Natural and synthetic benzophenones: interaction with the cytosolic binding domain of P-glycoprotein.

A benzophenone glycoside has been isolated from Davallia solida. Its structure was elucidated by chemical and spectral means as 4-O-beta-D-glucopyranosyl-2,6,4'-trihydroxybenzophenone. It bound with moderate affinity to the purified C-terminal cytosolic domain of P-glycoprotein, but the binding affinity was 6- to 10-fold increased for its aglycone derivative and other related benzophenones.