A new flavonol glycoside, isorhamnetin 5-O-beta-D-gaIactopyranoside, w
as isolated from the aerial parts of Pyrus bourgaeana. The known compo
unds isorhamnetin 3-galactoside, 3-rutinoside, 3-glucoside, 3-rhamnosi
de and quercetin 3-rutinoside were also identified in the plant. The s
tructures of the compounds were determined with spectroscopic methods
including 2D NMR techniques.