Topical antiinflammatory activity of the major lipophilic constituents of the rhizome of Zingiber cassumunar. Part II: Hexane extractives.

A hexane extract of the rhizome of Zingiber cassumunar was found to exhibit topical antiinflammatory activity, when tested in the model of 12-O-tetradecanoylphorbol-13-acetate-induced ear edema in rats (ID(50) = 854 μg/ear). Bioassay-guided fractionation (by MPLC on silica gel) of the hexane extract led to the isolation and identification of (E)-4-(3',4'-dimethoxyphenyl)but-3-enyl acetate (1), cis-3-(3',4'-dimethoxyphenyl)-4-[(E)-3,‴,4‴- dimethoxystyryl]cyclohex-l-ene (2), cis-3-(3',4'-dimethoxyphenyl)-4-[(E)-2‴,4‴,5‴- trimethoxystyryl]cyclohex-1-ene (3), cis-3-(2',4',5'-trimethoxyphenyl)-4-[(E)-2‴,4‴,5‴- trimethoxystyryl]cyclohex-l-ene (4) and (E)-4-(3'-4'-dime-thoxyphenyl)but-3-en-l-ol (5). Compounds 1-5 exerted potent topical antiinflammatory activities with ID(50)-values of 62, 21, 20, 2 and 47μg/ear, respectively. The ID(50) of the reference drug diclofenac was determined to be 61 μg/ear.