Anti-Ageing Effects of Sonchus oleraceus L. (pūhā) Leaf Extracts on H(2)O(2)-Induced Cell Senescence

Antioxidants protect against damage from free radicals and are believed to slow the ageing process. Previously, we have reported the high antioxidant activity of 70% methanolic Sonchus oleraceus L. (Asteraceae) leaf extracts. We hypothesize that S. oleraceus extracts protect cells against H(2)O(2)-induced senescence by mediating oxidative stress. Premature senescence of young WI-38 cells was induced by application of H(2)O(2). Cells were treated with S. oleraceus extracts before or after H(2)O(2) stress. The senescence- associated β-galactosidase (SA-β-gal) activity was used to indicate cell senescence. S. oleraceus extracts showed higher cellular antioxidant activity than chlorogenic acid in WI-38 cells. S. oleraceus extracts suppressed H(2)O(2) stress-induced premature senescence in a concentration-dependent manner. At 5 and 20 mg/mL, S. oleraceus extracts showed better or equivalent effects of reducing stress-induced premature senescence than the corresponding ascorbic acid treatments. These findings indicate the potential of S. oleraceus extracts to be formulated as an anti-ageing agent.