近日，中科院昆明植物研究所孙汉董研究员课题组与朱华结研究员课题组及其他合作者共同在著名杂志《欧洲化学》（Chemistry-A European Journal）（2008，14：11584-11592）上发表了五味子科降三萜化学研究学术论文。该文报道了从红花五味子(Schisandra rubriflora) 中分离得到一个新奇的具有生物活性的降三萜红花五味子二内酯C以及四个其他的降三萜化合物，并通过波谱数据分析和利用GIAO理论方法在B3LYP/6-311++G(2d,p)//B3LYP/6-31G(d)水平上计算的13C NMR数据比较，以及X－射线单晶衍射实验确定了化合物红花五味子二内酯C的结构；利用DFT理论方法，在B3LYP/6-311+G(d,p)的水平上，通过过渡态能量计算，从计算的角度阐明了小花五味子二内酯D和红花五味子二内酯C关键的生源步骤；并根据该新的生源机制，对其他可能形成的产物进行了预测。
据悉，孙汉董研究员课题组长期以来与中国医学科学院郑启泰、吕扬教授等合作，利用X-衍射解决了许多五味子科植物中结构复杂三萜类化合物的结构鉴定。近年来，与朱华结研究员合作利用量子化学计算的手段，解决了五味子科植物中一些三萜类化合物特殊基团构象问题，并已在Organic Letters以及Journal of Natural Products等发表了相关研究论文。此次合作，通过利用过渡态能量计算对五味子科降三萜关键的生源步骤进行了进一步的阐述，具有重要的学术意义。（生物谷Bioon.com）
生物谷推荐原始出处：
Chemistry-A European Journal，Volume 14 Issue 36, Pages 11584 - 11592，Wei-Lie Xiao，Han-Dong Sun
Structure Elucidation and Theoretical Investigation of Key Steps in the Biogenetic Pathway of Schisanartane Nortriterpenoids by Using DFT Methods
Wei-Lie Xiao, Dr. 1, Chun Lei 1, Jie Ren 1, Tou-Gen Liao 1, Jian-Xin Pu 1, Charles U. Pittman Jr., Prof. 2, Yang Lu, Prof. 3, Yong-Tang Zheng, Prof. 4, Hua-Jie Zhu, Prof. 1 *, Han-Dong Sun 1 *
1State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Heilongtan, Kunming 650204, Yunnan (China)
2Department of Chemistry, Mississippi State University, Mississippi State, 39762, MS (USA)
3Institute of Materia Medica, Chinese Academy of Medical Sciences, Beijing 100050 (China)
4Key Laboratory of Animal Models and Human Disease Mechanisms and Laboratory of Molecular Immunopharmacology, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, Yunnan (China)
Rubrifloradilactone C (4), a novel bioactive nortriterpenoid, along with four other nortriterpenoids (1-3, 5) were isolated from Schisandra rubriflora. The structure of 4 was determined by extensive NMR spectral analysis, computational evidence by using the GIAO method at the B3LYP/6-311++G(2d,p)//B3LYP/6-31G(d) levels, and X-ray analysis. DFT at the B3LYP/6-311+G(d,p) level was selected to clarify the key mechanistic steps in the formation of 1 and 4 through transition-state (TS) investigations. The effect of enzymes on the TS barriers was considered by using the polarized continuum model. Other possible products based on the new mechanism were predicted.
