Liu H, Heilmann J, Rali T, Sticher O
Department of Applied BioSciences, Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zurich, CH-8057 Zürich, Switzerland.
J Nat Prod. 2001 Feb;64(2):159-63. doi: 10.1021/np0002841.
Eight new tirucallane-type triterpenes, dyvariabilins A-H (1-8), three known tirucallanes, niloticin (9), dihydroniloticin (10), and tirucalla-7,24-diene-3 beta,23-diol (11), and two known sesquiterpenes, 1-(1-hydroxy-2-methylpropyl)-3a-methyl-7-methyleneoctahydroinden-4-ol and (+)-aphanamol I, were isolated from the stem bark of Dysoxylum variabile. Tirucallanes 1 and 11 with an allylic hydroxy group in the side chain and dyvariabilin C (3) with an alpha-epoxy group at positions 7 and 8 showed high instability in acidic medium and formed five hitherto unknown semisynthetic tirucallanes. Dyvariabilins B (2) and C (3) as well as the mixtures of dyvariabilins E and F (5 and 6) and dyvariabilins G and H (7 and 8) showed weak cytotoxicity against KB cells.
从异色木的茎皮中分离出8个新的四环三萜类化合物，即异色可变菌素A - H（1 - 8）、3个已知的四环三萜类化合物尼罗菌素（9）、二氢尼罗菌素（10）和四环-7,24-二烯-3β,23-二醇（11），以及2个已知的倍半萜类化合物1-(1-羟基-2-甲基丙基)-3a-甲基-7-亚甲基八氢茚-4-醇和(+)-阿法那莫醇I。侧链带有烯丙基羟基的四环三萜类化合物1和11以及在7和8位带有α-环氧基的异色可变菌素C（3）在酸性介质中表现出高度不稳定性，并形成了5个迄今未知的半合成四环三萜类化合物。异色可变菌素B（2）和C（3）以及异色可变菌素E和F（5和6）的混合物和异色可变菌素G和H（7和8）的混合物对KB细胞显示出较弱的细胞毒性。
