Suppression of DNCB-Induced Atopic Skin Lesions in Mice by Wikstroemia indica Extract

Ameliorative effects of Wikstroemia trichotoma 95% EtOH extract on a mouse model of DNCB-induced atopic dermatitis

ETHNOPHARMACOLOGICAL RELEVANCE

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).

AIM OF THE STUDY

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).

MATERIALS AND METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Supercritical CO2 fluid extract from Stellariae Radix ameliorates 2,4-dinitrochlorobenzene-induced atopic dermatitis by inhibit M1 macrophages polarization via AMPK activation

Yin chai hu (Radix Stellariae) is a root medicine that is frequently used in Chinese traditional medicine to treat fever and malnutrition. In modern medicine, it has been discovered to have anti-inflammatory, anti-allergic, and anticancer properties. In a previous study, we were able to extract lipids from Stellariae Radix using supercritical CO2 extraction (SRE), and these sterol lipids accounted for up to 88.29% of the extract. However, the impact of SRE on the development of atopic dermatitis (AD) has not yet been investigated. This study investigates the inhibitory effects of SRE on AD development using a 2,4-dinitrochlorobenzene (DNCB)-induced AD mouse model. Treatment with SRE significantly reduced the dermatitis score and histopathological changes compared with the DNCB group. The study found that treatment with SRE resulted in a decrease of pro-inflammatory cytokines TNF-α, CXC-10, IL-12, and IL-1β in skin lesions. Additionally, immunohistochemical analysis revealed that SRE effectively suppressed M1 macrophage infiltration into the AD lesion. Furthermore, the anti-inflammatory effect of SRE was evaluated in LPS + INF-γ induced bone marrow-derived macrophages (BMDMs) M1 polarization, SRE inhibited the production of TNF-α, CXC-10, IL-12, and IL-1β and decreased the expression of NLRP3. Additionally, SRE was found to increase p-AMPKT172, but had no effect on total AMPK expression, after administration of the AMPK inhibitor Compound C, the inhibitory effect of SRE on M1 macrophages was partially reversed. The results indicate that SRE has an inhibitory effect on AD, making it a potential therapeutic agent for this atopic disorder.

The Beneficial Roles of Sargassum spp. in Skin Disorders

As the body's largest organ, the skin is located at the internal and external environment interface, serving as a line of defense against various harmful stressors. Recently, marine-derived physiologically active ingredients have attracted considerable attention in the cosmeceutical industry due to their beneficial effects on skin health. Sargassum, a genus of brown macroalgae, has traditionally been consumed as food and medicine in several countries and is rich in bioactive compounds such as meroterpenoids, sulfated polysaccharides, fucoidan, fucoxanthin, flavonoids, and terpenoids. Sargassum spp. have various beneficial effects on skin disorders. They help with atopic dermatitis by improving skin barrier protection and reducing inflammation. Several species show potential in treating acne by inhibiting bacterial growth and reducing inflammation. Some species, such as Sargassum horneri, demonstrate antiallergic effects by modulating mast cell activity. Certain Sargassum species exhibit anticancer activity by inhibiting tumor growth and promoting apoptosis, and some species help with wound healing by promoting angiogenesis and reducing oxidative stress. Overall, Sargassum spp. demonstrate potential for treating and managing various skin conditions. Therefore, the bioactive compounds of Sargassum spp. may be natural ingredients with a wide range of functional properties for preventing and treating skin disorders. The present review focused on the various biological effects of Sargassum extracts and derived compounds on skin disorders.

Wikstroemia: A Review on its Phytochemistry and Pharmacology

BACKGROUND

Wikstroemia (the family Thymelaeaceae) consists of medicinal plants which established great value in traditional medicines for many years. For instance, W. indica is always recommended for treatments of syphilis, arthritis, whooping cough, and cancer. No systematic review of bioactive compounds from this genus has been recorded to date.

OBJECTIVES

The objective of the current study is to review phytochemical investigations and pharmacological effects of Wikstroemia plant extracts and isolates.

METHODS

By searching on the internet, the relevant data about Wikstroemia medicinal plants were retrieved from internationally renowned scientific databases, such as Web of Science, Google Scholar, Sci-Finder, Pubmed, and so on.

RESULTS

More than 290 structurally diverse metabolites were separated and identified from this genus. They include terpenoids, lignans, flavonoids, coumarins, mono-phenols, diarylpentanoids, fatty acids, phytosterols, anthraquinones, and others. Pharmacological records indicated that Wikstroemia plant crude extracts and their isolated compounds bring out various beneficial effects, such as anticancer, antiinflammatory, anti-aging, anti-viral, antimicrobacterial, antimalarial, neuroprotective, and hepatoprotective activities.

CONCLUSION

Wikstroemia has been regarded as a worthy genus with numerous phytochemicals and various pharmacological potentials. Modern pharmacological studies have successfully provided evidence for traditional uses. Nonetheless, their action mechanisms need to be further investigated. Although various secondary metabolites were identified from Wikstroemia plants, the current pharmacological research mainly concentrated on terpenoids, lignans, flavonoids, and coumarins.

Identification of Daphnane Diterpenoids from Wikstroemia indica Using Liquid Chromatography with Tandem Mass Spectrometry

Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) has emerged as a powerful tool for the rapid identification of compounds within natural resources. Daphnane diterpenoids, a class of natural compounds predominantly found in plants belonging to the Thymelaeaceae and Euphorbiaceae families, have attracted much attention due to their remarkable anticancer and anti-HIV activities. In the present study, the presence of daphnane diterpenoids in Wikstroemia indica, a plant belonging to the Thymelaeaceae family, was investigated by LC-MS/MS analysis. As a result, 21 daphnane diterpenoids (1-21) in the stems of W. indica were detected. Among these, six major compounds (12, 15, 17, 18, 20, and 21) were isolated and their structures were unequivocally identified through a comprehensive analysis of the MS and NMR data. For the minor compounds (1-11, 13, 14, 16, and 19), their structures were elucidated by in-depth MS/MS fragmentation analysis. This study represents the first disclosure of structurally diverse daphnane diterpenoids in W. indica, significantly contributing to our understanding of bioactive diterpenoids in plants within the Thymelaeaceae family.

Glycyrrhizic acid suppresses atopic dermatitis-like symptoms by regulating the immune balance

BACKGROUND

Glycyrrhiza is one of the most widely used traditional Chinese medicines in China. Its main bioactive ingredient glycyrrhizic acid (GA) has the potential to be used as a treatment for atopic dermatitis (AD) because it has similar actions to steroids, but with relatively few side effects.

AIMS

The objective of this study was to explore the potential mechanisms of GA on AD mice model.

METHODS

Calcipotriol, a vitamin D3 analogue (MC903) was applied topically to establish AD mouse model. Mice were intraperitoneally administrated with 2 mg/kg dexamethasone (DEX), 25 or 50 mg/kg GA for 15 days. After mice were executed, skin tissues were collected and detected the expression levels of IL-4, IFN-γ, TNF-α and thymic stromal lymphopoietin (TSLP). The percentages of Th1, Th2, Th17, langerhans cells (LCs) in draining lymph nodes (dLNs) were measured by flow cytometry.

RESULTS

Our data demonstrated that GA improved the symptoms of AD by exerting anti-inflammatory and anti-allergic functions in vivo. We found that GA treatment decreased the level of total IgE in serum, suppressed ear swelling, reduced the infiltration of mast cells in skin lesions and decreased expressions of IL-4, IFN-γ, TNF-α and TSLP in skin lesions. Furthermore, our experimental results demonstrated that GA suppressed the Th1/Th2/Th17-immune responses in the dLNs, inhibited the migration of LCs in dLNs.

CONCLUSIONS

In conclusion, our findings suggested potential therapeutic effects of GA against MC903-induced AD-like skin lesions in mice.

Anti-inflammatory effects of amarogentin on 2,4-dinitrochlorobenzene-induced atopic dermatitis-like mice and in HaCat cells

BACKGROUND

Amarogentin (AMA) is a secoiridoid glycoside extracted from Swertia and Gentiana roots and exhibits many biological effects such as antioxidative, anti-inflammatory, and antitumor activities. Atopic dermatitis (AD) is a chronic inflammatory skin disease caused by disorders in the regulation of multiple inflammatory cytokines. No effective cure has been found for AD now.

METHODS

We constructed the HaCat and splenocyte model and tested the inhibitory effect of AMA on IL-4, IL-6, and IL-13 secretions using enzyme-linked immunosorbent assay (ELISA). The AD mouse model was constructed and treated with AMA, the severity of skin lesions was observed, epidermal tissue was collected, and epidermal thickness and mast cell infiltration were observed using hematoxylin and eosin and toluidine blue staining, respectively. The expression of kallikrein-related peptidase 7 (KLK7) and filaggrin (FLG) was detected using immunostaining and Western blot analysis. The mRNA expression of KLK7 and FLG was detected using quantitative polymerase chain reaction (qPCR). Blood immunoglobulin E (IgE) secretion was detected.

RESULTS

AMA inhibited IL-6 secreted by tumor necrosis factor (TNF)-α-induced HaCaT cells and reduced IL-4 and IL-13 secreted by phytohemagglutinin (PHA)-induced primary cells in the mice spleen. It was found that the treatment of AMA with 2,4-dinitrochlorobenzene-induced AD-like mice could promote the recovery of dermatitis, reduce the score of dermatitis severity and the scratching frequency, treat the skin lesions, reduce the epidermal thickness, decrease the infiltration of mast cells, reduce the IgE level in serum, decrease the expression levels of AD-related cytokines, increase protein and mRNA expression of FLG, and reduce the protein and mRNA expression of KLK7 in the skin tissues of AD-like mice.

CONCLUSION

In conclusion, AMA inhibits inflammatory response at the cellular level, and AMA reduces the validation response of specific dermatitis mice, relieves pruritus, and repairs the damaged skin barrier.

(-)-α-Bisabolol Alleviates Atopic Dermatitis by Inhibiting MAPK and NF-κB Signaling in Mast Cell

(-)-α-Bisabolol (BIS) is a sesquiterpene alcohol derived mostly from Matricaria recutita L., which is a traditional herb and exhibits multiple biologic activities. BIS has been reported for treatment of skin disorders, but the effect of BIS on anti-atopic dermatitis (AD) remains unclear. Therefore, we investigated the effects of BIS on 2,4-dinitrochlorobenzene (DNCB)-induced AD in BALB/c mice and the underlying mechanism in Bone Marrow-Derived Mast Cells (BMMCs). Topical BIS treatment reduced AD-like symptoms and the release of interleukin (IL)-4 without immunoglobulin (Ig)-E production in DNCB-induced BALB/c mice. Histopathological examination revealed that BIS reduced epidermal thickness and inhibited mast cells in the AD-like lesions skin. Oral administration of BIS effectively and dose-dependently suppressed mast-cell-mediated passive cutaneous anaphylaxis. In IgE-mediated BMMCs, the levels of β-hexosaminidase (β-hex), histamine, and tumor necrosis factor (TNF)-α were reduced by blocking the activation of nuclear factor-қB (NF-қB) and c-Jun N-terminal kinase (JNK) without P38 mitogen activated protein (P38) and extracellular regulated protein kinases (Erk1/2). Taken together, our experimental results indicated BIS suppresses AD by inhibiting the activation of JNK and NF-κB in mast cells. BIS may be a promising therapeutic agent for atopic dermatitis and other mast-cell-related diseases.

Management of Atopic Dermatitis Via Oral and Topical Administration of Herbs in Murine Model: A Systematic Review

Over the past few decades, complementary and alternative medicine (CAM) using herbs, or their active constituents have garnered substantial attention in the management of a chronic and relapsing inflammatory skin disorder called atopic dermatitis (AD), particularly in attenuating disease recurrence and maintaining long-term remission. In Eastern Asian countries including China, Korea and Taiwan, herbal medicine available in both topical and oral preparation plays a significant role in treating skin diseases like AD as they possibly confer high anti-inflammatory properties and immunomodulatory functions. Conventional murine models of AD have been employed in drug discovery to provide scientific evidence for conclusive and specific pharmacological effects elicited by the use of traditional herbs and their active constituents. Coupled with the goal to develop safe and effective novel therapeutic agents for AD, this systematic review consists of a summary of 103 articles on both orally and topically administered herbs and their active constituents in the murine model, whereby articles were screened and selected via a specialized framework known as PICO (Population, Intervention, Comparator and Outcome). The objectives of this review paper were to identify the efficacy of oral and topical administered herbs along with their active constituents in alleviating AD and the underlying mechanism of actions, as well as the animal models and choice of inducer agents used in these studies. The main outcome on the efficacy of the majority of the herbs and their active constituents illustrated suppression of Th2 response as well as improvements in the severity of AD lesions, suppression of Immunoglobulin E (IgE) concentration and mast cell infiltration. The majority of these studies used BALB/c mice followed by NC/Nga mice (commonly used gender–male; commonly used age group – 6–8 weeks). The most used agent in inducing AD was 2, 4-Dinitrochlorobenzene (DNCB), and the average induction period for both oral and topical administered herbs and their active constituents in AD experiments lasted between 3 and 4 weeks. In light of these findings, this review paper could potentially assist researchers in exploring the potential candidate herbs and their active constituents using murine model for the amelioration of AD.

Mentha arvensis Essential Oil Exerts Anti-Inflammatory in LPS-Stimulated Inflammatory Responses via Inhibition of ERK/NF-κB Signaling Pathway and Anti-Atopic Dermatitis-like Effects in 2,4-Dinitrochlorobezene-Induced BALB/c Mice

The mechanism of atopic dermatitis (AD) is modulated by the release of cytokines and chemokines through the mitogen-activated protein kinase (MAPK)/nuclear factor-kappa B (NF-κB) signaling pathway. Topical steroids are used to treat AD, but some people need safer anti-inflammatory drugs to avoid side effects. Mentha arvensis has been used as a herbal plant with medicinal properties, but its anti-inflammatory effects have not been elucidated in an AD model. In this study, we investigated the anti-inflammatory effects of M. arvensis essential oil (MAEO) and its underlying molecular mechanism in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages and HaCaT cells (human epidermal keratinocyte). Additionally, we examined the ameliorating effects of the MAEO in a dinitrochlorobenzene (DNCB)-induced murine model of AD. We found, in both RAW 264.7 cells and HaCaT cells, MAEO inhibited LPS-stimulated inflammatory mediators such as nitric oxide (NO) and prostaglandin E₂ and proinflammatory cytokines, including IL-1β and IL-6, due to the suppression of COX-2 and iNOS expression. In LPS-stimulated macrophages, we also observed that MAEO inhibited the phosphorylation of ERK and P65. Furthermore, MAEO treatment attenuated AD symptoms, including the dermatitis score, ear thickness, epidermal thickness and infiltration of mast cells, in a DNCB-induced animal model of AD. Overall, our findings suggest that MAEO exerts anti-inflammatory and anti-atopic dermatitis effects via inhibition of the ERK/NF-κB signaling pathway.

Topical application with conjugated linoleic acid ameliorates 2, 4-dinitrofluorobenzene-induced atopic dermatitis-like lesions in BALB/c mice

Atopic dermatitis (AD) is a multifactorial chronic inflammatory skin disease characterized by skin barrier dysfunction, eczematous lesions, pruritus, and abnormal immune responses. In this study, we assessed the therapeutic effect of topical applied conjugated linoleic acid (CLA) on a murine AD model that was developed by repetitive applications of 2, 4-dinitrofluorobenzene (DNFB). 2% or 5% CLA could markedly ameliorate AD-like skin lesions, scratching behaviour and skin inflammation as evidenced by the reduced inflammatory blood cells, IgE and Th2-related cytokine levels, and the infiltration of mast cells and inflammatory cells to the dermal tissues. Moreover, topical application with CLA modulated skin barrier repair including maintaining a balanced skin pH and increasing skin hydration, partially mediated by upregulating skin barrier-related protein, filaggrin (FLG). In addition, topical CLA significantly dose-dependently inhibited pro-inflammatory cytokines including interleukin (IL)-6, IL-1β, tumour necrosis factor (TNF)-α and pro-inflammatory enzyme expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in inflamed mice skin. Its anti-inflammatory effect was associated with the inhibition of DNFB-stimulated IκBα and NF-κB p65 phosphorylation in mouse skin. Taken together, our results suggest that locally applied CLA exerts potentially protective effects against AD lesional skin at least in part, due to regulation of skin barrier function and inflammatory response.

Curcumin and wikstroflavone B, a new biflavonoid isolated from Wikstroemia indica, synergistically suppress the proliferation and metastasis of nasopharyngeal carcinoma cells via blocking FAK/STAT3 signaling pathway

BACKGROUND

Curcumin (CUR) is a natural diarylheptanoid with marked anti-tumor activities. Recent investigations demonstrate that CUR combines with some other phytochemicals exerts advantages over its single application manifested as lower toxicity, higher efficacy or more significant reversal of multidrug resistance.

PURPOSE

This study aimed to elucidate a new biflavonoid (wikstroflavone B, WFB) isolated from Wikstroemia indica and to assess the synergistic inhibition of combined CUR and WFB (CUR/WFB) on human nasopharyngeal carcinoma (NPC) cell lines proliferation and metastasis.

METHODS

WFB was obtained through sequential chromatographic methods including silica gel, Sephadex LH-20 and preparative HPLC. Its structure was determined by HRESIMS, 1D and 2D NMR spectroscopic analysis. The absolute configuration of WFB was assigned through comparison of experimental and calculated optical rotation (OR) values. Changes in cellular viability, migration and invasion were assessed by MTT, colony formation, wound healing and Transwell assays. The nature of synergistic interaction of CUR/WFB was determined through the combination index (CI) method under the median-effect analysis. Expression levels of indicated mRNAs and proteins were measured by qRT-PCR and Western blotting assays, respectively.

RESULTS

WFB was isolated and structural elucidated. Compared with CUR or WFB used alone, CUR/WFB treatment inhibited more effectively on the cell viability, colony formation, cell migration and invasion. Both CI and dose reduction index (DRI) values indicated the significant synergistic effects existed between CUR and WFB. Besides, CUR/WFB showed the marked modulation on the genes involved in cell proliferation (survivin, cyclin D1, p53 and p21) and metastasis (MMP-2, MMP-9 and FAK). CUR/WFB treatment was also found to restrain the phosphorylation of FAK and STAT3 proteins. When pretreatment with a FAK inhibitor, the cell viability and metastasis were significantly attenuated.

CONCLUSION

The results indicate that WFB can synergistically increase the inhibitory effects of CUR on NPC cells proliferation and metastasis, and these findings may afford a rational approach for developing the antitumor medications.

Quercitrin, the Main Compound in Wikstroemia indica, Mitigates Skin Lesions in a Mouse Model of 2,4-Dinitrochlorobenzene-Induced Contact Hypersensitivity

Hapten-induced contact hypersensitivity (CHS) is widely utilized to induce immune activation in animal models of allergic contact dermatitis. Our previous findings suggested that the 95% EtOH extract of Wikstroemia indica (L.) C. A. Mey. has antiallergic and anti-inflammatory effects in DNCB-treated CHS SKH-1 hairless mice. The aim of this study was to evaluate the protective effects of compounds isolated from the EtOAc fraction of W. indica in RBL-2H3 cells and 2,4-dinitrochlorobenzene- (DNCB-) induced CHS mice. Of eight compounds in W. indica, that is, umbelliferone, daphnoretin, wikstrocoumarin, (+)-syringaresinol, tricin, (+)-lariciresinol, erythro-guaiacylglycerol-β-coniferyl ether, and quercitrin, quercitrin exhibited the most antiallergic activity against antigen-induced β-hexosaminidase release and IL-4 mRNA expression, which are markers of degranulation in RBL-2H3 cells. After a 7-sensitizing period, 14 days of DNCB treatment with or without topical pimecrolimus (1%) or quercitrin (0.5%) treatment, quercitrin was found to suppress DNCB-induced increases in serum IL-4 and IgE concentrations and transepidermal water loss. These results indicate that quercitrin has therapeutic potential for treatment of allergies and allergy-related contact dermatitis.