A cell-permeable inhibitor of TLR4 signaling, blocking LPS-induced production of NO, TNF-α, IL-6, and IL-1β in macrophages with IC₅₀ values of 1-11 nM; effective in vivo, suppressing the production of NO, TNF-α, IL-6, and IL-1β in mice treated with LPS when given intravenously.