Comparison of chemical composition and antimicrobial activity of essential oils from three Pinus species

The essential oils of the leaves of three Pinus species (Pinus densiflora, P. thunbergii, P. rigida) were analyzed by gas chromatography/mass spectrometry (GC/MS). Analysis of the oils from P. densiflora, P. thunbergii and P. rigida revealed the presence of α-humulene (18.09%, 19.59%, 14.08%), caryophyllene (7.69%, 5.32%, 10.20%), β-pinene (4.95%, 4.45%, 7.39%), β-cadinene (3.28%, 1.30%, 3.71%), cinnamic acid (2.62%, 1.24%, 2.87%), α-terpinolene (2.10%, 0.51%, 0.3%), spathulenol (2.04%, 0.34%, 2.78%), α-cadinol (1.85%, 0.97%, 2.60%), caryophyllene oxide (1.82%, 0.23%, 0.13%) and α-pinene (1.79%, 0.68%, 0.13%) as major constituents. Essential oil from P. thunbergii showed stronger inhibitory activity against Bacillus subtilis, Bacillus natto, Staphylococcus aureus, Escherichia coli, Salmonella typhosa and Pseudomonas aeruginosa than the other two Pinus species, and essential oils of the three Pinus species showed strong antimicrobial activity against Salmonella enteritidis and P. aeruginosa. The essential oils from the three Pinus species also showed higher antimicrobial activity against Gram-negative bacteria than Gram-positive bacteria. Saccharomyces cerevisiae (yeast) was not inhibited by any essential oil.