Posters

Background and aim: Silybin is the main component of Silymarin with an increasing number of documented effects. The main effects attributed both in vitro and in vivo to Silybin are related to its antioxidant, antiinflammatory and cytoprotective actions. This study was designed to compare, in vitro, the effect of Silybin used as single substance, Silybin–phosphatidylcholine complex (SilPho), and derivatives of Silibinin (MpSil, GpSil, GlpSil, LipSil) on MKN28 and HepG2 cell viability and cell death after the induction of oxidative stress. Material and methods: Oxidative stress was induced by incubating HepG2 and MKN28 cells with xanthine oxidase in the presence of its substrate xanthine for periods of up to three hours. Cell viability was determined by the MTT assay. We evaluated whether X-XO increased cellular MDA, a marker of lipid peroxidation, and whether Silybin and SilPho pretreatment was able to counteract any such effect. Results: In basal conditions, the pre-incubation of MKN28 and HepG2 cells with Silybin, SilPho, and new Silibinin glycoconjugates lead to two different results. In fact, SilPho and new Silibinin glycoconjugates don’t affect cell viability, while Silybin induced a cell death of about 50%, also at the lower dose used, both in MKN28 and in HepG2 cells. The pre-incubation with Silybin and new Silibinin glycoconjugates don’t affect cell viability, while SilPho shows a protective effect. Exposure of MKN28 cells to X-XO caused a twofold increase in cellular MDA concentration compared with control untreated cells. Moreover, pretreatment with SilPho but not with Silybin significantly prevented X-XO induced increase in cellular MDA. Conclusions: This suggests that the protective effect of SilPho is partially due to inhibition of ROS induced lipid peroxidation.