Batatasin I, a Naturally Occurring Phenanthrene Derivative, Isolated from Tuberous Roots of Dioscorea batatas Suppresses Eicosanoids Generation and Degranulation in Bone Marrow Derived-Mast Cells

Abstract

To find anti-inflammatory compounds from the tuberous roots of Dioscorea batatas, we isolated 6-hydroxy-2,4,7-trimethoxyphenanthrene (batatasin I) from the dichloromethane (CH₂Cl₂) fraction of this plant. Batatasin I inhibited both the generation of prostaglandin D₂ (PGD₂), leukotriene C₄ (LTC₄) and degranulation reaction in mouse bone marrow-derived mast cells (BMMCs). This compound inhibited cyclooxygenase-2 (COX-2) dependent PGD₂ generation in a dose dependent manner, with IC₅₀ values of 1.78 μM. Western blotting probed with specific anti-COX-2 antibodies showed that the decrease in the quantity of the PGD₂ generation was accompanied by a decrease in the COX-2 protein level. In addition, this compound also inhibited the production of 5-lipoxygenase (5-LOX) dependent LTC₄ in a dose dependent manner (IC₅₀, 1.56 μM). Batatasin I also inhibited the mast cell degranulation reaction (IC₅₀, 6.7 μM) in BMMCs. This result indicates that batatasin I could be developed as an anti-inflammatory agent through further investigation.