Direct Observation of Hydrangea Blue-Complex Composed of 3-O-Glucosyldelphinidin, Al(3+) and 5-O-Acylquinic Acid by ESI-Mass Spectrometry.
Direct Observation of Hydrangea Blue-Complex Composed of 3-O-Glucosyldelphinidin, Al(3+) and 5-O-Acylquinic Acid by ESI-Mass Spectrometry.
复制标题
DOI：
10.3390/molecules23061424
复制
发表时间：
2018-06-12
期刊：
影响因子：
--
通讯作者：
Yoshida K
中科院分区：
文献类型：
--
作者：
Ito T;Oyama KI;Yoshida K
绣球的蓝色缘于由3-O-葡萄糖基雀巢蛋白(1)和铝离子与5-O-咖啡酰奎宁酸(2)和/或5-O-对香豆酰奎宁酸(3)组成的金属络合物花青素。花青素、Al3+和5-O-酰基奎宁酸是蓝色形成所必需的三种成分，但络合物是不稳定的，只存在于水溶液中。此外，该络合物没有给出可分析的核磁共振谱或晶体。因此，到目前为止，许多确定绣球蓝复合体详细化学结构的试验都没有成功。相反，通过实验将1，Al3+和2或3混合在pH为4.0的缓冲溶液中，我们得到了来自萼片的相同的蓝色溶液。然而，这一比例并不是化学计量的，而是波动的。为了确定络合物的组成，我们尝试用电喷雾电离质谱仪直接观察络合物的分子离子。在pH 4.0的极低浓度缓冲溶液(2.0 mM)中，1、2和Al3+以1：1：1、1：2：1和1：3：1的比例混合，产生绣球蓝的颜色。所有溶液在m/z=843处都有相同的分子离子峰，表明蓝色溶液与络合物的比例为1：1：1。1，3-O-咖啡酰奎宁酸(4)与Al3+的混合物不呈现蓝色而是紫色，分子离子峰强度在m/z=843处很低。这些结果有力地表明，绣球蓝络合物是由1：1：1的比例组成的，Al3+和2或3。
The blue sepal color of hydrangea is due to a metal complex anthocyanin composed of 3-O-glucosyldelphinidin (1) and an aluminum ion with the co-pigments 5-O-caffeoylquinic acid (2) and/or 5-O-p-coumaroylquinic acid (3). The three components, namely anthocyanin, Al3+ and 5-O-acylquinic acids, are essential for blue color development, but the complex is unstable and only exists in an aqueous solution. Furthermore, the complex did not give analyzable NMR spectra or crystals. Therefore, many trials to determine the detailed chemical structure of the hydrangea-blue complex have not been successful to date. Instead, via experiments mixing 1, Al3+ and 2 or 3 in a buffered solution at pH 4.0, we obtained the same blue solution derived from the sepals. However, the ratio was not stoichiometric but fluctuated. To determine the composition of the complex, we tried direct observation of the molecular ion of the complex using electrospray-ionization mass spectrometry. In a very low-concentration buffer solution (2.0 mM) at pH 4.0, we reproduced the hydrangea-blue color by mixing 1, 2 and Al3+ in ratios of 1:1:1, 1:2:1 and 1:3:1. All solution gave the same molecular ion peak at m/z = 843, indicating that the blue solution has a ratio of 1:1:1 for the complex. By using 3, the observed mass number was m/z = 827 and the ratio of 1, 3 and Al3+ was also 1:1:1. A mixture of 1, 3-O-caffeoylquinic acid (4) and Al3+ did not give any blue color but instead was purple, and the intensity of the molecular ion peak at m/z = 843 was very low. These results strongly indicate that the hydrangea blue-complex is composed of a ratio of 1:1:1 for 1, Al3+ and 2 or 3.
登录
查看更多内容
影响因子：
15
作者：
Robinson, GM
通讯作者：
Robinson, GM
影响因子：
3.8
作者：
TAKEDA, K;YAMASHITA, T;TIMBERLAKE, CF
通讯作者：
TIMBERLAKE, CF
影响因子：
4.9
作者：
KINRAIDE, TB
通讯作者：
KINRAIDE, TB
影响因子：
3.8
作者：
Mori, Mihoko;Kondo, Tadao;Yoshida, Kumi
通讯作者：
Yoshida, Kumi
影响因子：
1.6
作者：
Ito, Daisuke;Shinkai, Yosuke;Yoshida, Kumi
通讯作者：
Yoshida, Kumi