Effective separation of maslinic acid and oleanolic acid from olive pomace using high-speed shear off-line coupled with high-speed countercurrent chromatography and their antibacterial activity test

Abstract

In this work, a high-speed shear extraction off-line coupling high-speed countercurrent chromatography method was developed to separate maslinic acid and oleanolic acid from olive pomace. To improve extraction efficiency, the polar disparity between maslinic acid and oleanolic acid necessitated the concurrent utilization of both polar and non-polar solvents during high-speed shear extraction. Then, the high-speed shear extraction was directly feed to high-speed countercurrent chromatography for subsequently separation. A total of 250 min were needed to complete the extraction and separation process. This yielded two molecules from 3.3 g of defatted olive pomace: 7.2 mg of 93.8 % pure maslinic acid and 2.3 mg of 90.1 % pure oleanolic acid, both determined by HPLC at 210 nm. Furthermore, the compounds exhibited inhibitory activity against Escherichia coli and Staphylococcus aureus. At a concentration of 100 μg/mL, its efficacy in inhibiting hyaluronidase was comparable to that of the standard drug indomethacin. Compared with the conventional separation method, this coupled technique reduced the whole time due to the direct injection of sample extraction solution. This technique provides a useful approach for the separation of natural products with significant polarity differences.