Among royal jelly’s (RJ) various biological activities, its possible antitumour activity deserves particular attention. The purpose of this study was to investigate the influence of RJ, its bioactive component 10-hydroxy-2-decenoic acid (10- HDA), and human interferon-alpha (HuIFN-αN3) on the proliferation of human colorectal adenocarcinoma cells (CaCo- 2), and ascertain their effect on intracellular glutathione (GSH) level and lipid peroxidation. We studied the antiproliferative (AP) activity of RJ (0.1 g/10 mL phosphate buffer saline (PBS), HuIFN-αN3 (1000 I.U. mL-1), 10-HDA at 100.0 μmol L-1, and their different combinations, in the ratio 1:1, 1:2, and 2:1 on CaCo-2 cells. The GSH level was measured by glutathione assay. The lipid peroxidation was measured by malondialdehyde (MDA) assay. Single RJ had a low AP activity: 2.0 (0.5 mg mL-1). HuIFN-αN3 had an AP activity of 2.5 (208.33 I.U. mL-1), while 10-HDA had an AP activity of 1.5 (37.5 μmol mL-1). The highest AP activity of 3.8 was obtained when RJ and HuIFN-αN3 were applied at the ratio 2:1. In that combination the level of GSH was 24.9±2.4 nmol g-3 of proteins (vs. 70.2±3.2 nmol g-3 in the control) and the level of MDA was 72.3±3.1 nmol g-3 (vs. 23.6±9.1 nmol g-3 in the control). It is generally assumed that 10-HDA, an important constituent of RJ, together with HuIFN-αN3, is responsible for the inhibition of CaCo-2 cells proliferation in vitro. In our study, however, RJ and HuIFN-αN3 applied at 2:1 decreased the level of GSH the most and significantly increased lipid peroxidation via MDA in CaCo-2 cells. Future studies should show whether these GSH- and MDA-related activities of RJ, HuIFN-αN3, 10-HDA, and their combinations may decrease the tumorigenicity index and tumorigenic potential of various tumour cells in vitro. Kot del biološke aktivnosti MM (Matičnega mlečka) so avtorji preučevali njegovo protitumorsko delovanje kot tudi možno interakcijo s humanim interferonom alfa (HuIFN-αN3). Cilj opravljenih poskusov je bil preučiti vpliv kombinacije med MM in HuIFN-αN3 na proliferacijo celic Humanega kolorektalnega adenokarcinoma (CaCo-2) in njun vpliv na znotrajcelični nivo glutationa (GSH) in peroksidacijo lipidov. Avtorji so preučevali AP (Antiproliferativno) delovanje MM (0.1 g/10 mL fosfatnega pufra) (PBS), HuIFN-αN3, (1000 I.U. mL-1), 10-hidroxy-2-decenoične kisline (10-HDA) (100.0 μmol L-1) in različne kombinacije med njimi (1:1, 1:2 in 2:1) na celice CaCo-2 in vitro. Njihov vpliv na znotrajcelični nivo GSH so merili s pomočjo komercialnega kita. Peroksidacijo lipidov so merili s pomočjo meritve vrednosti malondialdehida (MDA). MM sam kaže AP aktivnost 2.0 (0.5 mg mL-1 ). HuIFN-αN3 ima AP aktivnost 2.5 (208.33 I.U. mL-1) medtem ko ima 10-HDA AP aktivnost 1.5 (37.5 μmol mL-1). AP aktivnost kombinacije MM:HuIFN-αN3 (2:1) je bila 3.8. Pri tej kombinaciji je bil viden vpliv na nivo GSH: 24.9±2.4 nmol g-3 proteinov (70.2±3.2 nmol g-3 pri kontroli). Nivo MDA je bil 72.3±3.1 nmol g-3 pri kontroli). 10-HDA je glavna sestavina MM, ki v kombinaciji s HuIFN-αN3 deluje antiproliferativno na CaCo-2 celice. MM in HuIFN-αN3 v kombinaciji 2:1 pospešujeta peroksidacijo lipidov (MDA) in zmanjšujeta nivo glutationa (GSH). Nadaljni poskusi bodo pokazali ali z GSH- in MDA- povezane aktivnosti MM, HuIFN-αN3, 10-HDA in kombinacij med njimi, zmanjšujejo indeks tumorigenosti in s tem tumorigeni potencijal različnih tumorskih celic in vitro.