Chemical Composition of Essential Oils from SixZanthoxylumSpecies and Their Repellent Activities against Two Stored-Product Insects
The objective of this study was to analyze six essential oils fromZanthoxylumgenus (family Rutaceae) in China and evaluate their repellent activities againstTribolium castaneumandLasioderma serricorneadults. Six essential oils fromZanthoxylumgenus, includingZ. armatum,Z. dimorphophyllum,Z. dimorphophyllumvar.spinifolium,Z. piasezkii,Z. stenophyllum,andZ. dissitum,were obtained by hydrodistillation and their yields were ranging from 0.02% to 0.53%. Totally, there were 39 chemical components revealed by GC-MS. Among them, some components with high relative content existed in more than threeZanthoxylumspecies. For instance, bothδ-cadinene (1.21%–17.15%) and spathulenol (0.36%–10.19%) appeared in essential oils ofZ. dimorphophyllum,Z. piasezkii,Z. stenophyllum,andZ. dissitumwhich were found to have higher content of sesquiterpenoids. The repellent activities of six essential oil samples againstT. castaneumandL. serricorneadults were investigated for the first time. Data demonstrated that sixZanthoxylumspecies had much stronger repellent activities againstT. castaneumthanL. serricorneadults, especially in 2 hours after exposure. The results indicate that these six essential oils fromZanthoxylumhave significant potential to be developed into natural repellents to control insects in grains, food, and traditional Chinese medicinal materials.