Studies on the Medicinal Resources. XIX

Flavonoid of the Leaves of Nelumbo nucifera GAERTN., Cosmos bipinnatus CAV., and Foeniculum vulgare MILLER

Abstract

Yellowish needles, m.p. 174-175°, [α]_D²⁶-21.1°, C₂₇H₂₈O₁₈⋅6 1/2H₂O, were isolated in respective yield of 0.1%, 0.01%, and 0.1% from the fresh leaves of Nelumbo nucifera GAERTN., Cosmos bipinnatus CAV., and Foeniculum vulgare MILLER. These three substances were all identical. This substance was named nelumboside. It colored dark greenish brown to ferric chloride and pink to magnesium or zinc and hydrochloric acid. Hydrolysis of nelumboside with 5% sulfuric acid gave 1 mole each of quercetin, glucose, and glucuronic acid and permethylation with diazomethane followed by hydrolysis afforded 5, 7, 3′, 4′-tetra-O-methylquercetin. It follows, therefore, that the sugar is bonded to the 3-position and nelumboside is quercetin 3-glucoglucuronide.