Fig. 1.

Quercetin protects yeast tel1 mutant cells exposed to different oxidants. a Spot assay. Exponentially growing wild type and tel1∆ cells were pretreated with 200 µM quercetin (Quer) or equal volume of DMSO (control) for 1 h. After incubation, cells were tenfold serially diluted and spotted on to YPD plates or YPD plates containing H₂O₂ (2 and 3 mM) or MBS (0.2 mM) or t-BHP (1 and 2 mM), and were incubated at 30 °C for 2–3 days. Representative images are shown from at least three independent experiments. b Colony forming unit assay. Viability of wild type and tel1∆ strains was measured after exposure of cells to different oxidants (H₂O₂-1 mM; MBS-0.2 mM; and tBHP-1 mM) for 1 h without (control) or with quercetin (200 µM). Values are mean ± SD of three independent experiments. *Significant increase in percent viability in quercetin treated tel1∆ cultures compared to tel1∆ cultures treated with H₂O₂, t-BHP and MBS alone, respectively (p < 0.05). c Detection of ROS using 2′,7′-dichlorodihydrofluorescein diacetate (H₂DCFDA) staining. Exponentially growing yeast cells were treated as described above, stained with H₂DCFDA and observed under fluorescence microscope. Representative images are shown from at least three independent experiments. BF, bright field; FM, fluorescence microscopy