Comparative transcriptomic effects of Harpephyllum caffrum extracts and sodium metabisulphite on hydrogen peroxide stressed Saccharomyces cerevisiae cells using RNA-seq

Plant extracts intended for application as natural food antioxidants are largely touted as safe antioxidants without mechanistic interpretation of their in vivo efficacy or tangible proof of their toxicological effects. The study used RNA-Seq analysis to evaluate the transcriptomic effects of Harpephyllum caffrum Berhn. Fruit peel extracts (HCP) at 250, 450 and 650 ppm in Saccharomyces cerevisiae and their ability to attenuate in vivo H2O2- induced oxidative stress in comparison with sodium metabisulphite (SMB) at 450 ppm. The HCP were influenced ribosome biogenesis and spliceosome relative to SMB. Additionally, HCP treatments primed cells for oxidative stress response and recovery with HCP-450 application being optimal, while SMB induced differential upregulation of thioredoxin, peroxiredoxin, glutathione peroxidase and catalase oxidative stress response genes. There were signs of mitochondrial damage in stressed HCP-650, while the proteasomal system and pro-apoptotic genes were induced in the stressed SMB treatment. Overall, the study demonstrates the antioxidant efficacy of HCP, especially at 450 ppm, and its potential to induce epitranscriptomic modifications beneficial for a healthful diet as opposed to SMB.