Spleen tyrosine kinase (Syk) plays an indispensable role through preliminary extracellular antigen-induced crosslinking of Fc receptor (FcR) in the pathogenesis of autoimmune disorders, such as rheumatoid arthritis. In this study, we identify Vam3, a dimeric derivative of resveratrol isolated from grapes, as an ATP-competitive inhibitor of Syk with an IC₅₀ of 62.95 nM in an in vitro kinase assay. Moreover, docking and molecular dynamics simulation approaches were performed to get more detailed information about the binding mode of Vam3 and Syk. The results show that 11b-OH on ring-C and 4b-OH on ring-D could form two hydrogen bonds with Glu449 and Phe382 of Syk, respectively. In addition, arene-cation interaction between ring-D of Vam3 and Lys402 of Syk was also observed. These results indicate that ring-C and D play an essential role in Vam3–Syk interaction. Our studies may be helpful in the structural optimization of Vam3, and also aid the design of novel Syk inhibitors in the future.

Hedyotis diffusa Willd (HDW) is a constituent of several Chinese medicines used clinically to treat inflammatory diseases, including airway inflammation. The aim of the present study was to investigate whether HDW serves a protective role in suppressing chronic airway inflammation and its underlying mechanisms. A mouse model of chronic smoking was induced via exposure to cigarette smoke (CS) for 30 days, increasing the exposure time for up to 5 min per day and the administration of lipopolysaccharide (LPS). Mice were gavaged with HDW (50 or 100 mg/kg body weight), dexamethasone (1 mg/kg body weight) or normal saline (NS, 0.9%) 1 h prior to CS challenge. Compared with CS and LPS (SL)‑induced mice, the levels of interleukin (IL)‑1β, tumor necrosis factor‑α and transforming growth factor‑β in bronchoalveolar lavage fluid from HDW+SL mice were significantly decreased and IL‑10 was markedly reduced. Histological examination of the lung tissues revealed that HDW treatment alleviates airway inflammation. In addition, the administration of HDW to human bronchial epithelial BEAS‑2B cells suppressed the activity of the nuclear factor (NF)‑κB signaling pathway. The results of the present study demonstrate that HDW has a therapeutic effect in COPD and the underlying mechanism may be attributed to inhibition of the NF‑κB pathway.