Molecular imprinting-based extraction of rosmarinic acid from Salvia hypoleuca extract

Abstract

This study presents selective and efficient extraction of a medicinally important compound rosmarinic acid (RA) via molecular imprinting. Molecularly imprinted polymer (MIP) and its respective non-imprinted polymer (NIP) were synthesized using methacrylamide (MAAm), itaconic acid (IA), and 4-vinyl-1,3-dioxolan-2-one (VD) as functional monomers, and trimethylolpropane trimethacrylate (TRIM) as a crosslinker via bulk polymerization, and characterized by SEM, BET, FT-IR, and TGA. The adsorption properties of MIP were evaluated by batch rebinding experiments, Scatchard analysis, LF-isotherm, and kinetic models. The MIP showed higher adsorption capacity towards RA compared to the corresponding NIP: 41.9 mg/g compared to only 9.6 mg/g. In addition, the synthesized RA-MIP displayed a good selectivity towards RA compared to its structural analogs in competitive recognition studies, confirming the development of RA specific imprinting sites. HPLC was utilized to determine the concentration of RA and analogous compounds in competitive recognition tests and in the real sample analysis. Finally, RA-MIP was successfully utilized for the selective enrichment of RA from the ethanolic extract of Salvia hypoleuca. The obtained results show that RA-MIP can be a promising alternative to conventional extraction methods for the selective extraction and enrichment of RA from complex plant matrices.