Larvicidal and oviposition deterrent activity of sesquiterpenes from Laurencia johnstonii seaweed against Aedes aegypti

Abstract

Abstract Aedes aegypti is the main vector of dengue, chikungunya and Zika. Efforts to control insects have focused on the development of insecticides based on new active compounds. The red seaweed Laurencia is an important source of brominated compounds, in particular sesquiterpenes with antifungal, antimalarial, larvicidal and insect repellent activities. The objective of the study was to assess larvicidal and oviposition deterrent activity of Laurencia johnstonii against Aedes aegypti. Ethanolic extract and fractions of L. jhonstonii were evaluated against third instar Aedes aegypti larvae, New Orleans strain. All of the fractions showed larvicidal activity. The most active fraction F2A (LC50 = 240 µg mL− 1) was analyzed by GC/MS and six sesquiterpenes were identified. The major compound, laurinterol was isolated and identified by NMR analysis. Furthermore, acetylcholinesterase inhibition has been considered as a bioprospecting mechanism of action to identify larvicidal compounds. Due to the chemical diversity and biological activity identified on Laurencia genus, L. johnstonii represents a potential source of compounds with larvicidal activities.