L. cuneifolia var. cuneifolia which is the natural substitute for the European mistletoe (Viscum album) in Argentina exerts distinct effects: hypotension, immuno-modulation and induction of apoptosis. Incubation of murine cells with acellular extracts of the plant resulted in an antiproliferative effect on both, activated splenocytes and leukaemic cells, while normal splenocytes were stimulated. Apart from the induction of an apoptotic cell death in leukemic cells, the plant enhances the production of macrophage nitric oxide.
Anatomical study shows that the main microscopical features to identify this species are the presence of crystalliferous branched stone cells in leaves and stems, the absence of other crystals and the lack of cork in stems. No lipids are detected. Along with leucoanthocyanidins and proanthocyanidins, the only detected flavonol is quercetin glycosylated with three sugars. The precursor dihydroquercetin follows two metabolic pathways: one leading to quercetin by means of a flavonol synthase and a second one leading to leucocyanidin by means of a 3-hydroxyflavanone-4-reductase (Stafford, 1990). The simultaneous presence of both flavonoids is useful to characterise this species when compared to other Loranthaceae and Viscaceae. Macromolecular protein components of the extracts analysed by electrophoresis present a pattern quite dissimilar to V. album but proteins present exhibit related antigenic epitopes. In most samples tyramine concentration fails to exceed 10 mg%, but may reach 360 mg% in samples parasiting G. decorticans.
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