Topical Application of Galgeunhwanggeumhwangryeon-Tang Recovers Skin-Lipid Barrier and Ameliorates Inflammation via Filaggrin-Thymic Stromal Lymphopoietin-Interleukin 4 Pathway

Probiotic-fermented Portulaca oleracea L. alleviated DNFB-induced atopic dermatitis by inhibiting the NF-κB signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Probiotic fermentation is a mild and safe biological method to boost the performance of herbs. Portulaca oleracea L. (PO), with folklore records of purgative, anti-dermatological and anti-epidemic effects, has been demonstrated to possess anti-inflammatory, immunomodulatory, and antioxidant properties. However, the potential of PO for the treatment of atopic dermatitis (AD) has not been sufficiently explored.

AIM OF STUDY

This study aimed to evaluate the therapeutic benefits of PO and fermented Portulaca oleracea L. (FPO) and explore their intrinsic mechanisms.

METHODS

By utilizing 2,4-dinitrofluorobenzene-induced AD mice as a model, the histopathology of the lesions was observed using H&E and toluidine blue staining methods; the levels of immunoglobulin E (Ig E), histamine (HIS), and thymic stromal lymphopoietin (TSLP) in serum were measured using ELISA, whereas, the expression of inflammatory cytokines in skin lesion was measured using ELISA and immunohistochemistry experiments. The expression of tumor necrosis factor-α (TNF-α), IKKα, NF-κB mRNA was measured using qPCR; and the expression of TNF-α、p-IKKα, p-IκBα, p-NF-κB was measured using western blotting.

RESULTS

Both 20 mg/mL PO and FPO alleviated mast cell infiltration and lesion pathology, reduced serum levels of Ig E, HIS and TSLP, down-regulated the expression of AD-related inflammatory cytokines, such as, TNF-α, interferon-γ, and interleukin-4, and increased filaggrin expression. Furthermore, they inhibited the expression of TNF-α, IKKα, and NF-κB genes and TNF-α, p-IKKα, p-NF-κB and p-IκBα proteins associated with the NF-κB signaling pathway.

CONCLUSIONS

PO and FPO has a positive therapeutic potential on AD, indicating that it may be employed as alternative therapies for AD.

Portulaca oleracea L. extracts alleviate 2,4-dinitrochlorobenzene-induced atopic dermatitis in mice

Atopic dermatitis (AD) is a common chronic allergic skin disease characterized clinically by severe skin lesions and pruritus. Portulaca oleracea L. (PO) is a resourceful plant with homologous properties in medicine and food. In this study, we used two different methods to extract PO, and compared the therapeutic effects of PO aqueous extract (POAE) and PO ultrasound-assisted ethanol extract (POEE) on 2,4-dinitrochlorobenzene (DNCB)-induced AD mice. The results showed that in POAE and POEE, the extraction rates of polysaccharides were 16.95% and 9.85%, while the extraction rates of total flavonoids were 3.15% and 3.25%, respectively. Compared with AD mice, clinical symptoms such as erythema, edema, dryness and ulceration in the back and left ear were alleviated, and pruritus behavior was reduced after POAE and POEE treatments. The thickness of the skin epidermis was thinned, the density of skin nerve fibers labeled with protein gene product 9.5 (PGP9.5) was decreased, and mast cell infiltration was reduced. There was a decrease in blood lymphocytes, eosinophils and basophils, a significant decrease in spleen index and a noticeable decrease in serum immunoglobulin E (Ig E). POEE significantly reduced the concentration of the skin pruritic factor interleukin (Il)-31. POAE and POEE reduced the concentration of skin histamine (His), down-regulated mRNA expression levels of interferon-γ (Ifnγ), tumor necrosis factor-α (Tnf-α), thymic stromal lymphopoietin (Tslp) and Il-4, with an increase of Filaggrin (Flg) and Loricrin (Lor) in skin lesions. These results suggested that POAE and POEE may inhibit atopic response and alleviate the clinical symptoms of AD by inhibiting the expression of immune cells, inflammatory mediators and cytokines. PO may be a potential effective drug for AD-like diseases.