quercetin 3-O-β-D-rutinoside (Q3Rut), myricetin 3-O-β-D-galactopyranoside (M3Gal), quercetin 3-O-β-D-galactopyranoside (Q3Gal) and quercetin 3-O-β-D-glucopyranoside (Q3Glc), for the first time were isolated from aerial parts of Euphorbia microsciadia. The chemical structure of them was elucidated on the basis of 1 and 2 D-NMR spectra and different spectroscopic techniques. The immunomodulatory activities of isolated compounds were compared using standard T-cell proliferation assay. These data showed that lymphocyte suppression activity of flavonoids (1-4) were comparatively lower than prednisolon as a standard drug. Immunosuppressive activity of flavonoids with hydroxyl groups at both 3'-and 4'-positions in their B-ring (Q3Gal) were more than those with 3'-,4'-and 5'-hydroxyl substitution (M3Gal). In these compounds, Q3Gal showed the most inhibitory activity, whereas M3Gal showed the least lymphocyte antiprolifeartive activity.
Keywords: Euphorbia microsciadia; Flavonoids; Flavonol glycosides; Immunomodulatory activity.