Siamois polyphenols and withasteroids inhibit endogenous NFκB-dependent transcription in K562 and K562/Adr cells. K562 and K562/Adr cells were pretreated with 100 μM of quercetin, kaempferol, eriodictyol, WP283, or 6 μM of withaferin A for 2 h followed by incubation with PMA (0.1 μg/ml) for 3 h. Total RNA was isolated and mRNA was converted into cDNA. Relative mRNA levels were quantified by QPCR by specific primer sets for A) IL6, IL8, A1/Bfl1, MCP1, B) A20, cyclin D1, VEGF, mdr1. Specific mRNA transcription levels were normalized by transcription levels of cells incubated in control medium with 0.1% DMSO. Data of two independent experiments, each done in triplicate, are presented as mean ± S.E.M.