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:

Antioxidant and Anti-inflammatory Meroterpenoids from the Brown Alga Cystoseira usneoides. A chemical study of the alga Cystoseira usneoides has led to the isolation of six new meroterpenoids, cystodiones A-F (1-6), together with six known related compounds (7-12). The structures of the new metabolites have been established by spectroscopic techniques. In antioxidant assays all of the tested meroterpenes, and in particular cystodiones A (1) and B (2), 6-cis-amentadione-1'-methyl ether (7), and amentadione-1'-methyl ether (8), exhibited strong radical-scavenging activity. In anti-inflammatory assays, usneoidone Z (11) and its corresponding 6E isomer (12) showed significant activity as inhibitors of the production of the proinflammatory cytokine TNF-α in LPS-stimulated THP-1 human macrophages.
{"Chemical": ["meroterpenoids", "cystodiones A-F", "usneoidone Z", "meroterpenes", "6-cis-amentadione-1\u0027-methyl ether", "amentadione-1\u0027-methyl ether", "cystodiones A (1) and B", "Meroterpenoids"]}