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:

Free phenolics and polyphenol oxidase (PPO): The factors affecting post-cut browning in eggplant (Solanum melongena). Polyphenol oxidase (PPO) catalyses oxidation of phenolics, which results in instant but differential browning in many cut fruits and vegetables, including eggplant. Eight cultivars of eggplant were characterised by their PPO specific activity, phenolic content, browning index, and PPO polymorphism. In fresh eggplant, browning was found to be dependent on both the phenolic content and PPO specific activity, whereas, total phenolic content played a major role in browning of stored fruits. Interestingly, although browning index increased in stored eggplant fruits, PPO activity reduced in four out of eight cultivars studied. Phenolic level was found to increase in all these cultivars during storage. Although a significant level of homology was observed in PPO nucleotide and conceptually translated protein sequence, two cultivars, which displayed highest PPO specific activity, differed in the 38 amino acid stretch in the peptide region 301-338.
{"Chemical": ["phenolic", "amino acid", "Phenolic", "Polyphenol", "phenolics", "polyphenol", "nucleotide"]}