Phytochemical-rich Fractions from Foxtail Millet (Setaria italica (L.) P. Beauv) Seeds Exhibited Antioxidant Activity and Reduced the Viability of Breast Cancer Cells In Vitro by Inducing DNA Fragmentation and Promoting Cell Cycle Arrest.

Background: The demand for millet-based diets has increased significantly in recent years due to their beneficial effects on human health. Foxtail Millet (Setaria italica (L.) P. Beauv, previously known as Panicum italicum L., referred as FTM in this manuscript) seeds have been not only used as astringent and diuretic agents, but they are also used to treat dyspepsia and rheumatism. Recent studies have shown that solvent extracts from FTM seeds exhibited antioxidant and antiinflammatory activities. However, the nature and antiproliferative potential of phytochemical constituents of solvent extracts are not much explored.

Objectives: Major objectives of this study are to generate and characterize the phytochemical-rich fractions from Foxtail millet seeds, test the antioxidant activity, and antiproliferative potential against cell lines representing carcinomas of the breast, and determine the mechanisms of cell growth inhibition.

Method: Phytochemical-rich fractions were generated by extracting the seeds using 70% ethanol (FTM-FP) and 10% alkali (FTM-BP). Antioxidant potential was determined by ferric reducing antioxidant power (FRAP) assay and DPPH radical scavenging activity assays. The antiproliferative potential was determined using sulforhodamine-B assay. The impact on cell cycle and DNA fragmentation was analyzed by staining the cells with DAPI followed by analyzing the stained cells using NC-3000.

Results: Analysis of the results showed the presence of phenolics and flavonoids in the FTM-FP and FTM-BP fractions. Both fractions exhibited antiproliferative potential against breast cancer cell lines. Mechanistically, both fractions induced G2/M cell cycle arrest and increased the fragmentation of DNA, which lead to the accumulation of cells in the Sub-G1 phase.

Conclusion: In summary, results of this study demonstrated the potential of foxtail millet phytochemical fractions for retarding the proliferative potential of breast cancer cells.