Protein from red cabbage (Brassica oleracea) seeds with antifungal, antibacterial, and anticancer activities

A 30 kDa antifungal protein was purified from red cabbage (Brassica oleracea) seeds. It exhibited a molecular mass and N-terminal amino acid sequence disinct from those of previously isolated Brassica antifungal proteins. The protocol used entailed ion exchange chromatography on Q-Sepharose and SP-Sepharose followed by fast protein liquid chromatography on Mono S. The protein hindered mycelial growth in Mycosphaerella arachidicola (with an IC₅₀ = 5 μM), Setospaeria turcica, and Bipolaris maydis. It also inhibited the yeast Candida albicans with an IC₅₀ = 96 μM. It exerted its antifungal action by permeabilizing the fungal membrane as evidenced by staining with Sytox green. The antifungal activity was stable from pH 3 to 11 and from 0 to 65 °C. It manifested antibacterial activity against Pseudomonas aeruginosa (IC50 = 53 μM). Furthermore, after 48 h of culture, it suppressed proliferation of nasopharyngeal cancer and hepatoma cells with IC50 = 50 and 90 μM, respectively.