Repellent Effect of Borneols and Bornanediols against Aedes Albopictus: in Search of New Natural Repellents - Abstract
Aedes mosquitoes are the main vectors of several arboviruses. The use of repellents is one of the most effective strategies to prevent mosquito bites
and limit host-vector interactions. This work describes the synthesis of borneols and isoborneols from camphor as well as 2-exo-3-exo-bornanediols via the
camphorquinone and the evaluation of their repellents properties. The repellent activity of the synthesized products was evaluated using a tunnel olfactometer.
2R-(?)-isoborneol (1a), 2S-(+)-isoborneol (1b), (+)-1R-2-exo-3-exo-bornanediol (3a) and (+)-1S-2-exo-3-exo-bornanediol (3b) demonstrated repellent
activity against Aedes albopictus at different doses ranging from 1 to 40 mg. In addition, 2S-(+)-borneol (2a) and 2R-(+)-borneol (2b) exhibited repellency
at doses of 0.25 to 10 mg. Human volunteer tests indicated that (+)-1R-2-exo-3-exo-bornanediol (3a) and (+)-1S-2-exo-3-exo-bornanediol (3b) provided
an average of 50% protection against Aedes albopictus during the 60-minute test. The repellent effect of 2S-(+)-isoborneol (1b) was not satisfactory, and no
synergistic effect was observed with the mixture of the two bornanediols (3a and 3b). We conclude that terpene diols act as the pharmacophore responsible
for the repellent activity.