Honeybush Extracts (Cyclopia spp.) Rescue Mitochondrial Functions and Bioenergetics against Oxidative Injury

Figure 6

Effect of honeybush extracts on ROS levels under H₂O₂-induced oxidative stress. (a) H₂O₂ treatment at 400 μM caused an increase of 29.5% in mitochondrial ROS which were detected using the dye DHR. This increase was significantly ameliorated up to 23.1% by C. subternata aqueous extract. (b) H₂O₂ caused an elevation of 31.2% in cytosolic ROS (detected with the dye DCF). All the extracts could bring the cytosolic ROS levels down, but the ones that reduced them significantly and most effectively were the aqueous extract of C. subternata at 1 ng/ml and the 70% ethanolic extract of C. genistoides at 0.5 ng/ml. (c) H₂O₂ increased the mitochondrial superoxide anion levels by 43%. All the extracts, except the ethanolic extract of C. genistoides, significantly reduced the mitochondrial superoxide anion levels. The aqueous extracts of C. subternata, C. genistoides, and C. longifolia at the concentration of 1 ng/ml each completely neutralized the mitochondrial superoxide anion levels. (d) The total superoxide anion levels were elevated by 67.9% in the H₂O₂-treated cells. All 4 extracts could ameliorate this increase but only the aqueous extracts of C. subternata at 1 ng/ml, C. longifolia at 1 ng/ml, and the ethanolic extract of C. genistoides at 0.5 ng/ml significantly reduced the superoxide anion levels. The red bar represents the H₂O₂-treated cells, and the grey bars represent cells that were pretreated for 24 h with the indicated honeybush extract and then treated for 3 h with H₂O₂.Values represent as the mean ± SEM of three independent experiments and were normalized on the untreated group (=100%). One-way ANOVA and post hoc Dunnett’s multiple comparison test versus (a) untreated (CTRL) or (b) H₂O₂.  < 0.05;  < 0.01;  < 0.001.

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