ABSTRACT
Objective: The mosquito Aedes aegypti is the primary vector for spreading the dengue virus, which causes Dengue Hemorrhagic Fever (DHF). Marigold (Tagetes erecta L.) is a plant with potential as a biopesticide. This study aims to determine marigold's larvicidal and repellent activities and identify the chemical groups responsible.
Methods: Extraction was performed using the maceration method with 96% ethanol. Fractionation was carried out using the Liquid-Liquid Extraction (LLE) method with three solvents: n-hexane, ethyl acetate, and water. Fraction separation utilized Vacuum Liquid Chromatography (VLC), followed by classical column chromatography, and compound groups were identified through Thin Layer Chromatography (TLC) monitoring. Larvicidal tests were conducted using samples of the Mariold Flowers Extract (MFE), n-Hexane Fraction (nHF), Ethyl Acetate Fraction (EAF), and Water Fraction (W. F.). Repellent testing was conducted using samples of the MFE and nHF at 1% and 2% concentrations.
Results: Phytochemical screening identified flavonoids, polyphenols, steroids/triterpenoids, monoterpenoids, and sesquiterpenoids in MFE. The nHF showed the highest larvicidal efficacy against A. egypti larvae, with an LC50 value of 18.80 µg/ml. The nHF exhibited the highest repellent activity, achieving 88.07% repellency at 2% concentration after 3 h. Terpenoids, detected through TLC with an Rf value of 0.58, were further analyzed using Gas chromatography–mass spectrometry (GC-MS), revealing o-cymene, a monoterpene derivative with potential larvicidal and
repellent properties.
Conclusion: Marigold flowers have the potential for development as a natural larvicide against A. aegypti larvae and as a mosquito repellent.
Keywords: Tagetes erecta L., Repellent, Larvicide, n-hexane fraction, Monoterpene