Chemical composition of the essential oil and -hexane extract of subsp. Boiss., an endemic species of Turkey, and their mosquitocidal activity against dengue vector .

subsp. Boiss. is endemic to Turkey and is a species of the genus L. which is one of the largest genera of the family Lamiaceae with about 300 species. The aims of this study were to examine the chemical composition of the essential oil and -hexane extract of subsp. as natural sources of insecticidal activity against the dengue vector, . Analysis of the essential oil by GC-FID and gas chromatography-mass spectrometry (GC-MS) systems identified hexahydrofarnesyl acetone (15%), viridiflorol (10%), hexadecanoic acid (7%) and 9-geranyl--cymene (6%) as major components. The volatile components of the -hexane extract were extracted using headspace solid-phase microextraction (HS-SPME) and were analyzed using GC-MS. The principal constituents were 3,4-dimethyl decane (16%), 3-methyl-3-pentanol (15%), 2-methyl-2-pentanol (12%), 1,4-bis (1,1-dimethylethyl) benzene (12%), heptanal (10%), acetic acid (6%) and decane (4%). Bioassay of the -hexane extract, at 5 µg/mosquito, produced 90% mortality against adult while the essential oil demonstrated 13% mortality. No larvicidal activity was observed both in essential oil and -hexane extract. Further studies are needed to assess the adulticidal activity of the responsible compounds in the crude extract.