Chemical Profiles and Bioactivities of the Essential Oils from Four Lauraceae Plants for Controlling Tribolium castaneum Herbst

Essential oils (EOs) from Lauraceae plants have been extensively investigated in the control of storedproduct insects. In this work, four Lauraceae species namely Lindera communis Hemsl., Phoebe neurantha (Hemsl.) Gamble, Litsea rotundifolia Hemsl. var. oblongifolia (Nees) Allen and Litsea variabilis Hemsl. var. oblonga Lec. were collected for extracting EOs by hydro-distillation and their chemical compositions were comparatively analyzed by GC/MS and GC/FID. Furthermore, contact toxicity and repellency of these EOs were evaluated against Tribolium castaneum Herbst, a universal model insect used in fundamental and applied research. Results indicated that EOs from Lin. communis, P. neurantha, Lit. rotundifolia and Lit. variabilis were mainly composed of sesquiterpenoids including (E)-beta-famesene, cis-alpha-bisabolene, alpha-selinene, eremophilene, beta selinene, etc. In bioassays, all the EOs at maximum testing concentration of 78.63 nL/cm(2) were significantly repellent to T. castaneum adults at 2 and 4 h post-exposure, which were comparable to the positive control DEET. Among them, EOs from P. neurantha, Lit. rotundifolia, Lin. communis P and Q also had contact toxicity with LD50 values of 14.52, 17.58, 23.82 and 86.63 mu g/adult respectively. It suggests that the four species of Lauraceae have promising potential to be developed into botanical repellents and contact toxicants against stored-product insects.