Department of Pharmaceutical Sciences, University of KwaZulu-Natal, Durban, 4000, South Africa.
Department of Chemistry, Faculty of Applied Science, Durban University of Technology, Durban, 4000, South Africa.
Sci Rep. 2019 Dec 5;9(1):18414. doi: 10.1038/s41598-019-54626-9.
The metal complexes can demonstrate various interesting biological activities in the human body. However, the role of certain metal ions for specific cell activities is still subject to debate. This study is aimed at comparing the thermochemical properties of neotame (artificial sweetener) and α, β-fructose in gas phase and water medium. The interaction of α and β-fructose, neotame with monovalent and divalent metal ions was studied and comprehended by density functional theory (DFT) using B3LYP functional, 6-311 + G (d, p) and D3 basis set. Metal ion affinities (MIA) values depicted that ionic radius of metal ions played an important role in the interaction of α, β-fructose and neotame. The ∆G parameter was calculated to predict and understand the interaction of metal ions with α and β-fructose, neotame. The results suggested that the presence of hydroxyl groups and oxygen atoms in sugar molecules acted as preferred sites for the binding and interaction of mono and divalent ions. For the first time computational study has been introduced in the present study to review the progress in the application of metal binding with sugar molecules especially with neotame. Moreover, voltammetric behaviour of neotame-Zn was studied using cyclic and differential pulse voltammetry. The obtained results suggest that the peak at -1.13 V is due to the reduction of Zn in 0.1 M phosphate buffer medium at pH 5.5. Whereas, addition of 6-fold higher concentration of neotame to the ZnCl.2HO resulted in a new irreversible cathodic peak at -0.83, due to the reduction of neotame-Zn complex. The Fourier transform infrared spectroscopy (FTIR) results indicates that the β-amino group (-NH) and carboxyl carbonyl (-C = O) groups of neotame is participating in the chelation process, which is further supported by DFT studies. The findings of this study identify the efficient chelation factors as major contributors into metal ion affinities, with promising possibilities to determine important biological processes in cell wall and glucose transmembrane transport.
金属配合物在人体内可以表现出各种有趣的生物活性。然而，某些金属离子对特定细胞活动的作用仍存在争议。本研究旨在比较纽甜（人工甜味剂）和α、β-果糖在气相和水介质中的热化学性质。通过密度泛函理论（DFT），使用 B3LYP 函数、6-311 + G（d，p）和 D3 基组，研究了α和β-果糖、纽甜与单价和二价金属离子的相互作用，并进行了理解。金属离子亲和力（MIA）值表明，金属离子的离子半径在α、β-果糖和纽甜的相互作用中起着重要作用。计算了∆G 参数以预测和理解金属离子与α和β-果糖的相互作用。结果表明，糖分子中的羟基和氧原子作为结合和相互作用的优先位点存在于单和二价离子中。本研究首次引入了计算研究，以综述金属与糖分子结合，特别是与纽甜结合的应用进展。此外，还使用循环伏安法和差分脉冲伏安法研究了纽甜-Zn 的伏安行为。研究结果表明，在 pH 值为 5.5 的 0.1 M 磷酸盐缓冲介质中，-1.13 V 处的峰归因于 Zn 的还原。而在 ZnCl2HO 中加入 6 倍更高浓度的纽甜，由于纽甜-Zn 配合物的还原，在-0.83 处出现新的不可逆阴极峰。傅里叶变换红外光谱（FTIR）结果表明，纽甜的β-氨基（-NH）和羧基羰基（-C=O）基团参与了螯合过程，这进一步得到了 DFT 研究的支持。本研究的结果确定了有效的螯合因子作为金属离子亲和力的主要贡献因素，为确定细胞壁和葡萄糖跨膜转运中的重要生物学过程提供了有希望的可能性。
