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 activity-guided separation of coumarins and lignan from Melicope glabra (Rutaceae). The ethyl acetate and methanol bark extracts of Melicope glabra were evaluated for their antioxidant capacities by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity and β-carotene bleaching/linoleic acid system. Both extracts exhibited strong inhibition against the DPPH radical (IC50 values of 24.81 and 13.01 μgml(-1), respectively) and strong antioxidant activity in β-carotene bleaching assay. Both samples were found to have high phenolic content with values of 39 and 44mg GAE/g as indicated by Follin-Ciocalteau's reagent. Antioxidant TLC assay-guided isolation on the methanol extract led to the isolation of a new pyranocoumarin, glabranin (1), umbelliferone (2), scopoletin (3) and sesamin (4), and their structures were determined by spectroscopy. Compounds (1-3) showed significant activities on DPPH free radical with the IC50 of 240.20, 810.02 and 413.19μgml(-1), respectively. However, in β-carotene bleaching assay, sesamin (4) showed higher inhibitory activity (1mgml(-1), 95%) than glabranin (1) (1mgml(-1), 74%), whilst umbelliferone (2) and scopoletin (3) were slightly pro-oxidant.
{"Chemical": ["1,1-diphenyl-2-picrylhydrazyl", "pyranocoumarin", "glabranin", "ethyl acetate", "coumarins", "methanol", "scopoletin", "lignan", "\u03b2-carotene", "umbelliferone", "sesamin", "DPPH", "linoleic acid"]}