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

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 (CH(2)Cl(2)) fraction of this plant. Batatasin I inhibited both the generation of prostaglandin D(2) (PGD(2)), leukotriene C(4) (LTC(4)) and degranulation reaction in mouse bone marrow-derived mast cells (BMMCs). This compound inhibited cyclooxygenase-2 (COX-2) dependent PGD(2) generation in a dose dependent manner, with IC(50) values of 1.78 µM. Western blotting probed with specific anti-COX-2 antibodies showed that the decrease in the quantity of the PGD(2) 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 LTC(4) in a dose dependent manner (IC(50), 1.56 µM). Batatasin I also inhibited the mast cell degranulation reaction (IC(50), 6.7 µM) in BMMCs. This result indicates that batatasin I could be developed as an anti-inflammatory agent through further investigation.