Blends of Furanosesquiterpenes from Smyrnium olusatrum: An Alternative Strategy for Mosquito Control

The recent outbreak of vector-borne diseases has highlighted the crucial importance of effective mosquito control programs. Nevertheless, mosquito management still represents a challenge due to the rapid onset of resistance to conventional insecticides. In this regard, there is an increasing research interest in botanicals as attracting valuable sources of insecticidal compounds. Smyrnium olusatrum L. (Apiaceae), an aromatic plant of great scientific relevance, owes its bioactivity to furanosesquiterpenes, whose major constituents include isofuranodiene (IFD), curzerene, 1-β-acetoxyfuranoeudesm-4(15)-ene, and atractylon. Since these compounds have demonstrated promising larvicidal activity against different mosquito species, in this study they were tested individually and in blends against Culex quinquefasciatus Say larvae, demonstrating the occurrence of synergistic interactions leading to enhanced larvicidal activity. In detail, the blend (1:1) consisting of curzerene and atractylon displayed the highest synergistic action (61.25% mortality), double with respect to that expected (33.75%). Moreover, the pure compounds were tested at their LC50 concentrations against the non-target species Daphnia magna Straus, Chaoborus flavicans Meigen, and Tubifex tubifex Müller, with mortalities from 7.5 to 33.7%. Overall, these findings demonstrate that synergistic furanosesquiterpene blends represent a promising botanical strategy for mosquito control, while minimizing the environmental impact associated with conventional insecticides.