Protein composition analysis and cytotoxicity of gulbulin hydrolysates of Brucea javanica seeds

To analyze the protein composition of Brucea javanica seeds and evaluate the cytotoxicity of its gulbulin hydrolysates. Four protein fractions of albumin, gulbulin, prolamin and glutelin were sequentially extracted and then quantified by Kjeldahl method. Different kinds of proteases were applied to hydrolyze B.javanica gulbulin, and MTT assay was used to evaluate the cytotoxicity of low molecular weight hydrolysates (≤3 kDa) on human breast cancer MCF-7 cell. The results showed that： the total protein content of B.javanica seeds was 17.47%, albumin, gulbulin, coxin, glutelin and residue protein accounted for 15.01%, 8.11%, 2.47%, 44.92% and 23.62% of the total protein content, respectively. The hydrolysates (≤3 kDa) of B.javanica globulin produced by pepsin showed significant growth inhibitory activity on MCF-7 cells, and the IC₅₀ value was（6.52±0.01） mg•L⁻¹ after 72 h of incubation. Protein was abundant in B.javanica seeds, and its peptides demonstrated specific cytotoxicity on MCF-7 cell line in vitro, suggesting antitumor active ingredient can be further generated from B.javanica seeds.