Chemical Composition and Multiple Bioactivities of Ageratum conyzoides Essential Oil Collected in Dak Lak, Vietnam

The essential oil of Ageratum conyzoides collected from Dak Lak Province, Vietnam, was investigated for its chemical composition and biological activities. Gas chromatography-mass spectrometry (GC-MS) analysis identified 26 volatile constituents, accounting for 78.8 % of the total oil content, predominantly composed of monoterpenoids (60.6 %) and sesquiterpenoids (18.2 %). The major components included caryophyllene (15.57 %), sabinene (14.78 %), isomyocorene (3.62 %), eucalyptol (12.46 %), humulene (8.91 %), nerolidol (5.80 %), α-pinene (3.09 %), and 3-carene (3.05 %). The essential oil exhibited notable antioxidant activity in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay with an IC₅₀ value of 6.03 ± 0.4 mg/mL. In addition, moderate antibacterial activity against Escherichia coli was observed, with an inhibition zone diameter of 27.0 mm at 3.00 mg/mL and a minimum inhibitory concentration of 100 µg/mL. The oil also demonstrated moderate α-glucosidase inhibitory activity with an IC₅₀ value of 415.4 μg/mL. Molecular docking analysis provided only preliminary and hypothesis-generating insights, suggesting that major constituents such as caryophyllene and nerolidol may be associated with the observed activities. However, these in silico results do not provide direct evidence of DNA GyrB or α-glucosidase inhibition by individual compounds. These findings indicate that A. conyzoides essential oil represents a potential natural source of multifunctional bioactive compounds for further pharmacological investigation.