Essential oil from Mentha rotundifolia harvested in Northeast Algeria: Chemical Composition, Larvicidal and Enzymatic Activities on Culex pipiens larvae

Abstract

Background: Plant extracts constitute an alternative to conventional insecticides. Culex pipiens is the most abundant mosquito species in Algeria. This research aimed to investigate the eficacy of essential oils from Mentha rotundifolia against the fourth instar larvae of Cx pipeins. Materials and Methods: The aerial parts of the plant were harvested in the Annaba region (Northeast of Algeria) between March and June 2017, the essential oils EOs) were extracted by a Clevenger hydrodistiller andanalyzed by gas chromatography-mass spectrometry (GC-MS). The larvicidal activities of EOs were tested against fourth instar larvae of Culex pipiens following the procedure of the World Health Organization under laboratory conditions. Furthermore, the effect of EO was examined on the activity of glutathione S-transferase (GST) and acetylcholinesterase (AChE), biomarkers of oxidative stress and neurotoxicity, respectively. Results: GC-MS analyses revealed sixteen compounds in M. rotundifolia EO and the main components are: Carvacrol (60.54%), Pulegone (5.95%) and M-cymene (5.25%). The larvicidal assay showed that the EO exhibited insecticidal activity against the fourth instar larvae of C. pipiens (LC₅₀= 62.08 ppm and LC₉₀= 178.64 ppm at 72 hour exposure). When applied at it’s LC₅₀ and LC₉₀EOwas found to present a neurotoxic activity and a stimulation of the detoxification system, as evidenced by an inhibition of AChE and an induction of GST, respectively. Conclusion: rotundifolia EO presents an efficacy against Cx pipiens larvae and could be considered as a potential alternative to conventional insecticides for mosquito control.