arctigenin also dramatically suppressed immunoreceptor tyrosine-based activation motif-mediated costimulatory signaling molecules, including Syk and PLCγ2, and Gab2. Notably, arctigenin inhibited the activation of Syk through RANKL stimulation. Furthermore, arctigenin prevented osteoclast differentiation in the calvarial bone of mice following stimulation with lipopolysaccharide. Our results show that arctigenin inhibits osteoclast differentiation in vitro and in vivo. Therefore, arctigenin may be useful for treating rheumatoid arthritis and osteoporosis.

Induction of Apoptosis and Acetylation of Histone H3 and H4 by Arctigenin in the Human Melanoma Cell Line SK-MEL-28

Cutaneous melanoma is one of the most aggressive forms of skin cancer. Arctigenin, one of the major bioactive compo-nents of Arctii Fructus, has been reported to exhibit antioxidant, antitumor and anti-inflammatory activities. In the pre-sent study, we investigated the effect of arctigenin on induction of apoptosis in highly metastatic SK-MEL-28 human melanoma cells. Arctigenin inhibited growth of SK-MEL-28 cells in a dose-dependent manner. Treatment of SK-MEL-28cells with arctigenin caused cleavage of caspases 3, 7 and 9, and poly (ADP-ribose) polymerase in a dose-dependent manner. Furthermore, acetylation of histone H3 and H4 in the SK-MEL-28 cells was dramatically increased by arctigenin treatment. Collectively, these findings indicate that arctigenin-induces apoptosis of SK-MEL-28 melanoma cells via activation of caspases and histone acetylation.

Potent inhibition of lipopolysaccharide-inducible nitric oxide synthase expression by dibenzylbutyrolactone lignans through inhibition of I-κBα phosphorylation and of p65 nuclear translocation in macrophages

Aims: Arctigenin and demethyltraxillagenin, dibenzylbutyrolactone lignans, are phenylpropanoid metabolites with antioxidant and anti-inflammatory activities. The effects of arctigenin and demethyltraxillagenin on the nuclear factor-κB (NF-κB)-mediated inducible nitric oxide synthase (iNOS, EC1.14.13.39) gene expression were studied in Raw264.7 cells. Methods: Activation of NF-κB was determined by gel mobility shift assay, immunocytochemistry and immunoblot analysis of I-κBα. Expression of the iNOS gene was assessed by Northern and Western blot analyses. NO production was monitored by chemiluminescent detection using a nitric oxide analyzer. Results: Arctigenin (1 μM) inhibited lipopolysaccharide (LPS)-inducible nuclear NF-κB activation and nuclear translocation of p65, which was accompanied by inhibition of I-κBα phosphorylation, whereas demethyltraxillagenin was less active. LPS-inducible increase in the iNOS mRNA was 80–90% inhibited by 0.01–1 μM arctigenin, whereas similar extents of inhibition were noted by 50–100 μM demethyltraxillagenin. Immunoblot analysis revealed that arctigenin potently inhibited the induction of iNOS by LPS (IC50≤0.01 μM). The IC50 value of demethyltraxillagenin was ∼50 μM. Production of nitrite and nitrate by LPS in culture medium was also comparably suppressed by the lignans. Conclusion: These results demonstrated that arctigenin potently inhibited LPS-inducible iNOS expression in murine macrophages through suppression of I-κBα phosphorylation and nuclear translocation of p65. Potent inhibition of LPS-inducible NO production in macrophages may constitute anti-inflammatory effects of the dibenzylbutyrolactone lignans.