Ameliorative effects of Paulownia tomentosa flower absolute on atopic dermatitis‑related responses in mast cells and keratinocytes and its chemical composition.

Abstract

Paulownia tomentosa (PT) exhibits diverse biological activities, including anti‑inflammatory and antioxidant effects; however, its potential effects on atopic dermatitis (AD) are unclear. The present study examined the effects of PT flower absolute (PTFAb) on AD‑related responses, particularly mast cell activation and keratinocyte barrier‑related responses. PTFAb was isolated from PT flowers using a solvent extraction method and its chemical composition was analyzed by gas chromatography/mass spectrometry, through which 13 components were identified. In vitro biological tests on rat basophilic leukemia cells (RBL‑2H3 cells; a commonly used mast cell model) and human epidermal keratinocytes (HaCaT cells) were performed using water‑soluble tetrazolium salt, 5‑bromo‑2'‑deoxyuridine incorporation, Boyden chamber, immunoblotting and enzyme‑linked immunosorbent assay methods. All experiments were conducted on cells at nontoxic PTFAb concentrations. PTFAb reduced the expression of the v‑soluble N‑ethylmaleimide‑sensitive factor attachment protein receptor proteins vesicle‑associated membrane protein (VAMP)7 and VAMP8 in RBL‑2H3 cells. In RBL‑2H3 cells stimulated with anti‑dinitrophenyl (DNP)‑immunoglobulin E and DNP‑bovine serum albumin, PTFAb suppressed the release of β‑hexosaminidase and histamine (indicators of mast cell degranulation), and the phosphorylation of spleen tyrosine kinase, phosphatidylinositol 3‑kinase and protein kinase B. PTFAb also induced proliferation, migration, and type Ⅰ and Ⅳ collagen synthesis. Furthermore, PTFAb upregulated tumor necrosis factor‑α (TNF‑α)‑reduced filaggrin expression and the expression of hyaluronan synthase (HAS)‑2 and HAS‑3 in HaCaT cells, and reduced TNF‑α‑increased intercellular adhesion molecule‑1 expression in HaCaT cells. In conclusion, PTFAb may exert inhibitory effects on mast cell degranulation‑related responses and potentiate skin barrier‑related responses, suggesting its potential to modulate AD‑related cellular responses or skin barrier function.