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

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.

Automated summary

This review critically discusses the separation of three relevant triterpenic acids (betulinic, oleanolic, and ursolic acids) by liquid and supercritical fluid chromatography. These acids, commonly found in biomass residues, have attracted significant research attention due to their therapeutic properties. The review compiles, analyzes, and thoroughly discusses various aspects including solubilities, stationary phases, adsorbents, mobile phases, pre-column derivatization strategies, and temperature effects. The achievements and gaps in this research area are highlighted, and a final comparison of chromatographic systems is provided.