Purification and Biochemical Characterization of Lectins Extracted from Natural Korean Mistletoe (Viscum album L. var. coloratum) and Lectins Extracted from in vitro Cultured Mistletoe Callus
Background : With the increasing demand of the mistletoe in larger quantities for cancer therapy, it has been depleted from its natural habitat in the Far East countries including Korea because of overharvesting for high-value products (e.g., lectins and viscotoxins). The rapid multiplication of mistletoe by tissue culture can help this problem and provide the benefits in the phamaceutical industry. Methods and Results : Mistletoe plants growing on oak trees were collected and their leaf and stem segments were inoculated on MS basal medium supplemented with various concentrations of growth regulators. Calli were induced only from stem explants on MS medium containing 2,4-D and transferred onto MS medium supplemented with various concentrations of 2,4-D, NAA and BAP, respectively, for their propagation. The best callus multiplication rate of more than 15 folds (759 mg) was obtained in treatment of 2,4-D (4 mg/L) that produced yellowish-green, white and friable callus on this medium. To compare biochemical characterization, lectins were partially purified from natural mistletoe plants (nML) and in vitro cultured mistletoe calli (cML), respectively. The former was purified by lactose-agarose affinity chromatography and the latter was done by ammonium sulfate precipitation followed Sephadex G-25 chromatography. Both nML and cML showed similar molecular weight on SDS-PAGE and Western blot analyses. In addition, they showed similar carbohydrate-binding specificities and hemagglutination activities. Conclusion : From the above results, we may suggest that nML and cML showed the similarity in biochemical characters.