Citrus aurantium L. and Citrus latifolia extracts as alternative control agents for Aedes aegypti (Diptera: Culicidae)

BACKGROUND: Aedes aegypti is a vector of arboviral diseases. Their control has traditionally relied on the use of chemical insecticides; however, this strategy has failed. As an alternative, the use of natural products with a high content of biologically active compounds has been evaluated for the control of this mosquito. It is well known that citrus fruits contain compounds with insecticidal activity. For this reason, and considering the high production of Citrus aurantium L. and Citrus latifolia Tanaka ex Q. Jiménez in Colombia, the aim of this research was to establish the susceptibility of Ae. aegypti to extracts from the exocarp of these two citrus species as an environmentally sustainable approach to vector control. METHODS: Following WHO methodology, the adulticidal activity of exocarp extracts of Citrus aurantium L. and Citrus latifolia Tanaka ex Q. Jiménez strain Moniquirá, obtained with ethanol, n-hexane, or chloroform by reflux for 4–6 h, was evaluated. The chemical composition of the extracts was established using GC-MS. RESULTS: 100% mortality was achieved with the ethanolic extract of C. aurantium and the chloroform extract of C. latifolia obtained during 6 h of extraction, with concentrations of 90 and 120 mg/mL at 12 and 6 h p.e. respectively. Highly significant differences (p < 0.001) were determined in concentration, type of solvent, and extraction time regarding Ae. aegypti mortality for the two species. For the 6 h ethanol extract of C. aurantium, the LC50 was 32.2 mg/mL after 12 h p.e, while for the 6 h chloroform extract of C. latifolia, the LC50 was 9 mg/mL after 6 h p.e. The composition of the chloroform extracts is similar, but the concentration of most compounds increased in the 6 h extract. Sabinene, β-Pinene, R-limonene and γ-terpinene were the major components. CONCLUSIONS: The chemical composition of the extracts showed variable concentrations depending on the extraction time. Indeed, the chloroform extracts of C. latifolia exocarps obtained by reflux at 6 h showed the better potential as control agents for Aedes aegypti. These results form the basis for the future development of a natural product that can be used by residents of endemic areas to Ae. aegypti.