Phytochemical Profile of Achillea millefolium Extracted by Supercritical CO₂

Edlira Kaloshi; Lirika Kupe; Kleva Shpati; Aida Dama; Marsela Alikaj; Aurora Brace

Authors

Edlira Kaloshi Department of Pharmacy, Albanian University, Tirana, Albania https://orcid.org/0009-0001-4648-9468
Lirika Kupe Faculty of Agriculture and Environment, Agricultural University of Tirana, Tirana, Albania https://orcid.org/0000-0001-9032-4815
Kleva Shpati Department of Pharmacy, Albanian University, Tirana, Albania https://orcid.org/0000-0002-3213-1158
Aida Dama Department of Pharmacy, Albanian University, Tirana, Albania https://orcid.org/0000-0002-1993-3420
Marsela Alikaj Faculty of Agriculture and Environment, Agricultural University of Tirana, Tirana, Albania https://orcid.org/0009-0003-7309-6592
Aurora Brace Department of Pharmacy, Albanian University, Tirana, Albania https://orcid.org/0000-0002-6014-1708

Keywords:

Achillea Millefolium, Essential Oils, Medicinal Plant, Supercritical CO₂ Extraction

Abstract

Achillea millefolium is a medicinal plant widely used in traditional and modern medicine. This study characterised the chemical composition of essential oils obtained from A. millefolium collected in four regions of Albania (Tirana, Pogradeci, Kukësi and Kruja) using supercritical CO₂ extraction. Volatile compounds were analysed using gas chromatography with flame ionization detection (GC-FID). A total of 23 volatile compounds were identified, representing 88–93% of the total chromatographic area. The major constituent was β-caryophyllene, ranging from 18.02 ± 0.03% in Tirana to 24.40 ± 0.53% in Kukësi. Germacrene D ranged from 9.23 ± 0.05% in Kruja to 13.00 ± 0.01% in Tirana. The monoterpene 1,8-cineole showed regional variation, with the highest level in Tirana (9.39 ± 0.01%) and lower levels in Kukësi (6.45 ± 0.13%). Sabinene showed the highest values in Kukësi (7.65 ± 0.14%) and Kruja (6.28 ± 0.07%), while linalool was most abundant in Kruja (3.62 ± 0.07%). In addition, α-thujone showed the highest value in Kukësi (3.95 ± 0.23%) compared to the lowest in Tirana (0.90 ± 0.01%). Statistical analysis (one-way ANOVA and Tukey's HSD test) revealed significant differences in compound composition among regions. Principal component analysis (PCA) showed clear clustering of replicate samples within each region, with Tirana associated with relatively higher monoterpene content, Kukësi and Kruja associated with higher sesquiterpene abundance, and Pogradeci showing an intermediate profile. The observed variation in essential oil composition may be influenced by regional environmental conditions. The major compounds identified have been reported in the literature to exhibit anti-inflammatory, neuroprotective, antioxidant, and antimicrobial properties. These findings provide the first region-specific phytochemical dataset of A. millefolium essential oils in Albania obtained by supercritical CO₂ extraction and contribute to the chemotypic characterisation of the species.