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Cinnamomum kanehiraeHayata is an endemic tree species in Taiwan. Leaf essential oils from 26 sources ofC. kanehiraewere obtained by hydrodistillation and their chemical constituents were analyzed by gas chromatography-mass spectrometry (GC-MS). Fifty-eight compounds were identified fromC. kanehiraeleaf essential oils. The main constituents in leaf essential oils were linalool, 1,8-cineole, β-selinene, 1-hexadecyne, and α-cadinol. According to the chemical compositions of leaf essential oils and their relative contents obtained from GC-MS analyses, cluster analysis, and principal component analysis, the 26 sources examined were classified into five chemotypes: linalool type, linalool/1,8-cineole type, 1,8-cineole type, linalool/α-cadinol type, and mixed type. The biochemical correlations between the major constituents ofC. kanehiraewere examined and their relationship is discussed. [ABSTRACT FROM AUTHOR]

BACKGROUND Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), is a major urban pests in many countries throughout the world. In an attempt to find natural products that could be employed in the effective and environmentally friendly control of the termite, this study investigates, for the first time, the insecticidal activities of the wood and leaf essential oils and ethanolic extracts from Cunninghamia konishii Hayata against C. formosanus according to direct contact application. RESULTS Wood and leaf essential oils and wood ethanolic extract showed the excellent antitermitic activities. Among the four fractions of wood ethanolic extract, the hexane-soluble fraction showed the strongest antitermitic activities. In addition, β-elemol and α-cadinol showed excellent inhibitory action against C. formosanus. CONCLUSION The results clearly reveal that the wood and leaf essential oils and ethanolic extract from C. konishii, and their effective constituents, served as potential, eco-friendly termite-control agents. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

In this study antifungal activities of essential oils from wood and leaf and their constituents of Cunninghamia konishii against four wood decay fungi and six plant pathogenic fungi were investigated. GC and GC-MS analyses show that the major compounds of wood essential oil were cedrol and α-pinene, while those of leaf essential oil were α-pinene and p-cymene. Antifungal tests demonstrated the wood oil from C. konishii used against Trametes versicolor, Lenzites betulina, Laetiporus sulphureus, and Gloeophyllum trabeum and leaf oil from C. konishii used against L. sulphureus had strong antifungal activities. Moreover, wood oil used against Rhizoctonia solani, Fusarium solani, Pestalotiopsis funereal, and Ganoderma australe also had strong antifungal activities. Among the seven constituents of wood oil, cedrol displayed the best antifungal properties, indicating that it may be used as potential antifungal agents for the control of fungal diseases in plants. [ABSTRACT FROM AUTHOR]

Abstract: Eleven compounds from indigenous cinnamon (Cinnamomum osmophloeum) leaf essential oil were identified by GC–MS and the dominant constituent was trans-cinnamaldehyde (79.85%). The toxicity of leaf essential oil and trans-cinnamaldehyde were then determined to study their effectiveness in controlling the red imported fire ant, Solenopsis invicta Buren. The results of the toxicity tests indicated that both the indigenous cinnamon leaf essential oil and trans-cinnamaldehyde had an excellent inhibitory effect in controlling the red imported fire ant. The LT50 values for both 2% leaf essential oil and 2% trans-cinnamaldehyde after open exposure were 105.0min and 32.2min; after close exposure were 18.5min and 21.2min, respectively. [Copyright &y& Elsevier]

The thermal stability of leaf essential oils from various Cinnamomum osmophloeum and their constituents was investigated for the first time. The results indicated that trans-cinnamaldehyde (Cin) content in eugenol-free essential oil from C. osmophloeum was affected by high temperatures. The retention of Cin (RC) decreased to 17.4% after the essential oil was incubated for 8 h at 100 °C. In contrast, essential oils containing eugenol showed greater thermal stability. Seven kinds of antioxidants were added to Cin to improve its thermal stability. Among them, eugenol endowed Cin with the best thermal stability. We also investigated the influence of various amounts of eugenol on the thermal stability of both essential oil and Cin. Both essential oil and Cin showed excellent thermal stability when 0.62 and 2.60% (v/v) eugenol were added. In short, the thermal stability of essential oil and Cin could be effectively improved by adding appropriate amounts of eugenol.

The aims of the present study were to isolate and identify the antifungal compounds from the ethanolic extract of Cunninghamia konishii wood and to evaluate their antifungal activities against wood decay fungi. The results showed that the n-Hex soluble fraction of the ethanolic extract from C. konishii wood had an excellent inhibitory effect against Lenzites betulina, Trametes versicolor, Laetiporus sulphureus, and Gloeophyllum trabeum, with IC(50) values of 33, 46, 62, and 49 μg/mL, respectively. By following the bioactivity-guided fractionation procedure, four sesquiterpenes, T-cadinol, cedrol, T-muurolol, and (-)-epi-cedrol, and three diterpenes, 13-epi-manool, cis-abienol, and isoabienol, were identified from the active subfractions. Among the main constituents of the ethanolic extract from C. konishii, T-cadinol, cedrol, and T-muurolol efficiently inhibited the growth of four wood-rot fungi at the concentration of 100 μg/mL, with antifungal indices of 51.4-100.0%, 68.3-100.0%, and 39.5-100.0%, respectively. Results of this study show that the ethanolic extract of C. konishii wood may be considered as a potent source of T-cadinol, cedrol, and T-muurolol as new natural antifungal agents.

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., Conclusion: 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., (2008 Society of Chemical Industry)