Determination of possible cytotoxicity or unspecific host cell receptor inhibition.

<p>(<b>A</b>) Cell metabolic activity after 24 h of incubation of A549 cells with DMSO (no treatment), 2.5 µM of staurosporine, 10 µg/ml of UF-concentrate or 50 µg/ml of the remaining drugs was determined in triplicates using XTT assay. Optical density (OD) was determined at 450 nm after background (650 nm) subtraction and expressed as % of the untreated samples. (<b>B</b>) Caspase 3/7 activity after 24 h of A549 cell incubation with DMSO (no treatment), 2.5 µM of staurosporine, 10 µg/ml of UF-concentrate or 50 µg/ml of the remaining drugs was assayed in at least triplicates using detection of a luminogenic caspase 3/7 cleavage product. (<b>C</b>) A549 cells were infected in triplicates with adenovirus type 5 (MOI of 0.05) and simultaneously treated with UF-concentrate. TCID50 was determined at 24 h post infection. (<b>D</b>) Interference of the drugs with cellular TNF-α signaling. A549 cells were preincubated for 30 or 0 minutes (“Preinc.”+or −, respectively) with 50 µg/ml of bark extract (“Bark”) or UF-concentrate (“UF-c”). Then, 0 or 30 ng/ml TNF-α were and 15 minutes later, total proteins were extracted. IκB-α and the loading control β-actin were detected on a Western blot using specific primary and Cy-5 and Cy-3 labeled secondary antibodies. * significantly elevated caspase expression (p<0.05) as compared to “No treatment”.