Medicinal flowers. I. Aldose reductase inhibitors and three new eudesmane-type sesquiterpenes, kikkanols A, B, and C, from the flowers of Chrysanthemum indicum L.

The methanolic extract from the flowers of Chrysanthemum indicum L., Chrysa nthemi Indici Flos, was found to show inhibitory activity against rat lens aldose reductase. By bioassay-guided separation, the active components, suc h as flavone and flavone glycosides, were isolated from the extract togethe r with three new eudesmane-type sesquiterpenes, kikkanols A, B, and C. The structures of kikkanols A, B, and C were elucidated on the basis of chemica l and physicochemical evidence, which included application of the modified Mosher's method.