ABSTRACT
Agaricus bisporus (button mushroom) is one of the most consumed edible mushrooms in the world. The components of its methanol and ethyl acetate extracts were tested for their ability to inhibit the growth of a soil bacterium Bacillus subtilis utilizing direct bioautography (thin-layer chromatography (TLC) coupled with bioassay). The active components separated were also characterized by different chemical reagents. The major antibacterial compound was eluted from the layer and further investigated by the use of high-performance liquid chromatography coupled with photodiode array detector and mass spectrometer (HPLC-DAD-ESI/MS) and identified as linoleic acid by comparison of retention time and mass spectra with authentic standards.