Phenolics extracted from tartary (Fagopyrum tartaricum L. Gaerth) buckwheat bran exhibit antioxidant activity, and an antiproliferative effect on human breast cancer MDA-MB-231 cells through the p38/MAP kinase pathway

• Published in: Food & function Vol. 8; no. 1; pp. 177 - 188
• Main Authors: Li, Fuhua, Zhang, Xiaoli, Li, Yao, Lu, Keke, Yin, Ran, Ming, Jian
• Format: Journal Article
• Language: English
• Published: England 01.01.2017
• Subjects: Adaptor Proteins, Signal Transducing - genetics; Adaptor Proteins, Signal Transducing - metabolism; Antioxidants - pharmacology; Breast Neoplasms - drug therapy; Breast Neoplasms - genetics; Breast Neoplasms - metabolism; Breast Neoplasms - physiopathology; Cell Cycle - drug effects; Cell Line, Tumor; Cell Proliferation - drug effects; Fagopyrum; Fagopyrum - chemistry; Female; Humans; MAP Kinase Signaling System - drug effects; Phenols - pharmacology; Plant Extracts - pharmacology; Tumor Suppressor Protein p53 - genetics; Tumor Suppressor Protein p53 - metabolism
• ISSN: 2042-6496; 2042-650X
• DOI: 10.1039/c6fo01230b

Phenolics extracted from tartary buckwheat (Fagopyrum tartaricum L. Gaerth) bran were analyzed quantitatively and qualitatively. The bioactivity of the phenolic extracts was evaluated, such as the antioxidant activity, and the inhibition capacity on the growth of cancer cells. The molecular mechanism for the inhibitive effect on cancer cells was explored. Results indicated that tartary buckwheat bran phenolics mainly exist in a free form, and free phenolics were twice as abundant as bound phenolics. Free caffeic acid (119.75 μg per 100 mg DW) and bound rutin (51.66 μg per 100 mg DW) represented the main free and bound phenolic compounds, respectively. The free phenolic extract contributed to the major (>90%) antioxidant activities including the oxygen radical antioxidant capacity (ORAC) and cellular antioxidant activity (CAA). The free phenolic extract exhibited anticancer activity for human breast cancer MDA-MB-231 cells in a dose-dependent manner. This significant inhibition effect was achieved through the p38/MAP kinase pathway by inducing cell apoptosis (up-regulating p-p38 and p-ASK1 expressions and down-regulating TRAF2 and p-p53 expressions), and negatively regulating the progression of the cell cycle from the G1 to S phase (increased expression of p21 and suppressed expressions of PCNA, cyclin D1 and CDK4). All these results indicated that tartary buckwheat bran could be a rich resource of natural antioxidants and inhibitors for the growth of MDA-MB-231 cells.