Multiplex planar bioassay with reduced diffusion on normal phase, identifying androgens, verified antiandrogens and...

Hormonal active compounds affecting health by altering the hormonal system are present in food. The planar yeast antagonist androgen screen (pYAAS) bioassay is a powerful tool to detect individual hormonal active compounds in complex samples separated by high-performance thin-layer chromatography (HPTLC). Previous methods lacked either detection sensitivity or zone sharpness. To overcome diffusion caused by long bioassay incubation on the normal-phase (NP) plate, zone fixation (^fix) was achieved with a new polyisobutyl methacrylate coating, leading to enhanced zone sharpness. The exclusion of false-positive antagonists was integrated in the workflow, which allowed the verification (V) of true antagonists, apart from the detection of synergists. With the new multiplex bioassay providing information on 4 activities, 68 different botanicals were screened and hormonal active zones were identified by elution from the bioautogram to orthogonal reversed-phase high performance liquid chromatography with diode array detection and high-resolution mass spectrometry including fragmentation, resulting in the 12D hyphenation NP-HPTLC^fix-UV/Vis/FLD-pYAVAS-FLD-heart cut-RP-HPLC-DAD-HRMS/MS.