Antioxidants in neoplastic cells: IV. Evidence that the phenolic antioxidant A274 is 9-(4-hydroxyphenyl)xanthene, an artifact in tissue culture media.

An extensively conjugated phenol (A274), recently shown to be present as a common trace constituent in randomly selected batches of commercial tissue culture media, was diazomethylated; the monomethyl derivative so prepared was shown to exhibit gas chromatographic and mass spectrometric properties identical to those observed for synthetically prepared 9-(4-methoxyphenyl)xanthene, but different from those of several isomeric compounds. The structure 9-(4-hydroxyphenyl)xanthene is thus proposed for A274.