Abstract

SUPERCRITICAL CO₂ EXTRACTION AND GC–MS PROFILING OF GERANIUM MACRORRHIZUM AND PELARGONIUM RADULA CULTIVATED IN BULGARIA

Debora Sabotinova*, Iliya Zhelev

Abstract

Supercritical carbon dioxide extraction (SC-CO₂) is a promising modern extraction method increasingly used to extract lipophilic bioactive compounds from aromatic and medicinal plants. This study aimed to compare the extraction yields and chemical compositions of supercritical CO₂ extracts from Geranium macrorrhizum L. and Pelargonium radula (Cav.). L’Hér., cultivated in Bulgaria. The dried aerial parts of both species were subjected to SC-CO₂ extraction at 200 bar and 40 °C using a laboratory extraction system. The extraction yield was determined gravimetrically, and the chemical composition of the extracts was characterized by gas chromatography-mass spectrometry (GC-MS). It was found that the extraction yield of Geranium macrorrhizum (1.80%) was significantly higher than that of Pelargonium radula (0.25%) under identical operating conditions. GC-MS analysis identified 25 constituents, mainly long-chain hydrocarbons, oxygenated sesquiterpenoids, and other lipophilic compounds. The main constituents in both extracts were n-nonacosane and ntetratriacontane. However, significant species-related differences in composition were also observed. Geranium macrorrhizum contained higher levels of germacrone, curcuminone, and bisabolol derivatives, while Pelargonium radula was characterized by the presence of eugenol and a higher relative content of vitamin E. Also, phytol was found exclusively in the extract from Geranium macrorrhizum. The results indicate that botanical origin significantly influences both the extraction efficiency and the phytochemical composition under identical supercritical extraction conditions. This study provides new data on the chemical profiles of SC-CO₂ extracts of Geranium macrorrhizum and Pelargonium radula grown in Bulgaria and contributes to further evaluation of their potential biological and industrial applications.

Keywords: Geranium macrorrhizum; Pelargonium radula; supercritical carbon dioxide extraction; GC–MS; phytochemical profiling; lipophilic compounds.