Chemical composition and insecticidal property of Myrsine stolonifera (Koidz.) walker (Family: Myrsinaceae) on Musca domestica (Diptera: Muscidae)

Musca domestica is one of the most important pests of human health, and has developed strong resistance to many chemicals used for its control. One important approach for creating new pesticides is the exploration of novel compounds from plants. During a wide screening of plants with insecticidal properties that grow in southern China, we found that the methanolic extracts of Myrsine stolonifera had insecticidal activity against the adults of M. domestica. However, the insecticidal constituents and mechanisms of the M. stolonifera extracts remain unclear. The insecticidal components of the methanolic extracts of M. stolonifera were isolated with activity-guided fractionation. From the spectra of nuclear magnetic resonance (NMR) and mass spectrometry (MS), the compounds were identified as syringing (1), 2,6-dimethoxy-4-hydroxyphenol-1-O-β-d-glu (2), kaempferol-3-O-glu-rha-glu (3), and quercetin-3-O-glu-rha-glu (4). This study is the first to report the spectral data for compounds 3 and 4, and their LC50 values were 0.52 mg/g sugar and 0.36 mg/g sugar 24 h after treatment of the adults of M. domestica, respectively. Compounds 3 and 4 (LC25) also inhibited the activities of the enzymes carboxylesterase, glutathione S-transferase, mixed function oxidase, and acetylcholine esterase of adult M. domestica, particularly mixed function oxidase and acetylcholine esterase. The cytotoxic effects of compounds 3 and 4 on cell proliferation, mitochondrial membrane potentials (MMP) and reactive oxygen species (ROS) were demonstrated on SL-1 cells. From the extracts of M. stolonifera, quercetin-3-O-glu-rha-glu and kaempferol-3-O-glu-rha-glu have displayed comparable toxicities to rotenone on M. domestica and also exhibited cytotoxic effects on SL-1 cells; therefore, the extracts of M. stolonifera and their compounds have potential as botanical insecticides to control M. domestica.