Supercritical fluid extraction of mastic gum (Pistacia lentiscus var. chia) and phytochemical characterization of the generated extracts

The European Medicines Agency (EMA) recently issued an assessment report concerning the role of Chios mastic gum (the resin of Pistacia lentiscus L. var. chia) against mild dyspeptic disorders and the symptomatic treatment of minor inflammations. Mastiha has been proven to be effective against several gastrointestinal disorders, most of the times connected to the bacterium Helicobacter pylori [1]. Mastic is a complex chemical mixture, consisting of the polymer (beta-myrcene), the essential oil and the triterpenic fraction [2]. There are indications that the activity of mastic against H. pylori is localized to the total mastic extract without the polymer, i.e. the triterpenic fraction[3]. In the present study Supercritical fluid extraction technology was used for the development of an environmentally friendly and stepwise methodology, resulting in the extraction and enrichment of the valuable constituents of the resin. Application of several experimental conditions yielded to a volatile and a bioactive triterpenic fraction, while the polymer was finally isolated. The volatile fraction, analyzed by GC-MS, was found of improved composition and of higher resemblance to mastic resin in comparison to the essential oil obtained by distillation. The triterpenic fraction was separated to the acidic and the neutral part. The GC-MS analysis of the neutral part proved that triterpenes were the major constituents (mainly noroleanenone and noroleanenol derivatives, dammarane and oleanenone derivatives, beta-amyrin, beta-amyrone and oleanonic aldehyde). For the analysis of the acidic fraction a new LC-HRMS/MS methodology was developed for the first time on an Orbitrap platform. The extract was found to contain a large number of triterpenic acids. The major ones were identified as isomasticadienoic, masticadienoic, oleanonic and moronic, while the structures of minor triterpenic acids, like masticadienolic and isomasticadienolic were also identified.