Interference of linoleic acid fraction in some receptor binding assays.

An extract of a suspension culture of Tabernaemontana pandacaqui Poir. was fractionated by centrifugal partition chromatography. Aliquots were tested in an adenosine A1 receptor binding assay. This led to the isolation and identification of linoleic acid, which proved to be a noncompetitive inhibitor. This "false positive"effect also extended to some other binding assays.