Abstract
The concentrated ethanolic extract of the air-dried leaves of Dryopteris oligophlebia C. Chr. yielded a flavonol glucoside as yellow fine needles of m.p. 156-158° (anhydrate, m.p. 191-193°), corresponding to the formula C27H30O15⋅4H2O. Hydrolysis of the glucoside with 5% sulfuric acid gave kaempferol, m.p. 278-279° (tetraacetate, m.p. 185-186°), glucose and rhamnose. In order to determine the bonding position of the sugar, the glucoside was methylated with diazomethane and hydrolyzed with 5% sulfuric acid. The aglycone here obtained was pale yellow needles of m.p. 149-150° which showed no depression of the melting point when fused with 3-hydroxy-5, 7, 4′-trimethoxyflavone, m.p. 149-150°. This showed that the original glucoside was kaempferol-3-rhamnoglucoside.
