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:

Safety of purified decolorized (low anthraquinone) whole leaf Aloe vera (L) Burm. f. juice in a 3-month drinking water toxicity study in F344 rats. Decolorized (purified, low anthraquinone) whole leaf Aloe vera (L.) Burm. f. juice was administered at concentrations of 0%, 0.5%, 1% and 2% in the drinking water of F344Du® rats for 3months without any adverse effect. The no-observed-adverse-effect level (NOAEL) in this study was considered to be >2%w/v (>1845mg/kg bodyweight/day for males and >2920mg/kg bodyweight for females). The test material contained total anthraquinones at <0.1parts per million. In the present study there was a complete absence of any histological alteration in samples from the cecum, colon (proximal, mid and distal regions). Similar concentrations of non-decolorized (unpurified, high anthraquinone) Aloe vera extracts tested in other studies have resulted in an increased incidence and severity of diarrhea and colon adenomas and carcinomas. The results of this study supports the assertion that the high levels of anthraquinone present in orally administered, non-purified whole leaf Aloe vera extract may be responsible for the adverse effects observed on the colon.
{"Chemical": ["anthraquinones", "anthraquinone"]}