Fig. 5. Effect of the selected natural products on the cytotoxicity triggered by Zn(ii) and Zn(ii)–Aβ. (a) Toxicity of the selected natural products with and without Zn(ii) in 5Y cells. Cells were treated with compounds (10 μM) in the absence (light gray) and presence (light green) of Zn(ii) (same equivalent to compounds; 10 μM) for 24 h at 37 °C. (b) Aβ₄₀ (left) or Aβ₄₂ (right; 10 μM) with Zn(ii) (10 μM) was pre-incubated at room temperature for 1 h and then treated to 5Y cells with compounds (10 μM) for 24 h. Cell viability (%) was determined by the MTT assay compared to that obtained upon treatement with a volume of H₂O (1% v/v DMSO) equal to the samples added. Error bars represent the standard error of the mean from three independent experiments. *P < 0.05.