Insecticidal activities of leaf and twig essential oils from Clausena excavata against Aedes aegypti and Aedes albopictus larvae.
BACKGROUND
The current study investigates, for the first time, the mosquito larvicidal activities of leaf and twig essential oils from Clausena excavata Burm. f. and their individual constituents against Aedes aegypti L. and Aedes albopictus Skuse larvae. The yields of essential oils obtained from hydrodistillation were compared, and their constituents were determined by GC-MS analyses.


RESULTS
The LC(50) values of leaf and twig essential oils against fourth-instar larvae of Ae. aegypti and Ae. albopictus were 37.1-40.1 microg mL(-1) and 41.1-41.2 microg mL(-1) respectively. This study demonstrated that C. excavata leaf and twig essential oils possess mosquito larvicidal activity, inhibiting the growth of mosquito larvae for both species at a low concentration. In addition, results of larvicidal assays showed that the effective constituents in leaf and twig essential oils were limonene, gamma-terpinene, terpinolene, beta-myrcene, 3-carene and p-cymene. The LC(50) values of these constituents against both mosquito larvae were below 50 microg mL(-1). Among these effective constituents, limonene had the best mosquito larvicidal activity, with LC(50) of 19.4 microg mL(-1) and 15.0 microg mL(-1) against Ae. aegypti and Ae. albopictus larvae respectively.


CONCLUSIONS
The findings suggested that the essential oils from Clausena excavata leaf and twig and their effective constituents may be explored as a potential natural larvicide.
Cheng
Sen-Sung
SS
Experimental Forest, National Taiwan University, Nan-Tou 55750, Taiwan.
Chang
Hui-Ting
HT
Lin
Chun-Ya
CY
Chen
Pin-Sheng
PS
Huang
Chin-Gi
CG
Chen
Wei-June
WJ
Chang
Shang-Tzen
ST
D000330:Aedes / Q000187:drug effects*; D000818:Animals; D054700:Clausena / Q000737:chemistry*; D053138:Cyclohexenes / Q000737:chemistry / Q000494:pharmacology; D007306:Insecticides / Q000737:chemistry / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects; D000077222:Limonene; D009822:Oils, Volatile / Q000737:chemistry / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry*; D010938:Plant Oils / Q000737:chemistry / Q000494:pharmacology; D018520:Plant Shoots / Q000737:chemistry*; D013729:Terpenes / Q000737:chemistry / Q000494:pharmacology
D053138:Cyclohexenes; D007306:Insecticides; D009822:Oils, Volatile; D010938:Plant Oils; D013729:Terpenes; D000077222:Limonene