Silybin ( ) is a flavonoligan containing five functional hydroxyl groups, thus the selective esterification between the carboxylic acid group of madecassic acid (MA, 2) and silybin moiety may be somewhat problematic (Figure ). Initially, we aimed at conjugating madecassic acid with hydroxy at C-23 of silybin through an ester. Accordingly, silybin was converted into 3,5,7,20-Otetraacetyl silybin as described by Armando , followed by reaction with 2,3,23triacetylmadecassic acid (3)/or its amide derivatives, which were linked to a glycine amino acid unit.