表儿茶素的碳酰化改性及其紫外吸收和抗氧化活性

Carbonylation Modification of Epicatechin and Its Activities of UV Absorption and Antioxidant

为增强表儿茶素衍生物的紫外吸收性能、改善其在油脂等非极性溶剂中的溶解度,以甲烷磺酸为溶剂和催化剂,由表儿茶素和对羟基苯甲酸合成了2,2'-二(对羟基苯甲酮基)-表儿茶素,经柱层析分离得到目标产物,采用高效液相色谱(HPLC)验证纯度,运用紫外-可见光(UV-vis)光谱、傅里叶变换红外(FT-IR)光谱、液相色谱-质谱联用(LC-MS)和核磁共振(NMR)波谱等表征手段确证目标产物结构。评价了2,2'-二(对羟基苯甲酮基)-表儿茶素的紫外吸收性能,以及对2,2-联氮-二(3-乙基苯并噻唑-6-磺酸)二铵盐阳离子自由基、1,1-二苯基-2-三硝基苯肼自由基和超氧阴离子自由基清除能力。结果表明,合成的2,2'-二(对羟基苯甲酮基)-表儿茶素与常用紫外线吸收剂4-甲氧基肉桂酸-2-乙基己酯(OMC)具有相似的紫外吸收范围和相当的摩尔吸光系数,有望成为一种性能优良的UVB波段紫外线吸收剂;2,2'-二(对羟基苯甲酮基)-表儿茶素具有良好的体外抗氧化活性,其体外抗氧化能力高于维生素C(VC)、略低于表儿茶素,有望应用于化妆品领域。

In order to enhance the UV absorption characteristic of epicatechin derivatives and improve their solubility in non-polar solvents such as oils and fats,2,2'-di(p-hydroxybenzocarbonyl)-epicatechin was synthesized from epicatechin and p-hydroxybenzoic acid using methane sulfonic acid as solvent and catalyst.The target products were separated by column chromatography,and the purity was verified by high performance liquid chromatography(HPLC),and the structure of the target products were verified by UV-vis,FT-IR,^(1)H NMR,^(13)C NMR,LC-MS spectroscopy.The UV absorption characteristic of 2,2'-di(p-hydroxybenzocarbonyl)-epicatechin and its ability to scavenge ABTS^(+)·,DPPH·and O^(2-)·were evaluated.The results show that the synthesized 2,2'-di(p-hydroxybenzocarbonyl)-epicatechin had similar UV absorption and comparable molar absorptivity to OMC,the commonly used UV absorber,and is expected to be an excellent UV absorber in the UVB band.2,2'-di(p-hydroxybenzocarbonyl)-epicatechin had good antioxidant activity in vitro,and its antioxidant capacity in vitro was higher than that of VC and slightly lower than that of epicatechin,which is expected to be used for cosmetic applications.