Inotodiol, an antiasthmatic agent with efficacy and safety, preferentially impairs membrane-proximal signaling for mast cell activation

•Inotodiol in a lipid-based formulation shows desirable oral bioavailability.•Inotodiol’s therapeutic index for asthma is >8 times better than dexamethasone’s.•Inotodiol selectively inhibits mast cell function both in vitro and in vivo.•Inotodiol suppresses receptor-proximal signaling for mast cell activation.