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 mu M), Setospaeria turcica, and Bipolaris maydis. It also inhibited the yeast Candida albicans with an IC50 = 96 mu M. 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 degrees C. It manifested antibacterial activity against Pseudomonas aeruginosa (IC50 = 53 mu M). Furthermore, after 48 h of culture, it suppressed proliferation of nasopharyngeal cancer and hepatoma cells with IC50 = 50 and 90 mu M, respectively.