Chemical Analysis, Biological Activities, and In Silico Approach of Essential Oils from Leaves, Stem Barks, and Roots of <i>Eupatorium clematideum</i>

The current study first describes a chemical analysis of essential oils from Vietnamese Eupatorium clematideum (Wall. Ex DC.) Sch. Bip. Gas chromatography-mass spectrometry/flame ionization detection analysis revealed α-pinene (16.50%), α-humulene (6.71%-19.05%), germacrene D (7.72%-18.92%), α-santalene (5.61%-14.58%), bicyclogermacrene (8.44%-16.69%), β-caryophyllene (5.50%), and cis-β-elemene (5.71%-9.72%) as the main compounds of essential oils from its leaves, stem barks, and roots. The essential oils from the leaves, stem barks, and roots showed strong cytotoxicity with the corresponding half-maximal inhibitory concentration (IC₅₀) values of 8.43 ± 0.51, 8.74 ± 0.29, and 8.65 ± 0.29 µg/mL against SK-LU-1; 9.42 ± 0.32, 7.93 ± 0.28, and 8.65 ± 0.29 µg/mL against HeLa; and 7.16 ± 0.33, 8.11 ± 0.48, and 9.75 ± 0.41 µg/mL against HepG2 cancer cell lines. The essential oils also exhibited strong inhibitory activity against nitric oxide production with IC₅₀ values of 29.68-33.55 µg/mL. Furthermore, the essential oils exerted antioxidant, antidiabetic, and antimicrobial activities. The molecular docking study revealed that α-santalene and α-humulene displayed the strongest binding affinity for two cancer-related protein targets: epidermal growth factor receptor and human epidermal growth factor receptor 2, respectively. The predicted toxicity profiles of the major compounds were also expected to provide insights for further research considerations.