Chemical compositions, yield variations and antimicrobial activities of essential oils from three species of Euodiae Fructus in China

Abstract

Euodiae Fructus from three species of the genus Euodia, i.e., Euodia rutaecarpa (Juss.) Benth. (ER), E. rutaecarpa (Juss.) Benth var. officinalis (Dode) Huang (ERO), and E. rutaecarpa (Juss.) Benth. var. bodinieri (Dode) Huang (ERB), has been used as a traditional herbal medicine in China for thousands of years. The aim of this study was to compare the differences of essential oils (EOs) from three species of Euodiae Fructus cultured in China. The chemical compositions, yield variations, and antimicrobial activities were compared. The EOs were obtained by hydrodistillation, and their yields varied from 0.18 to 2.60% in ER, from 0.64 to 3.36% in ERB, and from 0.52 to 2.96% in ERO without significant differences among them, but the oil yields showed a positive correlation with the use of 1000-grain weight plant material. Altogether, seventy-nine compounds, accounting for 75.86–99.11% of the total oils, were identified by gas chromatography/mass spectrometer (GC/MS) analysis from 24 samples. The main components were β-cis-ocimene (10.60–76.41%), β-myrcene (3.65–26.43%), limonene & β-phellandrene (0–31.5%), and β-trans-ocimene (1.68–16.02%). Furthermore, the 24 samples were separated into three chemotypes by hierarchical cluster analysis, of which ER samples were involved in all three groups, indicating great chemical variation within them. These intraspecies variabilities were greater than the interspecies differences in the chemical compositions and oil yields. Furthermore, the representative EOs exhibited moderate antibacterial and antifungal activities and showed the most potent activities against Bacillus subtilis and Staphylococcus aureus, with the largest inhibition zone diameters of 17.9 and 12.2 mm, respectively, and the lowest minimum inhibitory concentration (MIC) values of 3.2–6.4 mg/mL. β-cis-ocimene might be the active antibacterial ingredient.