Abstract：
An aqueous solution of 2,3-cis gallate type catechin (-)-epigallocatechin-3-O-gallate (EGCg) and caffeine afforded a precipitate of Creaming-down Phenomenon, which crystallized slowly for about three months to give a colorless block crystal. By X-ray crystallographic analysis, the crystal was determined to be a 2 : 2 complex of EGCg and caffeine, in which caffeine molecules were captured in a hydrophobic space formed with three aromatic A, B, and B\' rings of EGCg. It was considered that the solubility of the 2 : 2 complex in water rapidly decreased and the 2 : 2 complex precipitated from aqueous solution. The hydrophobic spaces of EGCg captured a variety of heterocyclic compounds, and the molecular capture abilities of heterocyclic compounds using EGCg from the aqueous solutions were evaluated. Since the C ring of EGCg has two chiral carbon atoms, C2 and C3, the hydrophobic space of EGCg was a chiral space. EGCg captured diketopiperazine cyclo(Pro-Xxx) (Xxx=Phe, Tyr) and pharmaceuticals with a xanthine skeleton, proxyphylline and diprophylline, in the hydrophobic space, and recognized their chirality.
摘要：
2,3-顺式没食子酸酯型儿茶素（-）-表没食子儿茶素-3-O-没食子酸酯（EGCg）和咖啡因的水溶液提供了乳油沉淀现象，缓慢结晶约三个月，得到无色块状晶体。通过X射线晶体学分析,晶体被确定为EGCg和咖啡因的2:2复合物，其中咖啡因分子被捕获在由三个芳香族A形成的疏水空间中，B,和B\'EGCg环。认为2:2络合物在水中的溶解度迅速降低,并且2:2络合物从水溶液中沉淀。EGCg的疏水空间捕获了多种杂环化合物，并使用EGCg从水溶液中评估了杂环化合物的分子捕获能力。由于EGCg的C环有两个手性碳原子，C2和C3，EGCg的疏水空间为手性空间。EGCg捕获的环二酮哌嗪（Pro-Xxx）（Xxx=Phe，Tyr）和带有黄嘌呤骨架的药物，proxyphyline和didiprepetroline，在疏水空间中，并认识到他们的手性。
