Larvicidal activity, enzyme inhibitory effect, and molecular docking by essential oil, hydrolate, aqueous extract, and major compounds from the leaves of Eugenia uniflora against Aedes aegypti

Eugenia uniflora is a plant native to Brazil that has a wide geographical distribution and produces a high content of essential oils. The aim of the present study was to investigate the larvicidal activity of the hydrolate (Eu-HYD), aqueous extract (Eu-AE), essential oil (Eu-EO), and major compounds obtained from E. uniflora leaves against Aedes aegypti as well as assess the effects on the digestive enzymes of the larvae. Eu-HYD and Eu-AE were obtained from the leaves as byproducts of the EO isolation by hydrodistillation. Selina-1,3,7(11)-trien-8-one (1, 57.55 %) and oxidoselina-1,3,7(11)-trien-8-one (2, 21.18 %) were the major chemical compounds in the EO, as determined by gas chromatography with flame ionization detection and gas chromatography coupled to mass spectrometry. Eu-EO exhibited the most promising larvicidal activity LC50 = 35.9 +/- 1.02 mg/L), followed by Eu-AE (LC50 = 12.205 +/- 1.04 mg/L) and Eu-HYD (LC50 = 42.4 +/- 1.02 mg/L), whereas compounds 1 and 2 had an LC50 of 77.8 +/- 1.06 and 41.2 +/- 1.06 mg/L, respectively. Moreover, Eu-EO, Eu-AE, and Eu-HYD inhibited alpha-amylase activity in the Ae. aegypti larvae. Docking studies on the altered enzymes indicated that the affinity of compound 2 for Ae. aegypti alpha-amylase is slightly higher than that of compound 1. These results suggest notable larvicidal activity for all products of Eugenia uniflora leaves, making such products bioactive candidates for interrupting the reproduction cycle of Ae. aegypti, which is the main vector of arboviruses.