Randialic acid B, a triterpenoid compound, is a formyl peptide receptor 1 (FPR1) antagonist. Randialic acid B blocks FPR1 in human neutrophils and attenuates psoriasis-like inflammation in vivo.In Vitro: Randialic acid B (0.1-3 μM; for 5 min) selectively inhibits reactive oxygen species production, elastase release, and CD11b expression in human neutrophils activated by FPR1. Randialic acid B inhibits the binding of N-formyl peptide to FPR1 in human neutrophils, neutrophil-like THP-1 cells, and hFPR1-transfected HEK293 cells, indicating FPR1 antagonism.
Randialic acid B acts competitively for its binding to the FPR1 receptor. The FPR1-downstream signaling such as Ca2+ mobilisation and activation of Akt and MAPKs is also competitively inhibited.
Randialic acid B shows significant cell-protective effects against H2O2-induced H9c2 cardiomyocyte injury[2].In Vivo: Randialic acid B (10 mg/kg; i.v.; every other day; for 5 days) significantly reduces Imiquimod-induced psoriasis-like symptom, including epidermal hyperplasia, desquamation with scaling, neutrophil skin infiltration, and transepidermal water loss.