Luteolin inhibits ceramide metabolism to complex sphingolipids.

<p>(A) CC cells were pulsed with 25 nM ³H-Sph (upper panel) or 200 nM ³H-serine (lower panel) in the absence (white bar) or presence (grey bar) of 100 μM luteolin for 2 h. At the end the content of cellular radiolabeled ceramide (Cer), sphingomyelin (SM) and glycosphingolipids (GSLs) was measured. **, p < 0.01. (B) CC cells were incubated in the absence (CT) or presence of luteolin (LU), then with BODIPY-C₅-Cer and analyzed by fluorescence microscopy (bar, 10 μm). (C) CC cells were incubated without (a) or with (b) BFA (1 μg/ml) for 30 min, and then pulsed with ³H-Sph or ³H-serine with luteolin (100 μM) for 2 h. The ceramide/complex sphingolipid ratio is reported. Data are the mean ± S.D. of two independent experiments. **, p < 0.01.