HONOKIOL

Alcoholic extracts of magnolia tree bark and seeds have been shown to contain several phenolic constituents, including honokiol (3',5-di-2-propenyl-[1,1'-biphenyl]2,4/-diol), C18H18O2, the structure of which was established previously by spectroscopic methods. We report here a crystal structure determination of honokiol and demonstrate that the rings of its biphenyl core adopt a non-planar orientation. Both hydroxyl substituents participate in intermolecular hydrogen bonding with O...O distances near 2.8 Angstrom.