Molecular and technical aspects on the interaction of serum albumin with multifunctional food preservatives.

Synthetic food preservatives like sodium acetate (SA), sodium benzoate (SB), potassium sorbate (PS) and Butyl paraben (BP) have been widely used in food and pharmacy industries. One of the toxicological aspects of food additives is evaluation of their interaction with serum proteins such as albumin. These additives interaction with human serum albumin (HSA) can exert considerable effect on the absorption, distribution, metabolism and toxicity of chemical compounds. It should be noticed that the aforementioned food preservatives intake increase mainly in the presence of glucose may lead to complex formation of SA, SB, PS and BP with HSA and accelerate the development of variety disease such as cancer, diabetes, multiple sclerosis, brain damage, nausea and cardiac disease. Therefore, to understand the mechanisms of aforementioned food additives interaction and conformational changes of proteins, we aim to review various studies that investigated albumin interaction with these additives using several procedures.

Cytotoxicity and Genotoxicity Assessment of Ascorbyl Palmitate (AP) Food Additive.

Purpose: Ascorbyl palmitate (AP) is a widely used food additive in food industry. In this study, AP was evaluated for potential cyto-genotoxicity on Human Umbilical Vein Endothelial Cells (HUVECs). Methods: MTT assay and flow cytometry analysis was used for cytotoxicity evaluation, while genotoxicity was carried out using DAPI staining assays and real time PCR. Results: The growth of HUVECs was decreased upon treatment with AP in dose-and time-dependent manner. Early/late apoptosis percentage in HUVECs treated with this additive was detected using flow cytometry analysis. Also morphology of DAPI stained HUVECs clearly showed chromatin fragmentation. Furthermore, real time PCR results showed that AP induces apoptosis by up-regulation of caspase-3, 9 and down-regulation of Bcl-2 ratio. Conclusion: The present results indicated that AP has capability to induce apoptosis in HUVECs and its better to make a thorough analysis about its extensive application in food industry.

Kinetic and thermodynamic studies of bovine serum albumin interaction with ascorbyl palmitate and ascorbyl stearate food additives using surface plasmon resonance.

Ascorbyl palmitate (AP) and ascorbyl stearate (AS) are examples of food additives, which have extensive use in food industry. In this study, we evaluated the interaction of bovine serum albumin (BSA) with AP and AS using surface plasmon resonance (SPR). In order to immobilize BSA, carboxymethyl dextran hydrogel (CMD) Au chip was used. After activation of carboxylic groups, BSA was immobilized onto the CMD chip through covalent amide binding formation. AP and AS binding to immobilized BSA at different concentrations was assessed. The dose-response sensorgrams of BSA upon increasing concentration of AP and AS have been shown. The low value of equilibrium dissociation constant or affinity unit (KD) showed high affinity of both AP and AS to BSA. The KD value for binding of AP and AS to BSA were 4.09 × 10-5 and 1.89 × 10-5, at 25 °C. Overall, the attained results showed that AP and AS molecules can bind to BSA.

Safety assessment of sodium acetate, sodium diacetate and potassium sorbate food additives.

Cytotoxicity and genotoxicity of sodium acetate (SA), sodium diacetate (SDA), and potassium sorbate (PS) was tested on Human Umbilical Vein Endothelial Cells (HUVEC). Cytotoxicity was investigated by MTT assay and flow cytometry analysis, while genotoxicity was evaluated using DNA fragmentation and DAPI staining assays. The growth of treated HUVECs with various concentrations of SA, SDA and PS decreased in a dose-and time-dependent manner. The IC50 of 487.71, 485.82 and 659.96 µM after 24 h and IC50 of 232.05, 190.19 and 123.95 µM after 48 h of treatment were attained for SA, SDA and PS, respectively. Flow cytometry analysis showed that early and late apoptosis percentage in treated cells was not considerable. Also neither considerable DNA fragmentation nor DNA smear was observed using DAPI staining and DNA ladder assays. Overall, it can be concluded that the aforementioned food additives can be used as safe additives at low concentration in food industry.

Multi-spectroscopic and molecular modeling studies of bovine serum albumin interaction with sodium acetate food additive.

Sodium acetate (SA) has been used as a highly effective protectant in food industry and the possible effect of this additive on the binding to albumin should be taken into consideration. Therefore, for the first time, the mechanism of SA interaction with bovine serum albumin (BSA) has been investigated by multi-spectroscopic and molecular modeling methods under physiological conditions. Stern-Volmer fluorescence quenching analysis showed an increase in the fluorescence intensity of BSA upon increasing the amounts of SA. The high affinity of SA to BSA was demonstrated by a binding constant value (1.09×103 at 310°K). The thermodynamic parameters indicated that hydrophobic binding plays a main role in the binding of SA to Albumin. Furthermore, the results of UV-vis spectra confirmed the interaction of this additive to BSA. In addition, molecular modeling study demonstrated that A binding sites of BSA play the main role in the interaction with acetate.