Chemical Analysis and Biological Activities of <i>Senecio scandens</i> Essential Oil: An Experimental and In Silico Study

The study first describes chemical profiles of essential oils from Vietnamese Senecio scandens Buch.-Ham. ex D. Don. From the gas chromatography-mass spectrometry (GC-MS) analysis, the stem bark essential oil was characterized by the major compounds β-myrcene (19.7%), (E)-β-ocimene (9.5%), and limonene (5.4%), while the leaf essential oil was dominated by trans-cadina-1(6),4-diene (11.0%), caryophyllene oxide (10.9%), (E)-caryophyllene (9.0%), α-humulene (6.9%), germacrene D (6.8%), β-myrcene (6.7%), and cis-isolongifolanone (6.7%). The essential oils from the stem barks (IC₅₀ = 8.75 ± 0.42 µg/mL) and leaves (IC₅₀ = 12.40 ± 0.56 µg/mL) surpassed the standard allopurinol (IC₅₀ = 14.7 ± 0.71 µg/mL) in the xanthine oxidase (XO) inhibitory activity. Additionally, they showed strong cytotoxic, antioxidant, and anti-inflammatory activities with IC₅₀ values of 18.2-42.8 µg/mL. The stem bark sample further strongly inhibited the bacterium Bacillus cereus ATCC 11778 with the minimum inhibitory concentration (MIC) value of 64 µg/mL. In general, the stem bark essential oil consistently demonstrated stronger potency than the leaf essential oil. Molecular docking studies further supported that germacrene D, trans-cadina-1(6),4-diene, (E)-caryophyllene, and α-humulene exhibited stronger binding affinities with the XO than the reference ligand guanine. These interactions were primarily mediated by hydrophobic contacts with key residues, with germacrene D and trans-cadina-1(6),4-diene emerging as the most potent inhibitors.