**Insecticidal and Biting Deterrent Activities of** *Magnolia grandiflora* **Essential Oils and Selected Pure Compounds against** *Aedes aegypti*

**Abbas Ali 1,\*, Nurhayat Tabanca 1,2, Betul Demirci 3, Vijayasankar Raman 1, Jane M. Budel 4, K. Hüsnü Can Baser <sup>5</sup> and Ikhlas A. Khan <sup>1</sup>**


Academic Editor: Maria Carla Marcotullio Received: 26 February 2020; Accepted: 14 March 2020; Published: 17 March 2020

**Abstract:** In our natural products screening program for mosquitoes, we tested essential oils extracted from different plant parts of *Magnolia grandiflora* L. for their insecticidal and biting deterrent activities against *Aedes aegypti*. Biting deterrence of seeds essential oil with biting deterrence index value of 0.89 was similar to *N*,*N*-diethyl-3-methylbenzamide (DEET). All the other oils were active above the solvent control but the activity was significantly lower than DEET. Based on GC-MS analysis, three pure compounds that were only present in the essential oil of seed were further investigated to identify the compounds responsible for biting deterrent activity. 1-Decanol with PNB value of 0.8 was similar to DEET (PNB = 0.8), whereas 1-octanol with PNB value of 0.64 showed biting deterrence lower than 1-decanol and DEET. The activity of 1-heptanol with PNB value of 0.36 was similar to the negative control. Since 1-decanol, which was 3.3% of the seed essential oil, showed biting deterrence similar to DEET as a pure compound, this compound might be responsible for the activity of this oil. In in vitro A & K bioassay, 1-decanol with MED value of 6.25 showed higher repellency than DEET (MED = 12.5). Essential oils of immature and mature fruit showed high toxicity whereas leaf, flower, and seeds essential oils gave only 20%, 0%, and 50% mortality, respectively, at the highest dose of 125 ppm. 1-Decanol with LC50 of 4.8 ppm was the most toxic compound.

**Keywords:** Magnoliaceae; GC-FID; GC-MS; mosquito control; 1-decanol; 1-octanol; larvicidal activity; deterrent; biopesticides
