Synthesis and biological evaluation of new derivatives of emodin.

Drugs containing an anthraquinone moiety such as daunorubicin (Daunoblastin) and mitoxantrone (Onkotrone) constitute some of the most powerful cytostatics. They suppress tumor growth mainly by intercalation into DNA and inhibition of topoisomerase II, and are suspected to generate free radicals leading to DNA strand scission. We established a novel strategy for obtaining new highly functionalized derivatives of emodin (1,3,8-trihydroxy-6-methyl-anthraquinone).

Flavonoid binding to a multi-drug-resistance transporter protein: an STD-NMR study.

Flavonoids are well known to inhibit the function of the multi-drug-resistance (mdr) transporter by interacting with their ATP binding domains. The precise orientation of these molecules inside the ATP binding pocket is still unclear. We applied the saturation transfer difference (STD) NMR technique to investigate the binding of the flavonoid luteolin and its 7-O-beta-D-glycopyranoside to the recombinant nucleotide binding domain (NBD2) of mouse-mdr.

Investigation of the membrane localization and distribution of flavonoids by high-resolution magic angle spinning NMR spectroscopy.

To investigate the structural basis for the antioxidative effects of plant flavonoids on the lipid molecules of cellular membranes, we have studied the location and distribution of five different flavonoid molecules (flavone, chrysin, luteolin, myricetin, and luteolin-7-glucoside) with varying polarity in monounsaturated model membranes. The investigated molecules differed in the number of hydroxyl groups attached to the polyphenolic benzo-gamma-pyrone compounds. To investigate the relation between hydrophobicity and membrane localization/orientation, we have applied (1)H magic angle spinning NMR techniques measuring ring current induced chemical shift changes, nuclear Overhauser enhancement cross-relaxation rates, and lateral diffusion coefficients.