*2.1. Hydrodistillation*

Fresh *C. osmophloeum* leaves were collected from Lienhuachih Research Center of Taiwan Forestry Research Institute in Nantou County, Taiwan. Leaves were hydrodistilled in a Clevenger apparatus for 6 h to obtain the leaf essential oil. The yield of leaf essential oil was 3.46 ± 0.06% (*w/w*). Leaf essential oil was stored in the dark glass bottle and kept in the refrigerator at 4 ◦C.
