The Essential Oil Composition and Antimicrobial Activity of Liquidambar formosana Oleoresin

The oleoresin essential oils of Liquidambar formosana have potential therapeutic benefits. However, current research on L. formosana oleoresin essential oil is still in its early stages, and its chemotypic characterization is undefined. For better leveraging of plant resources and application of the essential oil, we collected 25 L. formosana oleoresin essential oil samples of individual trees from different geographical areas of Southern China. The essential oils were obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detection (GC-FID). The major components of the essential oils were (E)-caryophyllene (3.3%-64.4%), α-pinene (0.6%-34.5%), β-pinene (0.6%-26.0%), camphene (0.3%-17.3%), and limonene (0.2%-7.9%). A chiral GC-MS analysis was carried out on the essential oil samples and (-)-α-Pinene, (-)-β-pinene, (-)-camphene, and (-)-limonene were the dominant enantiomers in L. formosana essential oil. The chemical categories of L. formosana oleoresin essential oils were clarified by agglomerative hierarchical cluster analysis (AHC) and principal component analysis (PCA). The multivariate analyses demonstrated that a total of four chemical groups can be delineated for L. formosana. The L. formosana essential oils were screened for antimicrobial activity against a panel of potentially pathogenic bacteria and fungi and showed promising antimicrobial activities with minimum inhibitory concentration (MIC) ≤ 625 μg/mL. These results highlight the economic value of L. formosana oleoresin essential oil, the importance of L. formosana sustainability, and the potential therapeutic benefits of its oleoresin essential oils.

Keywords: (E)-caryophyllene; antibacterial; antifungal; camphene; chemical composition; enantiomeric distribution; hierarchical cluster analysis; principal component analysis; sweetgum; α-pinene; β-pinene.