.alpha.-And .beta.-pinene, camphene, limonene, bornyl acetate (III), caryophyllene (IV), caryophyllene epoxide (V) and chavicol (VII) were identified as components of the leaf essential oil, and ethyl palmitate (trace), ethyl stearate (trace), and palmitic acid (VI) were also isolated and characterized. The main component of the essential oil of fresh leaves was IV, while that of dried leaves was V. The conversion of IV into V advanced with drying of the leaves and ratio of V to the total amount of IV + V reached 85% after drying for 30 days. From the observation of the conversion of IV, impregnated into fiber papers under various conditions, the conversion was found to be caused by air oxidation.