Ameliorative effects of Wikstroemia trichotoma 95% EtOH extract on a mouse model of DNCB-induced atopic dermatitis.
The genus Wikstroemia has been extensively utilized in traditional Chinese medicine (TCM) for the management of conditions such as coughs, edema, arthritis, and bronchitis. Studies have indicated that the crude extracts of Wikstroemia exhibit anti-inflammatory, anti-allergy, anti-aging, skin psoriasis, anti-cancer, and antiviral properties. In addition, these extracts are known to contain bioactive substances, including flavonoids, coumarins, and lignans. However, few studies have investigated the anti-inflammatory or anti-allergic activities of Wikstroemia trichotoma (Thunb.) Makino against atopic dermatitis (AD).
The study aimed to explore the potential of a 95% ethanol extract of W. trichotoma (WTE) on the dysfunction of skin barrier and immune system, which are primary symptoms of AD, in 2,4-dinitrochlorobenzene (DNCB)-induced SKH-1 hairless mice and phorbol 12-myristate 13-acetate (PMA)/ionomycin or immunoglobulin E (IgE) + 2,4-dinitrophenylated bovine serum albumin (DNP-BSA) stimulated rat basophilic leukemia cell line (RBL-2H3). Furthermore, we sought to identify the chemical contents of WTE using high-performance liquid chromatography equipped with a photodiode array detector (HPLC-PDA).
An in vitro study was conducted using RBL-2H3 cells stimulated with PMA/ionomycin or IgE + DNP-BSA to assess the inhibitory effects of WTE on mast cell degranulation and interleukin-4 (IL-4) mRNA expression levels. For the in vivo study, AD was induced in SKH-1 hairless mice by applying 1% DNCB to the dorsal skin daily for 7 days. Subsequently, 0.1% DNCB solution was applied on alternate days, and mice were orally administered WTE (at 30 or 100 mg/kg/day) dissolved in 0.5% carboxymethyl cellulose (CMC) daily for 2 weeks. Transepidermal water loss (TEWL), skin hydration, skin pH, and total serum IgE levels were measured.
In DNCB-stimulated SKH-1 hairless mice, WTE administration significantly improved AD symptoms and ameliorated dorsal skin inflammation. Oral administration of WTE led to a significant decrease in skin thickness, infiltration of mast cells, and level of total serum IgE, thus restoring skin barrier function in the DNCB-induced skin lesions. In addition, WTE inhibited β-hexosaminidase release and reduced IL-4 mRNA levels in RBL-2H3 cells. Chemical profile analysis of WTE confirmed the presence of three phenolic compounds, viz. chlorogenic acid, miconioside B, and matteucinol-7-O-β-apiofuranosyl (1 → 6)-β-glucopyranoside.
WTE ameliorates AD symptoms by modulating in the skin barrier and immune system dysfunction. This suggests that W. trichotoma extract may offer therapeutic benefits for managing AD.
Keem MJ
,Jo BG
,Lee SH
,Kim TY
,Jung YS
,Jeong EJ
,Kim KH
,Kim SN
,Yang MH
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(R)-(+)-pulegone suppresses allergic and inflammation responses on 2,4-dinitrochlorobenzene-induced atopic dermatitis in mice model.
(R)-(+)-pulegone (PLG), a biotransformation of monoterpene ketones, is one of essential oils of Labiatae family. Although PLG was reported to have anti-inflammatory and anti-histamine effects, the therapeutic effects of PLG on atopic dermatitis (AD) have not been reported yet.
This study investigated the anti-AD effects and underlying mechanisms of PLG in AD-induced mice.
BALB/c male mice were challenged with 2, 4-dinitrochlorobenzene (DNCB, 1%) to induce AD. After 4 days of rest, PLG (0.1, 1 and 10 μM) were topically applied to dorsal skin for 2 weeks with secondary elicitation using 0.5% DNCB. Histological changes were identified by H&E staining and mast cells were evaluated by toluidine blue staining. Pro-inflammatory cytokines and serum IgE levels were analyzed by ELISA. Inflammatory mediators were measured by western blotting assay.
Topical treatment with PLG significantly suppressed skin thickness and scratching behavior compared with control group. Expression of nerve growth factor was also decreased by PLG treatment. PLG administration decreased serum IgE levels and the number of mast cells in mice model of DNCB-induced AD. The levels of IL-4, IFN-γ, IL-6, TNF-α and IL-1β in dorsal skin of PLG-treated group were lower than those in the control group. PLG inhibited the phosphorylation of MAPKs, as well as IκBα degradation and NF-κB activation.
PLG attenuated the symptoms of AD by suppressing cytokines production, the phosphorylation of MAPKs and the activation of NF-κB signaling. These data suggest that PLG may be an effective natural compound for the treatment of inflammatory skin diseases.
Choi YY
,Kim MH
,Lee H
,Jo SY
,Yang WM
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