Sweroside inhibits the activation of the NLRP3 inflammasome in primary macrophages. (A) Chemical structure of sweroside. (B–D) Bone marrow-derived macrophages (BMDMs) were primed with LPS (100 ng/mL) for 4 h. The cells were treated with sweroside for 1 h and then stimulated with (B) ATP (5 mM) for 2 h, (C) nigericin (10 µM) for 16 h, or (D) MSU (500 µg/mL) for 6 h. Cell culture supernatants were analyzed for secreted IL-1β by ELISA. The values represent the means ± SEM (n = 3). #, significantly different from vehicle alone, p < 0.05. *, significantly different from ATP, nigericin, or MSU alone, p < 0.05. (E) BMDMs were primed with LPS (100 ng/mL) for 4 h. The cells were treated with sweroside for 1 h and then stimulated with ATP (5 mM) for 1 h, nigericin (10 µM) for 1 h, or MSU (500 µg/mL) for 4.5 h. The cell culture supernatants and cell lysates were immunoblotted for pro-caspase-1, caspase-1(p20), pro-IL-1 β, and IL-1 β.