Insecticidal and Biting Deterrent Activities ofEssential Oils and Selected Pure Compounds against.
Molecules. 2020 Mar 17 ;25(6). Epub 2020 Mar 17. PMID: 32192065
In our natural products screening program for mosquitoes, we tested essential oils extracted from different plant parts ofL. for their insecticidal and biting deterrent activities against. Biting deterrence of seeds essential oil with biting deterrence index value of 0.89 was similar to,-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 LCof 4.8 ppm was the most toxic compound.