title: Negative electrospray ionization tandem mass spectrometric investigation of ent-kaurane diterpenoids from the genus Isodon.
abstract: ent-Kaurane diterpenoids are a class of natural compounds isolated from genus Isodon, which have been found to have important bioactivities. Negative electrospray ionization tandem mass spectrometry ((-)ESI-MS(n)) was used to investigate the fragmentation pattern of C-20-nonoxygenated ent-kauranes and two subtypes of C-20-oxygenated ent-kauranes by using an ion trap instrument and accurate mass measurement on an ESI-Q-time-of-flight (TOF) mass spectrometer. The analysis revealed that loss of CH(2)O or CO(2) is the predominant process for 7, 20-epoxy and 7, 20 : 14, 20-diepoxy subgroup of C-20-oxygenated ent-kauranes. In addition, compounds of C-20-nonoxygenated ent-kauranes with a conserved core structure but different substituent groups, such as a hydroxyl, aldehyde, carboxyl, and acetyl moiety, resulted in diagnostic product ions through losses of H(2)O, CO, CO(2), and AcOH, respectively. This work clearly demonstrates the utility of tandem mass spectrometry for studies on the rationalization of the diagnostic fragmentation of a series of compounds from two main types of the ent-kaurane diterpenoids.
authors.affiliation: Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, Sichuan Province, People's Republic of China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhou
authors.forename: Sheng-Xiong
authors.initials: SX
authors.lastname: Huang
authors.forename: Li-Mei
authors.initials: LM
authors.lastname: Li
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.forename: Shu-Lin
authors.initials: SL
authors.lastname: Peng
authors.forename: Li-Sheng
authors.initials: LS
authors.lastname: Ding
authors.forename: Han-Dong
authors.initials: HD
authors.lastname: Sun
mesh_terms: D045786:Diterpenes, Kaurane / Q000737:chemistry*; D004365:Drugs, Chinese Herbal / Q000737:chemistry; D037602:Isodon / Q000737:chemistry*; D015394:Molecular Structure; D008517:Phytotherapy; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D045786:Diterpenes, Kaurane; D004365:Drugs, Chinese Herbal