Larvicidal, adulticidal and repellent effects of Kaempferia galanga.
Four fractions of Kaempferia galanga (hexane fraction, dichloromethane fraction 1, dichloromethane fraction 2 and methanolic fraction) were tested for larvicidal activity toward fourth instar Culex quinquefasciatus. The hexane fraction was found to exhibit the highest larvicidal effect with the LC50 of 42.33 ppm. Testing for adulticidal activity, the hexane fraction did not show any promising adulticidal effect. However, it caused a knockdown effect which might be useful as a repellent. It was then tested for repellent activity in human volunteers both in laboratory and field studies. In a laboratory study, the hexane fraction possessed repellency against Aedes aegypti (ED50 value of 30.73 microg/cm2), and provided biting protection for 3 hours. In a field study, it could protect against certain mosquitos, ie, Armigeres subalbatus, Anopheles barbirostris, An. aconitus, Mansonia uniformis, Cx. quinquefasciatus, Cx. gelidus, Cx. tritaeniorhynchus and Ae. aegypti. The hexane fraction did not cause dermal irritation when applied on human skin.
Choochote
W
W
Department of Parasitology, Faculty of Medicine, Chiang Mai University, Thailand.
Kanjanapothi
D
D
Panthong
A
A
Taesotikul
T
T
Jitpakdi
A
A
Chaithong
U
U
Pitasawat
B
B
D000330:Aedes / Q000187:drug effects; D000818:Animals; D003465:Culex / Q000187:drug effects*; D004365:Drugs, Chinese Herbal; D006801:Humans; D007302:Insect Repellents / Q000494:pharmacology; D007306:Insecticides / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects; D007928:Lethal Dose 50; D008297:Male; D009032:Mosquito Control / Q000379:methods*; D010936:Plant Extracts / Q000494:pharmacology*; D012044:Regression Analysis
D004365:Drugs, Chinese Herbal; D007302:Insect Repellents; D007306:Insecticides; D010936:Plant Extracts