Volatile compounds and antimicrobial and antioxidant activities of the essential oils of the needles of Pinus densiflora and Pinus thunbergii.

Background: To investigate the volatile compounds and the antibacterial and antioxidant effects of the essential oils of Pinus densiflora needles (EPDN) and Pinus thunbergii needles (EPTN), the volatile compounds of steam-distilled essential oils were analysed by gas chromatography-mass spectrometry. Antibacterial activities were analysed by performing disc-agar diffusion assay and determining the minimum inhibitory concentrations (MICs) of the essential oils. Antioxidant activities were analysed via radical- and nitrite-scavenging activity assays.

Results: The yields of EPDN and EPTN were 0.304% (v/w) and 0.296% (v/w), respectively. In the antibacterial activity assay, the MICs of EPDN and EPTN for Klebsiella pneumoniae, Shigella flexneri and Proteus vulgaris were < 0.4 mg mL(-1) . In the antioxidant activity assay, the 50% inhibitory concentrations (IC(50) ) of EPDN and EPTN were 120 and 30 µg mL(-1) , respectively. At 1680 µg mL(-1) , both EPDN and EPTN exhibited > 50% nitrite-scavenging activity.

Conclusion: EPDN can be used as a natural antimicrobial substance.