Semi-preparative HPLC separation followed by HPLC/UV and tandem mass spectrometric analysis of phorbol esters in Jatropha seed

- A group of phorbol esters (PEs) was extracted with MeOH from JCL seeds.
- More than seven isomers of phorbol esters with mw of 710 were identified.
- All of them were tigliane-type of diterpens with isomeric dicarboxylic moiety.
- Main five PEs are isolated using semi-preparative HPLC analysis.
- They were assigned as components of Jatropha factors as cited in the References.

Phorbol esters (PEs) are well known as the main toxic compounds in Jatropha curcas Linnaeus (JCL), the seed oil of which has been considered as a major feedstock for the production of biodiesel. In the present study, we investigated a series of PEs extracted from JCL seed kernels with methanol (MeOH), and identified more than seven components contained in the PEs. The isolation of main five components of a series of PEs was revised using a semi-preparative reversed phase HPLC analysis of ODS-3 column. The five peaks of components were successfully isolated, and peaks of J2, J3, J5, and J7 were assigned to be Jatropha factors C1, C2, C3, and C4/5, but J6 was a mixture of Jatropha factor C6 and its isomer based on the data of UV and LC-MS/MS, and J2 was identified using 1H NMR analysis. By characterization using LC-MS/MS analysis, all components of a series of PEs were elucidated to be the 12-deoxy-16-hydroxyphorbol esters composed of isomeric form of dicarboxylic groups with same m/z value of 380.