Essential oils sensory quality and their bioactivity against the mosquito Aedes albopictus

Abstract

Repellents are a main tool to prevent the outbreak of mosquito-borne diseases that represents a threat for millions of people worldwide. Plant-based products are very promising, low-toxic and eco-friendly alternative to synthetic repellents. Here, we performed an olfactory screening of the essential oils (EOs) of Artemisia verlotiorum Lamotte (Asteraceae), Lavandula dentata L. (Lamiaceae), and Ruta chalepensis L. (Rutaceae) for their possible use as ingredients in topical repellents. The EOs smell profiles were then matched with their repellence against the mosquito Aedes albopictus (Skuse) (Diptera Culicidae). To obtain a more complete bioactivity description, we also tested the EOs oviposition deterrence and the larvicidal activity. The best smell profile was associated with A. verlotiorum EO, while R. chalepensis EO showed the lowest overall pleasantness. All the EOs had a significant activity as skin repellent against Ae. albopictus, deterred the oviposition in the field, and exerted a clear larvicidal activity. Beside the best smell profile, A. verlotiorum EO showed also the longest lasting repellent effect, assuring the complete protection of the treated skin against Ae. albopictus for a time 60% longer than the synthetic repellent DEET.

Allium sativum, Rosmarinus officinalis, and Salvia officinalis Essential Oils: A Spiced Shield against Blowflies

“…This usually occurs when the doors are open to allow the unloading of the fresh meat and the loading of the hams. Even if EOs have been extensively studied as topical repellent against insects of medical or veterinary importance [20,[45][46][47], and proposed as repellents in food packaging [48][49][50][51] and stored foodstuff [18,44,52], to the best of our knowledge, this is the first report on the use of an EO-charged mist as an olfactory barrier to protect an indoor working space from the entrance of problematic flies. In line with our results, however, a good efficacy of the EOs as aerosol spray have been reported by Revay et al [53] who observed that a timed-released 0.3% aqueous geraniol emulsion significantly reduced mosquito-biting pressure of Culex pipiens L. and Aedes albopictus Skuse (Diptera: Culicidae) in outdoor conditions.…”

“…The larvae were fed with beef liver and maintained at room temperature until pupation. The pupae were held in cages until the emergence of the adults, which were provided with a sugar-yeast diet (sugar and yeast 1:1) to provide the proteins amount necessary to stimulate oviposition [19,20] and water ad libitum. Species identification of the emerged adults was confirmed by an expert dipterologist (Alfio Raspi, former Professor, Department of Agriculture, Food and Environment, University of Pisa).…”

Salvia Spp. Essential Oils against the Arboviruses Vector Aedes albopictus (Diptera: Culicidae): Bioactivity, Composition, and Sensorial Profile—Stage 1

“…This is why the determination of the protection time is an important parameter for the screening of EOs for possible practical use. In this experiment, S. dorisiana EO showed a very good persistency (CPT = 43 min at the dose of 20 nL cm −2 of skin) of the repellent effect that was longer than the one reported for the synthetic repellent N,N-Diethyl-meta-toluamide (DEET) (CPT = 10 min at the dose of 40 nL cm −2 of skin) [11]. Overall, S. dorisiana showed the highest toxicity against Ae.…”

“…We considered the test valid if at least 30 mosquitoes landed on the control hand and attempted to bite. If the number of probing was < 30, a new mosquito's cage was used [11]. The study was approved by the ethical committee of the University of Pisa (Comitato Bioetico dell'Università di Pisa).…”

“…However, despite their insecticidal and repellent properties, EOs still do not have the expected broad use. In fact, besides the composition variability and the high volatility, their strong smell prevents their widespread application [11,12]. For these reasons, the acceptance of EOs to the human sensorial system is an important feature for their success as an ingredient in commercial products for topical use or for environmental protection.…”