Silybin, a new iron-chelating agent

Silybin, a natural occurring flavolignan isolated from the fruits of Silibu m marianum, has been reported to exert antioxidant and free radical scaveng ing abilities. It was suggested to act also as an iron chelator. The comple xation and protonation equilibria of the ferric complex of this compound ha ve been studied by potentiometric, spectrophotometric and electrochemical t echniques. The formation of the complex silybin-Ga(III) in anhydrous DMSO-d 6 has been studied by H-1 NMR spectroscopy. Mass spectrometry and infrared spectroscopy on silybin-Fe(III) complex confirm all data obtained by H-1 NM R spectroscopy. The experimental results show that silybin binds Fe(III) ev en at acidic pH. Different ternary complexes were observed at increasing me thoxide ion concentration and their stability constants have been calculate d. The results show the possible role of silybin in relation to the chelati on therapy of chronic iron overload, as occurs in the treatment of Cooley's anemia. (C) 2001 Elsevier Science B.V. All rights reserved.