Seung Woong Lee

Oleanolic acid acetate inhibits atopic dermatitis and allergic contact dermatitis in a murine model

Atopic dermatitis (AD) and allergic contact dermatitis (ACD) are common allergic and inflammatory skin diseases caused by a combination of eczema, scratching, pruritus, and cutaneous sensitization with allergens. This paper examines whether oleanolic acid acetate (OAA) modulates AD and ACD symptoms by using an existing AD model based on the repeated local exposure of mite extract (Dermatophagoides farinae extract, DFE) and 2,4-dinitrochlorobenzene to the ears of BALB/c mice. In addition, the paper uses a 2,4-dinitrofluorobenzene-sensitized local lymph node assay (LLNA) for the ACD model. The oral administration of OAA over a four-week period attenuated AD symptoms in terms of decreased skin lesions, epidermal thickness, the infiltration of immune cells (CD4⁺ cells, eosinophils, and mast cells), and serum IgE, IgG2a, and histamine levels. The gene expression of Th1, Th2, Th17, and Th22 cytokines was reduced by OAA in the lymph node and ear tissue, and the LLNA verified that OAA suppressed ACD. The oral administration of OAA over a three-day period attenuated ACD symptoms in terms of ear thickness, lymphocyte proliferation, and serum IgG2a levels. The gene expression of Th1, Th2, and Th17 cytokines was reduced by OAA in the thymus and ear tissue. Finally, to define the underlying mechanism, this paper uses a TNF-α/IFN-γ-activated human keratinocyte (HaCaT) model. OAA inhibited the expression of cytokines and chemokines through the downregulation of NF-κB and MAPKs in HaCaT cells. Taken together, the results indicate that OAA inhibited AD and ACD symptoms, suggesting that OAA may be effective in treating allergic skin disorders.

Phenolic Compounds Isolated from Psoralea corylifolia Inhibit IL-6-induced STAT3 Activation

Inhibiting interleukin-6 (IL-6) has been postulated as an effective therapy in the pathogenesis of several inflammatory diseases. In this study, seven flavonoids were isolated from the methanol extracts of Psoralea corylifolia by bioactivity-guided fractionation. The structures of bakuchiol (1), bavachinin (2), neobavaisoflavone (3), corylifol A (4), corylin (5), isobavachalcon (6), and bavachin (7) were determined by spectroscopic analysis (1H-, 13C- NMR and MS). We demonstrated that compounds 1-7 showed an inhibitory effect on IL-6-induced STAT3 promoter activity in Hep3B cells with IC50 values of 4.57 ± 0.45, 3.02 ± 0.53, 2.77 ± 0.02, 0.81 ± 0.15, 1.37 ± 0.45, 2.45 ± 0.13, and 4.89 ± 0.05 µΜ, respectively. These compounds also inhibited STAT3 phosphorylation induced by IL-6 in Hep3B cells. Overall, several flavonoids from P. corylifolia might be useful remedies for treating inflammatory diseases by inhibiting IL-6-induced STAT3 activation and phosphorylation.

Alkamides from the fruits of Piper longum and Piper nigrum displaying potent cell adhesion inhibition.

Eight alkamides 1-8 were isolated by bioassay-guided isolation of EtOH extracts of the fruits of Piper longum and Piper nigum (Piperaceae). Their structures were elucidated by spectroscopic analysis ((1)H, (13)C NMR, and ESI-MS) as follows: guineensine (1), retrofracamide C (2), (2E,4Z,8E)-N-[9-(3,4-methylenedioxyphenyl)-2,4,8-nonatrienoyl]piperidine (3), pipernonaline (4), piperrolein B (5), piperchabamide D (6), pellitorin (7), and dehydropipernonaline (8). Their compounds 3-5, 7, and 8 inhibited potently the direct binding between sICAM-1 and LFA-1 of THP-1 cells in a dose-dependent manner, with IC(50) values of 10.7, 8.8, 13.4, 13.5, and 6.0 microg/mL, respectively.

Manassantin a and b isolated fromSaururus chinensis inhibit TNF-α-induced Cell adhesion molecule expression of human umbilical vein endothelial cells

Leukocyte adhesion to the vascular endothelium is a critical initiating step in inflammation and atherosclerosis. We have herein studied the effect of manassantin A (1) and B (2), dineolignans, on interaction of THP-1 monocytic cells and human umbilical vein endothelial cells (HUVEC) and expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin in HUVEC. When HUVEC were pretreated with1 and2 followed by stimulation with TNF-α, adhesion of THP-1 cells to HUVEC decreased in dose-dependent manner with IC50 values of 5 ng/mL and 7 ng/mL, respectively, without cytotoxicity. Also,1 and2 inhibited TNF-α-induced up-regulation of ICAM-1, VCAM-1 and E-selectin. The present findings suggest that1 and2 prevent monocyte adhesion to HUVEC through the inhibition of ICAM-1, VCAM-1 and E-selectin expression stimulated by TNF-α, and may imply their usefulness for the prevention of atherosclerosis relevant to endothelial activation.

Kansuinine A and Kansuinine B from Euphorbia kansui L. inhibit IL-6-induced Stat3 activation.

The current study was performed to examine the mechanisms underlying the potential effects of E. KANSUI on IL-6-induced cellular signaling in human hepatoma cells. We found that two diterpenoids, kansuinine A and B, from E. KANSUI have an inhibitory effect on IL-6-induced Stat3 activation by activating ERK1/2. Inhibition of MEK significantly blocked the effects of kansuinine A and B on IL-6-induced Stat3 activation and tyrosine phosphorylation. These results suggest that blocking of IL-6-induced signal transduction is partially due to the sustained activation of ERK1/2 by kansuinine A and B, which in turn results in an increase of Stat3 serine phosphorylation and SOCS-3 expression. Treatment with kansuinine A and B represents a novel method to block these IL-6-induced effects.

Vigna angularis inhibits IL-6-induced cellular signalling and ameliorates collagen-induced arthritis

OBJECTIVES The present study was conducted in order to assess whether extracts or isolated compounds from Vigna angularis were able to suppress IL-6 signalling and to show the therapeutic effect on collagen-induced arthritis (CIA) in mice. METHODS The effect of V. angularis on IL-6 signalling was studied by measuring Stat3-dependent luciferase activity, expression of inflammation-related genes, and phosphorylation of Janus kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3) and extracellular signal-regulated kinase (ERK) induced by IL-6. CIA was induced by immunizing with bovine type II collagen. V. angularis extract (VAE) was administrated orally at 50 and 100 mg/kg from day 1 to day 28. Induction of arthritis was evaluated with a visual scoring system and histological analysis. RESULTS Extracts or two triterpenoid compounds from V. angularis showed potent inhibitory effects on pSTAT3-inducible luciferase activity, STAT3 tyrosine phosphorylation and the expression of inflammation-related genes induced by IL-6. Administration of VAE significantly suppressed the progression of CIA, accompanied by a reduced antibody response to type II collagen and protection from tissue damage in knee joints. CONCLUSION Administration of VAE has a therapeutic effect on CIA and this effect is associated with the inhibitory activity on IL-6/STAT3 signalling. These results suggest that extracts or compounds from V. angularis could be a useful treatment for diseases related to IL-6, including RA.

Bavachin and isobavachalcone, acyl-coenzyme A: Cholesterol acyltransferase inhibitors from Psoralea corylifolia

Acyl-coenzyme A: cholesterol acyltransferase (ACAT) catalyzes cholesterol esterification and plays important roles in intestinal absorption of cholesterol, hepatic production of lipoproteins and accumulation of cholesteryl ester within macrophages and smooth muscle cells. Ethanol extract of Psoralea corylifolia showed a significant inhibition of ACAT enzyme. Via bioactivity-guided fractionation of the ethanol extract of Psoralea corylifolia, two prenylated flavonoids were isolated. Their structures were determined as bavachin (1) and isobavachalcone (2) by spectroscopic analysis (1H-, 13C-NMR, 2DNMR, and ESI-MS). The IC50 values were 86.0 (1) and 48.0 (2) μM in the ACAT assay system using rat liver microsome. Compound 2 also decreased cholesteryl ester formations in HepG2 cells. In addition, this compound showed a noncompetitive type of inhibition of ACAT.

Inhibition of LFA-1/ICAM-1-mediated cell adhesion by stilbene derivatives from Rheum undulatum

Six stilbenes were isolated from the methanol extract of Rheum undulatum rhizomes by bioactivity-guided fractionation. The structures of the compounds were determined by spectroscopic analysis (1H-, 13C-NMR and MS), to be desoxyrhapontigenin (1), rhapontigenin (2), trans-resveratrol (3), piceatannol (4), piceatannol-3′-O-β-D-glucopyranoside (5) and isorhapontin (6). Compounds 1–4 inhibited the direct binding between sICAM-1 and LFA-1 of the THP-1 cells in a dose-dependent manner with IC50 values of 50.1, 25.4, 33.4 and 45.9 μM, respectively. On the other hand, the other compounds 5 and 6 with a glucose moiety in each molecule did not show any inhibitory activity in the cell adhesion assay (IC50 values of >100.0 μM). Compounds 2, 3 and 4 also had an inhibitory effect on direct binding between sVCAM-1 and VLA-4 of THP-1 cells. This suggests that the stilbenes from Rheum undulatum rhizomes are good candidates for therapeutic strategies towards inflammation.

Anti-rotavirus effects by combination therapy of stevioside and Sophora flavescens extract

Anti-rotaviral activities of Sophora flavescens extract (SFE) and stevioside (SV) from Stevia rebaudiana Bertoni either singly or in various combinations were examined in vitro and in vivo using a porcine rotavirus G5[P7] strain. Combination of SFE and SV inhibited in vitro virus replication more efficiently than each single treatment. In the piglet model, SV had no effect on rotavirus enteritis, whereas SFE improved but did not completely cure rotaviral enteritis. Interestingly, combination therapy of SFE and SV alleviated diarrhea, and markedly improved small intestinal lesion score and fecal virus shedding. Acute toxicity tests including the piglet lethal dose 50, and body weight, organ weight and pathological changes for the combination therapy did not show any adverse effect on the piglets. These preliminary data suggest that the combination therapy of SV and SFE is a potential curative medication for rotaviral diarrhea in pigs. Determination of the efficacy of this combination therapy in other species including humans needs to be addressed in the future.

Saikosaponin D isolated from Bupleurum falcatum inhibits selectin-mediated cell adhesion.

Three saikosaponins were isolated from the MeOH extract of the roots of Bupleurum falcatum L.: saikosaponins B3 (1); B4 (2); and D (3). Of the three, compound 3 inhibited the interaction of selectins (E, L, and P) and THP-1 cells with IC50 values of 1.8, 3.0 and 4.3 µM, respectively. Also, the aglycone structure 4 of compound 3 showed moderate inhibitory activity on L-selectin-mediated cell adhesion. From these results, we suspect that compound 3 isolated from Bupleurum falcatum roots would be a good candidate for therapeutic strategies to treat inflammation.