Simultaneous Supercritical Fluid Extraction of Heather (Calluna vulgaris L.) and Marigold (Calendula officinalis L.) and Anti-Inflammatory Activity of the Extracts

Heather (Calluna vulgaris L.) and marigold (Calendula officinalis L.) are two rich sources of bioactive pentacyclic triterpenes. The supercritical carbon dioxide (SCCO2) extraction of these two plants was explored at a pressure range of 25–50 MPa, 50 °C, with or without fractionation, different extraction times (1.5–4.0 h) and using ethanol as a co-solvent (0 and 10% w/w). In order to determine potential synergisms, a combined extraction (heather + marigold 50:50) was also studied. In general, higher extraction yields were achieved when the co-solvent was added. Higher concentrations of total triterpenic acids were obtained in heather extracts, specially using ethanol. The co-solvent did not increase the terpene concentration in marigold extracts. For the combined extraction, an antagonist effect in the triterpene concentration was observed in absence of a co-solvent, whereas a synergistic effect was exhibited in its presence, especially for ursolic acid. In general, the extracts showed a certain anti-inflammatory effect, although a straight correlation with the analyzed triterpenic acids concentration was not exhibited. Moreover, the combined extraction exposed a similar anti-inflammatory activity in comparison with the individual plant extracts.