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Free Radical Scavenging and Antioxidative Properties of ‘Silibin’ Complexes on Microsomal Lipid Peroxidation
Author(s) -
BASAGA H.,
POLI G.,
TEKKAYA C.,
ARAS I.
Publication year - 1997
Publication title -
cell biochemistry and function
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 61
eISSN - 1099-0844
pISSN - 0263-6484
DOI - 10.1002/(sici)1099-0844(199703)15:1<27::aid-cbf714>3.0.co;2-w
Subject(s) - lipid peroxidation , chemistry , microsome , superoxide , hydroxyl radical , radical , microsoma , scavenger , biochemistry , xanthine oxidase , antioxidant , in vitro , enzyme
Abstract The antioxidant properties of silibin complexes, the water‐soluble form silibin dihemisuccinate (SDH), and the lipid‐soluble form, silibin phosphatidylcholine complex known as IdB 1016, were evaluated by studying their abilities to react with the superoxide radical anion (O 2 .− ), and the hydroxyl radical (OH . ). In addition, their effect on pulmonary and hepatic microsomal lipid peroxidation had been investigated. Superoxide radicals were generated by the PMS‐NADH system and measured by their ability to reduce NBT. IC 50 concentrations for the inhibition of the NBT reduction by SDH and IdB 1016 were found to be 25 μ M and 316 μ M respectively. Both silibin complexes had an inhibitory effect on xanthine oxidase activity. SDH reacted rapidly with OH . radicals at approximately diffusion controlled rate and the rate constant was found to be ( K =8·2×10 9 M −1 s −1 ); it appeared to chelate Fe 2+ in solution. In hepatic microsomes, when lipid peroxidation was induced by Fe 2+ , SDH inhibited by 39·5 per cent and IdB 1016 by 19·5 per cent, whereas when lipid peroxidation was induced by CuOOH, IdB 1016 exerted a better protective effect than SDH (29·4 per cent and 19·4 per cent inhibition, respectively). In both microsomal systems lipid peroxidation proceeded through a thiol depletion mechanism which could be restored in the presence of silibin complexes. Low levels of lipid peroxidation in pulmonary microsomes point out the differences between in‐vitro lipid peroxidation occurring in microsomes of different tissues. The results support the free radical scavenger and antioxidative properties of silibin when it is complexed with a suitable molecule to increase its bioavailabilty. © 1997 John Wiley & Sons, Ltd.