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:

Cytotoxic and phytotoxic actions of Heliotropium strigosum. This study describes the cytotoxic and phytotoxic activities of the crude extract of Heliotropium strigosum and its resultant fractions. In brine shrimp toxicology assays, profound cytotoxicity was displayed by ethyl acetate (LD(50) 8.3 μg/ml) and chloroform (LD(50) 8.8 μg/ml) fractions, followed by relatively weak crude methanolic extract of H. strigosum (LD(50) 909 μg/ml) and n-hexane fraction (LD(50) 1000 μg/ml). In case of phytotoxicity activity against Lemna acquinoctialis, highest phytotoxic effect was showed by ethyl acetate fraction (LD(50) 91.0 μg/ml), while chloroform fraction, plant crude extract and n-hexane, respectively, caused 50%, 30.76 ± 1.1% and 30.7 ± 1.1% inhibitory action at maximum concentration used, that is, 1000 μg/ml. These data indicates that H. strigosum exhibits cytotoxic and phytotoxic potential, which explore its use as anticancer and herbicidal medicine. The ethyl acetate and chloroform fractions were more potent for the evaluated toxicity effects, thus recommended for isolation and identification of the active compounds.
{"Chemical": ["chloroform", "n-hexane", "ethyl acetate"]}