Studying the molecular mechanisms of tef (Eragrostis tef) antioxidant properties in human THP-1 monocytes

Brown tef (<i>Eragrostis tef</i>) grain extracts increase cellular glutathione (GSH) in THP-1 monocytes, however, the molecular mechanisms remained unclear. In this study, we found that the tef extracts induced luciferase activity by 19-fold in HEK293 cells stably expressing the luciferase gene under the control of the nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response element, indicating the activation of the antioxidant pathway. RNA-seq analysis revealed that the tef extract enhanced the expression of 87 genes, including some regulated by the Nrf2 transcription factor. Differentially expressed genes included <i>ferritin heavy chain pseudogenes,</i> tumor necrosis factor (TNF)-α, and <i>solute carrier</i> genes. Using LC-MS, we identified compounds that were differentially enriched in the active tef fraction as compared to the inactive fraction, including vernolic and α-linolenic acid, which were enhanced by over 60-fold. In summary, our findings indicate that tef grains contain phytochemicals that enhance the antioxidant levels through the Nrf2-signaling pathway.