ABSTRACT
Four known flavonoids: quercetin 3-O-beta-D-rutinoside [Q3Rut], myricetin 3-O-betaD-galactopyranoside [M3Gal], quercetin 3-O-beta-D-galactopyranoside [Q3Gal] and quercetin 3-Obeta-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