Biological activities of bombolitins from Bombus ardens, B. consobrinus, B. terrestris and B. ussurensis (bombolitinsA, C, T and U, respectively) were examined using hemolytic, anti-microbial, anti-fungal and anti-tumor activity assays.Among the four bombolitins tested, bombolitin T showed the highest hemolytic and anti-tumor activities. All bombolitinsexhibited strong anti-microbial and anti-fungal activities, and bombolitin A specifically possessed the highest anti-microbialactivity against the Gram-negative bacteria Escherichia coli. Circular dichroism spectrometry analysis revealed that allfour bombolitins had over 61.7% and 45.5% of α-helicity in 30 mM sodium dodecyl sulfate and 50% trifluoroethanolbuffers, respectively, which form lipid-membrane-mimicking environments. Bombolitin T showed the lowest IC50 valuesof 8.5 μM and 8.8 μM against SK-OV-3 and NIH-OVCAR-3 cell lines, respectively, after 72 h of treatment, but itsrelative hemolytic activity at a concentration of 200 μM was 2.3-fold higher than that of 0.1% Triton X-100. Thisstudy provides new information on the biological and molecular properties of venom peptides of bumblebees. However,further studies on reducing cytotoxicity of bombolitins are needed for designing selective anti-tumor peptides.

• Kyungjae Andrew Yoon(Department of Agricultural Biology, Seoul National University)
• Young Han Park(Department of Obstetrics and Gynecology, Hallym University Sacred Hospital)
• Young Ho Koh(Ilsong Institute of Life Science, Hallym University, Department of Biomedical Gerontology, Hallym University)
• Si Hyeock Lee(Department of Agricultural Biology, Seoul National University, Research Institute of Agriculture and Life Sciences, Seoul National University)