title: Four new triterpenoids from the leaves of Psidium guajava.
abstract: Four new triterpenoids, psiguanins A-D (1-4), along with 13 known ones (5-17), were isolated from the leaves of Psidium guajava. The structures of new compounds were determined as 2α,3β-dihydroxy-taraxer-20-en-28-oic acid (1), 2α,3β,12α,13β-tetrahydroxy-urs-28-oic acid (2), 2α,3β,12β,13β-tetrahydroxy-urs-28-oic acid (3), and 2α,3β,12β,13α-tetrahydroxy-urs-28-oic acid (4), respectively, on the basis of comprehensive spectroscopic methods and molecular modeling calculation. Among them, compound 4 was characterized as an unusual ursane-type triterpenoid with cis-fused C/D ring system.
authors.affiliation: Department of Natural Medicinal Chemistry, China Pharmaceutical University, Nanjing 210009, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Shao
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.forename: Xiao-Jun
authors.initials: XJ
authors.lastname: Huang
authors.forename: Chun-Lin
authors.initials: CL
authors.lastname: Fan
authors.forename: Qing-Wen
authors.initials: QW
authors.lastname: Zhang
authors.forename: Xiao-Qi
authors.initials: XQ
authors.lastname: Zhang
authors.forename: Wen-Cai
authors.initials: WC
authors.lastname: Ye
mesh_terms: D004365:Drugs, Chinese Herbal / Q000737:chemistry / Q000302:isolation & purification*; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D018515:Plant Leaves / Q000737:chemistry; D031647:Psidium / Q000737:chemistry*; D013237:Stereoisomerism; D014315:Triterpenes / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D004365:Drugs, Chinese Herbal; D014315:Triterpenes