Hyun Gyu Choi

Suppression of dust mite extract and 2,4-dinitrochlorobenzene-induced atopic dermatitis by the water extract of Lindera obtusiloba.

ETHNOPHARMACOLOGICAL RELEVANCE The Lindera obtusiloba has been used in traditional medicine for the treatment of inflammation and dermatitis. In this study, we investigated the effect of topical application of Lindera obtusiloba water extract (LOWE) on the house dust mite extract (Dermatophagoides farinae extract, DFE) and 2,4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis (AD). MATERIALS AND METHODS We established AD model in BALB/c mice by repeated local exposure of DFE/DNCB to the ears. After a topical application of LOWE on the skin lesions, the epidermal thickness, mast cell infiltration, and serum immunoglobulin E (IgE) and histamine were measured. In addition, the gene expression of interleukin (IL)-4, IL-13, IL-31, and tumor necrosis factor (TNF)-α in the ears was assayed. RESULTS LOWE reduced AD symptoms based on ear thickness, histopathological analysis, and serum IgE levels. LOWE inhibited mast cell infiltration into the ear and elevation of serum histamine in AD model. Moreover, LOWE suppressed DFE/DNCB-induced expression of IL-4, IL-13, IL-31, and TNF-α in the ears. CONCLUSIONS Our results showed that topical application of LOWE exerts beneficial effects in AD symptoms, suggesting that LOWE might be a candidate for the treatment of AD.

Chemical constituents of Cynanchum wilfordii and the chemotaxonomy of two species of the family Asclepiadacease, C. wilfordii and C. auriculatum

Definitive identification of original plant species is important for standardizing herbal medicine. Although only the dried roots of Cynanchum wilfordii (Asclepiadaceae) are prescribed as Cynanchi Wilfordii Radix in Korean Pharmacopoeia, the roots of C. wilfordii and C. auriculatum are often misused in the Korean herbal market due to their morphological similarity and similar name. Therefore, it would be very useful to discover an effective chemical marker for the identification of the two species. To this end, we carried out a phytochemical study on the roots of C. wilfordii. As a result, twenty compounds were isolated from the roots of C. wilfordii and their chemical structures were identified as β-sitosterol (1), wilfoside C1N (2), wilfoside C3N (3), wilfoside K1N (4), methyleugenol (5), wilfoside C1G (6), cynauriculoside A (7), daucosterol (8), 2,4-dihydroxyacetophenone (9), cynandione A (10), 2,5-dihydroxyacetophenone (11), acetovanillone (12), p-hydroxyacetophenone (13), sucrose (14), conduritol F (15), geniposide (16), succinic acid (17), 3-(β-D-ribofuranosyl)-2,3-dihydro-6H-1,3-oxazine-2,6-dione (18), bungeiside A (19), cynanoneside B (20). Among them, compounds 15, 16, 18, 19, and 20 were isolated for the first time from this species. Furthermore, conduritol F (15) was demonstrated to be contained only in C. wilfordii. Therefore, it may be useful as a chemical marker to identify the two species C. wilfordii and C. auriculatum.

Inhibitory effect of 1,2,4,5-tetramethoxybenzene on mast cell-mediated allergic inflammation through suppression of IκB kinase complex

As the importance of allergic disorders such as atopic dermatitis and allergic asthma, research on potential drug candidates becomes more necessary. Mast cells play an important role as initiators of allergic responses through the release of histamine; therefore, they should be the target of pharmaceutical development for the management of allergic inflammation. In our previous study, anti-allergic effect of extracts of Amomum xanthioides was demonstrated. To further investigate improved candidates, 1,2,4,5-tetramethoxybenzene (TMB) was isolated from methanol extracts of A. xanthioides. TMB dose-dependently attenuated the degranulation of mast cells without cytotoxicity by inhibiting calcium influx. TMB decreased the expression of pro-inflammatory cytokines such as tumor necrosis factor-α and interleukin (IL)-4 at both the transcriptional and translational levels. Increased expression of these cytokines was caused by translocation of nuclear factor-κB into the nucleus, and it was hindered by suppressing activation of IκB kinase complex. To confirm the effect of TMB in vivo, the ovalbumin (OVA)-induced active systemic anaphylaxis (ASA) and IgE-mediated passive cutaneous anaphylaxis (PCA) models were used. In the ASA model, hypothermia was decreased by oral administration of TMB, which attenuated serum histamine, OVA-specific IgE, and IL-4 levels. Increased pigmentation of Evans blue was reduced by TMB in a dose-dependent manner in the PCA model. Our results suggest that TMB is a possible therapeutic candidate for allergic inflammatory diseases that acts through the inhibition of mast cell degranulation and expression of pro-inflammatory cytokines.

Suppression of mast-cell-mediated allergic inflammation by Lindera obtusiloba.

Allergic disease is a consequence of exposure to normally innocuous substances that elicit the activation of mast cells. Mast-cell-mediated allergic response is involved in many diseases such as anaphylaxis, allergic rhinitis, asthma and atopic dermatitis. The discovery of drugs for the treatment of allergic disease is an important subject in human health. In this study, we investigated the effect of Lindera obtusiloba water extract (LOWE) on the mast-cell-mediated allergic inflammation and possible mechanism of action using in vitro and in vivo models. LOWE reduced histamine release from various types of mast cells activated by immunoglobulin E (IgE) or phorbol 12-myristate 13-acetate and calcium ionophore A23187 (PMACI). The inhibitory effect of LOWE on histamine release was mediated by calcium signal. LOWE decreased the PMACI-stimulated gene expression of proinflammatory cytokines such as tumor necrosis factor-α and interleukin-6 in human mast cells. The inhibitory effect of LOWE on the proinflammatory cytokines was nuclear factor (NF)-κB dependent. In addition, LOWE suppressed compound 48/80-induced systemic allergic reaction and serum histamine release in mice and IgE-mediated local allergic reactions. Our results indicate that LOWE inhibits mast-cell-derived allergic inflammation and involvement of calcium, histamine, proinflammatory cytokines and NF-κB in these effects.

New Aromatic Compounds from the Fruiting Body of Sparassis crispa (Wulf.) and Their Inhibitory Activities on Proprotein Convertase Subtilisin/Kexin Type 9 mRNA Expression

Successive chromatography of EtOAc-soluble extracts of the fruiting body of Sparassis crispa (Wulf.) resulted in isolation of four new aromatic compounds, sparoside A (1) and sparalides A-C (3-5), two new naturally occurring compounds, 2 and 6, and eight known compounds, 7-14. The chemical structures were determined by interpretation of nuclear magnetic resonance and mass spectrometry spectroscopic data. Extract, solvent-soluble fractions of the extract, and all of the pure compounds isolated from the fractions were subjected to the mRNA expression assay for proprotein convertase subtilisin/kexin type 9 (PCSK9). Among them, sparoside A (1), hanabiratakelide A (8), adenosine (11), and 5α,6α-epoxy-(22E,24R)-ergosta-8(14),22-diene-3β,7β-diol (14) exhibited potent inhibitory activities on PCSK9 mRNA expression, with IC50 values of 20.07, 7.18, 18.46, and 8.23 μM, respectively (berberine, positive control, IC50 = 8.04 μM), suggesting that compounds 1, 8, 11, and 14 are suitable for use in supplements to the statins for hyperlipidemia treatments.

A new neolignan and lignans from the stems of Lindera obtusiloba Blume and their anti-allergic inflammatory effects

A new neolignan, linderin A (1), together with six known lignans, (+)-xanthoxyol (2), pluviatilol (3), actiforin (4), (+)-syringaresinol (5), (+)-(7S,8R,8′R)-acuminatolide (6), and (+)-9′-O-trans-feruloyl-5,5′-dimethoxylariciresinol (7) were isolated from the stems of Lindera obtusiloba Blume (Lauraceae). Their chemical structures were elucidated by a combination of spectroscopic analysis and chemical reaction, and the absolute configuration of 1 was determined by Mosher’s esterification. The effect of compounds 1–7 on tumor necrosis factor (TNF)-α, interleukin(IL)-6, and their inhibitory activity of histamine release were examined using human mast cells. Among the lignans tested, compounds 1, 3, 4, 6, and 7 inhibited release of histamine from mast cells. Especially, compounds 1 and 4 suppressed the gene expressions of pro-inflammatory cytokines, TNF-α, and IL-6 in human mast cells. Our findings suggest that the lignan constituents in L. obtusiloba may contribute to its anti-allergic inflammatory effects.

Oral Administration of 4-Hydroxy-3-Methoxycinnamaldehyde Attenuates Atopic Dermatitis by Inhibiting T Cell and Keratinocyte Activation

Atopic dermatitis (AD) is a skin condition caused by an imbalance of distinct subsets of T helper cells. Previously, we showed that 4-hydroxy-3-methoxycinnamaldehyde (4H3MC) inhibits T cell activation but does not induce apoptosis. Here, we examined the mechanism underlying the inhibitory effect of 4H3MC on AD both in vivo and in vitro. We sought to test the pharmacological effects of 4H3MC using a mouse model of 2, 4-‘2,4-dinitrocholorobenzene’ (DNCB)- and mite-induced AD. Also, we determined whether 4H3MC affects T cell differentiation and proliferation. Oral administration of 4H3MC attenuated the symptoms of DNCB- and mite-induced AD, including increased ear thickness, serum IgE levels, immune cell infiltration into inflammatory lesions, and pathogenic cytokine expression in ear tissues. In vitro, 4H3MC blocked T cell differentiation into Th1 and Th2 subtypes, as reflected by suppression of T-bet and GATA3, which are key transcription factors involved in T cell differentiation. In addition, 4H3MC downregulated T cell proliferation during Th1 and Th2 differentiation and keratinocyte activation. Collectively, these findings suggest that 4H3MC ameliorates AD symptoms by modulating the functions of effector T cells and keratinocytes.

Inhibition of Prostaglandin D2 Production by Trihydroxy Fatty Acids Isolated from Ulmus davidiana var. japonica

The stem and root barks of Ulmus davidiana var. japonica (Ulmaceae) have been used to treat inflammatory diseases including mastitis, rhinitis, sinusitis, and enteritis. In an ongoing study focused on the discovery of natural anti‐inflammatory compounds from natural products, a methanol extract of the stem and root barks of U. davidiana var. japonica showed anti‐inflammatory activities. Activity‐guided fractionation of the methanol extract yielded a new trihydroxy fatty acid, 9,12,13‐trihydroxyoctadeca‐10(Z),15(Z)‐dienoic acid (1), and a known compound, pinellic acid (2). These two trihydroxy fatty acids 1 and 2 inhibited prostaglandin D2 production with IC50 values of 25.8 and 40.8 μM, respectively. These results suggest that 9,12,13‐trihydroxyoctadeca‐10(Z),15(Z)‐dienoic acid (1) and pinellic acid (2) are among the anti‐inflammatory principles in this medicinal plant. Copyright

Oral Administration of p-Hydroxycinnamic Acid Attenuates Atopic Dermatitis by Downregulating Th1 and Th2 Cytokine Production and Keratinocyte Activation

Atopic dermatitis (AD) is a complex disease that is caused by various factors, including environmental change, genetic defects, and immune imbalance. We previously showed that p-hydroxycinnamic acid (HCA) isolated from the roots of Curcuma longa inhibits T-cell activation without inducing cell death. Here, we demonstrated that oral administration of HCA in a mouse model of ear AD attenuates the following local and systemic AD manifestations: ear thickening, immune-cell infiltration, production of AD-promoting immunoregulatory cytokines in ear tissues, increased spleen and draining lymph node size and weight, increased pro-inflammatory cytokine production by draining lymph nodes, and elevated serum immunoglobulin production. HCA treatment of CD4+ T cells in vitro suppressed their proliferation and differentiation into Th1 or Th2 and their Th1 and Th2 cytokine production. HCA treatment of keratinocytes lowered their production of the pro-inflammatory cytokines that drive either Th1 or Th2 responses in AD. Thus, HCA may be of therapeutic potential for AD as it acts by suppressing keratinocyte activation and downregulating T-cell differentiation and cytokine production.

Effects of Mollugin on Hepatic Cytochrome P450 in Male ICR Mice as Determined by Liquid Chromatography/Tandem Mass Spectrometry

Mollugin isolated from Rubia cordifolia is known to have anti-inflammatory, anti-cancer, and anti-viral activities. In the present study, a cocktail probe assay and LC-MS/MS were used to investigate the modulating effect of mollugin on cyto- chrome P450 (CYP) enzymes in male ICR mice. After mollugin was orally administrated to mice at the 20, 40, or 80 mg/kg for 3 days, the activities of CYP in hepatic S-9 fractions were investigated. Unlike the selective inhibitory effect of mollugin on CYP1A2-catalyzed phenacetin O-deethylation in vitro, mollugin only significantly inhibited the activity of CYP2E1-catalyzed chlorzoxazone 6-hydroxylase in vivo. The activities of other CYPs were only slightly altered by mollugin. The results of this study suggest that mollugin might cause herb-drug interactions via the selective inhibition of CYP2E1 in vivo.