Quercetin Differentially Modulates MTT-Derived Cellular Metabolic Activity and Apoptosis-Related Gene Expression in A549 and BEAS-2B Cells

Background/Objectives: Quercetin is a dietary flavonoid with potential anticancer activity, but comparative effects in malignant and non-malignant lung-derived epithelial cells remain incompletely characterized.

Methods

A549 and BEAS-2B cells were exposed to quercetin (1–250 µM) for 24, 48, and 72 h, and MTT-derived cellular metabolic activity was measured. Mean normalized concentration–response curves from three independent biological experiments (n = 3) were fitted with four-parameter logistic models, and Greenhouse–Geisser-corrected cell line × concentration × time interactions were tested. Apoptosis-related gene expression was assessed by qRT-PCR after exposure to 45 µM quercetin for 48 h; 45 µM was not a discrete concentration in the MTT series and was close to the directly tested 40 µM condition.