Antimicrobial activity of phenolic constituents of Magnolia grandiflora L.

Three phenolic constituents of Magnolia grandiflora L. were shown to possess significant antimicrobial activity using an agar well diffusion assay. Magnolol, honokiol, and 3.5'-diallyl-2'-hydroxy-4-methoxybiphenyl exhibited significant activity against Gram-positive and acid-fast bacteria and fungi. The minimum inhibitory concentrations were determined for each compound using a twofold serial dilution assay.