Date Published: May 2, 2018
Publisher: Springer Berlin Heidelberg
Author(s): Jie Wei, Dexin Xu, Xiao Zhang, Jing Yang, Qiuyu Wang.
The interaction between Anthocyanins in Aronia melanocarpa (AMA) and bovine serum albumin (BSA) were studied in this paper by multispectral technology, such as fluorescence quenching titration, circular dichroism (CD) spectroscopy and Fourier transform infrared spectroscopy (FTIR). The results of the fluorescence titration revealed that AMA could strongly quench the intrinsic fluorescence of BSA by static quenching. The apparent binding constants KSV and number of binding sites n of AMA with BSA were obtained by fluorescence quenching method. The thermodynamic parameters, enthalpy change (ΔH) and entropy change (ΔS), were calculated to be 18.45 kJ mol−1 > 0 and 149.72 J mol−1 K−1 > 0, respectively, which indicated that the interaction of AMA with BSA was driven mainly by hydrophobic forces. The binding process was a spontaneous process of Gibbs free energy change. Based on Förster’s non-radiative energy transfer theory, the distance r between the donor (BSA) and the receptor (AMA) was calculated to be 3.88 nm. Their conformations were analyzed using infrared spectroscopy and CD. The results of multispectral technology showed that the binding of AMA to BSA induced the conformational change of BSA.
Aronia melanocarpa Elliot, a member of the Rosaceae family, Aronia melanocarpa fruits are one of the richest plant sources of anthocyanins, AMA are water-soluble plant pigments, it has gained popularity due to their high content anthocyanins with antioxidant anti-inflammatory, antimicrobial, hepatoprotective, gastroprotective and other activities (Malinowska et al. 2013; Fares et al. 2011; Kokotkiewicz et al. 2010; Chrubasik et al. 2010). AMA have the better abilities on scavenging free radicals, improving immunity, anti-cancer, anti-aging, anti-cardiovascular disease and so on (Wei et al. 2017, 2016). The basic structure of AMA shown in Scheme 1, the main components of its monomer are cyanidin-3-O-arabinoside, cyanidin-3-O-galactoside, cyanidin-3-O-glucoside and cyanidin-3-O-Xyloside. In our previous study, we have carried out a series of optimization on the extraction and purification of AMA, its composition and biological activity were initially identified and studied (de Santiago et al. 2014). Based on this study, it was found that AMA can inhibit the occurrence of diabetes and obesity, and regulate the metabolism balance and the stability of the redox system, we also carried out AMA on mouse aging mechanism of intervention. Research also shows AMA can be used as food additives owing to its strong antioxidant capacity (Hassellund et al. 2012).Scheme 1The structure of anthocyanins
Bovine serum albumin (BSA) was purchased from Xi’an Rui Xi Biological Technology Co., Ltd; Aronia melanocarpa Elliot fruit was provided by Liaoning Academy of Forestry (Shenyang, China); Anthocyanin standards (cyanidin-3-O-arabinoside, cyanidin-3-O-galactoside, cyanidin-3-O-glucoside and cyanidin-3-O-Xyloside) were purchased from Weikeqi Biotechnology Co., Ltd.
It is reported that the content of AMA is up to 1%, far higher than other plants (Olszewska and Michel 2009), so in this paper, the aim of above research is to clarify the binding mechanism of AMA with BSA, we will provide valuable information about interaction of AMA as a plant-based food additives with BSA as an important carrier protein, this is of great significance for the follow-up study of AMA and BSA (Li et al. 2016), and we also provide useful information for understanding the Pharmacological effects at molecular level (Zhang et al. 2012).