Cytotoxic effects of the components in heat-treated mistletoe (Viscum album)

Major cytotoxic components were fractionated from Korean mistletoe and the changes of their cytotoxic effects caused by heat treatment were investigated. The high cytotoxicity of isolated lectin I completely disappeared by heating for 30 min. The fractions of viscotoxins and alkaloids maintained their activities even after heating for 60 and 180 min, respectively. The alkaloid fraction was more cytotoxic to tumor MSV cells than to non-tumor A31 cells and the activity pattern was not changed by heat treatment. The possible contributions of alkaloids and viscotoxins to the activities of heat-treated mistletoe extracts such as tea or decoctions are discussed.