Chemical Composition, Larvicidal Action, and Adult Repellency of Thymus magnus Against Aedes albopictus

Abstract

Thymus magnus, an endemic species, is found in the Republic of Korea. The volatile compounds extracted by SPME from T. magnus were investigated for their chemical composition and electrophysiological response against the Asian tiger mosquito, Aedes albopictus. The volatile compounds of T. magnus as determined by gas chromatography mass spectrometry were gamma-terpinene (33.0%), thymol (29.9%), beta-bisabolene (8.9%), p-cymene (8.3%), alpha-terpinene (5.0%), myrcene (4.7%), beta-caryophyllene (4.0%), alpha-thujene (2.7%), camphene (1.3%), carvacrol (1.2%), and alpha-pinene (1.1%). Among these candidates, thymol exhibited complete (100%) repellent activity against female Ae. albopictus, an effect that was confirmed through evaluating the electrophysiological response on the antenna of Ae. albopictus. The effectiveness of a binary 1:2 mixture of thymol and vanillin (0.05:0.1 microl per cm2) was found to be significantly more effective than thymol alone for a period of 120 min. In addition, thymol, alpha-terpinene, and carvacrol showed high larvicidal activity against on the third-stage larvae with LC50 values of 0.9 microl per 100 ml.

Comparative Investigation of Umbellularia californica and Laurus nobilis Leaf Essential Oils and Identification of Constituents Active against Aedes aegypti

“…Thymol, as well as the majority of active compounds here reported, is occurring widely in several essential oils, especially Thymus, Monarda, and Origanum species, and it is well-known to contribute to the mosquito repellent and larvicidal activity of these oils. 7,35,36 On the other hand, the monoterpene umbellulone (which is the major constituent of U. californica essential oil) is less abundant in nature, and its biological activity as mosquito repellent and larvicidal activity are here reported for the first time. Umbellulone was found to act as a reversible Michael acceptor targeting the human and rat isoform of the nociceptive receptor TRPA1, 18,24 as well as other TRP receptors involved in chemosensation.…”

Comparative study of the oil repellent activity of Copaifera officinalis Linnaeus and Copaifera reticulata Ducke front nymphs of Periplaneta americana Linnaeus

“…In a study carried out with Thymus magnus oil, β-bisabolene showed 39.8% repellency against Aedes albopictus females, whereas β-caryophyllene showed 18% repellency, being the second-and third-most repellent compounds of the oil, respectively. (Park, Koo, Kim, 2012).…”

Behavioral and Electrophysiological Effects of Ajowan (Trachyspermum ammi Sprague) (Apiales: Apiaceae) Essential Oil and Its Constituents on Nymphal and Adult Bean Bugs, Riptortus clavatus (Thunberg) (Hemiptera: Alydidae)

“…Kim et al [39] reported that thymol and carvacrol elicited strong repellent activity for Tribolium castaneum (Herbst), a common stored-products insect pest, at 0.03 and 0.006 mg/cm 2 . Park et al [40] found that thymol and carvacrol had the lowest repellent concentration (RC) values against female adult Asian tiger mosquitos (Aedes albopictus) of the compounds identified in Thymus magnus. Thymol and carvacrol repellency have also been reported for the castor bean tick, Ixodes ricinus, and the poultry red mite, Dermanyssus gallinae [41,42].…”