Biting deterrent activity of essential oils of Magnolia grandiflora against Aedes aegypti

In the search for mosquito biting deterrent compounds from natural sources, we investigated essential oils from different plant parts of Magnolia grandiflora L. (Magnoliaceae). We separately obtained essential oils from air dried samples of seeds, deseeded unripe and mature fruits and leaves of M. grandiflora by water distillation. Chemical composition of the oils was analyzed by GC-FID and GC-MS analyses. The following are the major constituents found in different plant parts: Seeds with aril: 8.8% β-caryophyllene, 7.3% β-phellandrene, 6.2% octanol, 5.5% p-cymene and 3.3% 1-decanol; deseeded unripe fruit: 12.9% β-elemene, 12.7% β-pinene, 7.9% β-caryophyllene and 5.1% α-terpineol; deseeded mature fruit: 12.2% 1,8 cineole, 7.2% caryophyllene oxide, 6.9% β-pinene and 5.7% β-elemene; leaves: 23.0% β-pinene, 13.6% β-elemene and 6.3% α-pinene. Biting deterrent activity of the essential oil of seed (10µg/cm²) was equivalent to DEET (25nmol/cm²) with proportion not biting value of 0.83 versus 0.87, respectively and 1-Decanol showed biting deterrence equivalent to DEET at 25nmol/cm².