Pentacyclic triterpene in Olea europaea L: A simultaneous determination by high-performance liquid chromatography coupled to mass spectrometry.

Pentacyclic triterpenes are gaining interest due to their beneficial health effects, as anti-inflammatory, anti-diabetic and anti-tumoral, among others. In this study, an analytical LC-MS method was developed for the simultaneous determination of maslinic, oleanolic and ursolic acids along with erythrodiol and uvaol, which are the main triterpenic compounds present in the fruits and leaves of Olea europaea L. A Zorbax Eclipse PAH column at 30°C with mobile phase of water (17%) and methanol (83%) at 0.8mL/min conformed the optimal chromatographic conditions that allowed the separation of the compounds of interest, two pairs of which are isomers differing only in the position of one methyl group (oleanolic-ursolic and erythrodiol-uvaol). The ionization was performed in an APCI source at 450°C programmed in negative mode for the triterpenic acids, and in positive for the alcohols. An ion trap (LC-IT-MS) and a triple quadrupole (LC-QqQ-MS) were assessed for maximal sensitivity that was achieved with LC-QqQ-MS. The LODs of triterpenic acids were lower than 1nM, whereas for erythrodiol and uvaol were 4.5 and 7.5nM, respectively. The method was linear for the five analytes in the range of concentrations from 0.005 to 15μM with correlation coefficients exceeding 0.99. The precision and accuracy were ≤9.90% and ≤9.57%, respectively. The applicability of the validated method was assessed in the analysis of the pentacyclic triterpenes in Marfil table olives, after the optimization of the extraction procedure. The developed method constitutes the first step for future studies of triterpenic compounds present in foods that would allow establishing their effects on human health.