Essential oil from the stems of Croton kongensis Gagnep.: chemical composition, antimicrobial and anti-inflammatory activities

The current study describes the chemical compositions, antimicrobial and anti-inflammatory activities of the essential oil (EO) from the stems of Croton kongensis Gagnep., collected from two wild-growing populations in Thanh Hoa province, Vietnam, namely Nhu Xuan and Thuong Xuan. According to gas chromatography/mass spectrometry (GC/MS) analyses, the major components in the Nhu Xuan EO sample were (E)-caryophyllene (10.62%), bornyl acetate (9.81%), (E)-nerolidol (9.15%), and linalool (8.10%). In contrast, linalool (15.05%), bornyl acetate (9.52%), (E)-caryophyllene (7.91%), bicyclogermacrene (7.36%), 1,8-cineole (6.53%), and (E)-nerolidol (6.00%) were the dominant components in the Thuong Xuan EO sample. The two EO samples were screened for antimicrobial activity against a panel of pathogenic bacteria and fungi using a broth microdilution assay and showed promising antimicrobial activities with minimum inhibitory concentration (MIC) <= 200 mu g/mL. Among them, the Nhu Xuan EO sample exhibited better activity against four bacteria and three fungi compared to the Thuong Xuan EO sample, which only showed activity against one bacterium and three fungi. Additionally, the anti-inflammatory study demonstrated that the EO samples from Nhu Xuan and Thuong Xuan inhibited nitric oxide production in lipopolysaccharide-stimulated RAW 264.7 macrophage cells, with IC50 values of 105.71 +/- 0.96 mu g/mL and 94.93 +/- 1.31 mu g/mL, respectively. In conclusion, this is the first report describing the antimicrobial and anti-inflammatory effects of the EO from C. kongensisstems. Our results suggest that the EO from C. kongensis stems in both regions could be potentially utilized as new natural antimicrobial and anti-inflammatory ingredients in the medicine and food industries