Terpenoids of quinoa bran suppresses colorectal cancer by inducing cell apoptosis

Colorectal cancer (CRC) is one of the most common malignant tumors worldwide, occurring in the colon or rectum portion. Quinoa is a dicotyledonous plant, and the quinoa bran is the outer seed coat of quinoa. Functional molecules in plants play an important role in the treatment and alleviation of chronic diseases. In this study, quinoa bran was used as the raw material. The active components with an anti-colorectal cancer effect were extracted by acetone and separated with an AB-8 macroporous resin column, which was further identified as terpenoids by liquid-mass spectrometry (LMS), named Quinoa bran terpenoids (QBT). The yield of quinoa bran terpenoids was 0.77%. Moreover, the results showed that QBT significantly inhibited the proliferation of colorectal cancer cells DLD-1 and HCT-8 with a concentration gradient dependent manner. Respectively, the IC50 values of DLD-1 and HCT-8 cells were 0.42 +/- 0.02 and 0.54 +/- 0.05 mg/mL. Further studies showed that QBT upregulated apoptosis-related proteins such as activated-caspase-3, 8, and 9. In addition, QBT decreased mitochondrial membrane potential, promoted the expression of the pro-apoptotic protein Bax, and inhibited the antiapoptotic protein Bcl-2. The experiments showed that QBT significantly repressed the growth of tumors in nude mice. In conclusion, these results indicated that QBT largely inhibits the development of colorectal cancer to large extent through upregulation of caspase-3, 8, and 9 and reduction of mitochondrial membrane potential, and has great potential for anti-tumor progression.