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:

Two new anthraquinone dimers from the fruit bodies of Bulgaria inquinans. Two new dimeric anthraquinone derivatives, bulgareone A(1) and bulgareone B(2), were isolated from the fruit bodies of Bulgaria inquinans. Their structures were elucidated on the basis of extensive spectroscopic analysis. The in vitro cytotoxic activity of compounds 1 and 2 was assayed. They displayed inhibitive activities against human cancer cell lines HL60 and K562.
{"Chemical": ["anthraquinone", "bulgareone A", "bulgareone B"]}