State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Xueyuan Road, Beijing 100191, China.
Molecules. 2013 May 6;18(5):5172-89. doi: 10.3390/molecules18055172.
Phytochemical investigation of the n-BuOH-soluble fraction of the EtOH extract of the herbaceous stems of Ephedra sinica, which is known as Ephedrae Herba in Traditional Chinese Medicine, led to the isolation and identification of 12 A-type proanthocyanidins, containing five dimers, two trimers and five tetramers [i.e., (+)-epigallocatechin-(2α→O→7,4α→8)-(-)-catechin, named ephedrannin D₁, a dimer; epigallocatechin-(2α→O→7,4α→8)-epigallocatechin-(4α→8)-catechin (ephedrannin Tr₁), a trimer; and epigallocatechin-(2α→O→7,4α→8)-epigallocatechin-(4α→8)-epigallocatechin-(2α→O→7,4α→8)-gallocatechin, named ephedrannin Te1, a tetramer). Tetramers composed of gallocatechin are reported for the first time in Ephedraceae. Catechin, epicatechin, gallocatechin, epigallocatechin and four known dimers were also isolated. The structures were elucidated by extensive spectroscopic analysis. The absolute configurations of the 4α linkages, which were confirmed by NOESY and CD experiments, are the outstanding characteristic of most of these isolated A-type proanthocyanidins. The antimicrobial activities of these compounds were tested by measuring the minimum inhibitory concentrations (MIC) against bacteria (both Gram positive and Gram negative) and fungi, and were found to be in the range of 0.00515-1.38 mM. Compounds 6, 8, 10 and 11 exhibited moderate antimicrobial activities against Canidia albicans.
对中国传统草药麻黄草（即麻黄的草本部分）的乙醇提取物的正丁醇可溶部分进行了植物化学研究，从中分离并鉴定了 12 种 A 型原花青素，其中包含 5 个二聚体、2 个三聚体和 5 个四聚体[即（+）-表儿茶素-(2α→O→7,4α→8)-(-)-儿茶素，命名为 ephedrannin D₁，二聚体；表儿茶素-(2α→O→7,4α→8)-表儿茶素-(4α→8)-儿茶素（ephedrannin Tr₁），三聚体；和表儿茶素-(2α→O→7,4α→8)-表儿茶素-(4α→8)-表儿茶素-(2α→O→7,4α→8)-没食子儿茶素，命名为 ephedrannin Te1，四聚体]。在麻黄科中首次报道了由没食子酸组成的四聚体。还分离出了儿茶素、表儿茶素、没食子酸、表没食子儿茶素和四个已知的二聚体。通过广泛的光谱分析阐明了结构。通过 NOESY 和 CD 实验确认的 4α 键的绝对构型是大多数分离出的 A 型原花青素的突出特征。通过测量最低抑菌浓度（MIC）来测试这些化合物对细菌（革兰氏阳性和革兰氏阴性）和真菌的抗菌活性，发现其范围在 0.00515-1.38 mM 之间。化合物 6、8、10 和 11 对白色念珠菌具有中等抗菌活性。
