Toxicity of the essential oil from Tetradenia riparia (Hochstetter.) Codd (Lamiaceae) and its principal constituent against malaria and dengue vectors and non-target animals

• Published in: Pesticide biochemistry and physiology Vol. 188; p. 105265
• Main Authors: de Oliveira, André C., Simões, Rejane C., Tavares, Cláudia P.S., Lima, Carlos A.P., Costa Sá, Ingrity S., da Silva, Felipe M.A., Figueira, Elder A.G., Nunomura, Sergio M., Nunomura, Rita C.S., Roque, Rosemary A.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-11-2022
• Subjects: Aedes; Amazonia; Anopheles; Elephant mosquito; Gambusie; Mosquitofish; Amazonia; Anopheles; Gambusie; Aedes; Mosquitofish; Elephant mosquito
• ISSN: 0048-3575; 1095-9939
• DOI: 10.1016/j.pestbp.2022.105265

Malaria and dengue are diseases transmitted by mosquitoes of the genera Anopheles and Aedes resistant to commercial insecticides, which are toxic to non-target animals. Alternatively, eco-friendly strategies have focused on searching for essential oil (EO) from plants to control these mosquitoes. In this aspect, this study was carried out to investigate the toxicity of the EO from Tetradenia riparia and its main constituent against Anopheles and Aedes larvae and non-target animals Toxorhynchites haemorrhoidalis and Gambusia affinis. The mechanism of the larvicidal action of the EO and its main compound was investigated by the acetylcholinesterase (AChE) inhibition. The EO from T. riparia was extracted by hydrodistillation with yield of 1.4 ± 0.17%. The analysis of the EO by GC–MS and GC-FID revealed fenchone (38.62%) as the main compound. The EO (100 ppm) showed larvicidal activity against Anopheles and Aedes larvae (91 to 100% of mortality) (LC50 from 29.31 to 40.76 ppm). On the other hand, fenchone (10 ppm) showed more activity (89 to 100% of mortality) (LC50 from 5.93 to 7.00 ppm) than the EO. The EO and fenchone caused the inhibition of AChE (IC50 from 1.93 to 2.65 ppm), suggesting the inhibition of this enzyme as a possible mechanism of larvicidal action. Regarding toxicity, the EO (1000 ppm) and fenchone (100 ppm) showed low toxicity against T. haemorrhoidalis and G. affinis (9 to 74% of mortality) (LC50 from 170.50 to 924.89 ppm) (SI/PSF from 17.99 to 31.91) than the α-cypermethrin (0.52 ppm) which was extremally toxic against these non-target animals (100% of mortality, LC50 from 0.22 to 0.29 ppm). This significant larvicidal activity of the T. riparia EO and its main constituent, along with the low toxicity towards non-target organisms indicate these samples as a possible eco-friendly alternative for the control of malaria and dengue vectors.
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•The EO from T. riparia and fenchone were evaluated for its larvicidal activity.•The EO and fenchone showed larvicidal activity with LC50 from 5.93 to 29.31 ppm.•The EO and fenchone showed lower toxicity against T. haemorrhoidalis and G. affinis.•The AChE inhibition was proposed as mechanism of larvicidal action for EO and fenchone.