Identification of Acarcidal Compounds in Inula japonica Extracts against Tetranychus cinnnabarinus

In this study, we aimed to identify acaricidal compounds in Inula japonica against Tetranychus cinnabarinus. Here, I. japonica petroleum-ether extracts were found toxic to T. cinnabarinus with a LC50 value of 1.18 mg/ml. Silica gel column chromatography was used to further separate acaricidal components from I. japonica petroleum-ether extracts. Contact toxicity data showed that 17 out of 38 fractions groups had mite mortality rates above 50%, 9 fraction groups above 60 %, and fractions groups G5, G7 and G15 even above 80 % at a concentration of 2 mg/ml. The major vital compounds in the bioactive fraction groups were identified by GC/MS, and four compounds, namely beta-Sitosterol (1), Stigmasterol (2), Lupeol (3), and alpha-Amyrin (4) were determined to have acaricidal activity to Tetranychus cinnabarinus.