Chemical Composition, Insecticidal Activity and Action Mode of Artemisia scoparia Methanolic Extracts on Aedes albopictus

Abstract

Objectives To identify new active compounds with mosquito larvicidal properties from natural products, the larvicidal activity of several traditional Chinese medicinal herbs extracts against Aedes albopictus (Diptera: Culicidae) was screened. Methods The ultrasonic-assisted extraction method was employed to process seven Chinese medicinal herbs. Subsequently, the extractums were fractionated using solvents with varying polarities and identify the extract phase exhibiting potent larvicidal activity. The active extract phase was further purified via silica gel column chromatography, followed by the identification of active components using gas chromatography-mass spectrometry (GC-MS). Additionally, the larvicidal activity of the identified components, as well as their inhibitory effects on acetylcholinesterase (AChE) and alkaline phosphatase (ALP), were evaluated. Results The Q1 fraction of the petroleum ether phase extract of Artemisia scoparia exhibited a 100% mortality rate against mosquito larvae at 100 ppm. GC-MS analysis results showed that capillene, methyl eugenol, capillin, and caryophyllene oxide are the most representative constituents. The following larvicidal activity results showed that caryophyllene oxide and methyl eugenol had potent larvicidal activity with 50% lethal concentration (LC 50 ) values of 67.6 ppm and 101.6 ppm, respectively. These two monomer compounds had potent inhibitory activity against ALP with inhibition rates of 47% and 37% respectively. Conclusion In this study, the Q1 fraction of A. scoparia PE extract demonstrated potent larvicidal activity against Aedes albopictus . Notably, methyl eugenol and caryophyllene oxide were found to exhibit significant larvicidal activity. Enzyme inhibition assays further revealed that these two compounds may induce larval mortality by inhibiting ALP activity. These findings suggest that A. scoparia extract, as well as its active constituents, holds promise as an effective larvicide for mosquito control.