Eleutherococcus senticosus (Araliaceae) leaf morpho-anatomy, essential oil composition and its biological activity against Aedes aegypti (Diptera: Culicidae)

Authors: ZHAI, CHUNMEI - University Of Mississippi; WANG, MEI - University Of Mississippi; RAMAN, VIJAYASANKAR - University Of Mississippi; REHMAN, JUNAID - University Of Mississippi; MENG, YONGHAI - University Of Mississippi; ZHAO, JIANPING - University Of Mississippi; AVULA, BHARATHI - University Of Mississippi; WANG, YAN-HONG - University Of Mississippi; TIAN, ZHENKUN - University Of Mississippi; KHAN, IKHLAS - University Of Mississippi

Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/24/2016
Publication Date: 11/24/2016
Citation: Zhai, C., Wang, M., Raman, V., Rehman, J.U., Meng, Y., Zhao, J., Avula, B., Wang, Y., Tian, Z., Khan, I.A. 2016. Eleutherococcus senticosus (Araliaceae) leaf morpho-anatomy, essential oil composition and its biological activity against Aedes aegypti (Diptera: Culicidae). Journal of Medical Entomology. 54(3):658-669. doi:10.1093/jme/tjw221.

Interpretive Summary: Vector-borne diseases, especially that are associated with mosquitoes, have caused many deaths worldwide during the past few decades. As part of the mosquitoe management, several synthetic repellents and insecticides are commonly utilized for personal protection. Much effort has been focused recently on plant extracts, essential oils or phytochemicals as potential sources of mosquito-control agents. For the first time, the leaf essential oil of Eleutherococcus senticosus, a traditional Chinese medicinal plant, was studied for its repellent/biting deterrent activity against mosquito Ae. aegypti and the resulted manuscript is submitted here for publication in your esteemed journal. The chemical compositions of volatile compounds that contribute to the characteristics of the oil were determined by GC/MS. Additionally, the manuscript provides morpho-anatomical descriptions of the leaf for correct identification of the species.

Technical Abstract: The roots of Eleutherococcus senticosus, a well-known medicinal plant from Eastern Asia, are used worldwide for their known beneficial medicinal properties. Recently the leaves have been used as an alternative to the roots. The present study was aimed at exploring the leaf essential oil as a potential source of compounds for mosquito management. GC/MS analysis of the leaf essential oil revealed 87 compounds, constituting 95.2% of the oil. a-Bisabolol (26.46%), ß-caryophyllene (7.45%), germacrene D (6.87%), ß-bisabolene (4.95%) and a-humulene (3.50%) were five of the major constituents. The essential oil was subjected to biting deterrence and repellent activity against mosquito Aedes aegypti. The biting deterrence of the oil produced a proportion not biting (PNB) value of 0.62 at 10 µg/cm2 as compared to 0.86 of control DEET (N,N-diethyl-3-methylbenzamide) at a standard dose of 25 nmol/cm2. Among individual selected compounds present in the oil (a-bisabolol, ß-caryophyllene, a-humulene and caryophyllene oxide), only a-bisabolol produced a PNB value of 0.80, equivalent to DEET at 25 nmol/cm2 while the others were not repellent. The artificial mixture (AMES-1) of these four selected compounds produced a relatively high PNB value of 0.80. The repellent activity measured by minimum effective dosage (MED) for a-bisabolol and a-humulene produced MED values of 0.094 and 0.104 mg/cm2, respectively, as compared to 0.023 mg/cm2 of DEET. The leaf essential oil, the artificial mixture and other binary and tertiary combinations of major compounds showed no repellent activity. Additionally, morpho-anatomical features of the leaf are provided for correct identification of the species.