title: Structure elucidation and theoretical investigation of key steps in the biogenetic pathway of schisanartane nortriterpenoids by using DFT methods.
abstract: 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.
authors.affiliation: State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Heilongtan, Kunming 650204, Yunnan, China.
authors.forename: Wei-Lie
authors.initials: WL
authors.lastname: Xiao
authors.forename: Chun
authors.initials: C
authors.lastname: Lei
authors.forename: Jie
authors.initials: J
authors.lastname: Ren
authors.forename: Tou-Gen
authors.initials: TG
authors.lastname: Liao
authors.forename: Jian-Xin
authors.initials: JX
authors.lastname: Pu
authors.forename: Charles U
authors.initials: CU
authors.lastname: Pittman
authors.forename: Yang
authors.initials: Y
authors.lastname: Lu
authors.forename: Yong-Tang
authors.initials: YT
authors.lastname: Zheng
authors.forename: Hua-Jie
authors.initials: HJ
authors.lastname: Zhu
authors.forename: Han-Dong
authors.initials: HD
authors.lastname: Sun
mesh_terms: D045744:Cell Line, Tumor; D018360:Crystallography, X-Ray; D006801:Humans; D020128:Inhibitory Concentration 50; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D015394:Molecular Structure; D018515:Plant Leaves / Q000737:chemistry; D018547:Plant Stems / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry; D032141:Schisandra / Q000737:chemistry* / Q000201:enzymology; D014315:Triterpenes / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology
chemical_list: D014315:Triterpenes; C534998:rubriflordilactone C; C512131:schisanartane