Effect of UV radiation on DPPG and DMPC liposomes in presence of catechin molecules

Catechin molecules are known to reduce the oxidative stress-induced by radiation acting as scavenger of the reactive oxygen species, preventing in this way the damage in biomolecules. In this work, the effect of radiation on liposomes of 1,2-dipalmitoyl-sn-glycero-3-[phospho-rac-(1-glycerol)(sodium salt) (DPPG) and of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) is analyzed in the absence and presence of epigallocatechin-3-gallate (EGCG) molecules, having in view the evaluation of the photosensitizing properties and the efficacy of these molecules to modulate cell membrane damage mechanisms. The obtained results demonstrate that the damage by UV radiation on DPPG and DMPC liposomes is strongly dependent of the presence of EGCG molecules. While DPPG liposomes are protected from radiation in presence of EGCG, the EGCG molecules are damaged by the radiation supporting the idea that EGCG are strongly adsorbed on the inner and outer liposome surfaces due hydrogen bonding. This suggests that EGCG molecules in the inner surface can be protected from radiation. In the case of DMPC liposomes, the EGCG molecules are affected by radiation as well as the DMPC molecules. This is explained if the EGCG chroman group is positioned between DMPC lipids while the gallic acid groups float over the liposomes.