Total ion chromatogram of crude serum organic extract. (A) Total ion current of bulk serum following liquid/liquid extraction and HPLC-coupled mass spectrometry as explained in the methods. (B) Extracted mass spectra of all masses from (A). (C) Extracted ion chromatograms of GTAs 446, 448 and 450 from the total ion current shown in A. (D) Cell proliferation, as assayed by MTT, for SW620 cells treated with up to 80 ug/ml of the crude serum extract.