Selective inhibition of 5‐lipoxygenase by natural compounds isolated from Chinese plants, Artemisia rubripes Nakai

Abstract

Three of four natural compounds, which are caffeic acid, eupatilin and 4′-demethyleupatilin, isolated from Chinese plant, Artemisia rubripes Nakai selectively inhibited 5-lipoxygenase of cultured mastocytoma cells. Half-inhibition doses (ID ₅₀) for caffeic acid, eupatilin and 4′-demethyleupatilin were 3.7, 14 and 18 × 10⁻⁶ M, respectively. The inhibition by caffeic acid was non-competitive types. Prostaglandin synthase activities were little inhibited by eupatilin and 4′-demethyleupatilin, but rather stimulated by affeic acid. The formation of leukotriene C₄ and D₄ by mast tumor cells was almost completely suppressed by these compounds at 10⁻⁴ M.