Luo Honghui, Deng Shuangfan, Fu Wei, Zhang Xin, Zhang Xuelian, Zhang Zhaoqi, Pang Xuequn
State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou 510642, China.
College of Life Sciences, South China Agricultural University, Guangzhou 510642, China.
Int J Mol Sci. 2017 Mar 25;18(4):699. doi: 10.3390/ijms18040699.
Anthocyanin degradation decreases ornamental or nutritional values of horticultural products. To investigate factors that may influence colour change in flower development, anthocyanin degradation was compared between the flowers of and , which show rapid and slow degradation, respectively. In-gel activity assays, high performance liquid chromatography (HPLC) analysis of tannins, enzyme kinetics measurement and immune-detection of anthocyanin degradation related-perioxidases (PODs) were carried out for the comparison. Rose petals possessed significantly lower anthocyanin degradation-related POD activities than petals, which may be related to the high tannin contents. Epicatechin gallate (ECG) and gallocatechin gallate (GCG) were detected in rose as 161.3 ± 12.34 and 273.56 ± 41.23 μg/g FW (Fresh Weight) respectively, while not detected in . ECG and GCG inhibited the activities of the POD with half maximal inhibitory concentrations (IC50s) as 21.5 and 29.7 μM respectively, and increased the colour intensities of the anthocyanins. Catechin and epicatechin did not inhibit the POD activity, while serving as POD substrates, with m (the Michaelis constant) as 0.48 and 1.23 mM. Similar protein levels of the anthocyanin degradation-related 40-kDa PODs were detected in and rose. In summary, high amount of tannins, particularly ECG and GCG, in red rose petals may inhibit the degradation-related enzymes, leading to the maintenance of anthocyanins in vivo.
花青素降解会降低园艺产品的观赏价值或营养价值。为了研究可能影响花朵发育过程中颜色变化的因素，对分别表现出快速和缓慢降解的[具体品种1]和[具体品种2]花朵的花青素降解情况进行了比较。通过凝胶内活性测定、单宁的高效液相色谱（HPLC）分析、酶动力学测量以及对花青素降解相关过氧化物酶（POD）的免疫检测来进行比较。玫瑰花瓣中与花青素降解相关的POD活性明显低于[具体品种2]花瓣，这可能与高单宁含量有关。在玫瑰中检测到表儿茶素没食子酸酯（ECG）和没食子儿茶素没食子酸酯（GCG），含量分别为161.3±12.34和273.56±41.23μg/g鲜重（FW），而在[具体品种2]中未检测到。ECG和GCG抑制[具体品种2]POD的活性，半数最大抑制浓度（IC50）分别为21.5和29.7μM，并增加了花青素的颜色强度。儿茶素和表儿茶素不抑制POD活性，但作为POD底物，米氏常数（m）分别为0.48和1.23mM。在[具体品种2]和玫瑰中检测到与花青素降解相关的40 kDa POD的蛋白质水平相似。总之，红玫瑰花瓣中大量的单宁，特别是ECG和GCG，可能会抑制降解相关酶，从而导致花青素在体内的维持。
