Evaluation of ethephon induced oxidative stress to gonadal disorder and its amelioration by ethanolic extract of shoot of Bambusa balcooa Roxb. in Albino rat

Abstract

Polyethylene glycol (PEG) fatty acid esters are used in various industries for their interfacial properties, especially because their emulsifying characteristics can be varied considerably by altering the size of the PEG or fatty acid chains. In this study, we combine experimental surface-specific methods and molecular dynamics (MD) simulations to probe the effects from changing both the hydrophilic and hydrophobic chain sizes. PEG fatty acids containing either stearic or palmitic acid ethoxylated PEG chains of average molecular weight 200 or 400 g mol−1 (referred to as PEG200 and PEG400, respectively) had critical aggregation concentrations between 30 and 50 μM, and formed Langmuir films at the air/water interface with compressibility modulus typical of liquid-expanded phases. The area per molecule was consistently smaller for the PEG200 series owing to an increased ordering of the hydrophilic chains inferred from the polarization-modulated infrared reflection absorption (PM-IRRAS) spectra, which was corroborated by MD simulations. With PM-IRRAS and MD simulations, we also noted that the hydrophobic chain had increased order when its size increased from palmitic to stearic acid, which was attributed to a higher melting temperature for longer saturated hydrocarbon chains.