Cytotoxic Activity and Phytochemical Analysis of Artemisia biennis Essential Oils at Different Growth Stages

Background: The Artemisia genus is well-known for its medicinal properties, particularly in Iranian traditional medicine. Artemisia biennis, a species within this genus, is widely distributed across Iranian rangelands. Objectives: This study aimed to evaluate the cytotoxic activity and chemical composition of essential oils (EO) isolated from the aerial parts of A. biennis in Iran at different growth stages. Methods: The aerial parts of A. biennis from northeast Iran were collected during June (early vegetative stage), July (pre-flowering stage), August (full-flowering stage), and October (late vegetative stage). The essential oils (EOs) of the A. biennis species were extracted by hydro-distillation using a Clevenger-type apparatus and analyzed using gas chromatography–mass spectrometry (GC/MS). The cytotoxic activity of the EOs against normal fibroblasts, MCF-7, and HT-29 cell lines was evaluated using the MTT assay. Results: Data from GC/MS analysis revealed that (Z)-nerolidol (22.62 - 54.4%), (E)-β-farnesene (6.89-16.38%), and (Z)-tonghaosu (12.33 - 18.61%) were the most abundant chemical constituents. The essential oil (EO) of A. biennis was characterized by a high content of oxygenated sesquiterpenes, with (Z)-nerolidol being the main constituent identified. Based on the MTT assay, the EO of the plant species collected in June exhibited the most potent cytotoxicity against MCF-7 (IC50 = 2.84 ± 0.15 µg/mL) and HT-29 cell lines (IC50 = 2.41 ± 0.2 µg/mL). Conclusions: The growth stage of A. biennis affects EO yields, the composition of extracted secondary metabolites, and cytotoxic activity. A. biennis EOs can be considered potential sources of cytotoxic phytochemicals.