Chemical composition, antibacterial and antifungal activities of the essential oil of Haplophyllum tuberculatum from Oman

The chemical composition of the essential oil of Haplophyllum tuberculatum (Forsskal) A. Juss (Rutaceae) was analyzed by gas chromatography-mass spectral (GC-MS) and ¹³C NMR spectroscopy. Thirty compounds, constituting about 99.7% of the total oil, were identified. The most abundant oil components are β-phellandrene (23.3%), limonene (12.6%), (Z)-β-ocimene (12.3%), β-caryophyllene (11.6%), myrcene (11.3%), and α-phellandrene (10.9%). Ten microlitres (25 mg) of pure oil partially inhibited the growth of Escherichia coli, Salmonella choleraesuis, and Bacillus subtilis to the same extent as 0.10 μg of gentamycin sulfate. The oil also affected the mycelial growth of Curvularia lunata and Fusarium oxysporium in a dose-dependent manner but had no effect on the germination of their spores.