Chemical composition, anti-cancer and anti-microbial activities of the leaf essential oil of Parakmeria robusta (B. L. Chen & Nooteboom) Q. N. Vu & N. H. Xia

The objective of this study was to investigate the chemical composition, anticancer, and antimicrobial activities of the essential oils extracted from Parakmeria robusta (B. L. Chen & Nooteboom) Q. N. Vu & N. H. Xia collected in Lam Dong Province, Vietnam. The essential oils obtained from P. robusta leaves by hydrodistillation were analyzed by gas chromatography–mass spectrometry (GC–MS). A total of thirty-three components were identified, with the oil being predominantly composed of monoterpenoids (65.3%). The major constituents were δ-2-carene (23.2%), α-phellandrene (23.4%), (E)-β-ocimene (6.2%), dihydrocarveol (5.3%), cis-thujopsene (5.0%), α-pinene (4.6%), and ledol (4.3%). Cytotoxicity assays were conducted against KB, HepG2, MCF-7, and A549 human cancer cell lines using the MTT assay. The essential oil exhibited moderate cytotoxicity against all tested cell lines, with IC50 values ranging from 95.26 ± 6.31 to 147.78 ± 4.94 µg/mL. In contrast, assessment of antibacterial activity using the MIC method showed no inhibition of the microbial strains tested at the applied concentrations, as evidenced by MIC and IC50 values greater than 256 μg/mL. To the best of our knowledge, this is the first study reporting the chemical composition and biological activities of the essential oils of this species.