Negative electrospray ionization tandem mass spectrometric investigation of ent-kaurane diterpenoids from the genus Isodon

• Published in: Journal of mass spectrometry. Vol. 43; no. 1; pp. 63 - 73
• Main Authors: Zhou, Yan, Huang, Sheng-Xiong, Li, Li-Mei, Yang, Jing, Liu, Xin, Peng, Shu-Lin, Ding, Li-Sheng, Sun, Han-Dong
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.01.2008; Wiley
• Subjects: Analytical, structural and metabolic biochemistry; Biological and medical sciences; Chemistry; Diterpenes, Kaurane - chemistry; Drugs, Chinese Herbal - chemistry; ent-kaurane diterpenoid; ESI-MSn; Exact sciences and technology; fragmentation pattern; Fundamental and applied biological sciences. Psychology; General pharmacology; Isodon - chemistry; Isodon genus; Mass spectrometry; Medical sciences; Molecular Structure; Organic chemistry; Other biological molecules; Pharmacognosy. Homeopathy. Health food; Pharmacology. Drug treatments; Phytotherapy; Reactivity and mechanisms; Spectrometry, Mass, Electrospray Ionization - methods; Tandem Mass Spectrometry - methods; Terpenes, steroids. Hormones; Pentacyclic compound; Tandem mass spectrometry; Saturated compound; Ketol; Fragmentation pattern; Oxygen heterocycle; Electrospray; Ion trap; Dicotyledones; Enantiomer; Angiospermae; Glycoside; Polyol; ESI-MSn; Terpenoid; Tetracyclic compound; Hemiacetal; Aldehyde; Isodon genus; Labiatae; Plant origin; Diterpene; Spermatophyta; ent-kaurane diterpenoid; Structural analysis
• ISSN: 1076-5174; 1096-9888
• DOI: 10.1002/jms.1273

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-MSn) 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 CH₂O or CO₂ 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 H₂O, CO, CO₂, 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. Copyright © 2007 John Wiley & Sons, Ltd.