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:

Three new lanostanoid triterpenes from the fruiting bodies of Ganoderma tropicum. Three new lanostanoid triterpenes, 3β,7β,15β-trihydroxy-11,23-dioxo-lanost-8,16-dien-26-oic acid (1), 3β,7β,15β-trihydroxy-11,23-dioxo-lanost-8,16-dien-26-oic acid methyl ester (2), and 3β,15β-dihydroxy-7,11,23-trioxo-lanost-8,16-dien-26-oic acid methyl ester (3) were isolated from the EtOAc extract of the fruiting bodies of Ganoderma tropicum. Their structures were elucidated on the basis of 1D and 2D NMR spectroscopy as well as MS. The bioassay of inhibitory activity against acetylcholinesterase (AChE) of these isolates was evaluated and compound 2 exhibited definite inhibitory activity against AChE.
{"Chemical": ["3\u03b2,7\u03b2,15\u03b2-trihydroxy-11,23-dioxo-lanost-8,16-dien-26-oic acid", "lanostanoid triterpenes", "3\u03b2,15\u03b2-dihydroxy-7,11,23-trioxo-lanost-8,16-dien-26-oic acid methyl ester", "3\u03b2,7\u03b2,15\u03b2-trihydroxy-11,23-dioxo-lanost-8,16-dien-26-oic acid methyl ester", "EtOAc"]}