Adsorbents, mobile phases, and strategies for the chromatographic separation of betulinic, oleanolic, and ursolic acids

Abstract

A critical overview of the separation of three relevant triterpenic acids, namely betulinic, oleanolic, and ursolic acids, by liquid and supercritical fluid chromatography is presented in this review. These triterpenic acids are commonly found in different biomass residues and have raised great research attention in recent years due to their broad and valuable therapeutic properties. Accordingly, fundamental aspects such as solubilities in single and mixed solvents, commercial stationary phases (octadecylsilyl and other bonded phases like triacontylsilyl, as well as porous graphitic columns), custom adsorbents (molecularly imprinted polymers and other polymeric adsorbents), mobile phases (conventional HPLC solvents and super/subcritical fluids), mobile-phase modifiers (acidic, basic, and cyclodextrins), pre-column derivatization strategies, and influence of temperature have been compiled, analyzed and thoroughly discussed in terms of (calculated) separation selectivities, peaks resolution, orders of elution, systems descriptors, etc. The most relevant achievements and gaps in this area of research are highlighted, together with a final comparison of the separation performance of the chromatographic systems reported in the literature.

Determination of Pentacyclic Triterpenoids in Plant Biomass by Porous Graphitic Carbon Liquid Chromatography—Tandem Mass Spectrometry

“…The only difference between them lies in the position of the two methyl groups in the E cycle-in the oleanane-type structures, they are attached to the same C-20 carbon atom, while the oleanane family is distinguished by the methylated C-19 and C-20 carbon atoms. Therefore, ursane-type PCTs have a higher degree of planarity [36] and thus higher retention when compared with the similar compounds of the oleanane family. In the case of lupane-type compounds, the C-19 carbon atom has a prop-2-enyl substituent, which greatly distinguishes this family by having lower planarity and lower retention on PGC.…”