Abstract:

Objective: This study was aimed to investigate the antitumor activity of millet bran polypeptides (MBPEs) andtheir inhibitory effect on chemically induced liver injury. Methods: Three kinds of polypeptides were obtained by enzymatichydrolysis of millet bran with bromelain, papain and 537 acid protease, respectively. MTT assay was applied to detect thein vitro antitumor effect of MBPEs. The mice with hepatic injury chemically induced by aminopyrine and sodium nitritewere fed with the polypeptide with the strongest antitumor effect, and the liver was histologically observed. Results: Theinhibitory rates of MBPE (50 mg/mL) prepared with bromelain on S180 and H22 tumor cells were 56.28% and 53.73%, respectively.In the high-dose MBPE group (10 g /(kg·d)), the serum levels of aspartate transaminase (AST) and alanine transaminase (ALT) andthe liver content of malondialdehyde (MDA) were significantly decreased（P ＜ 0.01). The activity of liver glutathione peroxidase (GSH-Px)was significantly increased（P ＜ 0.01). The histological examination of the liver tissue showed that liver cells were severely injured.However, the morphology of hepatocytes in the high-dose group was basically normal. Conclusion: The polypeptides from millet branhydrolyzed by bromelain have significantly inhibitory efects on liver injury and precancerous lesions

Key words: millet bran polypeptide, aminopyrine, antitumor, liver injury, hepatic precancerous lesions