Triterpene Acids in Plantago major: Identification, Quantification and Comparison of Different Extraction Methods

Seeds and leaves of cultivated great plantain (Plantago major L.) were extracted with conventional Soxhlet extraction using a variety of solvents and with pilot scale supercritical fluid (CO2) extraction (SFE-CO2). Hydroxy pentacyclic triterpene acids (HPTAs), oleanolic acid and ursolic acid, were identified from the SPE purified extracts with LC-(UV)-APCI-MS and quantified with LC-UV. Dried P. major leaves contained 0.07% of oleanolic acid and 0.22% of UA. Seeds had very small amounts of HPTAs, 0.005% of OA and 0.007% of ursolic acid in the oil extracted. SFE-CO2 extraction without polar modifier was found not to be a suitable technology for the leaf extraction due to the low content of lipophilic and volatile compounds. Soxhlet extraction with diethyl ether and SFE-CO2 extraction were similar in the efficiency of extracting HPTAs from the seeds.