Antioxidant and genoprotective effects of spent coffee extracts in human cells

• Spent coffee has antioxidant and genoprotective (comet assay) effects in HeLa cells.
• Cell viability (MTT) was not affected by spent coffee extracts (>80%) up to 1000 μg/mL after 2 h.
• Arabica and Robusta spent coffee extracts reduce H2O2-induced ROS level in HeLa cells.
• Spent coffee extracts strongly protect against H2O2-induced DNA strand breaks.
• Robusta spent coffee extract decreases Ro-induced oxidative DNA damage after 24 h.

Spent coffee has been shown as a good source of hydrophilic antioxidant compounds. The ability of two spent coffee extracts rich in caffeoylquinic acids, mainly dicaffeoylquinic acids, and caffeine (Arabica filter and Robusta espresso) to protect against oxidation and DNA damage in human cells (HeLa) was evaluated at short (2 h) and long (24 h) exposure times. Cell viability (MTT) was not affected by spent coffee extracts (>80%) up to 1000 μg/mL after 2 h. Both spent coffee extracts significantly reduced the increase of ROS level and DNA strand breaks (29–73% protection by comet assay) induced by H2O2. Pretreatment of cells with robusta spent coffee extract also decreased Ro photosensitizer-induced oxidative DNA damage after 24 h exposure. The higher effectiveness of Robusta spent coffee extract, with less caffeoylquinic acids and melanoidins, might be due to other antioxidant compounds, such as caffeine and other Maillard reaction products. This work evidences the potential antioxidant and genoprotective properties of spent coffee in human cells.