title: Euphorikanin A, a Diterpenoid Lactone with a Fused 5/6/7/3 Ring System from Euphorbia kansui.
abstract: Euphorikanin A (1), an unprecedented diterpenoid lactone which possesses a novel 5/6/7/3-fused tetracyclic ring skeleton, was isolated from the roots of Euphorbia kansui. The chemical structure and absolute stereochemistry were elucidated on the basis of extensive spectroscopic methods and single-crystal X-ray diffraction analysis. Compound 1 exhibited moderate cytotoxicity against two human tumor cell lines HeLa and NCI-446. A proposed biosynthetic pathway of compound 1 is also described.
authors.affiliation: School of Pharmacy and ‡State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University , Lanzhou 730000, People's Republic of China.
authors.forename: Dong-Qing
authors.initials: DQ
authors.lastname: Fei
authors.affiliation: School of Pharmacy and ‡State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University , Lanzhou 730000, People's Republic of China.
authors.forename: Le-Le
authors.initials: LL
authors.lastname: Dong
authors.affiliation: School of Pharmacy and ‡State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University , Lanzhou 730000, People's Republic of China.
authors.forename: Feng-Ming
authors.initials: FM
authors.lastname: Qi
authors.affiliation: School of Pharmacy and ‡State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University , Lanzhou 730000, People's Republic of China.
authors.forename: Gai-Xia
authors.initials: GX
authors.lastname: Fan
authors.affiliation: School of Pharmacy and ‡State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University , Lanzhou 730000, People's Republic of China.
authors.forename: Hui-Hong
authors.initials: HH
authors.lastname: Li
authors.affiliation: School of Pharmacy and ‡State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University , Lanzhou 730000, People's Republic of China.
authors.forename: Zheng-Yu
authors.initials: ZY
authors.lastname: Li
authors.affiliation: School of Pharmacy and ‡State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University , Lanzhou 730000, People's Republic of China.
authors.forename: Zhan-Xin
authors.initials: ZX
authors.lastname: Zhang