Activity of Syzygium aromaticum essential oil and its main constituent eugenol in the inhibition of the development of Ctenocephalides felis felis and the control of adults

•The major constituent of Syzygium aromaticum essential oil is eugenol.•Syzygium aromaticum essential oil and eugenol are effective for control of C. felis.•Positive results point to the development of natural insecticides for flea control. The aim of this study was to evaluate the in vitro activity of Syzygium aromaticum essential oil (SAEO) and its main constituent eugenol (EG) against adult fleas and their action in the maturation of eggs into adults of Ctenocephalides felis felis. In order to evaluate the pulicidal activity, 10 adult fleas were exposed to a filter paper impregnated with SAEO and EG at increasing concentrations of 0.047; 0.094; 0.188; 0.375; 0.750; 1.50; 3.00; 6.00; 12.00 and 24.00 μg cm−2. Flea mortality was evaluated 24 and 48 h after exposure. In order to evaluate the inhibition of the maturation of eggs into adults, 10 eggs were exposed to filter paper impregnated with SAEO and EG at the same concentrations used in the pulicidal test, and the evaluation was performed 30 days after incubation. Untreated repetitions were maintained in both studies (control group). The lethal concentration 50 (LC50) of pulicidal activity to SAEO was 5.70 μg cm−2 in 24 h and 3.91 μg cm−2 in 48 h. The LC90 was 16.10 μg cm−2 and 15.80 μg cm−2 in 24 and 48 h, respectively. The LC50 of inhibition of the maturation of eggs into adults was 0.30 μg cm−2 and the LC90 3.44 μg cm−2. The LC50 of pulicidal activity to EG was 2.40 μg cm−2 in 24 h and 1.40 μg cm−2 in 48 h; the LC90 was 8.10 μg cm−2 and 3.70 μg cm−2 in 24 h and 48 h, respectively. The LC50 of inhibition of the maturation of eggs into adults was 0.10 μg cm−2 and the LC90 0.68 μg cm−2. Based on the results obtained, it is possible to conclude that the both SAEO and EG have in vitro pulicidal activity as well as acting as inhibitors of the maturation of eggs into adults of the flea C. felis felis.