You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Organ accumulation in mice after inhalation of single or mixed essential oil compounds. Essential oils are composed of multiple components. It is thought that the effect of essential oils is due to specific component ratios, which may differ from the original ratio when the essential oil is absorbed. However, very little detailed research exists in this area. We studied the distribution of essential oil components after inhalation of single and mixed components in mice. This research was done using four main components of Alpinia zerumbet (Pers.) B. L. Burtt. and R. M. Sm.: α-pinene, p-cymene, 1,8-cineole, and limonene. After inhalation of single or mixed components for 90 min, component levels in the brain and liver of mice were measured. The results indicated that the amount of α-pinene in the brain and liver was twofold greater after mixed-component inhalation than that after single-component inhalation. In a comparison of the components of the mixed inhalation, the ratio of α-pinene increased to about three times that of 1,8-cineole. It is thought that the absorption via the nasal mucus greatly influences this phenomenon. The results of this investigation of the bodily distribution of essential oil volatile components may provide clues for elucidating their action.
{"Chemical": ["limonene", "p-cymene", "\u03b1-pinene", "1,8-cineole"]}