Larvicidal activity of Kaempferia galanga rhizome phenylpropanoids towards three mosquito species.
BACKGROUND
This study was aimed at assessing the toxicity of ethyl cinnamate and ethyl p-methoxycinnamate (EMC) identified in Kaempferia galangal L. (Zingiberaceae) rhizome and another 12 known compounds to third-instar larvae from laboratory-reared Culex pipiens pallens Forskal, Aedes aegypti L. and Ochlerotatus togoi Theobald and field-collected C. pipiens pallens (Jinhae colony). Results were compared with those for fenthion and temephos.


RESULTS
Ethyl p-methoxycinnamate was the most toxic of the test compounds to larvae of the three mosquito species (LC(50) 12.3-20.7 mg L(-1)) but less toxic than either fenthion (0.0096-0.021 mg L(-1)) or temephos (0.0039-0.0079 mg L(-1)). Ethyl cinnamate and 3-carene were highly active against C. pipiens pallens larvae (24.1 and 21.6 mg L(-1)) but less toxic to A. aegypti and O. togoi larvae (ca 40 and 60 mg L(-1) respectively). The toxicity of these compounds to larvae from the Jinhae colony of C. pipiens pallens was almost the same as their toxicity to the laboratory-reared larvae, although the larvae from the colony exhibited low levels of resistance to fenthion (resistance ratio 9.1) and temephos (5.8).


CONCLUSIONS
Kaempferia galanga rhizome-derived materials, particularly ethyl p-methoxycinnamate, merit further study as potential mosquito control agents for protection of humans and domestic animals from vector-borne diseases and nuisance caused by mosquitoes.
Kim
Nam-Jin
NJ
School of Agricultural Biotechnology, Seoul National University, Seoul 151-921, Republic of Korea.
Byun
Sang-Gi
SG
Cho
Jang-Eun
JE
Chung
Keun
K
Ahn
Young-Joon
YJ
D000330:Aedes / Q000187:drug effects; D000818:Animals; D002934:Cinnamates / Q000494:pharmacology*; D003465:Culex / Q000187:drug effects; D009033:Culicidae / Q000187:drug effects*; D007306:Insecticides / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects; D009032:Mosquito Control; D044969:Ochlerotatus / Q000187:drug effects; D027343:Rhizome / Q000737:chemistry; D030521:Zingiberaceae / Q000737:chemistry
D002934:Cinnamates; D007306:Insecticides; C531364:ethyl 4-methoxycinnamate; C451418:ethyl cinnamate