Twenty-one natural and unnatural phenolic compounds containing a carbohydrate moiety were synthesized and their structure–activity relationship (SAR) was evaluated for α-glucosidase inhibition and antioxidative activity. Varying the position of the galloyl unit on the 1,5-anhydro-d-glucitol (1,5-AG) core resulted in changes in the α-glucosidase inhibitory activity and notably, particularly strong activity was demonstrated when the galloyl unit was present at the C-2 position. Furthermore, increasing the number of the galloyl units significantly affected the α-glucosidase inhibition, and 2,3,4,6-tetra-galloyl-1,5-AG (54) and 2,3,4,6-tetra-galloyl-d-glucopyranose (61) exhibited excellent activities, which were more than 13-fold higher than the α-glucosidase inhibitory activity of acertannin (37). Moreover, a comparative structure-activity study suggested that a hemiacetal hydroxyl functionality in the carbohydrate core and a biaryl bond of the 4,6-O-hexahydroxydiphenoyl (HHDP) group, which are components of ellagitannins including tellimagrandin I, are not necessary for the α-glucosidase inhibitory activity. Lastly, the antioxidant activity increased proportionally with the number of galloyl units.
合成了二十一种含有碳水化合物基团的天然和非天然酚类化合物,并评估了它们在α-葡萄糖苷酶抑制和抗氧化活性方面的结构-活性关系(SAR)。在1,5-脱氧-D-葡萄糖醇(1,5-AG)核心上改变没食子酸单元的位置导致了α-葡萄糖苷酶抑制活性的变化,特别是当没食子酸单元位于C-2位置时表现出明显的强活性。此外,增加没食子酸单元的数量显著影响了α-葡萄糖苷酶抑制作用,2,3,4,6-四没食子酸-1,5-AG(54)和2,3,4,6-四没食子酸-D-葡萄糖吡喃糖(61)表现出卓越的活性,其α-葡萄糖苷酶抑制活性比没食子酸(37)高出13倍以上。此外,一项比较结构-活性研究表明,碳水化合物核心中的半缩醛羟基官能团和4,6-O-六羟基二苯甲酰(HHDP)单元的双芳基键,包括tellimagrandin I在内的椰子酸鞣质并不是α-葡萄糖苷酶抑制活性所必需的。最后,抗氧化活性随没食子酸单元数量的增加而成比例增加。