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:

Chalcones in Cancer: Understanding their Role in Terms of QSAR. II Part. Chalcones are a group of plant-derived polyphenolic compounds belonging to the flavonoids family and possess a wide variety of cytoprotective and modulatory functions. In this research we tried to review the anticancer effect of chalcones derivatives and to evaluate new QSARs which will help in the understanding of the role of chalcones and of their analogs on cancer. Simultaneously a comparative study will be presented. Our QSAR results reveal that: 1) the clog P (hydrophobicity/hydrophilicity) parameter plays an important part in three QSAR relationships (linear model), 2) the steric factors such as molar volume MgVol, molar refractivity CMR or the substituents molar refractivity MR (linear) are important. Electronic effects are comparatively unimportant. These results compared to our previous findings on the QSAR of anti-proliferative chalcones support primarily the role of bulk.
{"Chemical": ["chalcones", "flavonoids", "polyphenolic", "Chalcones"]}