STUDY OF AN ARGENTINE MISTLETOE, THE HEMIPARASITE LIGARIA-CUNEIFOLIA (R. ET P.) TIEGH. (LORANTHACEAE)

Ligaria cuneifolia (R. et P.) Tiegh, is an hemiparasite species used i n Argentine folk medicine as a substitute for the European mistletoe ( Viscum album L.) based on its putative activity of decreasing high blo od pressure. This paper analyzes flavonoid composition, protein consti tuents and the possible immunomodulatory and antitumoral effects of th is species. Micromolecular study disclosed quercetin-free, quercetin-g lycosylated and proanthocyanidins corresponding to cyanidin monomers, which implies a particular metabolic pathway. Proteins present in L. c uneifolia extracts analyzed by SDS-PAGE presented multiple bands with molecular weights ranging from 14 to 90 kD. These features contribute to the characterization of the native mistletoe. As V. album is being used in cancer treatment due to its immunomodulatory and antitumoral a ctivity, the action of aqueous L. cuneifolia extracts on murine lympho cytes was investigated. Culture of murine spleen cells alone or stimul ated with Concanavalin A or lipopolysaccharide in presence of L. cunei folia extracts indicated a certain stimulation of splenocytes alone an d an inhibition of splenocytes stimulated with Concanvalin A or lipopo lysaccharide. An inhibitory effect was also observed on the proliferat ion of murine leukemia cells. In addition, aqueous extracts increased nitric oxide production by murine macrophages. These results suggest t hat L. cuneifolia extracts exert an immunomodulatory effect on the mou se immune system. (C) 1998 Elsevier Science Ireland Ltd. All rights re served.