title: Micranthanone A, a new diterpene with an unprecedented carbon skeleton from Rhododendron micranthum.
abstract: A new diterpene with an unprecedented carbon skeleton, micranthanone A (1), two new grayanane diterpenoids bearing an unusual 5,6-(3,4-dihydroxylbenzylidene acetal) motif, rhodomicranols A (2) and B (3), and three known grayanane diterpenoids (4-6) were isolated from Rhododendron micranthum. Their structures were elucidated by spectroscopic analyses, calculated ECD, and single-crystal X-ray diffraction. The in vitro immunomodulatory activities of 1-6 were evaluated, and a plausible biogenetic pathway for 1 is proposed.
authors.affiliation: Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology , Wuhan 430030, Hubei, P. R. China, School of Chemistry and Chemical Engeering, Taishan Medical University , Tai-An 271016, Shandong, P. R. China, and Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou 350002, Fujian, P. R. China.
authors.forename: Mengke
authors.initials: M
authors.lastname: Zhang
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhu
authors.forename: Guanqun
authors.initials: G
authors.lastname: Zhan
authors.forename: Penghua
authors.initials: P
authors.lastname: Shu
authors.forename: Rongjian
authors.initials: R
authors.lastname: Sa
authors.forename: Liang
authors.initials: L
authors.lastname: Lei
authors.forename: Ming
authors.initials: M
authors.lastname: Xiang
authors.forename: Yongbo
authors.initials: Y
authors.lastname: Xue
authors.forename: Zengwei
authors.initials: Z
authors.lastname: Luo
authors.forename: Qian
authors.initials: Q
authors.lastname: Wan
authors.forename: Guangmin
authors.initials: G
authors.lastname: Yao
authors.forename: Yonghui
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D002244:Carbon / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004224:Diterpenes / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D007155:Immunologic Factors / Q000032:analysis / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D029793:Rhododendron / Q000737:chemistry*
chemical_list: D004224:Diterpenes; D007155:Immunologic Factors; C000588623:micranthanone A; D002244:Carbon