Effect of Thymoquinone on DMPC liposomes: Study by FTIR, Raman and SERS spectroscopies

M. E. DEFONSI LESTARD; M. E. TUTTOLOMDO; S. B. DÍAZ; A. BEN ALTABEF

Congreso; XLV Reunion Anual SAB 2016; 2016

Título: Effect of Thymoquinone on DMPC liposomes: Study by FTIR, Raman and SERS spectroscopies.M. E. Defonsi Lestard1,2, S. B. Díaz2, A. Ben Altabef1,2and M. E. Tuttolomondo1,21Instituto de Química del Noroeste Argentino (INQUINOA-CONICET), 2Instituto de Química Física. Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, San Lorenzo 456, T4000CAN Tucumán, R. Argentina. E-mail: elianadefonsi@yahoo.com.arA great deal of natural origin quinones has pharmacologically interesting properties [1].Thymoquinone (TQ) is one of the most studied quinines because of its potential anti-cancer, anti-oxidant and anti-inflammatory effects [2].However, the molecular pathways involved in these activities are not well understood.Hence, we decided to carry out research on TQ interaction with model lipid membranes.In this work, TQ interaction with dipalmiristoylphosphatidylcholine (DMPC) bilayers was studied by FTIR, Raman and SERS spectroscopies.The results showed that TQ interacted to different extents with the phosphate and carbonyl groups of membranes in the gel and the liquid crystalline states.The absorption band of the symmetric stretching of the methylene groups of fatty acid was studied to determine if TQ interaction with lipidic membranes affected the hydrophobic region bilayer [3].From different molar ratios of TQ:DMPC we observed a gradual decrement of the transition temperature that was proportional to TQ concentration until reaching a limit value of 20 °C.This suggested that the stability of the DMPC liquid crystallinephase would increase as a result of TQ partition into the membrane because the lipid molecules need energy to carry out the phase change [4].From the phospholipid Raman signature we could obtain information about the lateral order in the characteristic film of the inter and intrachain interactions. In particular, the peaks height ratiosI_(ν_a (〖CH〗_2))⁄I_(ν_s (〖CH〗_2)) and I_(ν〖CC〗_g )⁄I_(ν〖CC〗_t ) have been recognized for a long time as representative of chain packing and mobility. These ratios increased from 0.90 to 0.98 and 1.80 to 3.00, respectively when TQ concentration increased.This behavior is in agreement with the results observed in SERS for this region, where an increase in I_(ν〖CC〗_g )⁄I_(ν〖CC〗_t ) to be observed.References:Cragg G. M., GrothausP. G., Newman D. J., Chem. Rev.(2009), 109:3012?3043.TingfangY., Sung-Gook C., Zhengfang Y., Mol. Cancer Ther., (2008)7:1789-1796.Severcan F., Sahin I., Kazancı N., Biochim. Biophys. Acta (2005) 1668 215.LhertF., Capelle F., Blaudez D., HeywangC. and TurletJ. M., J. Phys. Chem. B (2000) 104,11704-11707.