Hyun-Mee Oh

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.

Salvia plebeia extract inhibits the inflammatory response in human rheumatoid synovial fibroblasts and a murine model of arthritis

Salvia plebeia R. Br. has been used to treat a variety of inflammatory diseases and as an antioxidant in many countries, including Korea and China. In this study, we investigated the effects of S. plebeia extract (SPE) on inflammatory arthritis and the underlying mechanisms of action. We used a collagen-induced arthritis (CIA) mouse model. TNF-α-stimulated rheumatoid arthritis (RA) synovial fibroblasts were used to elucidate the underlying mechanisms of action. Oral administration of SPE improved the clinical arthritis score, footpad thickness, and histologic changes, as well as serum IgG1 and IgG2a levels. SPE administration inhibited Th1/Th2/Th17 phenotype CD4(+) T lymphocyte expansion in inguinal lymph node and expression of inflammatory mediators such as cytokines, MMP-1, and MMP-3 in the ankle joint tissue. SPE significantly suppressed the expression of cytokines and MMP-1 by down-regulating NF-κB, Akt, and mitogen-activated protein kinases in RA synovial fibroblasts. Taken together, these results indicate that SPE is therapeutically efficacious against chronic inflammatory arthritis, suggesting that SPE is a candidate for treating RA.

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.

Oleanolic acid acetate inhibits rheumatoid arthritis by modulating T cell immune responses and matrix-degrading enzymes.

Rheumatoid arthritis (RA) is a chronic autoimmune disease associated with a combination of synovium joint inflammation, synovium hyperplasia, and destruction of cartilage and bone. Oleanolic acid acetate (OAA), a compound isolated from Vigna angularis, has been known to possess pharmacological activities, including anti-inflammation and anti-bone destruction. In this study, we investigated the effects of OAA on RA and the underlying mechanisms of action by using a type-II collagen-induced arthritis (CIA) mouse model and tumor necrosis factor (TNF)-α-stimulated RA synovial fibroblasts. Oral administration of OAA decreased the clinical arthritis symptoms, paw thickness, histologic and radiologic changes, and serum total and anti-type II collagen IgG, IgG1, and IgG2a levels. OAA administration reduced Th1/Th17 phenotype CD4(+) T lymphocyte expansions and inflammatory cytokine productions in T cell activated draining lymph nodes and spleen. OAA reduced the expression and production of inflammatory mediators, such as cytokines and matrix metalloproteinase (MMP)-1/3, in the ankle joint tissue and RA synovial fibroblasts by down-regulating Akt, mitogen-activated protein kinases, and nuclear factor-κB. Our results clearly support that OAA plays a therapeutic role in RA pathogenesis by modulating helper T cell immune responses and matrix-degrading enzymes. The immunosuppressive effects of OAA were comparable to dexamethasone and ketoprofen. We provide evidences that OAA could be a potential therapeutic candidate for RA.

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.

Salvia plebeia R.Br. inhibits signal transduction of IL-6 and prevents ovariectomy-induced bone loss by suppressing osteoclastogenesis

The interleukin-6 (IL-6) family of cytokines plays a key role in the pathogenesis of rheumatoid arthritis and osteoporosis through the regulation of bone formation and resorption. In this study, it was observed that ethanol extract of Salvia plebeia R.Br. (S.P-EE) inhibited IL-6-induced signaling cascade including phosphorylation of JAK2/STAT3 and ERK. Subsequently, it was examined whether S.P-EE treatment could recover bone loss in ovariectomized (OVX) mice. Indeed, S.P-EE exhibited both preventive and therapeutic effect on OVX-induced bone loss in trabecular microarchitecture along with significant increase in bone mineral density and content. To understand the mechanism of action of S.P-EE in bone metabolism, the effect of S.P-EE on osteoclast differentiation and activity was investigated. S.P-EE significantly inhibited RANKL-induced osteoclast differentiation by suppressing phosphorylation of MAPK and Akt, and expression of NFATc1 and osteoclast marker genes. S.P-EE also inhibited bone-resorbing activity of osteoclasts. Furthermore, isolation and identification of the active compounds which are responsible for the inhibitory effect of S.P-EE on osteoclast differentiation was carried out. Six major flavonoids and plebeiolide A–C were isolated and examined their effects on osteoclast differentiation. Luteolin and hispidulin, and plebeiolide A and C, not B exhibited potent inhibitory activity on RANKL-induced osteoclast formation.

Norkurarinol inhibits toll-like receptor 3 (TLR3)-mediated pro-inflammatory signaling pathway and rotavirus replication.

Abstract This study examined the effect of norkurarinol on the toll-like receptor 3 (TLR3)-mediated signaling pathways and rotavirus replication. Norkurarinol, a lavandulylated flavanone, was isolated from the roots of Sophora flavescens, which has been shown to have anti-inflammatory activity. Norkurarinol suppressed the NF-κB and AP-1 inducible secreted embryonic alkaline phosphatase (SEAP) activity induced by poly(I:C), TLR3 ligand, in THP1-Blue-CD14 cells with IC50 values of 20.9 μM. Norkurarinol also significantly suppressed the mRNA expression of proinflammatory and adhesive molecules induced by poly(I:C) and rotavirus infection. Pretreatment of norkurarinol blocked the NF-κB and AP-1 signaling pathway and the phosphorylation of MAPKs induced by poly(I:C). On the other hand, norkurarinol increased the level of IRF3 phosphorylation and IFNβ expression in a dose-dependent manner. Moreover, norkurarinol inhibited the rotavirus-induced cytopathic effects. These results suggest that norkurarinol can modulate the TLR3-mediated inflammatory responses and rotavirus replication.