Bioassay-guided Supercritical Fluid Extraction of Cyclooxygenase-2 Inhibiting Substances in Plantago major L.
2013 (English)In: Phytochemical Analysis, ISSN 0958-0344, E-ISSN 1099-1565, Vol. 24, no 2, 176-183 p.Article in journal (Refereed) Published
Introduction - Selective extraction of plant materials is advantageous for obtaining extracts enriched with desired constituents, thereby reducing the need for subsequent chromatography purification. Such compounds include three cyclooxygenase-2 (COX-2) inhibitory substances in Plantago major L. targeted in this investigation: alpha-linolenic acid (alpha-LNA) (18:3 omega-3) and the triterpenic acids ursolic acid and oleanolic acid. Objective - To investigate the scope for tuning the selectivity of supercritical fluid extraction (SFE) using bioassay guidance, and Soxhlet extraction with dichloromethane as solvent as a reference technique, to optimise yields of these substances. Method - Extraction parameters were varied to optimise extracts' COX-2/COX-1 inhibitory effect ratios. The crude extracts were purified initially using a solid phase extraction (SPE) clean-up procedure and the target compounds were identified with GC-MS, LC-ESI-MS and LC-ESI-MS2 using GC-FID for quantification. Results - alpha-LNA was preferentially extracted in dynamic mode using unmodified carbon dioxide at 40 degrees C and 172 bar, at a 0.04% (w/w) yield with a COX-2/COX-1 inhibitory effect ratio of 1.5. Ursolic and oleanolic acids were dynamically extracted at 0.25% and 0.06% yields, respectively, with no traces of (alpha-LNA) and a COX-2/COX-1-inhibitory effect ratio of 1.1 using 10% (v/v) ethanol as polar modifier at 75 degrees C and 483 bar. The Soxhlet extracts had ursolic acid, oleanolic acid and alpha LNA yields up to 1.36%, 0.34% and 0.15%, respectively, with a COX-2/COX-1 inhibitory effect ratio of 1.2. Conclusion - The target substances can be extracted selectively by bioassay guided optimisation of SFE conditions.
Place, publisher, year, edition, pages
2013. Vol. 24, no 2, 176-183 p.
In vitro enzyme assay, Soxhlet, supercritical fluid extraction (SFE), cyclooxygenase-2, Plantago major L.
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:uu:diva-200457DOI: 10.1002/pca.2398ISI: 000318002600012OAI: oai:DiVA.org:uu-200457DiVA: diva2:623756