Chemical compositions of leaf essential oils from eight provenances of indigenous cinnamon
(Cinnamomum osmophloeum Kaneh.) were compared. According to GC-MS and cluster analyses,
the leaf essential oils of the eight provenances and their relative contents were classified into five
chemotypesscinnamaldehyde type, linalool type, camphor type, cinnamaldehyde/cinnamyl acetate
type, and mixed type. The larvicidal activities of leaf essential oils and their constituents from the five
chemotypes of indigenous cinnamon trees were evaluated by mosquito larvicidal assay. Results of
larvicidal tests demonstrated that the leaf essential oils of cinnamaldehyde type and cinnamaldehyde/
cinnamyl acetate type had an excellent inhibitory effect against the fourth-instar larvae of Aedes
aegypti. The LC50 values for cinnamaldehyde type and cinnamaldehyde/cinnamyl acetate type against
A. aegypti larvae in 24 h were 36 ppm (LC90 ) 79 ppm) and 44 ppm (LC90 ) 85 ppm), respectively.
Results of the 24-h mosquito larvicidal assays also showed that the effective constituents in leaf
essential oils were cinnamaldehyde, eugenol, anethole, and cinnamyl acetate and that the LC50 values
of these constituents against A. aegypti larvae were