Interaction of sulforaphane with DNA and RNA.

Sulforaphane (SFN) is an isothiocyanate found in cruciferous vegetables with anti-inflammatory, anti-oxidant and anti-cancer activities. However, the antioxidant and anticancer mechanism of sulforaphane is not well understood. In the present research, we reported binding modes, binding constants and stability of SFN-DNA and -RNA complexes by Fourier transform infrared (FTIR) and UV-Visible spectroscopic methods. Spectroscopic evidence showed DNA intercalation with some degree of groove binding. SFN binds minor and major grooves of DNA and backbone phosphate (PO2), while RNA binding is through G, U, A bases with some degree of SFN-phosphate (PO2) interaction. Overall binding constants were estimated to be K(SFN-DNA)=3.01 (± 0.035)×10(4) M(-1) and K(SFN-RNA)= 6.63 (±0.042)×10(3) M(-1). At high SFN concentration (SFN/RNA = 1/1), DNA conformation changed from B to A occurred, while RNA remained in A-family structure.

Study on the interaction of sulforaphane with human and bovine serum albumins.

Sulforaphane; [1-isothiocyanato-4-(methylsulfinyl) butane], (SFN) is an isothiocyanate derived from glucoraphanin present in cruciferous vegetables and has a variety of potential chemopreventive actions. This study was designed to examine the interaction of sulforaphane with HSA and BSA. FTIR, UV-Vis spectroscopic methods as well as molecular modeling were used to determine the drug binding mode, binding constant and the effect of drug complexation on serum albumins stability and conformation. Structural analysis showed that SFN bind HSA and BSA via polypeptide polar groups with overall binding constants of KSFN-HSA=6.54×10(4) and KSFN-BSA=8.55×10(4) M(-1). HSA and BSA conformations were altered by a major reduction of α-helix upon SFN interaction. These results suggest that serum albumins might act as carrier proteins for SFN in delivering them to target tissues.

Phase transition study of confined water molecules inside carbon nanotubes: hierarchical multiscale method from molecular dynamics simulation to ab initio calculation.

In this study, the mechanism of the temperature-dependent phase transition of confined water inside a (9,9) single-walled carbon nanotube (SWCNT) was studied using the hierarchical multi-scale modeling techniques of molecular dynamics (MD) and density functional theory (DFT). The MD calculations verify the formation of hexagonal ice nanotubes at the phase transition temperature T(c)=275K by a sharp change in the location of the oxygen atoms inside the SWCNT. Natural bond orbital (NBO) analysis provides evidence of considerable intermolecular charge transfer during the phase transition and verifies that the ice nanotube contains two different forms of hydrogen bonding due to confinement. Nuclear quadrupole resonance (NQR) and nuclear magnetic resonance (NMR) analyses were used to demonstrate the fundamental influence of intermolecular hydrogen bonding interactions on the formation and electronic structure of ice nanotubes. In addition, the NQR analysis revealed that the rearrangement of nano-confined water molecules during the phase transition could be detected directly by the orientation of ¹7O atom EFG tensor components related to the molecular frame axes. The effects of nanoscale confinements in ice nanotubes and water clusters were analyzed by experimentally observable NMR and NQR parameters. These findings showed a close relationship between the phase behavior and orientation of the electronic structure in nanoscale structures and demonstrate the usefulness of NBO and NQR parameters for detecting phase transition phenomena in nanoscale confining environments.