Improved separation of the curcuminoids, syntheses of their rare earth complexes, and studies of potential antiosteoporotic activity

The first reported homogenous rare earth curcumin (HCurc; ((1E,6E)-1,7-bis(4-hydroxy-3-methoxyphenyl) hepta-1,6-diene-3,5-dione)) complexes with the formula ML3, where M3+ is Eu(III), Gd(III) or Lu(III), were synthesized and characterized by mass spectrometry, infrared spectroscopy and, in the case of the lutetium complex, H-1 NMR spectroscopy. Most importantly an improved separation of the three curcuminoids, HCurc, HDMC ((lE,6E)-1-(4-hydroxy-3-methoxypheny1)-7-(4-hydroxyphenyl)hepta-1,6-dien e-3,5-dione) and HBDMC ((1E,6E)-1,7-bis(4-hydroxyphenyl)hepta-1,6-diene-3,5-dione) was realized using a combination of normal-phase column and phosphate-impregnated preparative-thin layer chromatographies. The toxicities of the metal curcumin complexes and ligands were investigated in MG-63 cells, an osteoblast-like cell line, for potential activity as antiosteoporotic agents. (c) 2013 Elsevier Inc. All rights reserved.