Mass spectrometric profiling of valepotriates possessing various acyloxy groups from Valeriana jatamansi.
Valepotriates, plant secondary metabolites of the family Valerianaceae, contain various acyloxy group linkages to the valepotriate nucleus and exhibit significant biological activities. Identification of valepotriates is important to uncover potential lead compounds for the development of new sedative and antitumor drugs. However, making their structure elucidation by nuclear magnetic resonance (NMR) experiments is too difficult to be realized because of the overlapped carbonyl carbon signals of acyloxy groups substituted at different positions. Thus, the mass spectrometric profiling of these compounds in positive ion mode was developed to unveil the exact linkage of acyloxy group and the core of valepotriate. In this study, electrospray ionization tandem multistage mass spectrometry (ESI-MS/MS(n)) in ion trap and collision-induced dissociation tandem MS were used to investigate the fragmentation pathways of four types of valepotriates in Valeriana jatamansi, including 5-hydroxy-5,6-dihydrovaltrate hydrin (5-hydroxy-5,6-dihydrovaltrate chlorohydrin), 5,6-dihydrovaltrate hydrin (5,6-dihydrovaltrate chlorohydrin), 5-hydroxy-5,6-dihydrovaltrate and valtrate hydrin (valtrate chlorohydrin). The high-resolution mass spectrum (HRMS) data of all the investigated valepotriates from quadrupole time-of-flight MS/MS were used as a supportive of the fragmentation rules we hypothesized from ion-trap stepwise MS(n). As a result, the loss sequence of acyloxy groups and the abundance of key product ions, in combination with the characteristic product ions corresponding to the valepotriate nucleus, could readily differentiate the four different types of valepotriates. The summarized fragmentation rules were also successfully exploited for the structural characterization of three new trace valepotriates from V. jatamansi. The results indicated that the developed analytical method could be employed as a rapid, effective technique for structural characterization of valepotriates, especially for the trace compounds that could not be identified by NMR techniques. This study may also arouse interest for further structural analysis of other valepotriate-containing type herbal medicines.
Department of Natural Product Chemistry, School of Pharmacy, Second Military Medical University, Shanghai, 200433, China.|State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China.
Sheng
S
Lin
Department of Natural Product Chemistry, School of Pharmacy, Second Military Medical University, Shanghai, 200433, China.
Ji
J
Ye
Department of Natural Product Chemistry, School of Pharmacy, Second Military Medical University, Shanghai, 200433, China.
Xu
X
Liang
Department of Natural Product Chemistry, School of Pharmacy, Second Military Medical University, Shanghai, 200433, China.
Xi
X
Zhang
Department of Natural Product Chemistry, School of Pharmacy, Second Military Medical University, Shanghai, 200433, China.
Juan
J
Su
Department of Natural Product Chemistry, School of Pharmacy, Second Military Medical University, Shanghai, 200433, China.|Department of Pharmacy, Changhai Hospital, Second Military Medical University, Shanghai, 200433, China.
Peng
P
Fu
Department of Natural Product Chemistry, School of Pharmacy, Second Military Medical University, Shanghai, 200433, China.
Di-Ya
DY
Lv
Department of Natural Product Chemistry, School of Pharmacy, Second Military Medical University, Shanghai, 200433, China.
Lei
L
Shan
Department of Natural Product Chemistry, School of Pharmacy, Second Military Medical University, Shanghai, 200433, China.
Yun-Heng
YH
Shen
Department of Natural Product Chemistry, School of Pharmacy, Second Military Medical University, Shanghai, 200433, China.
Hui-Liang
HL
Li
Department of Natural Product Chemistry, School of Pharmacy, Second Military Medical University, Shanghai, 200433, China.
Xian-Wen
XW
Yang
Department of Natural Product Chemistry, School of Pharmacy, Second Military Medical University, Shanghai, 200433, China.|School of Pharmacy, Shanghai Jiao Tong University, Shanghai, 200240, China.
Wei-Dong
WD
Zhang
D039823:Iridoids / Q000032:analysis / Q000737:chemistry; D015394:Molecular Structure; D064210:Secondary Metabolism; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014632:Valerian / Q000737:chemistry* / Q000378:metabolism
C000609811:5,6-dihydrovaltrate hydrin; C000609808:5-hydroxy-5,6-dihydrovaltrate hydrin; D039823:Iridoids; C000609809:valtrate hydrin
ESI-MS/MSn; Valeriana jatamansi; exact linkage; fragmentation pathways; valepotriates