Lignans from Machilus thunbergii as Thymic Stromal Lymphopoietin Inhibitors

Thymic stromal lymphopoietin (TSLP) plays an important role in the pathophysiology of various allergic diseases that are mediated by T helper cell type-2 (Th2) responses, including asthma and atopic dermatitis. The primary focus of this study was the identification of potent inhibitors of the TSLP signaling pathway for potential therapeutic use. The 80% methanol extract of bark significantly inhibited the signal transducer and activator of transcription 5 (STAT5) phosphorylation in human mast cell (HMC)-1 cells. Through activity-guided isolation, three lignans ( - ) were obtained and identified as (+)-galbelgin ( ), -dihydroguaiaretic acid ( ), and machilin A ( ). Among them, two lignans ( and ) significantly inhibited STAT5 phosphorylation and TSLP/TSLPR interaction, as determined by ELISA. Our results indicated that lignans isolated from are a promising resource for the treatment of allergic diseases.