Testovima in vitro citotoksičnosti moguće je ispitati djelovanje novih spojeva, a dobiveni se rezultati mogu koristiti za planiranje budućih in vivo ispitivanja. Imela Viscum album je bogat izvor biološki aktivnih tvari, a od davnina se koristi u terapeutske svrhe. U prethodnim je istraživanjima utvrđen antitumorski potencijal pripravaka imele, posebno u kombinaciji s klasičnim metodama liječenja karcinoma. U ovom istraživanju su korištene dvije tumorske stanične linije: HeLa i HepG2, te je određen biološki učinak ekstrakta imele pri različitim koncentracijama. Rezultati su izraženi kao vijabilnost stanica u odnosu na volumni udio ispitivanog ekstrakta imele, a promatrana je i promjena morfologije stanica. Ekstrakt imele je pokazao blagi inhibitorni učinak na rast i proliferaciju obje stanične linije, pri svim ispitivanim koncentracijama. Maksimum inhibicije rasta HeLa stanica bio je 24,55%, a HepG2 stanica 35,48%. Za daljnja je razmatranja antitumorskog djelovanja ekstrakta imele potrebno provesti ispitivanja na drugim staničnim linijama i po mogućnosti u kombinaciji s drugim metodama liječenja tumora.

In vitro cytotoxicity assays are used to examine the biological effects of new compounds and to plan future in vivo experiments. Mistletoe Viscum album is a great source of biologically active substances, and has long been used for therapeutic purposes. Antitumor potential of mistletoe extracts has been confirmed in previous research, especially in combination with common cancer treatment. Two cancer cell lines: HeLa and HepG2, were used in this research for testing the biological effects of mistletoe extract at different concentrations. The results were expressed as cell viability relative to the volume fraction of the extract. Morphological changes were also observed. The mistletoe extract showed a slight inhibitory effect on growth and proliferation of both cell lines. Maximum growth inhibition of HeLa cells was 24,55%, and the one of HepG2 cells 35,48%. For further consideration of antitumor activity of the mistletoe extract it is necessary to perform studies with other cell lines and possibly in combination with other cancer treatment methods.